层状金属配位聚合物[{MX_2(bipy)}n](M=Ni,Cu,Hg;X=F,Cl,Br,I;)bipy=4,4′bipyridyl)的电子结构和导电机理研究

用紧束缚 (EHT)晶体轨道方法对层状金属配位聚合物 [{HgX2 (bipy) }n](X =Cl,Br ;bipy =4 ,4′ bipyridyl)进行了能带结构计算 ,并利用键向量方法对这一系列聚合物能带特征和成键性质进行了讨论。研究表明 ,Fermi能级附近的能带主要是金属汞原子和卤素原子及氮原子之间形成的d pσ 反键和d pσ成键作用 ,这两者作用的强弱对导电性起决定作用。本文还对系列聚合物 [{HgX2 (bipy) }n](M =Ni,Cu ,Hg ;X =Cl,Br;bipy =4 ,4′ bipyridyl)可能具有的导电机理和规律进行了探讨。     

层状金属配位聚合物[｛NIX_2(bipy)｝n](X=F,Cl,Br,I;bipy=4,4'-bipyridyl)的能带结构研究

用紧束缚（EHT）晶体轨道方法对层状金属配住聚合物[{Nix2。（bipy）｝n]（X=F，Cl，Br，I；bipy=4，4’－bipyridyl）进行了能带结构计算，并利用键向量方法对这一系列聚合物能带特征和成键性质进行了讨论。研究表明，Fermi能级附近的能带主要是金属镍原子和卤素原子之间形成的d－pσ反键作用，这一反键作用的强弱对导电性起决定作用。     

过渡金属M (M=Cu,Ag, Au)对X…Cl (X = F,Cl, Br)卤键相互作用强度的影响

采用量子化学方法,通过MCH2X…ClF(M=Cu,Ag,Au;X=F,Cl,Br)和CH3X…ClF两类复合物的对比,探讨了过渡金属对卤键相互作用强度的影响.CH3X…ClF复合物只有卤键相互作用,而优化MCH2X…ClF复合物除了得到一种只含有卤键相互作用的构型外,还得到一种含有过渡金属和Cl原子相互作用的稳定构型.含有过渡金属的复合物稳定性明显增加,Ag取代的复合物稳定性增加最为明显,Cu次之,Au最不明显.X原子最负分子表面静电势(MEP)减小是复合物稳定性增加的根本原因.利用自然键轨道(NBO)及分子中原子(AIM)分析进一步对体系的分子间相互作用进行了探讨.二阶稳定化能与键鞍点处拓扑性质的计算结果与相互作用能符合得很好.     

金属四重键化合物M2X4(PMe3)4(M=Cr,Mo,W;X=F,Cl,Br,I)结构和电子光谱的密度泛函理论研究

采用密度泛函理论方法,在TZ2P-STO基组水平下,对金属四重键化合物M2Cl4(PMe3)4(M=Cr,Mo,W)和Mo2X4(PMe3)4(X=F,Cl,Br,I)的几何结构进行优化,分析了电子结构,并运用TDDFT方法对其低占据激发态进行了计算.考虑相对论效应的ZORA方法能够较好地重现M2X4(PMe3)4的几何结构.M2X4(PMe3)4的电子结构分析表明其d电子的组态为σ2π4δ2,前线轨道能级顺序为πlig<πd/σd<δd<δd*.金属原子和卤素配体的改变虽然使轨道能量发生变化,但没有影响轨道的排布顺序.TDDFT方法对M2X4(PMe3)4δd→δd*和πd→δd*跃迁能量的计算较为准确,对πlig→δd*(LMCT)跃迁能量的计算误差较大.金属原子、卤素配体以及相对论效应对激发能的影响可以根据分子轨道能级的变化给予解释.     

NCO/NCS自由基与XY（X=H,Cl;Y=F,Cl,Br）间σ-型弱作用的理论研究

NCO和NCS是大气化学中非常引人关注的自由基,它们均有三个原子并且两个端基原子均可作为电子给体形成σ-型氢/卤键.本文在MP2/aug-cc-pVDZ水平上研究了NCO/NCS...XY（X=H,Cl;Y=F,Cl,Br）体系中的弱化学键.计算结果表明,氢/卤原子与N原子相连形成的复合物比与O/S原子相连形成的复合物稳定;氢/卤键的稳定性由分子静电势决定,而非原子电负性;对相同的电子给体B（B=N,O/S）和相同的卤原子来说,化学键的强度按Y=F,Cl,Br的顺序逐渐减弱.在氢/卤键形成过程中,自旋电子密度在电子给体和电子受体间的转移较少,但它在自由基内部发生重排,就本文研究的所有复合物而言,自旋电子密度均转移向XY分子的相反位置.     

层状金属配位聚合物[{NiX2（bipy）}n]（X=F,Cl,Br,I;bipy=4,4‘—bipy …

用紧束缚晶体轨道方法对层状金属配位聚合物「｛ＮｉＸ２（ｂｉｐｙ）｝ｎ「（Ｘ＝Ｆ，Ｃｌ，Ｂｒ，Ｉ；ｂｉｐｙ＝４，４’－ｂｉｐｙｒｉｄｙｌ）进行了能带结构计算，并利用键向量方法对这一系列聚合物能带特征和成键性质进行了讨论。     

HCHO+X(X=F、Cl、Br)的反应机理

采用CCSD/6-311++G(d,p)//B3LYP/6-311++G(d,p)方法研究了HCHO与卤素原子X(X=F、Cl、Br)的反应机理. 计算结果表明, 卤素原子X(X=F、Cl、Br)主要通过直接提取HCHO中的H原子生成HCO+HX(X=F、Cl、Br). 另外还可以生成稳定的中间体, 中间体再通过卤原子夺氢和氢原子直接解离两个反应通道分别生成HCO+HX(X=F、Cl、Br)和H+XCHO(X=F、Cl、Br). 其中卤原子夺氢通道为主反应通道, HCO和HX(X=F、Cl、Br)为主要的反应产物; 且三个反应的活化能均较低, 说明此类反应很容易进行, 计算结果与实验结果符合很好. 电子密度拓扑分析显示, 在HCHO+X反应通道(b)中出现了T型结构过渡态, 结构过渡态(STS)位于能量过渡态(ETS)之后. 并且按F、Cl、Br的顺序, 结构过渡态出现得越来越晚.     

C_(80)X_(12)(X=H,F,Cl,Br)的结构和稳定性

为了考察勒烯衍生物结构与稳定性关系,采用密度泛函理论方法对C80X12(X=H,F,Cl,Br)进行了系统计算究.结表明,在C80X12(X=H,F)异构体中,最低能量异构体都违反五元环分离规则.然而,在C80X12(X=Cl,Br)异构体中,最低能量异构体都满足五元环分离规则.由于van der Waals半径较小,H或F加成到碳笼上时外部原子之间排斥作用小,因此在其优结构中,H或F优先加成到2个五元环共用碳原子上.相反,对于氯化、溴化勒烯,为了避免外部加成原子之间在重空间排斥作用,其优结构中Cl或Br优先加成到1,4-位点上.计算结还显,氢化、卤化反应热(C80+6X2→C80X12)遵循如下顺序,即C80F12>C80Cl12>C80H12>C80Br12.这些结表明勒烯衍生物稳定性和衍生化模与加成原子尺和电性有关.     

MX~4(M=Ti,Zr,Hf;X=Cl,Br)的电子结构研究

本文利用单电子非相对论Hartree-Fock-Slater和完全相对论Dirac-Fock-Slater两种离散变分局域密度泛函方法(DV-Xα), 对MX~4(M=Ti,Zr,Hf;X=Cl,Br)的电子基态和相应于低能UV光谱的激发态进行了计算, 结果与实验符合得较好。用Mulliken布居分析方法研究了分子的共价性质, 发现除HfBr~4外,相对论效应对金属与配体之间的键级影响很小。     

电场对金属串配合物M3(dpa)4Cl2 (M=Co,Rh, Ir; dpa=dipyridylamide)结构的影响

应用密度泛函理论PBE0 方法研究具有分子导线潜在应用的金属串配合物M₃(dpa)₄Cl₂ (1: M=Co, 2: M=Rh, 3: M=Ir; dpa=dipyridylamide)在电场作用下的几何和电子结构. 结果表明: 配合物基态均是二重态. 1和2的M₃⁶⁺金属链形成三中心三电子σ键, 3 中M₃⁶⁺形成三中心四电子σ键且存在弱的δ键. 随金属原子周期数增大其M―M键增强、LUMO与HOMO能隙减小、金属原子的反铁磁耦合减弱以至消失且自旋密度向配体的离域增强. 在Cl4→Cl5 电场作用下, 低电势端的M3－Cl5 键缩短, 高电势端的M2―Cl4 键增长, M―M平均键长略为缩短, M―M键增强, 有利于分子线的电子传递; 分子能量降低, 偶极矩线性增大. 低电势端Cl5的负电荷向高电势端Cl4 转移, 且3 中金属原子的正电荷由高电势端向低电势端的转移较明显, 自旋电子由低电势端向高电势端金属原子移动, 但桥联配体dpa^-与M和Cl 所在的分子轴间没有电荷转移. 电场使LUMO与HOMO能隙减小, 有利于分子的电子输运. 随金属原子周期数增大, 电场作用下M―M平均键长变化减小, LUMO、HOMO的能级交错现象减少.     

Über verschiedene Reaktionen der CO-verbrückten Komplexe [Mo(CO)3bipy]2 und [Mo(CO)3phen]2 (bipy = 2,2′-Bipyridyl,phen = 1,10-Phenanthrolin)

The interaction of [Mo(CO)₃bipy]₂ with various monodentate ligands L (L = NH₃, pyr, P(C₆H₅)₃, P(C₆H₅)Cl₂, CN^?, SO₂) yields, according to the reaction equation in ?Inhaltsübersicht”?, mixed tricarbonyl compounds Mo(CO)₃bipyL by cleavage of the CO bridges of the dimeric starting carbonyl. Oxidation of [Mo(CO)₃D]₂ (D = bipy, phen) by means of iodine, partly in the presence of free bipy or phen, leads to the covalent and ionic, respectively, compound types [Mo^II(CO)₃DI₂]₂, [Mo^I(CO)₂DI]₂, [Mo^II(CO)₂D₂I]I and [Mo^II(CO)₂D₂I]I₃.     

From model compounds to protein binding: syntheses, characterizations and fluorescence studies of [RuII(bipy)(terpy)L]2+ complexes (bipy = 2,2'-bipyridine; terpy = 2,2':6',2''-terpyridine; L = imidazole, pyrazole and derivatives, cytochrome c)

Compounds [RuII(bipy)(terpy)L](PF6)2 with bipy = 2,2'-bipyridine, terpy = 2,2':6',2"-terpyridine, L = H2O, imidazole (imi), 4-methylimidazole, 2-methylimidazole, benzimidazole, 4,5-diphenylimidazole, indazole, pyrazole, 3-methylpyrazole have been synthesized and characterized by 1H NMR, ESI-MS and UV/Vis (in CH3CN and H2O). For L = H2O, imidazole, 4,5-diphenylimidazole and indazole the X-ray structures of the complexes have been determined with the crystal packing featuring only few intermolecular C-H...pi or pi-pi interactions due to the separating action of the PF6-anions. Complexes with L = imidazole and 4-methylimidazole exhibit a fluorescence emission with a maximum at 662 and 667 nm, respectively (lambdaexc= 475 nm, solvent CH3CN or H2O). The substitution of the aqua ligand in [Ru(bipy)(terpy)(H2O)]2+ in aqueous solution by imidazole to give [Ru(bipy)(terpy)(imi)]2+ is fastest at a pH of 8.5 (as followed by the increase in emission intensity). Coupling of the [Ru(bipy)(terpy)]2+ fragment to cytochrome c(Yeast iso-1) starting from the Ru-aqua complex was successful at 35 degrees C and pH 7.0 after 5 d under argon in the dark. The [Ru(bipy)(terpy)(cyt c)]-product was characterized by UV/Vis, emission and mass spectrometry. The location where the [Ru(bipy)(terpy)] complex was coupled to the protein was identified as His44 (corresponding to His39 in other numbering schemes) using digestion of the Ru-coupled protein by trypsin and analysis of the tryptic peptides by HPLC-high resolution MS.     

Synthesis, crystal structure and magnetic properties of a chloranilate-bridged manganese(II) chain compound: [Mn(bipy)(CA)]n (bipy = 2,2′-bipyridine, CA = chloranilate anion)

The compound [Mn(bipy)(CA)]_n (where bipy is 2,2′-bipyridine and CA²⁻ is the dianion of 3,6-dichloro-2,5-dihydroxy-1,4-benzoquinone) has been synthesized and its crystal structure determined by single-crystal X-ray diffraction at room temperature. The crystal is built from infinite chains of chloranilate-bridged manganese(II) affording a zigzag structure, with the bipyridine ligands being stacked between the chains. The variable-temperature (2.0–300 K) magnetic susceptibility and EPR data are reported and a weak antiferromagnetic exchange interaction is observed with the exchange parameter estimated as J = −0.20 cm⁻¹.     

Luminescence characteristics and X‐ray crystal structure of [Cd(bipy)3][PF6]2 (bipy = 2,2′‐bipyridine)

The photoluminescence characteristics of the [Cd(bipy)₃][PF₆]₂ complex are reported. A moderately large quantum yield (φ) of 1.07 × 10^?2 is exhibited in acetonitrile solution at 298 K. Crystallography shows the dication to have a distorted octahedral geometry and the crystal structure to be stabilized by C? H···π and C? H···F interactions. Copyright © 2005 John Wiley & Sons, Ltd.     

Absorption, Circular Dichroism, and Luminescence Spectroscopy of Electrogenerated Delta-[Ru(bipy)(3)](+/0/)(-) and Delta-[Os(bipy)(3)](+/0/)(-) (bipy = 2,2'-Bipyridine)

The electronic absorption and circular dichroism (CD) spectra of the complexes produced by the one, two, and three electron reduction of Delta-[Ru(bipy)(3)](2+) and Delta-[Os(bipy)(3)](2+) are reported. The CD spectra give unequivocal proof that the added electrons are localized on individual bipiridine ligands and thus that the complexes are correctly formulated [M(bipy)(2)(bipy(-))](+), [M(bipy)(bipy(-))(2)](0), and [M(bipy(-))(3)](-). The absorption spectra of the triply reduced species [M(bipy(-))(3)](-) (M = Ru, Os) are compared to those of the Fe(II) and Ir(III) analogs. The luminescence spectra of the two triply reduced complexes [Ru(bipy(-))(3)](-) and [Os(bipy(-))(3)](-). are also presented. The MLCT luminescence found in the parent complexes is completely quenched and is replaced by a weak luminescence attributed to the pi(10) --> pi(7) transition of the (coordinated) [bipy](-) ion.     

Crystallographic report: A three‐dimensional coordination polymer: [Zn6(btc)4(4,4′‐bipy)5]n (btc = 1,2,4‐benzenetricarboxylate; 4,4′‐bipy = 4,4′‐bipyridine)

The three‐dimensional (3D) coordination polymer [Zn₆(btc)₄(4,4′‐bipy)₅]_n ( 1 ) (btc = 1,2,4‐benzenetricarboxylate; 4,4′‐bipy = 4,4′‐bipyridine) has been prepared hydrothermally. The zinc(II) centers in 1 are bridged by btc ligands to form a trinuclear subunit, which is further linked by 4,4′‐bipy and btc ligands to construct the 3D coordination architecture. Copyright © 2003 John Wiley & Sons, Ltd.     

Synthesis,Structure and Fluorescence of a Copper(II) Complex [Cu_2(bipy)_2(Hpht)_2Cl](Hpht)(bipy=2,2'-Bipyridine,H_2pht=o-Phthalic Acid)

1 INTRODUCTION o-Phthalic acid (H2pht) is a versatile ligand for co-ordinating to metal ions in various modes, such asmonodentate bonding through a carboxylic O atom[1],bidentate fashion via two carboxylic O atoms[2] andtriple coordination through its three carboxylic Oatoms[3], and bridging mode with two or four Oatoms of its carboxylate groups[4]. The coordinationproperties thus allow for the preparation of complex-es with a large variety of architectures, forming iso-lated mono-, di…     

Structure of Coordination Polymer, 〔Zn(bipy)(H_2O)_3SO_4〕·2H_2O (bipy=4,4'-bipyridine)

1　INTRODUCTION4,4' bipyridine( bipy) is a good candidate for building open framework struc ture because of their rodlike rigidity and length.Framework structures formed bytransition metalsbridged by bipy vary with metaland anion.The structures of Zn bipy system include interpenetrating square grid sheets〔 Zn( bipy) 2 ( H2 O) 2 〕Si F6〔1〕,two dimensionallayer〔 Zn( bipy) ( H2 O) 4 〕( NO3) 2 · bipy〔2〕,〔 Zn( bipy) ( H2 O) 4 〕 ( NO3) 2 · 2 bipy· 3 H2 O〔2〕 and〔 Zn( bipy)…     

The 3D Supramolecular Compound {[Cu2(L‐val)2(4,4′‐bipy)(H2O)2](NO3)2}n (L‐val = L‐valine anion, 4,4′‐bipy = 4,4′‐bipyridine)

{[Cu₂(L‐val)₂(4,4′‐bipy)(H₂O)₂](NO₃)₂}_n was synthesized and its crystal structure was determined by X‐ray diffraction. In the presence of 4,4′‐bipyridine, deprotoned L‐valine chelates Cu^II ions into coordination layers which were linked into a framework by hydrogen‐bonded chains resulting from nitrate anions and water molecules.