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Benzene Molecules (benzene + molecule)
Selected AbstractsDynamics of molecules in crystals from multi-temperature anisotropic displacement parameters.ACTA CRYSTALLOGRAPHICA SECTION A, Issue 5 2000The temperature evolution of atomic anisotropic displacement parameters (ADP's) of perdeuterobenzene and of urea in the temperature range between 12 and 123,K is investigated in terms of the model presented in paper I. For the benzene molecule, the temperature-dependent contributions to the ADP's are well described by three molecular librations and three molecular translations. For the urea molecule, the analysis revealed a low-frequency high-amplitude normal mode (~64,cm,1), which combines out-of-plane deformations of the NH2 groups with molecular libration. The pyramidalization motion allows the hydrogen-bonding pattern to be retained quite well, whereas this pattern is heavily distorted in the higher-frequency molecular librations. The results presented for urea go a step beyond those obtainable in a conventional rigid-body or segmented-rigid-body analysis because they show how correlations of atomic displacements in molecular crystals can be determined from the temperature evolution of ADP's. For both molecules, the analysis reveals temperature-independent contributions to the ADP's accounting for the high-frequency internal vibrations. It is the first time that such contributions have been extracted directly from single-crystal diffraction data for light atoms like hydrogen and deuterium as well as for heavier atoms like carbon, nitrogen and oxygen. These contributions agree well with those calculated from independent spectroscopic information. [source] Sodium Cation Migration Above the Diimine ,-System of Solvent Coordinated dpp-BIAN Sodium Aluminum Complexes (dpp-BIAN=1,2-Bis[(2,6-diisopropylphenyl)imino]acenaphthene)CHEMISTRY - A EUROPEAN JOURNAL, Issue 15 2007Herbert Schumann Prof. Abstract The reactions of the disodium salt of the 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene (dpp-BIAN) ligand with one equivalent of Me2AlCl in diethyl ether, toluene, and benzene produced the complexes [Na(Et2O)2(dpp-BIAN)AlMe2] (1), [Na(,6 -C7H8)(dpp-BIAN)AlMe2] (2) and [Na(,6 -C6H6)(dpp-BIAN)AlMe2] (3), respectively. Recrystallization of 1 from hexane afforded solvent-free [{Na(dpp-BIAN)AlMe2}n] (4) or [Na(Et2O)(dpp-BIAN)AlMe2] (5) depending on the temperature of the solvent. The molecular structures of 1,5 have been determined by single-crystal X-ray diffraction. The sodium cation coordinates either one of the naphthalene rings (1) or the diimine part of the dpp-BIAN ligand (2,5). In the complexes 2 and 3, the sodium cation additionally coordinates the toluene (2) or benzene molecule (3) in an ,6 -fashion. [source] High-Electron-Density C6H6 Units: Stable Ten-,-Electron Benzene ComplexesCHEMISTRY - A EUROPEAN JOURNAL, Issue 10 2005Martin Diefenbach Dr. Abstract The first stable benzene molecule with ten , electrons is predicted. Stability is achieved through barium atoms acting as an electron-donating "matrix" to C6H6 in the inverted sandwich complex [Ba2(C6H6)]. The bis(barium)benzene complex has been computed at the density functional level of theory by using the hybrid functional mPW1PW91. Ab initio calculations were performed by using the coupled-cluster expansion, CCSD(T). Nucleus independent chemical shift (NICS) indices imply distinct aromatic character in the benzene ring of bis(barium)benzene. The D6h -symmetric structure with a 1A1g electronic ground state represents a thermochemically stable, aromatic benzene molecule with four excess , electrons, stabilised by two barium ions. A possible molecular wire, built up from Ba end-capped thorium,benzene "sandwiches", is discussed. [source] Reactions of platinum cluster ions with benzeneRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 12 2006Hongtao Liu In this work, the cation and anion products of the reactions between platinum clusters produced by laser ablation and the benzene molecules seeded in argon have been studied using a high-resolution reflectron time-of-flight mass spectrometer (RTOFMS). The dominant cation products are [C6nH6n,,,k]+ and [Ptm(C6H6)n]+ complexes, while the dominant anion products are dehydrogenated species, [C6H5PtH],, [PtC12Hk], and [PtmC6H4,·,·,·,(C6H6)n],, etc. Some important intermediate structures ([PtC6H6]+, [Pt(C6H6)2]+, [Pt2(C6H6)3]+, [C6H5PtH],, [Pt2C6H4],, [Pt3C6H4], and [Pt4C6H4],) have been analyzed using density functional theory (DFT) calculations. Different reaction mechanisms are proposed for platinum cluster cations and anions with benzene, respectively. Copyright © 2006 John Wiley & Sons, Ltd. [source] C,H..., interactions in cocrystals of bis(trimethylsilyl)acetylene and diphenylacetylene with benzeneACTA CRYSTALLOGRAPHICA SECTION C, Issue 4 2010Frank Meyer-Wegner We present here the crystal structures of two acetylene derivatives cocrystallized with benzene, namely bis(trimethylsilyl)acetylene benzene solvate, C8H18Si2·C6H6, (I), and diphenylacetylene benzene solvate, C14H10·C6H6, (II). In (I), both molecules belong to the symmetry point group C2h and are located about special positions with site symmetry 2/m. In (II), both molecules show crystallographic inversion symmetry. In both structures, there are C,H..., contacts between aromatic H atoms and the ,-electrons of the triple bond. In addition to these, in (II) there are C,H..., contacts between aromatic H atoms and the ,-electron cloud of the benzene molecules. [source] A benzene-rich pseudopolymorph of bis[,-1,3-bis(pentafluorophenyl)propane-1,3-dionato]-,3O,O,:O,;,3O:O,O,-bis{aqua[1,3-bis(pentafluorophenyl)propane-1,3-dionato-,2O,O,]nickel(II)} benzene tetrasolvateACTA CRYSTALLOGRAPHICA SECTION C, Issue 11 2009Akiko Hori The title complex comprises two Ni2+ ions, four fluorinated ligands and two water molecules in a centrosymmetric dinuclear complex. This compound was crystallized from benzene,CH2Cl2, and two types of crystals, viz. the title benzene tetrasolvate, [Ni2(C15HF10O2)4(H2O)2]·4C6H6, (I), and the previously reported benzene disolvate, [Ni2(C15HF10O2)4(H2O)2]·2C6H6, (II) [Hori et al. (2009). Bull. Chem. Soc. Jpn, 82, 96,98], were obtained as pseudopolymorphs. In the crystal structure of (I), the four benzene solvent molecules interact closely with all the pentafluorophenyl groups of the complex through arene,perfluoroarene interactions. The molecular structures of the two compounds show essentially the same conformation, although the benzene molecules are accommodated in a columnar packing in (I), while they are isolated from each other in (II). [source] Assembly of a two-dimensional layer structure with 1,4-bis(1H -benzimidazol-1-ylmethyl)benzene dihydrate via hydrogen bonds and ,,, interactionsACTA CRYSTALLOGRAPHICA SECTION C, Issue 3 2008Chuan-Mei Wu In the title compound, C22H18N4·2H2O, the organic fragment lies across a centre of inversion in the P21/n space group. The water molecules form C(2)-type hydrogen-bonded chains which are linked to the 1,4-bis(1H -benzimidazol-1-ylmethyl)benzene molecules through O,H...N hydrogen bonds, forming sheets reinforced by ,,, stacking interactions between the aromatic rings within the layers. [source] Crystal Structure of an Octanuclear Sandwich Cluster of Silver(I) and 4,4,-Bis(2,5-dimethylstyryl)biphenyl,CHINESE JOURNAL OF CHEMISTRY, Issue 9 2006Shu-Qin Liu Abstract Reaction of the oligo(phenylenevinylene) 4,4,-bis(2,5-dimethylstyryl)biphenyl (bdb) with CF3CO2Ag in benzene gave a novel octanuclear sandwich cluster [Ag8(bdb)2(C6H6)2(CF3CO2)8]·2C6H6 (1). The clusters are packed on each other through strong ,-, interactions to form 1D ,brick, chains, between which the solvated benzene molecules are located. TG analysis showed that cluster 1 could completely liberate the guest benzene molecules at 105 °C and the coordinated benzene molecules at 180 °C. In solid state, cluster 1 exhibits fluorescence, and the emission band is red-shifted compared with that of free ligand bdb. [source] | ||||||||||||||||||||||