十二氢十二硼酸双［π－芳烃－π－环戊二烯基铁］的紫外－可见光谱及Mossbauer参数

十二氢十二硼酸双［π－芳烃－π－环戊二烯基铁］的紫外－可见光谱及Ｍｏｓｓｂａｕｅｒ参数胡培植，季立才，孙绍发，张伦（武汉大学化学系，武汉４３００７２）祁守仁（华中师范大学物理系，武汉４３００７０）作者先前合成了一系列闭式十二氢十二硼酸双［π－芳烃－π...     

含氧酸离子RO4n-中的p-dπ配键

引用对ＲＯ＾ｎ－４进行ＣＮＤＯ计算结果定量说明Ｒ－Ｏ键中存在较强的－ｄπ配键，并讨论了ｐ－ｄπ配键密切相关的无机含氧酸及其盐的热稳定性，含氧酸的酸性及ＲＯ＾ｎ－４离子聚合作用。     

低维金属固体化合物的能带结构及化学键研究──（Ⅰ）低维固体的离域d－pπ键与导电性

通过对一系列层状及链状金属化合物能带结构的计算和理论分析，指出其分子结构的低维性是导致金属原子与主族桥原子间离域ｄ－ｐπ键的存在的主要原因，并阐述了其所形成的ｄ－ｐπ（π）能带的性质。通过对该能带的研究，建立了以ｄ电子数判断固体导电性的简便方法，阐明了电荷转移现象及其对导电性的影响，并指出了ｄ电子巡游性的本质。     

^3△,^3Π,^3Σ＋Ni—CO分子簇的从头算研究

用从头算研究了ｄ空穴位置不同对Ｎｉ－ＣＯ成键机制的影响。结果表明，Ｎｉ－ＣＯ键中σ／π授受作用的相对强弱，取决于Ｎｉ－ＣＯ簇所处的能态。σ空间电子云较π空间电子云弥散，因而Ｎｉ－ＣＯ簇的稳定性与σ空间电子云的排斥密切相关。随着Ｎｉ４ｐσ轨道上电子占据数的增加，Ｎｉ－ＣＯ稳定性减弱。比较了分子簇Ｎｉ－ＣＯ与ＮｉＣＯ分子及ＣＯ／Ｎｉ化学吸附体系之间的性质。     

多功能D-π-A染料体系LB膜的研究进展

D－π－A染料体系容易沿着π－共轭链发生分子内电子转移,使\其具有优良的二介非线性光学性质和光电转换性质;同时对它进行恰当的分子修饰能使其具有导电性和离子选择性,本文对D－π－A染料体系LB膜的发展现状及其应用领域进行了综述。重点介绍了在二阶非线性光学和光电转换等领域的应用研究。     

四元硼氮环成键的研究

在４－３１Ｇ基组水平上，对四元硼氮环做了ＳＣＦ－ＭＯ从头算．根据计算结果，由原子的轨道集居以及σ和π电子的分布，讨论了硼原子与氮原子间的成键情况．结果表明，硼有形成多中心σ键的倾向，且环上π电子极化是指向硼的，同时，硼和氮原子上加氢有利于环的稳定．     

分子晶体中的几种分子间相互作用

描述了ＨＥＫ－ＤＤＱ，［Ｃｏ（Ｃ_５Ｈ_５）_２］［Ｎｉ（ｄｍｉｔ）_２］，ＢＢＢＴ－ＤＴＴ三个晶体结构中的π…π；Ｓ…Ｓ；Ｂｒ…Ｂｒ分子间相互作用，讨论了分子晶体中的分子间相互作用的材料化学意义。     

含氧酸离子RO_4~(n-)中的p-dπ配键

引用对ＲＯｎ－４（Ｒ＝Ｃｌ，Ｓ，Ｓｅ，Ｔｅ，Ｐ，Ｓｉ）进行ＣＮＤＯ计算结果定量说明Ｒ—Ｏ键中存在较强的ｐｄπ配键，并讨论了与ｐｄπ配键密切相关的无机含氧酸及其盐的热稳定性、含氧酸的酸性及ＲＯｎ－４离子的聚合作用。     

分子晶体中的几种分子间相互作用

描述了ＨＥＫ－ＤＤＱ，（Ｃｏ（Ｃ５Ｈ５）２（Ｎｉ（ｄｍｉｔ）２）ＢＢＢＴ－ＤＴＴ三个晶体结构中的π．．．π，Ｓ．．．Ｓ；Ｂｒ．．．Ｂｒ分子间相互作用，讨论了分子晶体中的分子间相线作用的材料化学意义。     

脲衍生物型手性固定相拆分氟西汀对映体

利用脲衍生物型手性色谱柱拆分药物氟西汀，主要优化了正相分离条件，并讨论了异构体的出峰次序；认为固定相中两个手性中心分别与异构体发生氢键及π－π电子授－受作用，且这两种作用力的强度对不同构型的异构体是不同的，流动相组成主要影响异构体的分析时间。     

Nanoparticles and nanocrystals of a new bidentate nickel(II) complex of N-[ethyl(propan-2-yl)carbamothioyl]-4-nitrobenzamide: synthesis,characterization, and crystal structures

The nickel(II) complex of N-[ethyl(propan-2-yl)carbamothioyl]-4-nitrobenzamide has been synthesized and characterized by Fourier transform-infrared spectroscopy, elemental analysis, nuclear magnetic resonance spectroscopy, and mass spectrometry (atmospheric pressure chemical ionization mass spectrometry). The single-crystal X-ray structures of N-[ethyl(propan-2-yl)carbamothioyl]-4-nitrobenzamide (1) and bis[N-[ethyl(propan-2-yl)carbamothioyl]-4-nitrobenzamide]nickel(II) (2) have been determined from single-crystal X-ray diffraction data. Loss of the N–H proton resonance and the N–H stretching vibration and the shift of the ν_C=O and ν_C=S stretching vibrations confirm formation of the metal complex. These studies show that the metal complex is neutral in cis-configuration. The complex has been used as a single-source precursor for the deposition of nickel sulfide nanocrystals by thermolysis. The nickel sulfide nanocrystals were characterized by X-ray powder diffraction and transmission electron microscopy.     

Synthesis and Characterization of Homoleptic and Heteroleptic Complexes Involving Dithiocarbamates,Triphenylphosphine, and Nickel(II)

Abstract

Six new nickel complexes of two dithiocarbamate ligands (cyfdtc = N-cyclohexyl-N- furfuryldithiocarbamate and bztpedtc = N-benzyl-N-[2-thiophenylethyl]dithiocarbamate) namely, (Ni[cyfdtc]₂) (1), (Ni[bztpedtc]₂) (2), (Ni[cyfdtc][NCS][PPh₃]) (3), (Ni[bztpedtc] [NCS][PPh₃]) (4), (Ni[cyfdtc][PPh₃]₂)ClO₄ (5), and (Ni[bztpedtc][PPh₃]₂)ClO₄ (6) have been prepared and characterized using IR, electronic, and NMR (¹H and ¹³C) spectra. A single crystal X-ray structural analysis was carried out for complex 3 and showed that nickel is in a distorted square planar arrangement with the NiS₂PN chromophore. The shift in ν_C?N of the heteroleptic complexes to higher frequencies compared with the parent complex is assigned to mesomeric delocalization of electron density from the

dithiocarbamate ligand toward the metal atom, which increases the contribution of polar thioureide form in mixed ligand complexes. Electronic spectral studies suggest square planar geometry for the complexes. In the ¹³C NMR spectra, the upfield shift of NCS₂ carbon signal for 3 and 4 from the chemical shift value of 1 and 2 is due to effect of PPh₃ on the mesomeric drift of electron density toward nickel throughout thioureide C?N bond.     

Iron(III), nickel(II) and zinc(II) complexes based on acetophenone-S-methyl-thiosemicarbazone: synthesis,characterization, thermogravimetry,and a structural study

New complexes, [Fe(L)Cl], [Ni(L)], and [Zn(L)C₂H₅OH] (1–3), were synthesized by template reaction of 2-hydroxy-acetophenone-S-methyl-thiosemicarbazone with 2-hydroxy-benzaldehyde. The compounds were characterized by elemental analysis, magnetic measurements, FT-IR, ¹H NMR, UV–visible, and ESI–MS spectra. In these complexes, the ligand is coordinated to the metal ion as dinegatively charged tetradentate chelating agents via the N₂O₂ donor set. The iron(III) and zinc(II) complexes exhibit square pyramidal geometry whereas the nickel(II) complex has a square planar geometry. The crystal structure of 1, determined by X-ray diffraction method, indicates that 1 crystallizes in the monoclinic space group P21/c with Z = 4. Thermal decompositions of the compounds have been investigated using TGA in air.     

Synthesis,crystal structure and magnetic properties of an oxamato-bridged heterobinuclear NiIICuII complex [Ni(cyclam)Cu(opba)]2·3DMSO

An oxamato-bridged heterobinuclear Ni^IICu^II complex [Ni(cyclam)Cu(opba)]₂ · 3DMSO (1) has been synthesized, characterized by elemental analysis, infrared spectra and magnetic susceptibility, where cyclam is 1, 4, 8, 11-tetraazacyclotetradecane and opba is o-phenylenebis(oxamato). The complex crystallizes in the triclinic system, space group P 1 with a = 12.006(3) Å, b = 12.783(3) Å, c = 20.977(5) Å, α = 76.634(4)°, β = 75.172(4)°, γ = 80.818(4)° and Z = 2. According to X-ray crystallographic studies, the four-coordinate copper(II) atom is a slightly distorted planar geometry and is linked to nickel(II) through the exo-cis oxygen atoms of [Cu(opba)]^2?; the six-coordinate nickel(II) center lies in a highly distorted octahedral environment. Magnetic susceptibility measurements of the complex in the temperature range 2–300 K indicate that the heterobinuclear Ni^IICu^II units are coupled antiferromagnetically with J = ?57.38 cm^?1, g _Ni = 2.25 and g _Cu = 2.02.     

THE INTERACTIONS BETWEEN PERIPHERAL AND CENTRAL UNITS IN SUPRAMOLECULAR AND METALLOSUPRAMOLECULAR STRUCTURES: THE CHARACTERIZATION OF SOME MONO-, DI- AND TRINUCLEAR COMPLEXES OF A VICINAL OXIME-IMINE LIGAND

Abstract

The 1:1 molar ratio reaction of p-phenylenediamine with isonitrosoacetylacetone in chloroform led to the formation of the half unit ligand (HL); (1). Two types of the trans octahedral (L)₂Ni 2H₂O complex were characterized; the green molecular complex (2) and the associated supramolecular dark brown complex (3). Molecular association in (3) took place via inter-molecular hydrogen bonding between the amino group of a molecule and the oxygen sites of an adjacent molecule. The 1:1 molar ratio reactions of (2) with the metal acetates M(OAc)₂ (M = divalent nickel, copper or cobalt) produced the self-assembly structure (4) whereby the metal acetate is coordinated to the amino groups of the nickel(II) complex. Reaction of the dinuclear (4) with another metal acetate (1:1 molar ratio) gave the trinuclear terminated structure (5). Similar reactions of (3) with nickel acetate (1:1 or 1:2) led to formation of complexes with metallosupramolecular structures. An antiferromagnetic interaction between the peripheral and central paramagnetic units was observed from those complexes with copper(II) at the peripheral location. In all these cases the metal ions are bridged via the aromatic Schiff-base moiety. The suggested structures of the mono-, di- and trinuclear coordination compounds are in accordance with the analytical, spectral and magnetic moment data.     

Synthesis,crystal structure,and antibacterial activity of two new mononuclear nickel(II) complexes of a NNS Schiff base

Two new mononuclear nickel(II) complexes, [Ni(L)(N₃)] (1) and [Ni(L)₂(NCS)₂] (2), where HL = 2-{[phenyl(pyridin-2-yl)methylidene]amino}benzenethiol, a tridentate Schiff base derived from 2-aminothiophenol and 2-benzoylpyridine, have been prepared and characterized. The syntheses of 1 and 2 have been achieved by the reaction of equimolar amounts of nickel perchlorate and HL in the presence of azide and thiocyanate, respectively. The complexes have been characterized by microanalytical, spectroscopic, single-crystal X-ray diffraction, and other physicochemical studies. Structural studies reveal that 1 and 2 adopt two different geometries, distorted square planar in 1 and octahedral in 2. The two mononuclear complex units are held together by π…π or C–H…π weak intermolecular interactions to develop supramolecular networks in their solid states. The antibacterial activity of 1, 2 and their constituent Schiff base has been tested against some gram(+) and gram(?) bacteria.     

Synthesis and spectral studies on Ni(II) complexes involving N-furfuryl-N-substituted benzyldithiocarbamates and PPh3: Anagostic and C–H…π(chelate) interactions in (N-furfuryl-N-(4-fluorobenzyl)dithiocarbamato-S,S′)(thiocyanato-N)(triphenylphosphine)nickel(II)

Twelve new nickel(II) complexes of functionalized dithiocarabamates [Ni(S₂CNRR')₂](1-6) and [Ni(S₂CNRR')(NCS)(PPh₃)](7-12) [where R=furfuryl; R'=2-hydroxy benzyl (1,7), 3-hydroxy benzyl (2,8), 4-hydroxy benzyl (3,9), 4-methoxy benzyl (4,10), 4-fluoro benzyl (5,11), 4-chloro benzyl (6,12)] have been prepared and characterized by elemental analysis, IR, UV-Vis and NMR (¹H and ¹³C) spectroscopy. IR spectra of the complexes support the bidentate coordination of dithiocarbamate ligands. Electronic spectral studies on complexes 1-12 indicate square planar geometry around the nickel(II) central atom. In the ¹³C NMR spectra, the upfield shift of NCS₂ carbon signal for heteroleptic complex (7-12) compared to homoleptic complexes (1-6) is due to the effect of PPh₃ on the mesomeric drift of electron density toward nickel through thioureide C-N bond. Single crystal X-ray structural analysis of complex 11 confirms that the coordination geometry about the Ni(II) is distorted square planar. A rare intramolecular anagostic interaction C–H^…Ni [Ni???H=2.804 Å] is observed. The packing of complex 11 is stabilized by non-conventional C–H^…S, C–H?F and C–H?π(chelate, NiS₂C) bonding interactions.     

Synthesis,crystal structures and magnetic properties of two new nickel(II) complexes with α-amino acid Schiff base

Two nickel(II) complexes [Ni(napgly)(MeOH)] _n (1) and [Ni(napphe)(H₂O)₂(MeOH)] · H₂O (2), where the tridentate Schiff-base ligands H₂napgly and H₂napphe are condensed from 2-hydroxyl-1-naphthaldehyde with glycine and L-phenylalanine, respectively, were prepared and structurally characterized. In 1, two inversion-related Ni(II) ions were bridged by two O atoms from the phenolate groups of two napgly anions, forming a centrosymmetric dimeric unit which was further linked by carboxylate groups to give a two-dimensional network. Magnetic susceptibility studies performed on the complex revealed anti-ferromagnetic coupling between the metal centers. In 2, the crystal structures of the complex displayed a distorted octahedral coordination geometry in which the ONO-donor Schiff base was bonded to the metal. Intermolecular H-bonds linked the compound into a 2-D layer structure.     

Synthesis,characterisation and X-ray structure of an azido adduct of a tridentate (NNO) Schiff base nickel(II) complex

The tridentate Schiff base 1-(N-salicylideneimino)-2-(N,N-diethyl-aminoethane (HL), derived from the condensation of salicylaldehyde with N,N-diethylethylenediamine, reacted with nickel(II) nitrate and azide to give a mononuclear complex of formula [Ni(L)(N₃)], where HL?=?Et₂N(CH₂)₂NCHC₆H₄(OH). The complex was characterized by spectroscopic and X-ray crystallographic methods. Coordination around nickel(II) is square planar. The molecular and supramolecular structure of the complex is discussed.     

Ni(II) and Cu(II) complexes of new unsymmetrical N2O2 Schiff bases derived from 3-(2-aminobenzylimino)-1-phenylbutan-1-ol: synthesis,structure, antibacterial properties,and electrochemistry

Two new N₂O₂ unsymmetrical Schiff bases, H₂L¹ = 3-[({o-[(E)-(o-hydroxyphenyl)methylideneamino]phenyl}methyl)imino]-1-phenyl-1-buten-1-ol and H₂L² = 3-[({o-[(E)-(2-hydroxy-1-naphthyl)methylideneamino]phenyl}methyl)imino]-1-phenyl-1-buten-1-ol, and their copper(II) and nickel(II) complexes, [CuL¹] (1), [CuL²] (2), [NiL¹] (3), and [NiL²] (4), have been synthesized and characterized by elemental analyses and spectroscopic methods. The crystal structures of these complexes have been determined by X-ray diffraction. The coordination geometry around Cu(II) and Ni(II) centers is described as distorted square planar in all complexes with the CuN₂O₂ coordination more distorted than the Ni ones. The electrochemical studies of these complexes indicate a good correlation between the structural distortion and the redox potentials of the metal centers. The ligand and metal complexes were also screened for their in vitro antibacterial activity.