共查询到20条相似文献,搜索用时 15 毫秒
1.
A. I. V'yugin E. V. Antina D. V. Chernyshev G. A. Krestov 《Russian Chemical Bulletin》1992,41(7):1190-1192
Features of the solvation of zinctetraphenylporphyrin (ZnTPP) in benzene, toluene,ortho-, meta-, andpara-xylenes were studied by a thermogravimetric method. The temperature ranges of the stability and the compositions of the corresponding specific - complexes were determined from the results of the thermogravimetric investigation of the crystallosolvates of the metalloporphyrin with the solvent molecules, and the energy characteristics of the intermolecular metalloporphyrin—solvent interactions were calculated.Institute of the Chemistry of Nonaqueous Solutions, Russian Academy of Sciences, 153018 Ivanovo. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 7, pp. 1545–1548, July, 1992. 相似文献
2.
《Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy》1981,37(7):505-510
The charge transfer spectra of molecular complexes of chloro substituted p-benzoquinone(4)-chlorimides with aromatic π-donors in cyclohexane have been studied. The interaction of 2,6-dichloro p-benzoquinone with the same set of donors has also been studied. The spectroscopic and thermodynamic data indicate that the complexes are very weak in nature. A comparison of the absorption intensities and formation constants for these complexes shows that the contribution of charge transfer forces are not the only dominant stabilising factors. 相似文献
3.
Three new π-conjugated pyridine ligands with redox-active tetrathiafulvalene (TTF) derivatives, L1-L3, have been synthesized and characterized. The Diels-Alder reaction is the key step for this multistep synthetic strategy. The crystal structures of L1 and L3 have been studied. The electrochemical and spectroscopic properties of these new ligands, as well as the corresponding tricarbonyl rhenium(I) complexes (ReL1(CO)3X, X = Cl, 5; X = Br, 6) have also been investigated. 相似文献
4.
《Tetrahedron》1986,42(22):6269-6276
Electron affinities and electron attachment energies associated with the π* orbitals of several p-alkylanilines (alkyl = Me, Et, i-Pr, and t-Bu) have been determined in the gas phase by electron transmission spectroscopy and have been analyzed by ab initio molecular orbital calculations at the STO-3G and 6-31G levels of basis set. The results lead to the conclusions that (a) the 2A2 negative ion state in toluene lies below the 2B1 state, (b) the 2A2 state is stabilized in toluene relative to benzene by bonding overlap between the ortho carbon (C2(2pπ)) and the Me H(1s) orbitals in the LUMO, (c) the 2B1 state is stabilized on adding Me groups to toluene to form t-butylbenzene through reduced antibonding interactions between C1(2pπ) and Me C(2pπ) orbitals, and (d) the lowest resonance in t-butylbenzene is extensively overlapped with the second resonance and may involve strong mixing of the 2A2 and 2B1 states. 相似文献
5.
V. B. Nazarov V. G. Avakyan T. G. Vershinnikova M. V. Alfimov 《Russian Chemical Bulletin》2000,49(10):1699-1706
Fluorescence of the inclusion complexes with different compositions formed by naphthalene-h8, naphthalene-d8, 2,7-dimethylnaphthalene (DMN), and 2-benzylnaphthalene (BN) with β-cyclodextrin (β-CD) in water was studied. Two types of fluorescence are observed, monomer (MF) and excimer (EF_ fluorescence. The excimer fluorescence of the 2∶2 complex emitted by aggregated light-dispersing crystals forming a precipitate, whereas is the MF is concentrations, EF predominates for the resulting complexes. A proposed structure of the inclusion complexes was derived from MNDO/PM3 semiempirical quantum-chemical calculations. The EF is caused by the structure of the complex, in which both naphthalene molecules are separated by a distance of 4.7 Å: they lie in parallel orientation to each other, whereby one ring is displaced from the other by one-fourth of the length of the naphthalene ring. The complexes of 2,7-DMN and 2-benzylnaphthalene with β-CD do not exhibit EF. For the 2∶2 complex of 2,7-DMN with β-CD, this is due to the fact that the aromatic fragments are removed too far from one another 2-Benzylnaphthalene is unable to form an inclusion complex with β-CD, in whose structure the aromatic fragments inside the cavity could be arranged in parallel planes; instead, it forms a 1∶2 complex with β-CD. 相似文献
6.
The charge-transfer (CT) complexes of some methylated [2.2]para-, multibridged cyclo- and [2.2]indenophanes as π-donors with fluoranil (TFQ) as π-acceptor have been studied spectrophotometrically. The role of the molecular structure of the donors on their Lewis basicities and stability of their CT complexes with TFQ are discussed. Eight pure crystalline complexes were prepared. Their i.r. spectra indicate an increase of the electron density in the TFQ part of the CT complex. 相似文献
7.
《Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy》1989,45(10):985-991
Copper(II) and nickel(II) biguanides and O-alkyl-1-amidinourea can act as donors for the formation of charge transfer (CT) adducts with I2 and tetracyanoquinodimethane (TNCQ) as acceptors. Iodine adducts are characterized both in solid and solution states whereas TCNQ adducts obtain only in solution. Appearance of a broad band at 355 nm for iodine adducts and at 335 nm for TNCQ adducts and shifting of i.r. frequencies support the formation of donor acceptor associates. Elemental analysis establishes 1:1 stoichiometry of the solid adducts. The K and ε values determined by modified Benesi—Hildebrand, Scott and Rose—Drago equations are found to be of the order of 104 and 103 respectively at 298 K in methanol. The solvent effect on the K values is discussed in terms of coupled solute-solute and solute-solvent equilibria. 相似文献
8.
《Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy》1989,45(9):977-979
X-Benzylidenesanthranilic acid molecular complexes with π-acceptors, tetracyanoethylene, 2,3-dichloro-5,6-dicyano-p-benzoquinone and chloranil, have been studied. The intramolecular hydrogen bonding that exists in such compounds greatly inhibits the transition of the nitrogen azomethine n-electrons. The formation constant values and molar extinction coefficients of the p-dimethyl-aminobenzylidenean-thranilic acid-DDQ CT complexes have been determined in CH2Cl2, C2H4Cl2 and CHCl3 in the temperature range 10–30°C. Such CT complexes are of strong n-π type. 相似文献
9.
10.
Li Jia-Qiang Li Wen-Shuang Zhang Wen-Ting Zhu Shu Luo Chu-Yang Liu Wan-Shuang Zhang Li-Ying 《高分子科学》2023,41(8):1261-1268
Chinese Journal of Polymer Science - Thermoplastic polyimides (PIs) with shape memory potential have received growing attention in recent years. In this work, high-performance thermoplastic PIs... 相似文献
11.
Spectrophotometric studies of several substituted benzanilides as electron donors with tetracyanoethylene (TCNE) and 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) as electron acceptors have given results that are consistent with an interpretation of 1:1 charge-transfer (CT) complexes. The nature of interaction as well as the substituent effects on the CT complexation are discussed. 相似文献
12.
Qing-Xiang Liu Xiao-Jun Zhao Xiu-Mei Wu Jian-Hua Guo Xiu-Guang Wang 《Journal of organometallic chemistry》2007,692(25):5671-5679
The oligoether-linked bis-benzimidazolium salt 1,1′-[1,2-ethanediylbis(oxy-1,2-ethanediyl)]bis[(3-secbutyl)benzimidazolium-1-yl]iodide (H2L1 · I2), 1,1′-[1,2-ethanediylbis(oxy-1,2-ethanediyl)]bis[(3-ethyl)benzimidazolium-1-yl]iodide (H2L2 · I2) and 1,1′-[1,2-ethanediylbis(oxy-1,2-ethanediyl)]bis[(3-secbutyl)benzimidazolium-1-yl]hexafluorophosphate (H2L1 · (PF6)2) and their three new mercury(II) and silver(I) complexes containing NHC metallacrown ethers, HgL1 · (Hg2 · I6) (1), HgL2 · I2 (2) and AgL1 · PF6 (3) were prepared and characterized. In the packing diagrams of H2L2 · I2, 1, 2 and 3 benzimidazole ring head-to-tail π-π stacking interactions are observed. 相似文献
13.
Dom JJ van der Veken BJ Michielsen B Jacobs S Xue Z Hesse S Loritz HM Suhm MA Herrebout WA 《Physical chemistry chemical physics : PCCP》2011,13(31):14142-14152
A vibrational assignment of the anaesthetic sevoflurane, (CF(3))(2)CHOCH(2)F, is proposed and its interaction with the aromatic model compound benzene is studied using vibrational spectroscopy of supersonic jet expansions and of cryosolutions in liquid xenon. Ab initio calculations, at the MP2/cc-pVDZ and MP2/aug-cc-pVDZ levels, predict two isomers for the 1?:?1 complex, one in which the near-cis, gauche conformer of sevoflurane is hydrogen bonded through its isopropyl-hydrogen atom, the other in which the same conformer is bonded through a bifurcated hydrogen bond with the fluoromethyl hydrogen atoms. From the experiments it is shown that the two isomers are formed, however with a strong population dominance of the isopropyl-bonded species, both in the jet and liquid phase spectra. The experimental complexation enthalpy in liquid xenon, ΔH(o)(LXe), of this species equals -10.9(2) kJ mol(-1), as derived from the temperature dependent behaviour of the cryosolution spectra. Theoretical complexation enthalpies in liquid xenon were obtained by combining the complete basis set extrapolated complexation energies at the MP2/aug-cc-pVXZ (X = D,T) level with corrections derived from statistical thermodynamics and Monte Carlo Free Energy Perturbation calculations, resulting in a complexation enthalpy of -11.2(3) kJ mol(-1) for the isopropyl-bonded complex, in very good agreement with the experimental value, and of -11.4(4) kJ mol(-1), for the fluoromethyl-bonded complex. The Monte Carlo calculations show that the solvation entropy of the isopropyl-bonded species is considerably higher than that of the fluoromethyl-bonded complex, which assists in explaining its dominance in the liquid phase spectra. 相似文献
14.
A long-lived phosphorescence at room temperature (lifetime>1 s) of aqueous solutions of β-cyclodextrin complexes with naphthalene
and its derivatives was found. The phosphorescence isobserved for aggregated complexes that form in water a light-scattering
suspension, and its low intensity is due to predomination of 2∶2 complexes with efficient excimer fluorescence. Complexes
containing isolated aromatic molecules are assumed to be the centers of fluorescence.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2022–2024, October, 1999. 相似文献
15.
The — complexes of metal tetraphenylporphinates with benzene, toluene, and xylenes were characterized by means of thermogravimetry. The ability of metalloporphyrins to form — complexes with certain -donor molecules depends largely on the -acceptor capacity of the macroheterocycle, and on the peculiarities of the metal—porphyrin coordinative linkage. Stoichiometry, energy parameters, and thermal stability of the - complexes of metalloporphyrins with various aromatic ligands are determined to a great extent by the molecular structure of solvents.Translated fromIzyestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp.850–853, May, 1993. 相似文献
16.
The equilibrium constants [K=anti/syn] of a pair of atropisomers due to restricted rotation about Csp3-Csp2 bond for [2-(2-hydroxynaphthalen-1-yl)-3,3-dimethylindolin-1-yl](4-substituted phenyl)methanone were determined in some solvents. The presence of the effective π-π interaction was demonstrated by the correlation between the equilibrium constants (K) and the substituent effect of the phenyl groups (σp), suggesting that the ‘neutral-type’ interaction is operative. 相似文献
17.
《Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy》1990,46(3):389-396
Nitrofluorenes form π-π complexes with a series of hydrazones both in solution and in the solid state. The properties of the complexes, discussed on the basis of u.v.-vis and FT-i.r. data, suggest the presence of weak interactions, as confirmed by the formation constants and X-ray analysis. The presence of some degree of charge transfer is confirmed by ESR determinations. The X-ray analysis of the complex of benzaldehydediphenylhydrazone with 2,4,7-trinitrofluorenone is also reported. 相似文献
18.
《Journal of organometallic chemistry》2002,641(1-2):208-214
Reaction of fluoranthene with Cr(CO)3Py3/BF3·OEt2 at 25 °C affords a mixture of two isomeric complexes: traces of tricarbonyl(1-5,15-η6-fluoranthene)chromium (3) (coordination to benzene) and, as the major product, tricarbonyl(1-4,15,16-η6-fluoranthene)chromium (2) (coordination to naphthalene). The ratio 3:2 is less than 0.05 according to 1H-NMR of crude product before crystallization. Complex 2 is thermodynamically less stable than 3: at 100 °C in decane or C6D6 for 8 h or at 90 °C in C6F6 for 100 h 2 rearranges irreversibly to 3 via an inter-ring haptotropic shift of the Cr(CO)3 group from the naphthalene moiety to the benzene part of the fluoranthene ligand. NMR evidence for a degenerate reversible haptotropic shift within the naphthalene moiety is absent. The isomers 2 and 3 have been characterized by X-ray structural analysis. 相似文献
19.
Organometallic dithiolene complexes, which were formulated as [Cp*M(dcbdt)] and [Cp*M(dcdmp)] (M = Co, Rh, Ir; Cp* = η5-pentamethylcyclopentadienyl, dcbdt = 4,5-dicyanobenzene-1,2-dithiolate, dcdmp = 2,3-dicyano-5,6-dimercaptopyrazine) were prepared from a low valent Cp*CoI or high valent Cp*MIII species (MIII = CoIII, RhIII, IrIII). The UV-Vis absorption spectral and electrochemical data of them were obtained. The lowest absorption (HOMO-LUMO) energies of them became redshift in order of the Co > Rh > Ir complexes. The reduction potentials suggested that the central metal modifies their LUMO levels. The molecular and crystal structures of [Cp*Co(dcbdt)] (3a), [Cp*Co(dcdmp)] (4a) and [Cp*Rh(dcdmp)] (4b) were determined by X-ray diffraction studies. The cobalt complexes 3a and 4a were monomeric, formally 16-electron complexes and have two-legged piano-stool geometries. The crystal structure of 3a indicated some plane-to-plane intermolecular interactions such as benzene?benzene interaction on the dcbdt ligand and two Cp*?benzene π-π stackings. 4a showed plane-to-plane interaction with a pseudo-4-fold-symmetry arrangement between the pyrazine moieties on the dcdmp ligand. The rhodium complex 4b was dimeric in the crystal to form a criss-cross arrangement and had a three-legged piano-stool geometry, but it was monomerized in solution. The dimer of 3b was observed in the oxidation process of the cyclic voltammogram. 相似文献
20.
L. Kh. Faizullina M. G. Safarov L. V. Spirikhin V. S. Kolosnitsyn Yu. A. Kondrova F. A. Valeev 《Russian Journal of Organic Chemistry》2011,47(6):914-919
Michael reactions of levoglucosenone and its α-bromo and α-iodo derivatives with α,ω-dinitroalkanes were studied under conditions
of chemical and electrochemical generation of base. Procedures were developed for stereospecific fusion of a cyclopentane
ring to α-bromo- and α-iodolevoglucosenones, 2-iodocyclopent-2-en-1-one, and 2-iodocyclohex-2-en-1-one by the action of 2,2-dimethyl-1,3-dinitropropane. 相似文献