bluuebunny/crossref_metadata_2025_split huggingface dataset:
Self‐Assembly of Heterobimetallic Complexes and Reactive Nucleophiles: A General Strategy for the Activation of Asymmetric Reactions Promoted by Heterobimetallic Catalysts
Authors: Arai Takayoshi , Yamada Yoichi M. A. , Yamamoto Noriyoshi , Sasai Hiroaki , Shibasaki Masakatsu 
Published: July 2007

AbstractHeterobimetallic asymmetric catalysts, such as the lanthanum–lithium–binaphthol complex (La Li–BINOL), the aluminum–lithium–binaphthol complex (AlLi–BINOL), and a newly prepared gallium–sodium–binaphthol complex (Ga Na–BINOL), have been self‐assembled with reactive nucleophiles, such as lithium nitronates and sodium malonates, to generate more efficient catalysts than the parent heterobimetallic catalysts. For example, by the combined use of La Li–BINOL (1 mol%; contains one H2O molecule) and BuLi (0.9 mol%) as the catalyst system, asymmetric nitroaldol reactions are greatly accelerated in all cases without a decrease in the optical purity of the nitroaldol products. Kinetic analyses have also been carried out on the Ga Na–BINOL‐catalyzed Michael reaction of dibenzyl malonate with cyclohexenone, with or without NaOtBu. The calculated rate constants show that the combined use of Ga Na–BINOL and NaOtBu as the catalyst gives reaction rates that are about 50 times faster than with Ga Na–BINOL alone. This activation method should be useful for other asymmetric reactions catalyzed by heterobimetallic complexes.
Synthetic Methodology Allowing the Interconversion of Titanium–Oxygen Single Bonds and Double Bonds: The Self‐Assembly of Bridging and Terminal Oxotitanium(IV) into Oligomeric and Polymeric Linear Titanoxanes
Authors: Franceschi Federico , Gallo Emma , Solari Euro , Floriani Carlo , Chiesi‐Villa Angiola , Rizzoli Corrado , Re Nazzareno , Sgamellotti Antonio 
Published: July 2007

AbstractThe controlled ionization of the linear [Cl–Ti–O–Ti–Cl] skeleton allowed the generation of the [Cl–Ti–O–Ti]+ dimer, which is nonsymmetrical as a consequence of extended Cl–Ti–O π interactions. The [TiO] unit thus formed is a building block for a variety of titanoxane structures. This chemistry has been investigated from a theoretical point of view by ab initio MO analysis of the [Cl–Ti–O–Ti–Cl] and [Cl–Ti–OTi]+ fragments. These calculations lead to the conclusion that single ionization generates the [TiO] unit, whereas double ionization does not affect the μ‐oxo bonding mode in [Ti–O–Ti]2+ or [S–Ti–O–Ti–S]2+ (where S is a pure σ‐donor ligand or solvent). This observation has been confirmed experimentally by ionizing the following model complexes: [(Cl)(acacen)‐Ti–O–Ti(acacen)(Cl)] (3) (acacen = N,N'‐ethylenebisacetylacetoneiminato dianion) and [(Cl)(salen)Ti–O–Ti(salen)‐(Cl)] (4) (salen = N,N'‐ethylenebissalicylideneiminato dianion), where the linear Cl–Ti–O–Ti–Cl unit is assured by the square‐planar bonding mode of the tetradentate Schiff base ligand. The double ionization of 3 with AgNO3 gave the conventional μ‐oxo derivative [(acacen)(η1‐ONO2)Ti–O–Ti(acacen)(η1‐ONO2)] (5). In contrast, the stepwise ionization of 3 and 4 with NaBPh4 in THF led to the nonsymmetrical [Cl–Ti–OTi]+ intermediates, which are the parent compounds for a variety of linear titanoxanes. The following species containing a TiO unit have been isolated from the NaBPh4‐assisted ionization of 3: [(acacen)TiO–BPh3] (6) and [(L)(acacen)TiO–Ti(acacen)–O–(acacen)Ti–OTi(acacen)(L)]2+2 BPh‐4 (L = THF, 7; L = none, 8). The same reaction carried out on 4 led to [(THF)‐(salen)TiO – Ti (salen) – O – (salen)Ti‐(THF)]2+2 BPh‐4 (9) and [(L)(salen)‐TiO–Ti(salen) – O – (salen)Ti–OTi‐(salen)(L)]2+ 2BPh‐4 (L = THF, 10; L = Py, 11; L = none, 12, polymeric form). A scheme is proposed to explain the formation of the species derived from the single ionization of 3 and 4, where the origin and the binding properties of the [TiO] unit play a major role.
Isolation of Transmetalation Intermediates in the Stille Cross‐Coupling Reaction of Stannanes: Synthesis of Palladacycles, Ligand Substitution, and Insertion Reactions
Authors: Mateo Cristina , Cárdenas Diego J. , Fernández‐Rivas Carolina , Echavarren Antonio M. 
Published: July 2007

AbstractA strategy based on a Stille cross‐coupling reaction of organostannanes interrupted at the reductive elimination step has been applied to the synthesis of oxa‐ and azapalladacycles with the general formula cis‐[PdArR(L)2]. The synthesis of oxapalladacycles was achieved under mild conditions by reaction of 2‐iodo‐ or 2‐bromophenyloxymethylstannanes with [Pd(PPh3)4]. The synthesis of an aza analogue was similarly carried out from the corresponding 2‐iodoaniline derivative. One of the substituted oxapalladacycles rearranged to release steric strain between the palladium and a chloride substituent on the aryl ring, an isomerization promoted by traces of water. In one case, the arylpalladium(II) intermediate of oxidative addition was isolated by using a palladium(0) complex with a bidentate diphosphane. A variety of new palladacycles, including complexes with weakly coordinating ligands, were prepared by ligand substitution. Reaction of the palladacycles with dimethyl acetylene‐dicarboxylate led to the formation of chromenes or dihydroquinolines by insertion followed by reductive elimination.
The Unusual Properties of 5‐Methyl‐4,5,6,7‐Tetrahydro‐1H‐Indazole in the Solid State
Authors: Foces‐Foces Concepción , Hager Orm , Jagerovic Nadine , Jimeno María Luisa , Elguero José 
Published: July 2007

AbstractThe crystal structure of the title compound was determined by X‐ray analysis at 200 K. Three independent molecules form a trimer joined by strong and linear N‐H … N hydrogen bonds. There is another centrosymmetrically related trimer in the unit cell. Both tautomers (1H and 2H) are present in each trimer. Disorder of the NH protons involved in the N‐H … N hydrogen bonds has been observed. Solid‐state 13C CPMAS NMR was used to establish the dynamic nature of the NH‐proton disorder, the title compound being the first example of proton transfer in a tautomeric mixture of pyrazoles with an equilibrium constant other than 1.
Structural Effects in the Reductive Activation of (Indenyl)RhL2 Complexes: The Reduction of [Rh(η5‐C9H7)(η4‐cod)]
Authors: Amatore Christian , Ceccon Alberto , Santi Saverio , Verpeaux Jean‐Noël 
Published: July 2007

AbstractThe reduction of the indenyl complex [Rh(η5‐C9H7)(η4‐cod)] has been investigated in the context of structural effects induced by the transfer of one electron. The reduction of this complex occurs in two steps, leading first to the radical anion and then to the highly frangible dianion. Both species eliminate the indenyl anion. In the presence of free cyclooctadiene, the related cleavage leading to the indenyl anion and bis‐cyclooctadiene rhodium fragments now follows a Michaelis–Menten‐type mechanism involving precoordination of one extra COD ligand to the initial radical anion. These results suggest the modification of the hapticity of the indenyl ligand in connection with 17‐ and 19‐electron metalcentered intermediates.
A Joint Experimental and Theoretical Study of the Interaction between Aluminum and Electroluminescent Polymers: Cyano Derivatives of Poly(p‐phenylene vinylene)
Authors: Fahlman M. , Salaneck W. R. , Moratti S. C. , Holmes A. B. , Brédas J. L. 
Published: July 2007

AbstractThe early stages of metal/polymer interface formation between aluminum and poly(2,5,2′,5′‐tetrahexyloxy‐8,7′‐dicyanodi‐p‐phenylenevinylene) or their ring‐substituted derivatives have been studied theoretically by using quantum‐chemical calculations as well as experimentally by X‐ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy. This class of conjugated polymer is of interest in the development of organic light‐emitting diodes. The theoretical and experimental results indicate that aluminum preferentially reacts with the polymer by forming covalent bonds with the nitrogen and carbon atoms of the cyano groups. When the side chains of the phenylene rings include carbonyl groups, however, the theoretical results indicate that the carbonyl moiety is another preferred site of interaction.
Catalytic asymmetric synthesis of new halogenated chiral synthons
Authors: Vanhessche Koen P. M. , Barry Sharpless K. 
Published: July 2007

AbstractTwo‐step and practical asymmetric syntheses of enantiomerically pure 4‐trifluoromethyl‐2,2‐dioxo‐1,3,2‐dioxathiolane and 4‐trichloromethyl‐2,2‐dioxo‐1,3,2‐dioxathiolane (>98% ee) have been achieved. Catalytic asymmetric dihydroxylation (AD) of 3,3,3‐trifluoropropene and 3,3,3‐trichloropropene, respectively, is followed by direct cyclic sulfate formation by reaction with sulfuryl chloride. Opening of the cyclic sulfates with various nucleophiles provides easy access to important chiral synthons.
The C60 Core: A Versatile Tecton for Dendrimer Chemistry
Authors: Camps Xavier , Schönberger Hubert , Hirsch Andreas 
Published: July 2007

AbstractThe synthesis, complete characterization and molecular dynamics simulations of dendrimers 4–8 involving [60]fullerene as core tecton and first‐ to thirdgeneration benzyl‐ether‐based dendrons as branches is described. In dendrimer 7 a core branching multiplicity of 12, the highest known to date, is realized for the first time with a Th‐symmetrical C60 core having an octahedral addition pattern. This unique structural type of core building block is only possible on the base of C60 and has no precedent in organic chemistry. NMR investigations as well as molecular modelling studies show that, owing to high core branching multiplicity, dendrimer 7 and to a minor extent the mixed adduct 8 already represent globular and densely packed macromolecules, although only first‐generation dendrons are involved in their construction.
Nature of the Interactions between Polar β‐Substituents and Palladium in η3‐Allylpalladium Complexes—A Combined Experimental and Theoretical Study
Authors: Szabó Kálmán J. 
Published: July 2007

AbstractDeuteromethanolysis of six β‐methoxy‐substituted η3‐allylpalladium complexes (1–5) was studied under the same reaction conditions. The reaction rates depend on the ring size of the cyclic complexes, on the σ‐donor/π‐acceptor nature of the ancillary ligand, on the configuration of the allylic moiety, and on the position of the β‐substituent with respect to the palladium atom. Replacement of the methoxy group proceeds about 1000 times faster in the trans‐β‐substituted cycloheptylallyl palladium complex 2 than in the cyclooctyl analogue 3; this indicates that the C–O bond strength is a function of the ring and substituent conformations. A theoretical analysis of the structure and stability of slightly simplified model compounds 6–10 was performed with density functional theory at the B 3 PW91 level in order to elucidate the relationship between the rate of deuteromethanolysis and the electronic interactions between the β‐methoxy substituent and the palladium atom. It was concluded that the strength of these β‐substituent effects critically depends on the relative position of the Pd–C3 and C4–O bonds. In cyclohexyl and cycloheptylallyl complexes 6 and 7, the trans‐β‐methoxy substituent adopts a conformation that is particularly favoured by the β‐substituent effect. Since the η3‐allylpalladium complexes studied and their derivatives are key intermediates of important palladium‐catalysed transformations, the implications of the β‐substituent effect for the regio‐ and chemoselectivity of nucleophilic attack are also discussed.
Through‐Bond Interactions in Silicon–Phosphorus and Silicon–Arsenic Compounds: A Facile Synthesis of Dodecamethyl‐2,3,5,6,7,8‐hexasila‐1λ3,4λ3‐diphosphabicyclo[2.2.2]octane, Its Arsenic Analogue, and Related Compounds
Authors: Winkler Uwe , Schieck Mathias , Pritzkow Hans , Driess Matthias , Hyla‐Kryspin Isabella , Lange Holger , Gleiter Rolf 
Published: July 2007

AbstractDodecamethyl‐2,3,5,6,7,8‐hexa‐sila‐lλ3,4λ3‐diphosphabicyclo[2.2.2]oc‐tane (1) and its arsenic analogue 2 are readily accessible in 69 and 73% yield, respectively, by the cyclocondensation reaction of 1,2‐dichloro‐1,1,2,2‐tetrame‐thyldisilane (5) with the lithium pnictides [LiEH2(dme)] (E = P (6), As(7); dme = 1,2‐dimethoxyethane). The reactions proceed via 1,4‐diphosphaoctamethyltetrasi‐lacyclohexane (8) and its arsenic analogue 9, respectively, which were isolated and structurally characterized by X‐ray crystallography. The molecular structures of 1 and 2, which are isotypic, were also established by single‐crystal X‐ray analysis: they possess D3 point symmetry with the expected Si–E bond lengths (E = P, As) but unusually long Si–Si bonds. The latter are 0.02–0.03 Å longer than those in 8 and 9, mainly due to through‐bond interactions (TB) between donating n orbitals of the E atoms and the σ* acceptor orbitals of the Si–Si bond. The first expanded analogues of 1, namely, 12 and 14, with hexamethyltrisilane and dodecamethyl‐hexasilane chains bridging the two phosphorus atoms, were synthesized in a onepot cyclocondensation reaction of the corresponding 1,3‐ and 1,6‐dichloro‐oligosilanes 11 and 13, respectively, with [LiPH2(dme)]6. Ab initio calculations on the parent compounds 1a, 12a, and the second‐row analogue 1,4‐diazabicyclo‐[2.2.2]octane (B) were carried out in order to analyze the different coupling constants and magnitudes of intramolecular interactions (through‐space/through‐bond coupling). TS and TB coupling in B were found to be about two times stronger than in the congener 1a, due to the compactness of the N2C6 skeleton and the greater extent of s, p hybridization at nitrogen. Evidence for TB interactions in 1 was obtained by photoelectron spectroscopy and by comparison of the two first vertical ionization potentials with calculated values for 1a. The best agreement with experimental data was achieved when 1a was calculated at the MP2 level. Compound 1a preferentially adopts D3 point symmetry; the higher‐symmetry D3h form possesses one imaginary frequency and is slightly less stable (0.46 kcal mol−1 at HF/6–31 G*//HF/6–31 G* and 1.58 kcal mol−1 at MP2/ 6–31 G*//HF/6–31 G* level), suggesting that this structure corresponds to a transition state on the potential energy surface. The structures corresponding to the global minimum of B and 12a have D3h and C3h symmetry, respectively. At the HF/6–31 G*//HF/6–31 G* level the D3h form of 12a is 17.61 kcal mol−1 less stable than the C3h minimum.
Oligosilsesquioxane8‐OSS‐Ethyldiphenylphosphine: A New Functional Oligosilsesquioxane Ligand
Authors: Ruffieux Vincent , Schmid Günter , Braunstein Pierre , Rosé Jacky , Braunstein P. , Rosé J. 
Published: July 2007

AbstractOligosilsesquioxanes (OSS) may be considered as molecular sections of silica. The incompletely condensed (cy‐clopentyl)7T7(OH)3 (T = SiO3/2) has been used to generate a phosphine‐functionalized T8‐OSS system by reaction with 2‐(trichlorosilyl)diphenylphosphinoethane. The resulting model molecule (cyclopentyl)7T8(CH2)2PPh2 (1) is well suited to coordinate to transition metal clusters via the phosphorous atom. We selected the tetrahedral bimetallic cluster [HFeCo3‐(CO)12]. Depending on the stoichiometry, one or two phosphine ligands could be added to the cobalt atoms, with substitution of CO molecules. Owing to the cyclopentyl substituents, the resulting complexes [HFeCo3(CO)11{Ph2P(CH2)2T8‐(cyclopentyl)7}] (2) and [HFeCo3‐(CO)10{Ph2P(CH2)2T8(cyclopentyl)7}2] (3) are soluble in numerous organic solvents. Therefore, they could be completely characterized by 1H, 13C, 29Si, and 31P NMR spectroscopy.
Enantioselectivity Control with Metal Colloids as Catalysts
Authors: Bönnemann Helmut , Braun Gerhard A. 
Published: July 2007

AbstractMetal colloids protected with chiral molecules can lead to a new type of enantioselective catalyst combining good selectivity control with an extraordinarily high activity in hydrogenation reactions. This concept has been applied for the first time in the form of platinum sols stabilized by the alkaloid dihydrocinchonidine.
Tripodal Synthetic Peptide Bundles
Authors: Trojandt Gunter , Herr Ulrike , Polborn Kurt , Steglich Wolfgang 
Published: July 2007

AbstractThe stereochemical course of the formation of the two diastereomers of trimethyl 2,2′,2″‐nitrilotris[2‐(benzoylamino)acetate], 2a and 2b, is described. The structures of both isomers were confirmed by X‐ray diffraction studies. Diastereomer 2b could be obtained in larger quantities by epimerisation of 2 a to 2 b with catalytical amounts of NaOMe. The (RRR/SSS)‐triester 2 b is a suitable template for the synthesis of tripodal peptide bundles. Saponification of 2 b yielded the C3‐symmetrical racemic triacid 4 b, which was coupled with amino acid methyl esters and dipeptide esters to give pseudo‐hexapeptides and pseudo‐nonapeptides, respectively. The resulting mixtures of diastereomers were easily separated by crystallisation. Their absolute configuration at the template unit (RRR or SSS) was established by means of the CD spectra. The pseudo‐hexapeptide (SSS)N(BzGly*ValOMe)3 (14) was saponified to yield the optically pure triacid (SSS)N(BzGly*ValOH)3 (23). Compound 23 is an ideally preorganised template for the production of longer tripodal peptides. This was illustrated by the synthesis of two pseudo‐pentadecapeptides. Peptide bundles with polar side chains (histidine and serine) or end groups (catechol or hydroxamate units) were synthesised by using the templates 4 b, 22 and 23 as anchors.
Methyl Aryl Ketones in the Synthesis of Hexaazabicycloicosane Cage Complexes
Authors: Angus Patricia M. , Bygott Alexia M. T. , Geue Rodney J. , Korybut‐Daszkiewicz Bohdan , Mau Albert W. H. , Sargeson Alan M. , Sheil Margaret M. , Willis Anthony C. 
Published: July 2007

AbstractThe template syntheses of various CoIII‐hexaazaicosane‐type cage complexes with aromatic substituents are described. The parent template, [Co(sen)]3+ ion {sen = 4,4′,4″‐ethylidynetris(3‐azabutan‐1‐amine)}, paraformaldehyde, a methyl aryl ketone and a base were reacted in acetonitrile to give aroyl substituents attached to the fully saturated sarcophagine cage (1‐aroyl‐8‐methyl‐3,6,10,13,16,19‐hexaazabicyclo[6.6.6]‐icosane cobalt(III) ion) and aryl substituents attached to an analogous imine‐type cage (2‐aryl‐8‐methyl‐3,6,10,13,16,19‐hexaazabicyclo[6.6.6]icosa‐2‐ene cobalt(III) ion). Phenyl, napthyl, phenanthryl, anthracenyl and anthraquinonyl substituents have been bound to the cage simply by this route to give molecules that can act as intercalators in DNA or as photosensitizers attached to reversible redox‐active metal centres and can couple an organic two‐electron reagent with an inorganic one‐electron reagent. An X‐ray crystallographic analysis of a phenanthroyl cage complex has also been carried out. These substances and their progeny should be useful as biological probes and fluorescent indicators and for energy capture and conversion.
Two‐Dimensional Electronic Conjugation: Statics and Dynamics at Structural Domains Beyond Molecular Wires
Authors: Opsitnick Elizabeth , Lee Dongwhan 
Published: July 2007

AbstractChemical architectures supporting a high degree of electronic conjugation serve as important functional components in devices and materials for advanced electronic and photonic applications. Increasing the spatial dimensionality of such constructs can fundamentally modify their optoelectronic properties and significantly alter intra‐ and intermolecular interactions that are crucial for understanding and controlling charge/energy‐transfer processes. In this article, emerging design principles in the construction of well‐defined conjugated platforms beyond molecular wires are highlighted. Both covalent and noncovalent approaches can be strategically employed to position one‐dimensional (1D) substructures in a spatially well‐defined manner in order to enhance both structural and functional complexity in a two‐dimensional (2D) setting. A predictable and controllable switching mechanism can be designed and implemented with mobile 2D electronic conjugation that operates by correlated motions of inherently rigid 1D subunits. This emerging “dynamic” approach complements and challenges the prevailing “static” paradigm of conjugated chemical architectures.
Cellular pathways of energy metabolism in the brain: Is glucose used by neurons or astrocytes?
Authors: Nehlig Astrid , Coles Jonathan A. 
Published: July 2007

AbstractMost techniques presently available to measure cerebral activity in humans and animals, i.e. positron emission tomography (PET), autoradiography, and functional magnetic resonance imaging, do not record the activity of neurons directly. Furthermore, they do not allow the investigator to discriminate which cell type is using glucose, the predominant fuel provided to the brain by the blood. Here, we review the experimental approaches aimed at determining the percentage of glucose that is taken up by neurons and by astrocytes. This review is integrated in an overview of the current concepts on compartmentation and substrate trafficking between astrocytes and neurons. In the brain in vivo, about half of the glucose leaving the capillaries crosses the extracellular space and directly enters neurons. The other half is taken up by astrocytes. Calculations suggest that neurons consume more energy than do astrocytes, implying that astrocytes transfer an intermediate substrate to neurons. Experimental approaches in vitro on the honeybee drone retina and on the isolated vagus nerve also point to a continuous transfer of intermediate metabolites from glial cells to neurons in these tissues. Solid direct evidence of such transfer in the mammalian brain in vivo is still lacking. PET using [18F]fluorodeoxyglucose reflects in part glucose uptake by astrocytes but does not indicate to which step the glucose taken up is metabolized within this cell type. Finally, the sequence of metabolic changes occurring during a transient increase of electrical activity in specific regions of the brain remains to be clarified. © 2007 Wiley‐Liss, Inc.
Synthesis of 1,4‐oxathiocins and 1,3‐oxazines by the reactions of 2‐amino‐4,5‐dihydro‐3‐thiophenecarbonitriles with dibenzoyldiazomethane
Authors: Yamagata Kenji , Ohkubo Kimiko , Yamazaki Motoyoshi 
Published: July 2007

AbstractThe rhodium(II) acetate‐catalyzed reaction of dibenzoyldiazomethane with 4,5‐dihydro‐2‐(4‐morpholinyl)‐ or 2‐(1‐piperidinyl)‐ or 2‐(1‐pyrrolidinyl)‐3‐thiophenecarbonitriles 1 gave the corresponding 4H‐1,3‐oxazin‐4‐ones 3 through the cycloaddition of the cyano group of 1 to benzoylphenylketene which was formed by the Wolff rearrangement of dibenzoyldiazomethane. On the other hand, when bis(1,1,1‐trifluoroacetylacetonato)copper(II) was used instead of rhodium(II) acetate dimer, the corresponding 1,4‐oxathiocin‐7‐carbonitriles 2 and/or 3 were obtained. The formation of 2 could be explained by the mechanism involving the sulfonium ylide derived from the dibenzoylcarbenoid and 1.
Chiral polymethine dyes, V. syntheses, absolute configuration, spectroscopic, and chiroptical properties of chiral dinuclear tri‐ and pentamethinium as well as trinuclear [2.2.2]heptamethinediium cyanine dyes with 3‐sec‐butyl‐1,3‐dimethylindolyl end groups
Authors: Reichardt Christian , Budnik Ulrich , Harms Klaus , Schäfer Gerhard , Stein Jörg 
Published: July 2007

AbstractStarting with natural monochiral (−)‐(S)‐2‐methyl‐1‐butanol (1a) generated by alcoholic fermentations, we have synthesized the new monochiral heterocyclic iminium salt (+)‐(3R,15S)‐3‐sec‐butyl‐1,2,3‐trimethylindoleninium tetrafluoroborate (11) in an eight‐step reaction sequence. Important steps of this sequence are the zeolite‐catalyzed Fischer synthesis of the monochiral indole 6a from the phenylhydrazone of ketone 5a and the separation of the diastereomeric salts 9 and 10 by fourfold fractional recrystallization from ethanol. With the new quaternary iminium salt 11, new monochiral dinuclear tri‐ (13) and pentamethinium cyanine dyes (14) as well as the trinuclear [2.2.2]heptamethinediium 17 and [1.1.1]tetramethinium cyanine dyes 18 have been synthesized. The absolute configuration of the four stereogenic centers in the cyanine dye 14 has been confirmed by means of an X‐ray structural analysis. Spectroscopical and chiroptical properties of all new cyanine dyes have been determined.