Patent Description:
Graphene, an atomically thin layer of graphite, is attracting considerable interest in material science since the recent discovery of its appealing electronic properties such as high charge carrier mobility, ambipolar switching capability and the quantum Hall effect. The conjunction with its chemical robustness and superior mechanical properties makes graphene an ideal candidate for a number of applications that require ultrathin but yet stable and highly conductive layers or large specific areas as for instance in energy storage applications.

One of the major limitations for using graphene in efficient digital switching applications is the absence of an electronic band gap. This obstacle can be overcome by structuring graphene down to the nanometer scale where quantum confinement induces band gaps that are characteristic for a given shape and size of the graphene nanostructure. The most prominent examples using quantum confinement for the opening of a band gap are carbon nanotubes (CNTs), where periodic boundary conditions along the circumference are responsible for the existence of both, metallic and semiconducting CNTs, as well as armchair graphene nanoribbons (AGNRs), where confinement to a very narrow strip of graphene induces sizable band gaps if the width/diameter is limited to a few nanometers.

For both, CNTs, and AGNRs, the structural boundary conditions conserve the symmetry between the two atomic sublattices A and B (see <FIG> for AGN R).

A much richer diversity of electronic properties is predicted for graphene nanostructures where the edges break the symmetry between the A and B sublattices. The most prominent example are zigzag graphene nanoribbons (ZGNRs) where the atoms forming the two opposite edges belong to complementary sublattices (<FIG>). Electronic structure simulations reveal related localized edge states, which are magnetically coupled to each other [<NPL>); ]. In the case of ZGNRs, for instance, the localized states belonging to the two opposed edges couple antiferromagnetically to each other and thus allow for an efficient spatial separation of spin up and spin down electrons to the opposite respective edges.

Based on these edge-related spin-polarized properties, computational simulations have been used to explore a number of specific edge configurations. Among the most appealing predictions for ZGNRs are spin-polarized charge carrier injection into graphene, half-metallic charge carrier properties (metallic properties for one spin component and semiconducting properties for the other) as well as giant magnetoresistance.

Cove type GNRs (CGNR) can be described as a special case of ZGNR in which carbon atoms have been added, respectively removed from the perfect zigzag edge resulting in the characteristic cove type structure elements. As in the case of ZGNR, in CGNR the localized states belonging to the two opposed edges couple antiferromagnetically to each other and allow for an efficient spatial separation of spin up and spin down electrons to the opposite respective edges.

Armchair-type, zigzag-type or cove-type edges are shown in the following formulae:
<CHM>
<CHM>
wherein.

However, standard top-down fabrication techniques for the fabrication of GNR such as cutting graphene sheets e.g. using lithography, unzipping of carbon nanotubes (e.g. described in <CIT> and <CIT>), or using nanowires as a template are not suitable for ribbons narrower than <NUM>-<NUM>, because the edge configuration cannot be precisely controlled and they do not yield ribbons of monodisperse width. For high-efficiency electronic devices operating at ambient temperature, the ribbons need to be less than <NUM> wide, their width needs to be precisely controlled and, importantly, their edges need to be smooth because even minute deviations from the ideal edge shapes seriously degrade the electronic properties.

Due to the inherent limitations of lithographic methods and of other known approaches to fabricate graphene nanostructures, however, the experimental realization of GNRs with controlled zigzag and/or cove type edge structures in the hexagonal sp<NUM> carbon network with the required high precision has remained elusive. Bottom-up approaches based on cyclodehydrogenation reactions in solution (see e.g. <CIT>, <CIT>, <CIT>) or on solid substrates (see e.g. <CIT>, <CIT>) have recently emerged as promising routes to the synthesis of nanoribbons and nanographenes with precisely controlled structures.

<NPL>, describe the bottom-up synthesis of graphene nanofragments and nanoribbons by thermal polymerization of pentacenes.

<CIT> describes a graphene nanoribbon, comprising a repeating unit RU1 which comprises at least one modification, wherein the modification is selected from a heteroatom subsitution, a vacancy, a sp<NUM> hybridization, a Stone-Wales defect, an inverse Stone-Wales defect, and a hexagonal sp<NUM> hybridized carbon network ring size modification.

<NPL>, describe precursor polymers containing phenylene, naphthalene and anthracene units for fabrication of graphene nanoribbons by Suzuki coupling reaction.

At least two general types of precisely controlled linear nanoribbon structures can be distinguished. In a first type, the edges are forming a straight line along the nanoribbon, while in another type, sometimes called 'chevron' type or 'nanowiggles' (described e.g. in <NPL>or in <NPL>), the edges are lying on a corrugated or saw-toothed line. The latter case can also be described as a periodic repetition of alternatingly aligned graphitic nanoribbon subunits seamlessly stitched together without structural defects.

The edges of the graphene nanoribbons may be terminated either with hydrogen atoms and/or with any other organic or inorganic groups.

For solution-based approaches using oligo phenylene precursors a polymer is typically prepared in a first step which is subsequently converted into the graphitic structure by Scholl-type oxidative cyclodehydrogenation. All of the reported solution based methods yield graphene nanoribbons with exclusively armchair type edge carbon atoms (with exception of both ends of the GNR) or armchair type edge carbon atoms and cove type edge carbon atoms (with exception of both ends of the GNR), whereby in the latter case the proportion of unambiguously assignable cove type edge carbon atoms is less than <NUM>% of the sum of all edge carbon atoms.

The surface-confined bottom-up approach to controlled graphene nanoribbons as described in <NPL>), <CIT>, and <CIT>, typically results in armchair graphene nanoribbons. No graphene nanoribbons that do contain zigzag type edge carbon atoms and only graphene nanoribbons in which the proportion of unambiguously assignable cove type edge carbon atoms (with exception of both ends of the GNR) is less than <NUM>% of the sum of all edge carbon atoms have been obtained.

It is an object of the present invention to provide monomers for preparing a graphene nanoribbon (GNR) containing zigzag type edge carbon atoms, cove type edge carbon atoms or a combination thereof in positions which are not at the end of the GNR, wherein the position of zigzag type edge carbon atoms and cove type edge carbon atoms and the distance between zigzag type edge carbon atoms and cove type edge carbon atoms as well as the ratio of zigzag type edge carbons to cove type edge carbons and to armchair carbons is precisely controlled. A further object of this invention is a process for preparing such a graphene nanoribbon.

One aspect of the present invention is an aromatic monomer compound of formula I to X:
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
wherein.

By aromatic monomer compounds of the present invention, graphene nanoribbons can be prepared wherein the position of zigzag type edge carbon atoms and the distance between zigzag type edge carbon atoms as well as the number of zigzag type edge carbon atoms per repeating unit can be precisely controlled.

By aromatic monomer compounds of the present invention, graphene nanoribbons can be prepared wherein the position of armchair type edge carbon atoms and the distance between armchair type edge carbon atoms as well as the number of armchair type edge carbon atoms per repeating unit can be precisely controlled.

By aromatic monomer compounds of the present invention, graphene nanoribbons can be prepared wherein the position of cove type edge carbon atoms and the distance between cove type edge carbon atoms as well as the number of cove type edge carbon atoms per repeating unit can be precisely controlled.

According to another aspect, the present invention provides a process for preparing a graphene nanoribbon comprising a repeating unit RU1 which comprises at least <NUM>% of edge carbons which can unambiguously be assigned as zigzag or cove type carbon atom, wherein the process comprises:.

According to a further aspect, the present invention relates to the use of the aromatic monomer compounds as described above for preparing a graphene nanoribbon having a defined structure.

The graphene nanoribbon obtainable by the aromatic monomer compound of the present invention comprises a repeating unit RU1. Such repeating unit RU1 comprises at least <NUM>% of edge carbons which can unambiguously be assigned as zigzag type carbon atoms or unambiguously be assigned as cove type carbon atoms, or both.

For illustration the following formula shows an exemplary GNR structure which contains only armchair edges (with exception of both ends of the GNR). In this GNR, all carbon atoms at the edge (with exception of both ends of the GNR) can be assigned as armchair type carbon atoms:
<CHM>
wherein x is an integer greater or equal to <NUM>.

For illustration the following formula shows an exemplary GNR which contains only zigzag edges (with exception of both ends of the GNR). In this GNR, all carbon atoms at the edges (with exception of both ends of the GNR) can be assigned as zigzag type carbon atoms.

The following formula shows two illustrations of the same exemplary GNR which contains only cove edges (with exception of both ends of the GNR). In this GNR, all carbon atoms at the edges (with exception of both ends of the GNR) can be assigned as cove type carbon atoms:
<CHM>.

Some GNR structures do contain edge elements which cannot be assigned unambiguously as either armchair or zigzag ore cove type carbon atoms and some GNR structures do contain edge elements which can neither be assigned as armchair, zigzag, nor cove type (see following formulae for three illustrations of one and the same GNR structure, highlighting armchair type edge carbon atoms (top), cove type edge carbon atoms (middle), respectively the non-ambiguously assignable edge carbon atoms denoted Y (bottom) and the edge carbon atoms Z which can neither be assigned as armchair type or zigzag type, nor as cove type.

Similar to conventional polymers, the graphene nanoribbon being obtainable by the aromatic monomer compounds of the present invention has its specific repeating unit. The term "repeating unit" relates to the part of the nanoribbon whose repetition would produce either the complete ribbon (except for the ends) or, if the GNR is made of two or more segments, one of these segments (except for the ends). The term "repeating unit" presupposes that there is at least one repetition of said unit. In other words, if the repeating unit is referred to as RU1, the GNR or one of its segments is made of n RU1 units with n≥<NUM> (i.e. (RU1)n with n≥<NUM>). The upper limit depends on the desired final properties of the graphene nanoribbon and/or the process conditions, and can be, without limitation, e.g. n≤<NUM>.

The graphene nanoribbon may comprise just one repeating unit RU1 (with n repetitions as indicated above). However, it is also possible that the graphene nanoribbon comprises two or more different repeating units RU1, RU2,. RUm, thereby resulting in a segmented graphene nanoribbon.

The graphene nanoribbon may be non-segmented. Alternatively, the graphene nanoribbon may be a segmented graphene nanoribbon which comprises at least two different graphene segments S1 and S2 covalently linked to each other, wherein the neighbouring segments S1 and S2 have different repeating units RU1 and RU2.

The repeating unit RU1 may comprise just one type of edge carbon atoms (e.g. only zigzag type edge carbon atoms or only cove type edge carbon atoms). Alternatively, the repeating unit may contain two or three types of edge carbon atoms (i.e. zigzag type carbon edge atoms and/or cove type carbon edge atoms and/or armchair type edge carbon atoms). In some cases a specific carbon edge atom cannot unambiguously be assigned as armchair type or zigzag type or cove type carbon atom because it is fulfilling the conditions for more than one type of edge carbon atoms. Such a carbon edge atom is for instance an armchair type edge atom and a cove type edge atom at the same time, i.e. a non-ambiguously assignable edge carbon atom.

The number of zigzag type edge carbon atoms within the graphene nanoribbon repeating unit RU1 may vary over a broad range, depending on the desired final properties of the GNR.

The number of cove type edge carbon atoms within the graphene nanoribbon repeating unit RU1 may vary over a broad range, depending on the desired final properties of the GNR.

The number of armchair type edge carbon atoms within the graphene nanoribbon repeating unit RU1 may vary over a broad range, depending on the desired final properties of the GNR.

On the other hand, as already indicated above, it may be preferred that the number of zigzag type edge carbon atoms of the repeating unit is high. Preferably, the ratio of the number of zigzag type and/or cove type edge carbon atoms to the number of all edge carbon atoms in the repeating unit RU1 is <NUM> or more, preferably <NUM> or more, most preferably <NUM> or more.

The graphene nanoribbon may have exclusively zigzag type edge carbon atoms (with exception of both ends of the GNR).

Alternatively, the graphene nanoribbon may have exclusively cove type edge carbon atoms (with exception of both ends of the GNR).

Alternatively, the graphene nanoribbon may have exclusively zigzag type and cove type edge carbon atoms (with exception of both ends of the GNR).

As will be discussed below in further detail, the graphene nanoribbon containing zigzag type edge carbon atoms and/or cove type carbon atoms are obtained by polymerizing at least one aromatic monomer compound of the present invention, followed by partial or complete cyclodehydrogenation of the polymer.

The aromatic monomer compound has one of the following formulas I to X:
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
wherein.

Alternatively, two groups Ra, Rb and Rc, may together with the carbon atoms they are attached to, form a <NUM>-<NUM>-membered cycle or heterocycle;.

The average width of the graphene nanoribbon can be varied over a broad range, depending on the desired final properties.

Preferably, the graphene nanoribbon or a segment of the graphene nanoribbon made of the repeating unit RU1 has a width of <NUM> or less, more preferably <NUM> or less, even more preferably <NUM> or less, even more preferably <NUM> or less, most preferably <NUM> or less.

The GNR width and type of edge carbon structure is determined with scanning tunneling microscopy (STM). The apparent width is corrected for the finite tip radius by STM simulation as explained in <CIT>.

According to conventional notion, the width of a graphene nanoribbon maybe expressed by the number N of dimer lines across the width (<NPL>). The determination of N for the zig-zag, cove and armchair type GNRs, respectively, is shown in <FIG>. Preferably, the repeating unit RU1 of the graphene nanoribbon may have a number N of dimer lines across the width of from <NUM> to <NUM>, more preferably of from <NUM> to <NUM>, or of from <NUM> to <NUM>.

If the graphene nanoribbon comprises further repeating units RU2, RU3,. , the preferred width values indicated above apply to these additional repeating units as well.

In a particular embodiment of the aromatic monomer compound.

In another particular embodiment of the aromatic monomer compound.

The aromatic monomer compound may preferably be selected from the monomers of the following formulae <NUM>-<NUM>:
<IMG>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>.

The present invention provides a process for preparing the graphene nanoribbon as disclosed above, which comprises:.

As indicated above, step (a) includes providing the at least one aromatic monomer compound of the present invention on a solid substrate.

In another embodiment at least one of steps (a), (b) and (c) of the process is not processed on the solid substrate, but in solution. Preferably all steps (a), (b) and (c) are processed not on the solid substrate, but in solution.

Any solid substrate enabling the deposition of the aromatic monomer compound of the present invention and subsequent polymerization on its surface may be used. Preferably, the solid substrate has a flat surface.

The solid substrate on which the monomer compound is deposited may have a metal surface such as for example a Au, Ag, Cu, Al, W, Ni, Pt, or a Pd surface (which may e.g. be reconstructed or vicinal). The surface can be completely flat or patterned or stepped. Such patterned or stepped surfaces and manufacturing methods thereof are known to the skilled person. On patterned surfaces the growth of graphene nanoribbons may be directed by the surface pattern.

The solid substrate may also have a metal oxide surface such as silicon oxide, silicon oxynitride, hafnium silicate, nitrided hafnium silicates (HfSiON), zirconium silicate, hafnium (di)oxide and zirconium dioxide, or aluminium oxide, copper oxide, iron oxide.

The surface may also be made of a semiconducting material such as silicon, germanium, gallium arsenide, silicon carbide, and molybdenum disulfide.

The surface may also be a material such as boron nitride, sodium chloride, or calcite.

The surface may be electrically conducting, semiconducting, or insulating. The surface may be non-magnetic or magnetic (ferro- or anti-ferromagnetic).

The deposition on the surface may be done by any process suitable for providing organic compounds on a surface. The process may e.g. be a vacuum deposition (sublimation) process, a solution based process such as spin coating, spray coating, dip coating, printing, electrospray deposition, or a laser induced desorption or transfer process. The deposition process may also be a direct surface to surface transfer.

Preferably the deposition is done by a vacuum deposition process. Preferably it is a vacuum sublimation process. The vacuum may be in the range of <NUM>-<NUM> to <NUM>-<NUM> mbar.

As indicated above, step (b) of the process of the present invention includes polymerization of the aromatic monomer compound of the present invention so as to form at least one polymer (herein also referred to as "GNR precursor polymer") on the surface of the solid substrate.

Appropriate conditions for effecting polymerization of the aromatic monomer compound are generally known to the skilled person.

Preferably, the polymerization in step (b) is induced by thermal activation. However, any other energy input which induces polymerization of the aromatic monomer compound such as radiation can be used as well.

The activation temperature is dependent on the employed surface and the monomer and can be in the range of from <NUM> to <NUM>.

Optionally, step (a) and/or step (b) can be repeated at least once before carrying out partial or complete cyclodehydrogenation in step (c). When repeating steps (a) and (b), the same monomer compound or a different aromatic monomer compound of the present invention can be used.

As indicated above, step (c) of the process of the present invention includes at least partially cyclodehydrogenating the one or more GNR precursor polymers of step (b).

In general, appropriate reaction conditions for cyclodehydrogenation are known to the skilled person.

In a preferred embodiment, the polymer of step (b) is subjected to complete cyclodehydrogenation.

In one embodiment, at least two different monomer compounds are provided on the solid substrate in step (a).

According to this embodiment, two or more different monomer compounds, preferably having similar reactivity, are provided on the surface of the solid substrate, followed by inducing polymerization to form a co-polymer. Subsequently, a partial or complete cyclodehydrogenation reaction is carried out leading to a segmented graphene nanoribbon.

In a variation of this embodiment, a first aromatic monomer compound is deposited on the surface of the solid substrate, followed by inducing polymerization to form a polymer. A second monomer is then deposited on the same substrate surface, followed by inducing polymerization to form a block co-polymer. This step may optionally be repeated several times, either with identical or different monomer compounds to yield a multi block copolymer. Subsequently, the block co-polymer is subjected to a partial or complete cyclodehydrogenation reaction leading to a segmented graphene nanoribbon.

In another embodiment, the partial or complete cyclodehydrogenation reaction is induced by a spatially controlled external stimulus.

The external stimulus may be an electrical current, heat, an ion beam, oxidative plasma, microwave, light or electromagnetic radiation in general or it may be an oxidative chemical reagent. The spatial control of the activation may be done using a highly focused activation stimulus whose position versus the substrate can be controlled. The spatially confined activation stimulus may originate from a nano sized electrode, such as e.g. a tip of a tunneling microscope or from highly focused electromagnetic radiation such as e.g. a focused laser beam, or from a highly focused electron beam such as in an electron microscope. The spatial control of the activation may also be done using a nanostructured mask to direct the impact of the activation stimulus, such as e.g. a photo mask.

In a particular embodiment a further step (d) may be performed comprising at least partially coupling the methyl substituent of a cove type edge element of the one or more polymers of step (b) to an adjacent aryl group. In this way a cove type edge element is converted into a zigzag type edge element. By way of example, such coupling is shown in the conversion of monomer VIII to structure viii. This coupling step is also further illustrated in the examples.

Depending on the conditions applied and the monomers used such coupling step (d) may be performed before, after or along with step (c).

The graphene nanoribbon (GNR) may also be prepared via a solution based process, as already mentioned above and generally known to those skilled in the art. The process preferably comprises a solution polymerization of the at least one aromatic monomer compound of the present invention to an oligo-phenylene precursor polymer which can then be transformed into graphene nanoribbon using a solution based process such as cyclodehydrogenation (e.g. Scholl-type oxidative cyclodehydrogenation). The polymerization and cyclodehydrogenization processs is preferably done with monomers comprising long alkyl or alkoxy chain substituents, e.g. in position Rb of monomers defined above, in order to improve the solubility of the resulting GNR.

Graphene nanoribbon structures i-ix, which are non limiting examples that are thus formed from monomers I-X are shown by the following structures, wherein.

Graphene nanoribbon structure i contains cove type edges and zigzag type edges in the repeating unit RU1. <CHM>
<CHM>.

Graphene nanoribbon structure ii contains zigzag type edges and armchair type edges in the repeating unit RU1. <CHM>
<CHM>.

Graphene nanoribbon structure iii contains exclusively cove type edges in the repeating unit RU1.

Graphene nanoribbon structure iv contains exclusively zigzag type edges in the repeating unit RU1.

Graphene nanoribbon structure v contains exclusively zigzag type edges in the repeating unit RU1.

Graphene nanoribbon structure vi contains zigzag type edges and edges which can neither be assigned as zigzag, armchair, nor cove type edges in the repeating unit RU1.

Graphene nanoribbon structure vii contains cove type edges and zigzag type edges in the repeating unit RU1. <CHM>
<CHM>.

Graphene nanoribbon structure viii is derived of monomer VIII or X and contains exclusively zigzag type edges in the repeating unit RU1.

Graphene nanoribbon structure ix is derived of monomer IX and contains zigzag type edges and cove type edges in the repeating unit RU1. <CHM>
<CHM>.

In particular embodiments aromatic groups in the GNR structures above or substituents Rb and/or Rc may react with other groups so as to form a <NUM> membered carbocyclic ring.

Therefore, if in the GNR precursor polymer two neighboring groups Rc are hydrogen, the two carbon atoms substituted with hydrogen may form a <NUM>-membered carbocyclic ring by cycloannelation (see e.g. in GNR structure vii),.

The resulting graphene nanoribbons may be used directly on the substrate on which they are prepared or they may be transferred to another substrate.

Based on these zigzag-related and cove related spin-polarized properties completely new performance profiles relevant in spintronic and semiconductor applications can be envisaged on the basis of possibly 'allcarbon' devices.

All percent, ppm or comparable values refer to the weight with respect to the total weight of the respective composition except where otherwise indicated. All molecular weights refer to the weight average molecular weight Mw except where otherwise indicated.

The following examples shall further illustrate the present invention without restricting the scope of this invention.

To a stirring suspension of Triphenyl phosphine (<NUM>) in Acetonitrile (<NUM>) in a <NUM>-Schlenk-flaskwas added carefully Bromine (<NUM>) at <NUM> with a syringe over <NUM>. The yellow solution was warmed to room temperature and <NUM>,<NUM>-Dihydroxynaphthalene (<NUM>) was added in one portion. The reaction was refluxed at <NUM> for one hour. After cooling to room temperature, the solvent was removed under reduced pressure. The reaction flask was connected to a gas-washing bottle filled with a concentrated sodium hydroxide solution. The flask was heated to <NUM> for two hours and the black residue dissolved in <NUM> Dichloromethane and purified via column chromatography (DCM:Pentan <NUM>:<NUM> to pure DCM).

p-Bromo-benzaldehyde (<NUM>) and <NUM>,<NUM>-Dimethylphenyl boronic acid were added to a <NUM>-flask. After that, the solids were dissolved in THF (<NUM>), Ethanol (<NUM>) and <NUM> sodium carbonate solution (<NUM>) and Argon bubbled through the solution for one hour. <NUM> mol% Tetrakistriphenyl-Palladium(<NUM>) (<NUM>) were added and the reaction mixture refluxed for <NUM> hours. The red solution was cooled to room temperature, extracted with <NUM> of Ethylacetate and washed with water. The organic phase was dried over MgSO<NUM> and the solvents removed under reduced pressure. The black residue was dissolved and purified via column chromatography (EA:Hexane, <NUM>:<NUM>). The product <NUM> was collected as a yellow oil (<NUM>, <NUM>%).

Bromonaphthol <NUM> (<NUM>) and <NUM>',<NUM>'-Dimethylbiphenyl-<NUM>-Carbaldehyde <NUM> (<NUM>) were added together with p-Toluenesulfonic acid (<NUM>) in a microwave reactor and heated to <NUM> under stirring. After <NUM> at this temperature, the reaction mixture was cooled to room temperature and washed with a mixture of water and ethanol (<NUM>:<NUM>). The red solid was recrystallized from ethanol and the white powder filtered and washed with cold ethanol to give product <NUM> (<NUM>, <NUM>%).

The Xanthene <NUM> (<NUM>) was suspended together with lead(IV)oxide (<NUM>) in <NUM> acetic acid and stirred for <NUM> days at <NUM>. The mixture was cooled to room temperature and poured on <NUM> water. The brown solid was filtered and recrystallized from a mixture of water and acetone (<NUM>:<NUM>). The product <NUM> is collected as a beige powder, which could not be purified. The crude product was used in the next step. TLC: Ethylacetate:Hexane, <NUM>:<NUM>, Rf= <NUM>,<NUM>.

The Xanthenol <NUM> (<NUM>) was dissolved in Toluene (<NUM>) and acetic acid anhydride (<NUM>) and the solution cooled to <NUM>. Tetrafluoroboric acid (<NUM> w%, <NUM>) was added carefully to precipitate the red product. It was stirred for <NUM> and the product filtered and washed with <NUM> cold diethylether and a <NUM>:<NUM>-mixture of petroleum ether and dichloromethane to yield <NUM> (<NUM>, <NUM>%). <NUM>H-NMR: ∂ (<NUM>, C<NUM>D<NUM>Cl<NUM>) = <NUM> (d, <NUM>), <NUM> (d, <NUM>), <NUM> (d, <NUM>), <NUM> (d, <NUM>), <NUM> (d, <NUM>), <NUM> (d, <NUM>), <NUM> (s, <NUM>), <NUM> (s, <NUM>), <NUM> (s, <NUM>), <NUM> (s, <NUM>).

The Xanthenium-Tetrafluoroborate <NUM> (<NUM>) was suspended together with sodium-<NUM>-phenylacetate (<NUM>) in <NUM> acetic acid anhydride. It was stirred for <NUM> at <NUM> and the solvent removed under reduced pressure. The brown residue was dissolved in Dichlormethane and purified via column chromatography (DCM:PE, <NUM>:<NUM>). The yellow product <NUM> was recrystallized from chloroform (<NUM>, <NUM>%).

To a mixture of benzaldehyde (<NUM> mmol) and bromo-naphthol <NUM> (<NUM> mmol), p-TSA (<NUM> mmol) was added. The reaction mixture was stirred magnetically at <NUM> for about <NUM> and the reaction followed by TLC. After completetion of the reaction, the mixture was washed with EtOH-H<NUM>O (<NUM>:<NUM>). The crude product was purified by recrystallization from EtOH to give target compound <NUM>. White needles (yield = <NUM>%).

A mixture of pyrylium salt <NUM> (<NUM> mmol) and sodium <NUM>-phenylacetate (<NUM> mmol) in acetic anhydride (Ac<NUM>O <NUM>) was stirred at <NUM> for <NUM> under argon atmosphere. After cooling to room temperature, the precipitate was filtered off and washed with Ac<NUM>O, then methanol. The crude product was recrystallized from chloroform and hexane to give monomer <NUM>. Gray powder (yield = <NUM>%).

The compound <NUM> was prepared in analogy to monomer <NUM> from compound <NUM> and sodium <NUM>-(p-iodophenyl)acetate. Brown powder (yield = <NUM>%).

<NUM>-decyltetradecan-<NUM>-ol (<NUM>, <NUM> mmol) and triphenylphosphine (<NUM>, <NUM> mmol) were dissolved in dichloromethane (<NUM>) and cooled to <NUM>. To the mixture N-bromosuccinimide (<NUM>, <NUM> mmol) was added slowly, then stirred at room temperature for <NUM> hours. After evaporation of solvents in vacuo the products were dissolved in hexane. Purification by column chromatography (silica gel, hexane) yielded compound <NUM>. Colorless oil (yield = <NUM>%).

To a suspension of a lithium acetylide-ethylenediamine complex (<NUM> mmol) in DMSO (<NUM>) was added compound <NUM> (<NUM> mmol) at <NUM>. The reaction mixture was stirred for <NUM> at room temperature (<NUM>). NH<NUM>Cl (<NUM>) was added to the mixture. The mixture was extracted with ether, washed with brine, dried over MgSO<NUM>, and concentrated. The residue was chromatographed over silica gel (hexane) to afford <NUM>. Colorless oil (yield = <NUM>%).

To a mixture of compound <NUM> (<NUM> mmol) and PdCl<NUM>(PPh<NUM>)<NUM> (<NUM> mmol) in THF (<NUM>), compound <NUM> (<NUM> mmol) and Cul (<NUM> mmol) was added. The mixture was bubbled with argon for <NUM> and then stirred for <NUM> at room temperature. The reaction was monitored by TLC. After the reaction was completed, the mixture was extracted with ethyl acetate, washed with brine, dried over MgSO<NUM>, and concentrated. The residue was passed through a short pad of silca gel (AcOEt) to afford the crude Sonogashira coupling product.

The crude product was dissolved in <NUM> dry THF and Palladium on active carbon (Pd/C, <NUM>%) was added. The mixture was stirred in an autoclave under hydrogen (H<NUM>) atmosphere (<NUM> bar) at r. The reaction mixture was filtered and the solution concentrated under vacuum. The residue was chromatographed over silica gel (hexane/AcOEt =<NUM>/<NUM>) to afford compound <NUM>. Light yellow powder (yield = <NUM>%).

Bis(<NUM>,<NUM>-cyclooctadiene)nickel (<NUM>) (<NUM>, <NUM>. 084mmol), <NUM>,<NUM>-cyclooctadiene (<NUM>, <NUM> mmol), and <NUM>,<NUM>'-bipyridine (<NUM>, <NUM>. 084mmol) in dry DMF (<NUM>) was charged under argon in a microwave tube equipped with magnetic stirrer bar and heated at <NUM> for <NUM>. A solution of monomer <NUM> (<NUM>, <NUM> mmol) in dry toluene (<NUM>) was added. The mixture was vigorously stirred in a CEM Discover microwave reactor at <NUM> W and active cooling, keeping the temperature at <NUM> for <NUM> hours. After the reaction was completed, the mixture was poured into a mixture of methanol and concentrated HCl (<NUM>:<NUM>, <NUM>), and stirred for <NUM>. The precipitated yellow polymer <NUM> was filtered off and dried under vacuum at <NUM> overnight. Yellow powder (yield = <NUM>%).

Polymer <NUM> is transformed into the corresponding GNR by cyclodehyrogenation reaction in solution as described in <CIT>.

A stirred solution of <NUM>-bromoanisole (<NUM>, <NUM> mmol), HgO (<NUM>, <NUM> mmol), Ac<NUM>O (<NUM>) in CH<NUM>Cl<NUM> (<NUM>) was refluxed for <NUM>. Then, I<NUM> (<NUM>, <NUM> mmol) was added by <NUM> portions every <NUM>. After refluxing for <NUM> and filtration over a pad of celite, the filtrate was washed with a saturated Na<NUM>S<NUM>O<NUM> solution. The aqueous layer was extracted with CH<NUM>Cl<NUM> (<NUM> × <NUM>) and the combined organic layers were dried with MgSO<NUM> and evaporated to dryness. Purification by flash chromatography (cyclohexane) afforded the titled compound.

To a mixture of aryl iodide <NUM> (<NUM>, <NUM> mmol), PdCl<NUM>(PPh<NUM>)<NUM> (<NUM>, <NUM> mmol), Cul (<NUM>, <NUM> mmol), TEA (<NUM>) in THF (<NUM>) was added dropwise under an argon atmosphere a solution of (Triisopropylsilyl)acetylene (<NUM>, <NUM> mmol). The mixture was stirred at room temperature overnight. Then Et<NUM>O (<NUM>) was added to the crude and the mixture was filtered over a short pad of celite. The organic layer was washed with brine (<NUM>) twice, separated, dried over MgSO<NUM>, filtered, and concentrated. Purification by flash chromatography afforded alkyne <NUM>. Colorless oil (yield = <NUM>%).

A <NUM> round flask was charged with alkyne <NUM> (<NUM>, <NUM> mmol), Bis(pinacolato)diboron (<NUM>, <NUM> mmol), KOAc (<NUM>, <NUM> mmol) and PdCl<NUM>(dppf) (<NUM>, <NUM> mmol), then the stirring mixture was purged by Argon for <NUM>. After the mixture was stirred overnight at <NUM> under an argon atmosphere, the mixture was extracted with ethyl acetate (<NUM> X <NUM>). The combined organic layer was dried over MgSO<NUM>, filtered and concentrated. The crude residue was purified by pass through a short pad of silica gel to remove the catalyst and used directly for the next step. Brown yellow oil (Yield = <NUM>%).

A <NUM> round flask was charged with <NUM>-bromo-<NUM>,<NUM>-dimethylbenzene (<NUM>, <NUM> mmol), (<NUM>-(trimethylsilyl)phenyl)boronic acid (<NUM>, <NUM> mmol), K<NUM>CO<NUM> solution (<NUM> in <NUM> water), ethanol <NUM>, toluene <NUM>. The mixture was bubbled with argon for <NUM>, then Pd(PPh<NUM>)<NUM> (<NUM>, <NUM> mmol) was added. The resulting mixture was treated with liquid nitrogen bath. After three times freeze-pump-thaw procedure, the mixture was refluxed overnight. The reaction was monitored by TLC. After the reaction finished, the mixture was washed with deionized water and the water layer was extracted with ethyl acetate (<NUM> X <NUM>). The combined organic layer was dried over MgSO<NUM>, filtered and concentrated. The crude product was purified by chromatography to afford compound <NUM>. Colorless oil (yield = <NUM>%).

Compound <NUM> (<NUM>, <NUM> mmol) was treated with neat boron tribromide (<NUM>, <NUM>. 3mmol) under argon. A condenser was attached that was also charged with argon, and the solution was heated to <NUM> for <NUM>. Once cooled, excess boron tribromide was distilled off under vacuum at room temperature. The resulting gray-purple solid was dissolved in dry hexane (<NUM>) and cooled to <NUM> with an ice bath. Water was slowly added dropwise while stirring vigorously until the reaction had been fully quenched. The resulting mixture was filtered and the white solid was washed with deionized water and hexane. The white powder was dried at <NUM> under vacuum overnight, yielding boronic acid <NUM>. White powder (yield = <NUM>%).

At -<NUM>, butyllithium (<NUM> mmol) in hexanes (<NUM>) and diisopropylamine (<NUM> mmol) were added successively to tetrahydrofuran (<NUM>). After <NUM> <NUM>,<NUM>-dibromobenzene (<NUM>, <NUM>, <NUM> mmol) was added. The mixture was kept for <NUM> at -<NUM> before a solution of iodine (<NUM>, <NUM> mmol) in tetrahydrofuran (<NUM>) was added. After addition of a <NUM>% aqueous solution (<NUM>) of sodium thiosulfate, the mixture was extracted with diethyl ether (3X <NUM>). The combined organic layers were dried over sodium sulfate before being evaporated to dryness. Upon crystallization from ethanol (<NUM>), colorless platelets were obtained.

In a glove box, Pd<NUM>(dba)<NUM> (<NUM>, <NUM> mmol), PCy<NUM> (<NUM>, <NUM> mmol), compound <NUM> (<NUM>, <NUM> mmol), boronic acid <NUM> (<NUM>, <NUM> mmol) were added to a reaction vessel that was equipped with a stir bar. A degassed K<NUM>PO<NUM> (<NUM>, <NUM> mmol) water solution was then added, followed by <NUM> anhydrous THF. The reaction mixture was then stirred at <NUM> for <NUM> days. After the reaction finished, the reaction mixture was diluted with EtOAc, then extracted by EtOAc three times, dried, filtered and concentrated. The final product was obtained after purification by column chromatography on silica gel. Colorless oil (yield = <NUM>%).

A <NUM> round flask was equipped with compound <NUM> (<NUM>, <NUM> mmol), boronic ester <NUM> (<NUM>, <NUM> mmol) in <NUM> toluene and <NUM> K<NUM>CO<NUM> (<NUM>, <NUM> mmol) water solution. After bubbled with argon for <NUM>, the catalyst Pd(PPh<NUM>)<NUM> (<NUM>, <NUM> mmol) was added. The reaction mixture was then heated at reflux temperature overnight. The reaction was stopped after TLC indicated that the starting material was totally converted. The mixture was extracted with EtOAc (<NUM> X <NUM>), then the combined organic layer was dried, filtered and concentrated. The residue was purified by column chromatography yielding product <NUM>. Yellow solid (yield = <NUM>%).

Compound <NUM> (<NUM>, <NUM> mmol) was dissolved in <NUM> THF, and then TBAF (<NUM>, <NUM> mmol) was added to the yellow solution. After stirred for <NUM>, the reaction mixture was washed with water and then extracted with EtOAc. The combined organic layer was dried over MgSO<NUM> and filtered. The solvent was removed by rotation evaporator. The obtained white solid was used directly for the next step. White solid (yield = <NUM>%).

A <NUM> round flask was charged with compound <NUM> (<NUM>, <NUM> mmol) and PtCl<NUM> (<NUM>, <NUM> mmol), then the mixture was kept under vacuum condition for <NUM> and refilled with argon. <NUM> of anhydrous toluene was added by syringe. The mixture was heated at <NUM> for <NUM> until reaction finished which showed by TLC plate. The solvent was removed under vacuum condition and the residue was purified by chromatography yielding final product. White solid (yield = <NUM>%).

Compound <NUM> (<NUM>, <NUM> mmol) was dissolved in <NUM> dry DCM under argon protection. Then, <NUM> <NUM> BBr<NUM> (<NUM>, <NUM> mmol) was added dropwise to the solution at <NUM>. The solution was then allowed to warm to room temperature and stirred for <NUM>. Then, the reaction was quenched by adding <NUM> water slowly at <NUM>. The mixture was washed with water and extracted with DCM. The organic layer was dried over MgSO<NUM>, filtered and concentrated. The residue was recrystallized from DCM/hexane (<NUM>:<NUM>). White green powder (yield = <NUM>%).

Compound <NUM> (<NUM>, <NUM> mmol) was dissolved in <NUM> DCM and cooled to <NUM> by an ice bath, then <NUM> Et<NUM>N (<NUM> mmol) was added drop wise. <NUM> Tf<NUM>O (<NUM>) solution was added by syringe. The ice bath was then removed and the mixture solution was warmed to room temperature and stirred for <NUM>. After TLC showed the completion of the reaction, the solvent was removed and the residue was purified by chromatography yielding product. White solid (yield = <NUM>%).

A Schlenk tube was charged with compound <NUM> (<NUM>, <NUM> mmol), PdCl<NUM>(dppf) (<NUM>, <NUM> mmol), <NUM> dry dioxane and Et<NUM>N (<NUM>, <NUM> mmol), the solution was degassed and pinacolborane (<NUM>, <NUM> mmol) was added. The mixture solution was then heated at refluxing temperature for <NUM>. Then the solvent was removed and the residue was purified by chromatography. Light yellow oil (yield = <NUM>%).

Compound <NUM> (<NUM>, <NUM> mmol) and CuBr<NUM> (<NUM>, <NUM> mmol) was added to a sealtube, then <NUM> THF, <NUM> Methanol and <NUM> water was added. The tube was sealed and heated at <NUM> overnight. The mixture was then extracted with DCM (<NUM> X <NUM>), dried over MgSO<NUM>, filtered and concentrated. The residue was purified by chromatography and HPLC to afford monomer <NUM>. Colorless solid (Yield = <NUM>%)
FD-MS: m/z = <NUM>.

<CHM>
a) PdCl<NUM>(PPh<NUM>)<NUM>, Cul, Et<NUM>N, THF, r. b) n-BuLi,THF, ICH<NUM>CH<NUM>I, -<NUM> to r. c) CuCI, DMF, Air, <NUM>, <NUM>. d) Pd(PPh<NUM>)<NUM>/Na<NUM>CO<NUM>, THF/H<NUM>O/EtOH, <NUM>, <NUM>. e) PdCl<NUM>, Toluene, <NUM>, <NUM>.

A <NUM> round bottomflask equipped with a magnetic stir bar was charged with compound <NUM> (<NUM> mmol),THF (<NUM>), triethylamine (<NUM>, 150mmol), PdCl<NUM>(PPh<NUM>)<NUM> (<NUM>, <NUM>. 7mmol), Cul (<NUM>, <NUM> mmol) and trimethylsilylacetylene (<NUM>, <NUM>. 1mmol) under argon atmosphere. The reaction mixture was stirred overnight at room temperature, diluted in CH<NUM>Cl<NUM>, washed with NH<NUM>Cl and dried over Mg<NUM>SO<NUM>. The solvent was removed under reduced pressure and the crude product was purified by flash chromatography on silica gel with hexanes as eluent to afford the desired compound <NUM> (133a: <NUM>%, 133b: <NUM>%) as yellow orange oil.

A <NUM> round bottom flask equipped with a magnetic stir bar was charged with compound <NUM> ( <NUM> mmol), THF (<NUM>). The temperature was cooled to -<NUM> and n-BuLi (<NUM>, <NUM> mmol) was added slowly. The reaction mixture was stirred for one hour and <NUM>,<NUM>-diiodoethane was added ( <NUM> mmol). The reaction mixture was stirred overnight at room temperature, diluted in CH<NUM>Cl<NUM>, washed with H<NUM>O and dried over Mg<NUM>SO<NUM>. The solvent was removed under reduced pressure and the crude product was purified by flash chromatography on silica gel with hexanes as eluent to afford the desired compound <NUM> (134a:<NUM>%, 134b:<NUM>%) as dark orange oil.

To a dimethylformamide (DMF) (<NUM>) solution of compound <NUM> (<NUM> mmole) placed in round bottom flask was added CuCI (<NUM> mmol) equipped with a magnetic stirring bar. The reaction mixture was stirred for <NUM> at <NUM> and quenched with <NUM> HCl(aq). The aqueous layer was separated and extracted with <NUM> of diethyl ether. The combined ethereal layer was washed with brine and dried over Mg<NUM>SO<NUM>, concentration of the solution in vacuo gave a brown residue that was purified by column chromatography (dichloromethane/hexane = <NUM>/<NUM>) to afford compound <NUM> (135a:<NUM>%, 135b:<NUM>%) as a yellow solid.

Nitrogen was bubbled through a mixed solution of THF (<NUM>), EtOH (<NUM>) and water (<NUM>) for <NUM>, and to this solution was added compound <NUM> ( <NUM> mmol), Pd(PPh3)<NUM> (<NUM> mmol), K2CO3 (<NUM> mmol) and bromo-naphthalene-boronic acid (<NUM> mmol). The mixture was heated at <NUM> for <NUM>. The solution was extracted three times with ethyl acetate. After removal of the solvent in vacuo, the crude material was purified by column chromatography (dichloromethane/hexane = <NUM>/<NUM>) to afford compound <NUM> (136a:<NUM>%, 136b:<NUM>%) as a yellow solid.

A reaction tube containing PtCl<NUM> (<NUM> mmol) was dried in vacuo for <NUM>, and vacuum was filled with nitrogen with a nitrogen balloon. To this round bottom flask was added compound <NUM> (<NUM> mmol) and toluene (<NUM>), and the mixture was stirred at <NUM> for <NUM> before it was heated at <NUM> for <NUM>. After removal of solvent in vacuo, the crude material was purified by column chromatography (dichloromethane/hexane = <NUM>/<NUM>) to afford compound <NUM>, respectively <NUM> (<NUM>:<NUM>%, <NUM>: <NUM>%) as a yellow solid.

<NUM>: <NUM>H-NMR (CD<NUM>Cl<NUM>, <NUM>): <NUM>(dd, <NUM>), <NUM> (s, <NUM>), <NUM> (d,<NUM>), <NUM> (m, <NUM>), <NUM> (t, <NUM>), <NUM> (t, <NUM>), <NUM> (t, <NUM>), <NUM> (t, <NUM>); <NUM>C-NMR (CD<NUM>Cl<NUM>, <NUM>): <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. FD-MS (<NUM> KV): <NUM>/z.

<NUM>: <NUM>H-NMR (CD<NUM>Cl<NUM>, <NUM>): <NUM>(dd, <NUM>), <NUM> (s, <NUM>), <NUM> (d,<NUM>), <NUM> (m, <NUM>), <NUM>(t, <NUM>), <NUM> (t, <NUM>), <NUM> (s, <NUM>); <NUM>C-NMR (CD<NUM>Cl<NUM>, <NUM>):<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. FD-MS (<NUM> KV): <NUM>/z.

<CHM>
f) Sandmeyer reaction. g) PdCl<NUM>(PPh<NUM>)<NUM>, Cul, Et<NUM>N, THF, r. h) CuCI, DMF, Air, <NUM>, <NUM>. i) n-BuLi,THF, ICH<NUM>CH<NUM>I, -<NUM> to r. j) Pd(PPh<NUM>)<NUM>/Na<NUM>CO<NUM>, THF/H<NUM>O/EtOH, <NUM>, <NUM>. k) ICI, DCM, -<NUM>, <NUM>. I) hv, THF, <NUM>, r.

A mixture of dimethyl-bromoaniline (<NUM> mol), H<NUM>O (<NUM>), and <NUM>% aq. HCl(<NUM>) was heated to <NUM> while stirring. The mixture was stirred <NUM> followed by cooling to <NUM> on an ice/water bath. NaNO<NUM>(<NUM> mol) was added maintaining the internal temperature below <NUM>. The resulting clear, orange solution was stirred at <NUM> for <NUM> followed by addition of Kl(<NUM>. 055mol) as a solution in H<NUM>O (<NUM>) keeping the internal temperature below <NUM>. The black suspension was allowed to reach room temperature and stirred for <NUM>. The suspension was extracted with DCM, washed with water and brine, dried over with Mg<NUM>SO<NUM>, cncentration of the solution in vacuo gave a brown residue that was purified by column chromatography (hexane) to afford compound <NUM> (<NUM>%) as a yellow orange oil.

<NUM>:<NUM>H-NMR (CD<NUM>Cl<NUM>, <NUM>): <NUM> (s, <NUM>), <NUM> (s, <NUM>), <NUM> (s, <NUM>), <NUM> (s, <NUM>).

A <NUM> round bottomflask equipped with a magnetic stir bar was charged with compound <NUM> (<NUM> mmol),THF (<NUM>), triethylamine (<NUM>, 150mmol), PdCl<NUM>(PPha)<NUM> (<NUM>, <NUM>. 7mmol), Cul (<NUM>, <NUM> mmol) and trimethylsilylacetylene (<NUM>, <NUM>. 1mmol) under argon atmosphere. The reaction mixture was stirred overnight at room temperature, diluted in CH<NUM>Cl<NUM>, washed with NH<NUM>Cl and dried over Mg<NUM>SO<NUM>. The solvent was removed under reduced pressure and the crude product was purified by flash chromatography on silica gel with hexanes as eluent to afford the desired compound <NUM> (<NUM>%) as yellow solid. <NUM>: <NUM>H-NMR (CD<NUM>Cl<NUM>, <NUM>): <NUM> (s, <NUM>), <NUM> (s, <NUM>), <NUM> (s, <NUM>), <NUM> (s, <NUM>), <NUM> (s, <NUM>);.

To a dimethylformamide (DMF) (<NUM>) solution of compound <NUM> (<NUM> mmole) placed in round bottom flask was added CuCI (<NUM> mmol) equipped with a magnetic stirring bar. The reaction mixture was stirred for <NUM> at <NUM> and quenched with <NUM> HCl(aq). The aqueous layer was separated and extracted with <NUM> of diethyl ether. The combined ethereal layer was washed with brine and dried over Mg<NUM>SO<NUM>, concentration of the solution in vacuo gave a brown residue that was purified by column chromatography (dichloromethane/hexane = <NUM>/<NUM>) to afford compound <NUM> (<NUM>%) as a yellow solid.

<NUM>:<NUM>H-NMR (CD<NUM>Cl<NUM>, <NUM>): <NUM> (s, <NUM>), <NUM> (s, <NUM>), <NUM> (s, <NUM>), <NUM> (s, <NUM>). FD-MS (<NUM> KV): <NUM>/z.

A <NUM> round bottom flask equipped with a magnetic stir bar was charged with compound <NUM> ( <NUM> mmol), THF (<NUM>). The temperature was cooled to -<NUM> and n-BuLi (<NUM>, <NUM> mmol) was added slowly. The reaction mixture was stirred for one hour and <NUM>,<NUM>-diiodoethane was added ( <NUM> mmol). The reaction mixture was stirred overnight at room temperature, diluted in CH<NUM>Cl<NUM>, washed with H<NUM>O and dried over Mg<NUM>SO<NUM>. The solvent was removed under reduced pressure and the crude product was purified by column chromatography (dichloromethane/hexane = <NUM>/<NUM>) to afford the desired compound <NUM>(<NUM>%) as yellow solid.

Nitrogen was bubbled through a mixing solution of THF (<NUM>), EtOH (<NUM>) and water (<NUM>) for <NUM>, and to this solution was added compound <NUM> ( <NUM> mmol), Pd(PPh<NUM>)<NUM> (<NUM> mmol), K<NUM>CO<NUM> (<NUM> mmol) and bromo-naphthalene-boronic acid (<NUM> mmol). The mixture was heated at <NUM> for <NUM>. The solution was extracted three times with ethyl acetate. After removal of the solvent in vacuo, the crude material was purified by column chromatography (dichloromethane/hexane = <NUM>/<NUM>) to afford compound <NUM> (<NUM>%) as a yellow solid.

<NUM>: <NUM>H-NMR (CD<NUM>Cl<NUM>, <NUM>): <NUM>(s, <NUM>), <NUM> (s, <NUM>), <NUM> (s,<NUM>), <NUM> (t, <NUM>), <NUM> (d, <NUM>), <NUM> (t, <NUM>), <NUM> (t, <NUM>), <NUM>(s, <NUM>), <NUM> (s, <NUM>), <NUM> (s, <NUM>), <NUM> (s, <NUM>). FD-MS (<NUM> KV): <NUM>/z.

A solution of compound <NUM> (<NUM> mmol) in dry CH<NUM>Cl<NUM> (<NUM>) was maintained at -<NUM> with an acetone-liquid N<NUM> bath. To this solution was added ICI (<NUM>, <NUM> solution in CH<NUM>Cl<NUM>), using a standard syringe. The reaction was stirred for <NUM>. Quenched with a saturated sodium sulfite solution and warmed to RT. Extracted with CH<NUM>Cl<NUM> (<NUM>×<NUM>) and dried over MgSO<NUM>. After removal of solvent in vacuo, the crude material was purified by column chromatography (dichloromethane/hexane = <NUM>/<NUM>) to afford compound <NUM> (<NUM>%) as a yellow solid.

<NUM>: <NUM>H-NMR (CD<NUM>Cl<NUM>, <NUM>): <NUM>(s, <NUM>), <NUM> (s, <NUM>), <NUM> (d,<NUM>), <NUM> (s, <NUM>), <NUM> (dd, <NUM>), <NUM> (dd, <NUM>), <NUM> (t, <NUM>), <NUM> (s, <NUM>), <NUM> (s, <NUM>); 13C-NMR (CD<NUM>Cl<NUM>, <NUM>):<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. FD-MS (<NUM> KV): <NUM>/z.

A solution of <NUM> (<NUM>. 108mmol) in dry THF (<NUM>) was irradiated in a standard immersion well photoreactor with <NUM> high pressure mercury vapor lamp (<NUM>*<NUM>) for <NUM>. The reaction mixture was then washed with aqueous sodium thiosulfate, water, brine and dried over anhydrous MgSO<NUM>. The solvent was removed under vacuum and recrystallization from chloroform afforded monomer <NUM> (<NUM>%) as a yellow solid.

<NUM>: <NUM>H-NMR (CD<NUM>Cl<NUM>, <NUM>): <NUM> (s, <NUM>), <NUM> (s, <NUM>), <NUM> (s,<NUM>), <NUM> (dd, <NUM>), <NUM> (m, <NUM>), <NUM> (t, <NUM>), <NUM> (s, <NUM>), <NUM> (s, <NUM>); <NUM>C-NMR (CD<NUM>Cl<NUM>, <NUM>):<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. FD-MS (<NUM> KV): <NUM>/z.

A Au(<NUM>) single crystal (Surface Preparation Laboratory, Netherlands) was used as the substrate for the growth of the GNR structures v, vi and vii from the corresponding monomers <NUM>, <NUM> and <NUM>, respectively. The Au surface was cleaned under ultra-high vacuum conditions (UHV, pressure <NUM>×<NUM>-<NUM> mbar) by repeated cycles of argon ion bombardment and annealing to <NUM>. Once the surface was clean, the precursor monomers were deposited onto the substrate held at <NUM> by sublimation at rates of ~ <NUM>/min. After monomer deposition, the Au(<NUM>) substrate was kept at this temperature for a few minutes (<NUM>-<NUM>) to complete polymerization. Subsequently the sample was annealed to <NUM> for <NUM> to induce cyclodehydrogenation and thus the formation of the targeted GNR structures. A variable-temperature STM (VT-STM) from Omicron Nanotechnology GmbH, Germany, was used to characterize the morphology of the GNR structures. Images were taken at <NUM> (LHe cooling).

<FIG>, <FIG> show STM images of the polymer structures obtained after monomer deposition (a) and of the final GNR structures (b) obtained after cyclodehydrogenation. The characteristic apparent height of the final GNR structures is of <NUM> to <NUM>, in agreement with other GNR structures [e.g. <NPL>)].

The experiments are summarized in Table <NUM>.

A Au(<NUM>) single crystal (Surface Preparation Laboratory, Netherlands) was used as the substrate for the growth of the N=<NUM> cove-edge zigzag GNR structure iii from monomer <NUM>. The Au surface was cleaned under ultra-high vacuum conditions (UHV, pressure <NUM>×<NUM>-<NUM> mbar) by repeated cycles of argon ion bombardment and annealing to <NUM>. Once the surface was clean, the precursor monomers <NUM> were deposited onto the substrate held at <NUM> by sublimation at rates of ~ <NUM>/min. After monomer deposition, the Au(<NUM>) substrate was kept at this temperature for a few minutes (<NUM>-<NUM>) to complete polymerization. Subsequently the sample was annealed to <NUM> for <NUM> to induce cyclodehydrogenation and thus the formation of the targeted GNR structure iii. A low-temperature scanning tunneling microscope (LT-STM) from Omicron Nanotechnology GmbH, Germany, was used to characterize the morphology of the N=<NUM> cove-edge zigzag GNR structures. Images were taken at <NUM> (LHe cooling).

<FIG> shows a high resolution STM image of the terminus of the GNR structure iii. The image was taken at U = -<NUM>. 9V, I = <NUM>. 4nA, <NUM> (LHe cooling). The apparent height is <NUM>, in agreement with results for other GNR structures [e.g. <NPL>)]. <FIG> shows the same STM image with a chemical model of the corresponding GNR structure iii overlaid.

Claim 1:
An aromatic monomer compound of formula I-X:
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
wherein
X independently from each other, are Br or I;
Ra independently of each other are hydrogen or linear or branched or cyclic C<NUM>-C<NUM>alkyl, preferably hydrogen or methyl;
Rb independently of each other, are hydrogen; linear or branched or cyclic C<NUM>-C<NUM>alkyl which is unsubstituted or substituted by one or more OH, C<NUM>-C<NUM>alkoxy, phenyl, or by CN; C<NUM>-C<NUM>alkyl which is interrupted by one or more non-consecutive O; halogen; OH; OR<NUM>; SR<NUM>; CN; NO<NUM>; NR<NUM>R<NUM>; (CO)R<NUM>; (CO)OR<NUM>; O(CO)OR<NUM>; O(CO)NR<NUM>R<NUM>; O(CO)R<NUM>; C<NUM>-C<NUM>alkoxy; C<NUM>-C<NUM>alkylthio; (C<NUM>-C<NUM>alkyl)-NR<NUM>R<NUM>; or-O-(C<NUM>-C<NUM>alkyl)NR<NUM>R<NUM>; aryl or heteroaryl; wherein aryl is preferably phenyl, biphenyl, naphthyl, or anthryl all of which are unsubstituted or are substituted by one or more C<NUM>-C<NUM>-alkyl, CN, OR<NUM>, SR<NUM>, CH<NUM>OR<NUM>, (CO)OR<NUM>, (CO)NR<NUM>R<NUM> or halogen;
Rc independently of each other, are hydrogen; linear or branched or cyclic C<NUM>-C<NUM>alkyl which is unsubstituted or substituted by one or more OH, C<NUM>-C<NUM>alkoxy, phenyl, or by CN; C<NUM>-C<NUM>alkyl which is interrupted by one or more non-consecutive O; halogen; OH; OR<NUM>; SR<NUM>; CN; NO<NUM>; NR<NUM>R<NUM>; (CO)R<NUM>; (CO)OR<NUM>; O(CO)OR<NUM>; O(CO)NR<NUM>R<NUM>; O(CO)R<NUM>; C<NUM>-C<NUM>alkoxy; C<NUM>-C<NUM>alkylthio; (C<NUM>-C<NUM>alkyl)-NR<NUM>R<NUM>; or-O-(C<NUM>-C<NUM>alkyl)NR<NUM>R<NUM>;
or two groups Ra, Rb and Rc, may together with the carbon atoms they are attached to, form a <NUM>-<NUM>-membered cycle or heterocycle;
R<NUM> and R<NUM> are, independently of each other, hydrogen, linear or branched C<NUM>-C<NUM>alkyl or phenyl, or R<NUM> and R<NUM> together with the nitrogen atom to which they are bonded form a group selected from
<CHM>
R<NUM> is selected from H, C<NUM>-C<NUM>alkyl and phenyl, which may be unsubstituted or substituted by one or more C<NUM>-C<NUM> alkyl, phenyl, halogen, C<NUM>-C<NUM> alkoxy or C<NUM>-C<NUM> alkylthio.