bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dimeric 2,2′‐Bipyridylruthenium(II) Complexes Containing 2,2′‐Bis(1,2,4‐triazin‐3‐yl)‐4,4′‐bipyridine‐Like Bridging Ligands: Syntheses, Characterization and DNA Binding
Authors: Jiang Cai‐Wu 
Published: April 2004

AbstractThree new bridging ligands 2,2′‐bis(1,2,4‐triazin‐3‐yl)‐4,4′‐bipyridine (btb), 2,2′‐bis(1,2,4‐triazino[5,6‐f]acenaphthylen‐3‐yl)‐4,4′‐bipyridine (btapb), 2,2′‐bis(5,6‐diphenyl‐1,2,4‐triazin‐3‐yl)‐4,4′‐bipyridine (bdptb) and their dimeric 2,2′‐bipyridylruthenium(II) complexes [Ru(bpy)2(btb)Ru(bpy)2]4+ (1), [Ru(bpy)2(btapb)Ru(bpy)2]4+ (2), [Ru(bpy)2(bdptb)Ru(bpy)2]4+ (3) have been synthesized and characterized by elemental analysis, fast atom bombardment (FAB) mass spectrometry or electrospray mass spectrometry (ES‐MS), 1H NMR and UV/Visible spectroscopy. The binding behavior of these dimeric complexes with calf thymus DNA (CT‐DNA) was investigated by electronic absorption spectroscopy, viscosity measurements, and equilibrium dialysis experiments. The hypochromism of the metal‐ligand charge transfer (MLCT) band in the electronic absorption spectra of the dinuclear complexes 1, 2, and 3 is 8.7%, 19% and 33%, respectively, with bathochromic shifts of 5, 5 and 14 nm, respectively. The binding constants are 7.5×104 M−1, 4.8×105 M−1 and 7.6×105 M−1, respectively. Increasing the size of the plane of the bridging ligand increases the hydrophobicity of their complexes, leading to stronger binding by the complexes to calf thymus DNA. The effect of increasing concentrations of these novel dimeric ruthenium(II) complexes on the relative viscosities of CT‐DNA is less notable than that of well‐known intercalators such as [Ru(bpy)2(dppz)]2+. The equilibrium experiments showed that ΛΛ−3 binding is stronger than ΔΔ−3 binding to CT‐DNA. This is the first example of a dinuclear complex binding enantioselectively to CT‐DNA measured by equilibrium dialysis. The experiments suggest that the three complexes may be DNA groove binders. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Synthesis and Characterisation of Novel Main Group Element Clusters with Tin‐Phosphorus, Tin‐Arsenic, and Germanium‐Phosphorus Skeletons
Authors: Nikolova Donna , von Hänisch Carsten , Adolf Ariane 
Published: April 2004

AbstractThe reaction of iPr3SiPLi2 with SnCl2 in the mol ratio 1:1 leads to the formation of [Sn7(PSiiPr3)7] (1). The cluster [Sn8(PSiiPr3)6Cl2] (3) is obtained, if the same reaction is carried out with a slight excess of the metal salt. Similar lithium chloride elimination reactions between SnCl2 and iPr3SiAsLi2 in the mol ratio 1:1 and 2:3, however, yield [Sn7(AsSiiPr3)7] (2) and [Sn4(AsSiiPr3)6Li4(Et2O)2] (4), respectively. The metal salt GeCl2(diox)2 (diox = 1,4‐dioxane) reacts with iPr3SiPLi2 to give [Ge6(PSiiPr3)6] (5). Compounds 1−5 were characterised by NMR and IR spectroscopic techniques as well as elemental analysis. The crystal structures were identified by X‐ray diffraction analysis, which confirmed that the heptameric skeletons of 1 and 2 are structurally analogous. The Sn/P cluster 3 contains subvalent tin atoms, while 4 forms a Sn4As6Li4 rhombododecahedron and 5 a slightly distorted hexagonal prism. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
First ICN Adduct with a Selenium Donor (R = Se): Is It an Ionic [RSeCN]+I− or a “T‐Shaped” R(I)SeCN Hypervalent Compound?
Authors: Aragoni M. Carla , Arca Massimiliano , Demartin Francesco , Devillanova Francesco A. , Garau Alessandra , Grimaldi Patrizio , Isaia Francesco , Lelj Francesco , Lippolis Vito , Verani Gaetano 
Published: April 2004

AbstractThe reaction between 1,3‐dimethyl‐4‐imidazoline‐2‐selone (2) and ICN gave the adduct 2·ICN, whose crystal structure features dimers made up of two [2·CN]+ and two I− which strongly interact. Hybrid DFT calculations on the adduct 2·ICN, on the cation [2·CN]+, and on the dimer (2·ICN)2 account for a partially hypervalent selenium atom in 2·ICN and for the observed structural features. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Bis[di‐n‐alkyl(fluoro)stannyl]methanes, (R2FSn)2CH2 (R = n‐octyl, n‐dodecyl): Stable Fluoride‐Selective Carriers
Authors: Chaniotakis Nikolas , Jurkschat Klaus , Müller Dirk , Perdikaki Katerina , Reeske Gregor 
Published: April 2004

AbstractThe synthesis of bis[di‐n‐alkyl(fluoro)stannyl]methanes, [(R2)FSn]2CH2, (3, R = n‐octyl; 4, R = n‐dodecyl), is reported and their unprecedented dimeric structure in solution with pentacoordinate tin atoms is rationalized on the basis of 19F and 119Sn NMR spectroscopy, osmometric molecular mass determination and electrospray mass spectrometry (ESMS). 19F and 119Sn MAS NMR and Mössbauer spectroscopy also indicate pentacoordinate tin atoms for the solid state. The ability of compounds 3 and 4 to bind fluoride ion selectively and reversibly is evaluated through potentiometric measurements. Compared with the previously reported organotin(IV)‐based fluoride ionophore [Cl(Ph2)Sn]2CH2, 3 and 4 exhibit a drastically improved lifetime, while retaining their high preference for fluoride over all other lipophilic anions evaluated. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
A Fulvene Route to Group 4 Metallocene Complexes Bearing 4,7‐Bis(dimethylamino)‐Substituted Indenyl Ligands
Authors: Sierra Jesus Cano , Kehr Sierra Gerald , Fröhlich Roland , Erker Gerhard 
Published: April 2004

AbstractN,N,N′,N′‐Tetramethylsuccinamide (15) was selectively converted into the functionalized aminofulvene 16. Subsequent treatment with reagent 17, [ZrCl2(NMe2)2(L)2] (L = THF or 0.5 DME), resulted in the formation of the cyclization product 4,7‐bis(dimethylamino)indene (21). Deprotonation with n‐butyllithium, followed by the reaction of the resulting substituted indenyllithium reagent 22 with ZrCl4, gave the metallocene [4,7‐bis(dimethylamino)indenyl]2ZrCl2 (23). The reaction of 22 with ZrCl3Cp furnished the complex [4,7‐bis(dimethylamino)indenyl]CpZrCl2 (24). Fulvene 16, as well as the metallocene dichlorides 23 and 24, were characterized by X‐ray diffraction. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Different Coordination Modes of the Polyfunctional Ylide Ph3P=C(H)C(O)CH2C(O)OEt: C‐ vs. O,O′‐Bonding in PdII, PtII and AuI Complexes
Authors: Carbó Marta , Falvello Larry R. , Navarro Rafael , Soler Tatiana , Urriolabeitia Esteban P. 
Published: April 2004

AbstractTreatment of the polyfunctional ylide Ph3P=C(H)C(O)CH2COOEt (1) with the solvated complexes [M(C∧X)(THF)2]ClO4 gave the O,O′ derivatives [M(C∧X)(Ph3PCH2C(O)=C(H)−C(=O)OEt‐κ‐O,O′]ClO4 [M(C∧X) = Pd(C6H4CH2NMe2) (2), Pd(CH2C9H6N) (3), Pd(NC5H4‐2‐C6H4) (4), Pd(NC13H8) (5), Pd[(S)−C6H4C(H)MeNMe2] (6), Pt[o‐CH2C6H4P(o‐tol)2] (7), Pd[o‐CH2C6H4P(o‐tol)2] (8), and Pd(C6F5)(SC4H8) (9)]. During the reaction, one proton of the methylene unit is transferred to the ylidic carbon, which is transformed into a phosphonium group generating the zwitterion [Ph3PCH2C(O)=C(H)−C(=O)OEt], which coordinates to the metal center as an O,O′‐chelating ligand. Treatment of 1 with [AuCl(SC4H8)] or [Au(PPh3)(OCMe2)]ClO4 gave [AuCl{C(H)(PPh3)C(O)CH2COOEt}] (10) or [Au{C(H)(PPh3)C(O)CH2COOEt}(PPh3)]ClO4 (11), in which the ylide is C‐bonded. The X‐ray crystal structures of complexes 2a, 9 and 10 have been determined. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Syntheses, Structures, Bonding and Photoelectron Spectra of “Push‐Pull”‐Substituted P‐[2,6‐Bis(trifluoromethyl)phenyl]‐σ2λ3‐iminophosphanes
Authors: Miqueu Karinne , Sotiropoulos Jean‐Marc , Pfister‐Guillouzo Genevieve , Rudzevich Valentyn L. , Gornitzka Heinz , Lavallo Vincent , Romanenko Vadim D. 
Published: April 2004

Abstractσ2λ3‐“Push‐pull” iminophosphanes Arf−P=N−R, bearing an electron‐acceptor substituent at phosphorus [Arf = 2,6‐bis(trifluoromethyl)phenyl] and a donor group at nitrogen (R = tBu, NMe2), have been synthesized and characterized by NMR spectroscopy and X‐ray analysis. Density functional calculations [B3LYP/6‐311G(d,p)] have been carried out on different iminophosphanes: HP=NH (1), ArfP=NH (2), ArfP=NSiMe3 (3), ArfP=NtBu (4), HP=NNMe2 (5) and ArfP=NNMe2 (6) in order to determine the electronic effect of the Arf substituent and the influence of the donor group R on the stability of the monomeric species. A comparison of the theoretical results and UV photoelectron spectroscopy data for the iminophosphanes 4 and 6 is presented. Theoretical and experimental data suggest that for all iminophosphanes under investigation the π‐system of the Arf group is almost orthogonal to the πP=N system, preventing any stabilizing interaction between the πP=N and the π*b1(aryl) orbitals previously observed for the ArfPH− anion. Here, the Arf substituent effect is mainly steric. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Tuning the Stoichiometry of Lanthanide Complexes with Calixarenes: Bimetallic Complexes with a Calix[6]arene Bearing Ether‐Amide Pendant Arms
Authors: Ramírez Flor de María , Charbonnière Loïc , Muller Gilles , Bünzli Jean‐Claude G. 
Published: April 2004

AbstractA de‐tert‐butylated calix[6]arene (A6L6) fitted with six ether‐amide pendant arms was synthesized and characterized in solution. NMR spectroscopic data point to the six phenoxide units adopting an average D6h conformation on the NMR time scale. According to MM3 molecular mechanics, and MOPAC quantum mechanical calculations, A6L6 is a ditopic ligand featuring two nonadentate coordination sites, each built from three pendant arms, and extending in opposite directions with one above, and the other under the main ring. A6L6 reacts with LnIII ions (Ln = La, Eu) in acetonitrile to successively form 1:1 and 2:1 complexes. The isolated EuIII 2:1 complex is luminescent (quantum yield: 2.5% in acetonitrile, upon ligand excitation). In the solid state, the luminescence decay is bi‐exponential, with lifetimes equal to 1.66 and 0.46 ms (upon direct metal excitation), pointing to the presence of two differently coordinated metal ions, one with essentially no bound water molecules, and the other one with two ligated water molecules. According to molecular mechanics calculations, the more stable isomer is indeed asymmetric with two nine‐coordinated metal ions. Both EuIII ions are bound to three bidentate arms, and one monodentate triflate anion, but one metal ion completes its coordination sphere with two phenoxide oxygen atoms, and the other one with two water molecules, consistent with IR spectroscopic and luminescence data. In acetonitrile solution, the two metal ion sites become equivalent, and the relatively long lifetime (1.35 ms) is indicative of a coordination environment free of water molecules. This work demonstrates, that the stoichiometry of lanthanide complexes with calixarenes can be tuned by a suitable choice of the narrow and/or wide rim substituents. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Synthesis and Luminescence Properties of New Dinuclear Complexes of Lanthanide(III) Ions
Authors: Patroniak Violetta , Baxter Paul N. W. , Lehn Jean‐Marie , Hnatejko Zbigniew , Kubicki Maciej 
Published: April 2004

AbstractAs a result of coordination of the ligand L, containing two tridentate binding units, to samarium(III), europium(III), terbium(III), and dysprosium(III) ions, new dinuclear architectures containing two ions with coordination number 9 were formed. The structures of the complexes have been assigned on the basis of their solution spectroscopic and microanalytical data, and confirmed by X‐ray crystallography in the case of the europium(III) complex 2. The structural analysis of the dinuclear complex 2 showed the presence of two europium centers [Eu(1) and Eu(2)] and four ligands L. Each europium ion is coordinated by 9 donor atoms with typical Eu−N and Eu−O distances. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Synthesis, Crystal Structure and Magnetic Properties of A New Thiazolyl‐Substituted Nitronyl Nitroxide and Its Copper(II) Complexes
Authors: Wang Li‐Ya , Li Li‐Cun , Liao Dai‐Zheng , Jiang Zong‐Hui , Yan Shi‐Ping 
Published: April 2004

AbstractA new building block for molecule‐based magnetic materials — thiazole‐substituted nitronyl nitroxide NIT2‐thz [1, NIT2‐thz = 4,4,5,5‐tetramethyl‐2‐(2′‐ thiazolyl)imidazolin‐1‐oxyl 3‐oxide] and its copper(II) complexes [Cu(NIT2‐thz)2(N3)2] (2) and [CuCl2(NIT2‐thz)2] (3) — have been synthesized and characterized structurally and magnetically. Compound 1 is found to contain two crystallographically independent molecules; the shortest contact between nitroxide groups is 4.900 Å. Both 2 and 3 are mononuclear complexes, in which the copper(II) centers are hexacoordinate. In complex 2, the copper(II) ion has an elongated octahedral geometry, but complex 3 has a rare compressed‐octahedral coordination sphere. Magnetic susceptibility data for compounds 1−3 have been measured in the range 5−300 K. There are ferromagnetic interactions (J = 10.13 cm−1) between the CuII ions and the radicals of 2, and antiferromagnetic interactions (J = −8.17 cm−1) between the CuII ions and the radicals of 3. The magnetic properties of complexes 2 and 3 are discussed in connection with their crystal structures. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
[Ni(C4H13N3)2]3(Sb3S6)2: The First Structure Containing Isolated Heterocyclic [Sb3S6]3− Anions
Authors: Kiebach Ragnar , Studt Felix , Näther Christian , Bensch Wolfgang 
Published: April 2004

AbstractThe novel thioantimonate(III) compound [Ni(dien)2]3(Sb3S6)2, which was synthesised under solvothermal conditions, contains isolated [Sb3S6]3− anions. In the X‐ray crystal structure, isolated cyclic [Sb3S6]3− anions occupy a boat‐like conformation and two different isomeric [Ni(dien)2]2+ cations are arranged in separate stacks. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
The First Structurally Authenticated Organomercury(1+) Thioether Complexes − Mercury−Carbon Bond Activation Related to the Mechanism of the Bacterial Enzyme Organomercurial Lyase
Authors: Wilhelm Michaela , Deeken Stefan , Berssen Eva , Saak Wolfgang , Lützen Arne , Koch Rainer , Strasdeit Henry 
Published: April 2004

AbstractThe new compounds [MeHg([9]aneS3)](BF4) (1), [MeHg([12]aneS3)](BF4) (2), and [(MeHg)2([14]aneS4)](BF4)2 (3) have been prepared and their crystal structures determined. In 1, the thioether acts as a tridentate ligand [Hg−S 2.611(2)−2.768(2) Å] and thus the metal atom is tetrahedrally coordinated, which is rare in organomercury chemistry. Temperature‐dependent 1H and 13C NMR spectra showed that this coordination is retained in acetonitrile solution. In crystalline 2 and 3, linear‐coordinated HgII occurs with Hg−S bond lengths of 2.441(4) and 2.425(2) Å. [MeHg([9]aneS3)]+ was found to be stable towards ligand substitution by CF3SO3− in dimethyl sulfoxide, whereas the thioether was partly displaced by CF3CO2− and completely by CH3CO2−. Protonolysis by the very strong Brønsted acid CF3SO3H in [D3]nitromethane transformed the methanido ligand into methane. The degree of Hg−C bond cleavage was ca. 25% for the four‐coordinate [MeHg([9]aneS3)]+ after 1 h, whereas no reaction was observed for two‐coordinate [MeHg(SEt2)]+ or MeHgCl under similar conditions even after 24 h. The product Hg2+ was trapped as [Hg([9]aneS3)2]2+, which is a six‐coordinate complex, as shown by a crystal structure analysis of [Hg([9]aneS3)2](BF4)2·2 CH3CN. Quantum chemical calculations [MP2/SDD + SDD ECP Hg, 6‐31+G(d,p) other elements] confirmed that hydrogen transfer activation barriers are significantly lower for “high”‐coordinate (CN > 2) complexes. Hg−C bond activation by the enzyme organomercurial lyase is possibly also based on multiple (cysteinyl) sulfur ligation. We propose a hypothetical reaction mechanism that involves an OH‐containing amino acid side chain or a water molecule simultaneously serving as a proton acceptor (from Cys−SH) and donor (to R− of RHg+). This mechanism is supported by quantum chemical calculations on a model system. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
A New Dichroic, Nitroso‐Bridged Complex of Rhenium: Di‐μ2‐chloro[μ2‐(η2‐N,O)‐N,N‐dimethyl‐4‐nitrosoaniline]bis[tricarbonylrhenium(I)]
Authors: Wilberger Roland , Krinninger Christoph , Piotrowski Holger , Mayer Peter , Lorenz Ingo‐Peter 
Published: April 2004

AbstractThe dimeric μ2‐amino‐phenoxy complexes of rhenium [(CO)3Re(μ2‐O∩NH2)]2 (1) do not react with the C‐nitroso compounds R−C6H4NO [R = NMe2 (2), H (2′)] in the presence of AlCl3 by a condensation reaction to give the desired azo dye complexes [(CO)3Re(μ2‐O∩N=NC6H4R)]2. Instead, they react to give the novel neutral η2‐N,O‐bridged C‐nitroso complexes [{CO)3ReCl}2ONC6H4R] (3, 3′) by means of a substitution reaction. Both complexes yield golden gleaming crystals, and their solutions are deeply blue (3) or violet (3′) due to the broad UV/Vis absorption at λ = 617 (3) and 505 nm (3′). Single crystals of 3, 3′ show nonlinear optical properties, they are dichroic and have a red and blue (3) or violet and green (3′) side. The molecular structures of 3, 3′ have been determined by single‐crystal X‐ray analyses. Both compounds contain two face‐joined octahedra, with two chloro and the NO ligands as bridges. The C‐nitroso groups together with the NC2 moiety of NMe2 (3) lie almost exactly within the symmetry plane of the molecules. Both the N atoms of 3 have a trigonal‐planar geometry. 3 and 3′ are the first single, neutral and dinuclear C‐nitroso complexes with the rare non‐assisted μ‐(η2‐N,O) bridge and only single atoms as additional bridges. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
A New Route to Cationic Half‐Sandwich Ruthenium(II) Complexes with Chiral Cyclopentadienylphosphane Ligands
Authors: Doppiu Angelino , Salzer Albrecht 
Published: April 2004

AbstractOptically active cyclopentadienyl‐linked phosphane ligands Ln of general formula C5H5CH2CH(R)PR′2 (R = Ph, R′ = Ph, L1; R = Ph, R′ = Cy, L2; R = mesityl, R′ = Ph, L3) and C5H5CH(R)CH2PPh2 (R = Cy, L4; R = Bzl, L5) are synthesised by ring‐opening reactions of 1‐R‐spiro[2.4]hepta‐4,6‐dienes (R = Ph, Cy, mesityl, benzyl), with lithium phosphides LiPR′2 (Ar = Ph, Cy). Reaction of the ligands Ln with [RuH(η5‐C7H11)2][BF4] in acetonitrile at reflux affords the bis(acetonitrile) ruthenium(II) complexes [Ru(η5‐C5H4(C2H3R)PR′2‐κP)(CH3CN)2][BF4], in which the ligands are coordinated to the metal through the cyclopentadienyl and the phosphane moieties forming a chelate, in almost quantitative yields. The complexes are active catalysts in the redox isomerisation of geraniol affording chiral citronellal but with low enantioselectivity. They also catalyze an aldol‐type C−C coupling reaction between 3‐buten‐2‐ol and benzaldehyde affording almost racemic 4‐hydroxy‐3‐methyl‐4‐phenyl‐2‐butanone with good diastereoselectivity (syn/anti ratio up to 77:23). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Synthesis, Crystal Structures and Electrical Conductivities of the Ionic Liquid Compounds Butyldimethylimidazolium Tetrafluoroborate, Hexafluorophosphate and Hexafluoroantimonate
Authors: Kölle Philipp , Dronskowski Richard 
Published: April 2004

AbstractThe crystal structures of three very low‐melting ionic liquid (IL) salts containing the 1‐butyl‐2,3‐dimethylimidazolium cation and the fluoro anions BF4−, PF6− and SbF6− are reported. These are considered model compounds for ambient temperature ionic liquids, which are currently being explored as solvents for various types of synthetic reactions. All three compounds adopt significantly different structures in the solid state, highlighting the influence of counterion size in a series comprising a common cation. The crystal structures are discussed with respect to the possible existence of polar and non‐polar domains, which are considered to be involved with the solvation of polar and non‐polar substrates. The melting points of all three compounds are within the range 40−45 °C. A comparative measurement of conductivities of the molten salts in the vicinity of 20−50 °C has been made, including the new IL 1‐allyl‐2,3‐dimethylimidazolium tetrafluoroborate and the widely applied 1‐butyl‐3‐methylimidazolium tetrafluoroborate (BMIMBF4). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Inclusion Complexes of the Bicyclic Aryl‐Substituted Sulfur‐Nitrogen Compounds Ar−CN5S3 with Fluorocarbon and Hydrocarbon Aromatics
Authors: Knapp Carsten , Lork Enno , Mews Rüdiger , Zibarev Andrey V. 
Published: April 2004

AbstractInclusion compounds with a stoichiometry of 2:1 were prepared from 7‐Ar‐1λ4,3λ4,5λ4‐trithia‐2,4,6,8,9‐pentaazabicyclo[3.3.1]nona‐1(9),2,3,5,7‐pentaenes Ar−CN5S3 and hexafluorobenzene (Ar = C6H5, 4‐CH3C6H4, 4‐C6H5C6H4 and 2,6‐F2C6H3) and toluene (Ar = C6F5), by crystallization of the bicycles from the corresponding aromatics. Similar to the pure host compounds, the bicycles in the inclusion compounds form centrosymmetric dimers. The packing of the dimers in the pure host compounds is dominated by the interaction of the substituents at the aryl groups, and in the inclusion compounds by the interaction of the host and guest. The parallel‐displaced arrangement of the aromatic rings of the host and guest is typical of non‐covalent π‐stacking interactions of the arene‐polyfluroarene type. The inability of benzene (in contrast to hexafluorobenzene) to form an inclusion compound with the title bicycle (Ar = C6H5) indicates that inclusion is driven by π‐stacking interactions of the arene‐polyfluoroarene type. Crystallization of the title bicycle (Ar = C6H5) from a 1:1 molar mixture of benzene and hexafluorobenzene gave the same inclusion compound as the crystallization from pure hexafluorobenzene. This can be considered as molecular recognition based on π‐stacking interactions. The compounds prepared provide the first example of aromatic units bearing extremely sterically demanding polyheteroatom bicyclic substituents involved in non‐covalent arene‐polyfluoroarene π‐stacking interactions. Attempts to prepare inclusion compounds with octafluoronaphthalene and decafluorobiphenyl, as well as co‐crystals of para‐tolyl‐ and pentafluorophenyl‐substituted bicycles, failed. The origin of the 2:1 stoichiometry and the lack of inclusion in the case of C12F10 and C10F8 are discussed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Optimal allocation of tie points in radial distribution systems using a genetic algorithm
Authors: Haghifam M.‐R. 
Published: April 2004

AbstractFor reliability enhancement of radial distribution systems, normally open tie switches are located in feeders. Using tie switches and sectionalizers, the configuration of feeders can be changed in fault conditions for supplying customers from other routes. This is called load restoration in radial distribution systems. In this paper, it is shown that reliability and success of load restoration have a connection with location and number of tie switches. Also, a novel approach for optimal determination of the number and location of tie switches using a genetic algorithm is proposed. In the optimization procedure, load importance using fuzzy membership functions, cost of energy not supplied and cost of tie switches are considered. The effectiveness of the proposed method is shown by simulation results in a radial distribution network.