Nickel(II) complex with an asymmetric tetradentate Schiff base ligand: synthesis,characterization, crystal structure,and DFT studies

Abstract

A new asymmetric tetradentate Schiff base, bis(5-methoxysalicylidene)-4-methylbenzene-1,2-diamine), H₂L, and its Ni(II) complex were prepared and characterized using elemental analyses (CHN), FTIR, UV–Vis, ¹H NMR, and ¹³C{¹H} NMR spectroscopic techniques, and crystal structures of both were determined by X-ray crystallography. For both ligand and Ni(II) complex, density functional theory calculations to find geometry parameters, IR frequencies, electronic properties, and natural bond orbital analysis (NBO) were done with M062X method and Def2-TZVP basis set. All calculated data are consistent with the experiments. NBO data for the Ni(II) complex show that the main type of transition in UV-Vis is interligand charge-transfer, which is assigned as π-π*.     

Crystal structure and DFT analyses of a pentacoordinated PCP pincer nickel(II) complex

The reaction of NiCl₂ with 1,3‐bis[(diphenylphosphanyl)methyl]hexahydropyrimidine in the presence of 2,6‐dimethylphenyl isocyanide and KPF₆ afforded a new pentacoordinated PCP pincer Ni^II complex, namely {1,3‐bis[(diphenylphosphanyl)methyl]hexahydropyrimidin‐2‐yl‐κN²}(2,6‐dimethylphenyl isocyanide‐κC)nickel(II) hexafluoridophosphate 0.70‐hydrate, [Ni(C₉H₉N)(C₃₀H₃₀ClN₂P₂)]PF₆·0.7H₂O or [NiCl{C(NCH₂PPh₂)₂(CH₂)₃‐κ³P,C,P′}(Xylyl‐NC)]PF₆·0.7H₂O, in very good yield. Its X‐ray structure showed a distorted square‐pyramidal geometry and the compound does not undergo dissociation in solution, as shown by variable‐temperature NMR and UV–Vis studies. Density functional theory (DFT) calculations provided an insight into the bonding; the nickel dsp²‐hybridized orbitals form the basal plane and the nearly pure p orbital forms the axial bond. This is consistent with the NBO (natural bond orbital) analysis of analogous nickel(II) complexes.     

Synthesis and structure of the phosphinophosphide niobocene complex Cp2Nb(PPh2)(PHPh2)

The phosphinophosphido niobocene complex Cp₂Nb(PHPh₂)(PPh₂) (2) was prepared by deprotonation of the cationic diphosphino complex [Cp₂Nb(PHPh₂)₂]Cl (3). Complex 2 is thermally unstable and readily dissociates phosphine to give the ortho-metallated complex Cp₂Nb(PHPhC₆H₄−). Crystal structure determination of 2 supported its formulation as the phosphinophosphido compound. The Nb–P(1) (phosphino) bond length is 2.524(2) Å and Nb–P(2) (phosphido) bond length is 2.610(2) Å.     

钛配合物Cp2TiL,Cp2Ti2Cl2(μ-O)和Cp4Ti4Cl4(μ-O)4的合成与晶体结构研究(Cp=η5-C5H5,L=2,6-吡啶二羧酸盐)

利用溶剂热的方法将Cp2TiCl2(Cp=η5-C5H5)与2,6-吡啶二羧酸钠(L)反应,不同的反应时间得到了2个具有不同晶体空间群的化合物Cp2TiL(1a和1b),而在常温或低温下,Cp2TiCl2或CpTiCl3同羧酸盐或亚胺反应却得到了双核或四核氧桥联的钛化合物。     

(Hexafluorosilicato‐κ2F,F′)bis(1,10‐phenanthroline‐κ2N,N′)zinc(II) methanol monosolvate

The title compound, [Zn(SiF₆)(C₁₂H₈N₂)₂]·CH₃OH, contains a neutral heteroleptic tris‐chelate Zn^II complex, viz. [Zn(SiF₆)(phen)₂] (phen is 1,10‐phenanthroline), exhibiting approximate molecular C₂ point‐group symmetry. The Zn^II cation adopts a severely distorted octahedral coordination. As far as can be ascertained, the title complex represents the first structurally characterized example of a Zn^II complex bearing a bidentate‐bound hexafluorosilicate ligand. A density functional theory study of the isolated [Zn(SiF₆)(phen)₂] complex was undertaken to reveal the influence of crystal packing on the molecular structure of the complex. In the crystal structure, the methanol solvent molecule forms a hydrogen bond to one F atom of the hexafluorosilicate ligand. The hydrogen‐bonded assemblies so formed are tightly packed in the crystal, as indicated by a high packing coefficient (74.1%).     

Synthesis and Crystal Structure of Mn（phen）（PhCOO）2（H2O）

1 INTRODUCTION During the last decade the manganese che- mistry has aroused great interest due to its diverse redox functions of enzymes in photosystem Ⅱ and its specially structural, magnetic and spectroscopic properties[1, 2]. A lot of manganese complexes involving carboxylate ligands have been reported, and their properties been fully explored[3, 4]. The coordination environment of the manganese site in biosystem often consists of oxygen and nitrogen atoms from the carboxylate groups…     

大环镍配合物[Ni(teta)(NCS)2]的合成与结构研究

大环配体由于其独特的配位性能已吸引了广泛的注意,用大环化合物模拟生物功能,是当今大环化学发展的方向之一[1]。大环四胺配体5,7,7,12,14,14-六甲基-1,4,8,11-四氮杂环十四烷(简记为teta)的钴配合物已被用来作为研究维生素B12的模型分子[2],一些teta的配合物也已被陆续报道[3     

Crystal structures and thermodynamic investigations of NaSc(BH4)4 from first‐principles calculations

The double cation borohydride NaSc(BH₄)₄ has a total H₂ content of 12.67 wt.% and has been suggested as a potential candidate for hydrogen storage applications. This study reports first‐principles calculations of the structure and reaction thermodynamics of NaSc(BH₄)₄. The calculations indicate that NaSc(BH₄)₄ is decomposed into a mixture of ScB₂, NaBH₄, and Na₂(B₁₀H₁₀) with H₂ release of 9.3 wt.% at 118 K at a partial pressure of H₂ of 100 bar. Reactant compositions that can destabilize NaSc(BH₄)₄ were evaluated. This effort identified four destabilization reactions that are predicted to have reaction thermodynamics for hydrogen release within the temperature range of 78–109 K. Even though the reactions conclusively produce undesired compounds, such as refractory materials or kinetically stable B₁₂H₁₂‐containing species, the thermodynamic study suggests a direction for improving the thermodynamics of double cation borohydride‐based systems being actively considered for hydrogen storage applications. © 2012 Wiley Periodicals, Inc.     

Crystal Structure and Density Functional Theory Studies of （p-Methoxyphenyl） Thiosemicarbazide

1 INTRODUCTION Recently, the discoveries of antitumor effects ofinorganic complexes, especially of metal complexes,and their applications for curing cancer diseaseshave received increasing attention[1]. As a ligandwith potential S and N donors, thiosem…     

Crystal structure and fluorescence spectrum of the complex [Eu(III)(TTA)3(phen)]

The title complex Eu(III)(TTA)₃(phen) (where TTA = thenoyltrifluoroacetone monoanion; phen = 1,10-phenanthroline) has been synthesized in mixed solvents of acetone and ethanol (1:1 volume ratio) and its crystal structure has been determined by X-ray diffraction. The complex crystals are triclinic, space group P 1 (# 2) with cell dimensions of a = 1.32.41 (2) nm, b = 1.5278(4) nm, c = 0.9755(3) nm, α = 92.49 (2)°, β = 102.57(2)°, γ = 91.62(2)°, V = 1.9268(8) nm³, Z = 2, μ (Mo Ka)= 18.77 cm^?1, D_x=1.720 g/cm³. The coordination geometry of Eu atom is a distorted square antiprism, and the encapsulated structure that can meet the structural requirement of the typical europium luminescent sensor. The fluorescence spectrum suggests that the complex is a strong photoluminescent material.     

Crystal structure and triboluminescence of the [Eu(TTA)2(NO3)(TPPO)2] complex

The crystal structure of [Eu(TTA)₂(NO₃)(TPPO)₂] (I) (TTA = thenoyltrifluoroacetone, TPPO = triphenylphosphine oxide) possessing intense triboluminescence was established by X-ray crystallography. The crystals are triclinic, noncentrocymmetrical: a = 11.047(3) Å, b = 11.794(3) Å, c = 12.537(3) Å; α = 102.635 (4)°, β = 102.088(4)°,γ = 117.765(3)°; space group P1, Z = 1. The central Eu(III) atom coordinates two oxygen atoms of two TPPO molecules at distances of 2.271 Å and 2.282 Å, two oxygen atoms of the nitrate group at distances of 2.478 Å and 2.481 Å, four oxygen atoms of two TTA ions at distances of 2.365 Å, 2.381 Å, and 2.363 Å, 2.371 Å (coordination number is 8). The coordination polyhedron of the Eu(III) atom is a distorted dodecahedron. Possible reasons for spectral differences in the Stark structure of photo-and triboluminescence of I are discussed.     

CpRu(PPh3)2SSiiPr3与SCNR(R=Ph,1-Naphthyl)反应的结构、成键与机理的理论研究

应用密度泛函理论(DFT), 通过CpRu(PH₃)₂SSiⁱPr₃ (Cp＝环戊二烯负离子; ⁱPr＝异丙基)与SCNH模型化反应, 探讨了CpRu(PPh₃)₂SSiⁱPr₃ 与SCNR (R＝苯基, 萘基)的反应机理, 分析了反应所涉及的各相关化合物的结构与成键特征. 反应中首先失去一个膦配体, 生成一个中间体. 该中间体中, 硫原子采取sp²杂化, 硫原子剩余的一个p轨道与金属中心上的d轨道具有相同的对称性, 因而该p轨道上的孤电子对可与金属中心上的d轨道形成π键, 导致Cp环中心, Ru, S1, P和Si原子在同一平面内, 而不是S1, P和Si原子偏离该平面. 计算结果预测, S＝C双键中的p键打开, 生成含金属中心的四元环螯合物一步为反应的决速步骤. 空间位阻的减小、p共轭体系的生成以及螯合环的存在, 是导致该反应热力学有利的重要原因.     

Synthesis, spectroscopic characterization, X-ray structure and DFT calculations of rhenium(III) complex with bis(3,5-dimethylpyrazol-1-yl)methane

[ReCl₃(MeCN)(PPh₃)₂] reacts with bis(3,5-dimethypyrazol-1-yl)methane (bdmpzm) in acetone to give [ReCl₃(bdmpzm)(PPh₃)]. The compound has been studied by IR, UV–Vis spectroscopy and X-ray crystallography. The molecular orbital diagram of [ReCl₃(bdmpzm)(PPh₃)] has been calculated with the density functional theory (DFT) method.     

Synthesis and Crystal Structure of Bis（nitrate）bis（N—n—octyl—α—pyrrolidone）uranyl（Ⅱ）

The crystal structure of the title compound UO2(NO3)2[CH2(CH2)2CONC8H17] was determined by single-crystal X-ray diffraction. Crystal data: triclinic, space group P ī, a = 7.456(2), b = 8.371(2), c = 13.470(3)A, α = 95.66(1), β = 94.64(2), γ = 102.67(2)°, C24H46N4O10U, Mr = 788.68, V = 811.73A3, Dc = 1.613 g/cm3, Z = 1, F(000) = 390, μ = 5.052 mm-1, the final R = 0.0256 and wR = 0.0568 for 2826 observed reflections I>2σ(I). The central uranyl ions are coordinated by six oxygen atoms. Two of them are from the carbonyl groups of N-octyl--pyrrolidone molecules, and the other four from two nitrate groups.     

A new trans-dioxorhenium(V) complex with 4-aminopyridine: synthesis,structure, electrochemical aspects,DFT, and TD-DFT calculations

The reaction of 1?:?4.4?M proportion of cis-[ReO₂I(PPh₃)₂] and 4-aminopyridine (ampy) in acetone–water gives trans-[ReO₂(ampy)₄]I·2H₂O (1a) in 85% yield. 1a has been characterized by C, H, and N microanalyses, FT-IR, UV–vis, ¹H NMR spectroscopy, and molar conductivity. The X-ray crystal structure of 1a reveals an octahedral trans dioxorhenium(V) complex with a “N₄O₂” coordination for rhenium. 1a has an orthorhombic space group C2221 with a?=?17.576(4), b?=?19.370(4), c?=?15.730(4) Å, V?=?5355(2) ų, and Z?=?8. Geometry optimization of the trans-O,O complex, 1a and its cis-O,O analog, 1b performed at the level of density functional theory reveal that 1a is more stable than 1b by 25?kcal M^–1 in the gas phase. The electronic spectrum of 1a was also analyzed at the level of time-dependent density functional theory. Excitation of 1a in methanol at 450?nm leads to a fluorescent emission at 505?nm with a quantum yield (Ф) of 0.04. Electrochemical studies of 1a in acetonitrile show a quasi-reversible Re(V) to Re(VI) oxidation at 0.618?V versus Ag/AgCl. This redox potential matches with the calculated redox potential of 0.621?V versus Ag/AgCl.     

Photoinduced oxygen transfer and double-linkage isomerism in a cis-(NO)(NO2) transition-metal complex by photocrystallography, FT-IR spectroscopy and DFT calculations

Photocrystallographic experiments show that laser exposure of crystals of [Ru(bpy)2(NO)(NO2)](PF6)2 at 90 K produces a double isonitrosyl-nitrito linkage isomer and provide the detailed geometry of the metastable species generated. The analysis indicates that the isomerization is accomplished through an intramolecular redox reaction involving oxygen transfer from the nitro to the nitrosyl group. At 200 K only a single (nitrito) linkage isomer is formed with a U-shaped conformation of the nitrito group rather than the Z conformation observed at 90 K. A mechanism for the isomerization is proposed based on the crystallographic results and FTIR data collected at low temperatures during the isomerization process. The study presents the first structural evidence for double linkage isomerization in transition-metal complexes.     

Synthesis,spectroscopic characterization,X-ray structure and DFT calculations of five-coordinated chlorocopper(II) complex with bis(3,5-dimethylpyrazol-1-yl)methane

The reaction of copper dichloride dihydrate and bis(3,5-dimethylpyrazol-1-yl)methane affords [Cu{H₂C(3,5-Me₂pz)₂}₂Cl]Cl · 3H₂O. The compound has been studied by IR, UV–Vis spectroscopy and X-ray crystallography. The electronic structure of the [Cu{H₂C(3,5-Me₂pz)₂}₂Cl]⁺ cation has been calculated with the density functional theory (DFT) method. The spin-allowed doublet–doublet electronic transitions of [Cu{H₂C(3,5-Me₂pz)₂}₂Cl]⁺ have been calculated with the time-dependent DFT method, and the UV–Vis spectrum of the title compound has been discussed on this basis.     

Synthesis,spectroscopic characterization,X-ray structure and DFT calculations of copper(II) complex with 2-(2-pyridyl)benzimidazole

The reaction of copper(II) nitrate trihydrate and 2-(2-pyridyl)benzimidazole (pybzim) leads to [Cu(pybzim)₂(NO₃)](NO₃). The compound has been studied by IR, UV–Vis spectroscopy and X-ray crystallography. The electronic structure of the [Cu(pybzim)₂(NO₃)]⁺ cation has been calculated with the density functional theory (DFT) method. The spin-allowed doublet–doublet electronic transitions of [Cu(pybzim)₂(NO₃)]⁺ have been calculated with the time-dependent DFT method, and the UV–Vis spectrum of the title compound has been discussed on this basis.     

Synthesis and Crystal Structure of (CO)5ReSnMe2Re(CO)5

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Synthesis and Crystal Structure of [Cu（bbtz）（HCOO）2（H2O）2]n

1 INTRODUCTION Crystal engineering principles have been employ- yed in recent years to produce a variety of coordi- nation networks[1], which are of great current interest not only for their potential properties as functional solid materials[2] in host-guest chemistry, ion ex- change and catalysis, but also for their often com- plicated intriguing architectures and topologies. Ra- tional control the construction of polymeric net- works remains a great challenge in crystal engineer- ing. Mu…