异核Au基电荷转移配合物的结构与Au-Rh配合物取代基效应和激发态的理论研究

采用SVWN、XαVWN和MP2方法优化了Au基电荷转移配合物[Au^ⅠM^Ⅰ(CNH)₂(PH₂CH₂PH₂)₂]²⁺(M=Co(1),Rh (2)和Ir(3))的基态结构。计算表明3种方法都能描述Au-M弱相互作用(Au-M距离在0.268～0.302 nm范围内,伸缩振动频率在99～139     

一系列d8配合物1,3[(dz2)(pz)]激发态和金属间相互作用的理论研究

采用MP2和CIS方法分别优化trans-[M₂(CN)₄(PH₂CH₂PH₂)₂] [M＝Pt (1), Pd (2)和Ni (3)]和trans-[M(CN)₂(PH₃)₂] [M＝Pt (4), Pd (5)和Ni (6)]的基态和^1,3[(d_z2)(p_z)]激发态结构. CIS计算显示1的激发态Pt-Pt距离相对基态变短, 而2和3的金属间距离却增长. TD-DFT方法合理地预测了1～6发射能, 如: 1在CH₂Cl₂溶液中分别拥有348和404 nm的荧光和磷光发射, 与实验的386和448 nm相对应. 在1～3的激发态中, d⁸-d⁸相互作用依次递减, 相应的发射跃迁能增加; 与单核配合物4～6相比, 金属间相互作用使得双核Pt配合物的发射波长红移, 而对双核Pd和Ni配合物影响很小.     

烃基取代茚基钌羰基化合物的合成及晶体结构

配体C₉H₇R(R=CH₂CH₂CH₃ (1),CH₂(CH₃)₂ (2),C₅H₉ (3),CH₂C₆H₅ (4),CH₂CH=CH₂ (5))分别与Ru₃(CO)12在二甲苯或庚烷中加热回流,得到了6个双核配合物[(η⁵-C₉H₆R)Ru(CO)(μ-CO)]₂(R=CH₂CH₂CH₃ (6),CH₂(CH₃)₂ (7),C₅H₈ (8),CH₂C₆H₅ (9),CH₂CH=CH₂ (10))和[(η⁵-C₉H₆)(H₃CH₂C)CHCH(CH₂CH₃)(η⁵-C₉H₆)] [Ru(CO)(μ-CO)]₂ (11).通过元素分析、红外光谱、核磁共振氢谱对配合物的结构进行了表征,并用X-射线单晶衍射法测定了配合物6,9,10和11的结构.     

Au(II)化合物[Au(CH2)2PH2]2X2 (X＝F, Cl, Br, I)的量子化学理论研究

采用从头计算HF, MP2方法和密度泛函理论, 对Au(II)系列化合物[Au(CH₂)₂PH₂]₂X₂ (X＝F, Cl, Br, I)的几何结构、电子结构和振动频率进行了研究. 研究表明Au的5d和6s电子参与Au—Au以及Au—X之间的成键. Au—Au, Au—X键强烈的电子相关作用使HF方法不适于该体系的研究, BP86和B3LYP两种泛函给出较大的Au—Au和Au—X键长, 而MP2方法和局域的密度泛函方法则给出了合理的结构参数. 局域密度泛函方法计算得到的Au—Au键和 Au—X键振动频率也与实验数据符合较好. 还运用含时密度泛函理论计算了[Au(CH₂)₂PH₂]₂X₂的电子激发能, 对分子在紫外-可见光谱范围内的电子跃迁进行了分析, 考察了卤素配体对激发能的影响, 并结合分子轨道能级的变化对此给予了解释.     

Au(II)化合物[Au(CH2)2PH2]2X2 (X＝F, Cl, Br, I)的量子化学理论研究

采用从头计算HF, MP2方法和密度泛函理论, 对Au(II)系列化合物[Au(CH₂)₂PH₂]₂X₂ (X＝F, Cl, Br, I)的几何结构、电子结构和振动频率进行了研究. 研究表明Au的5d和6s电子参与Au—Au以及Au—X之间的成键. Au—Au, Au—X键强烈的电子相关作用使HF方法不适于该体系的研究, BP86和B3LYP两种泛函给出较大的Au—Au和Au—X键长, 而MP2方法和局域的密度泛函方法则给出了合理的结构参数. 局域密度泛函方法计算得到的Au—Au键和 Au—X键振动频率也与实验数据符合较好. 还运用含时密度泛函理论计算了[Au(CH₂)₂PH₂]₂X₂的电子激发能, 对分子在紫外-可见光谱范围内的电子跃迁进行了分析, 考察了卤素配体对激发能的影响, 并结合分子轨道能级的变化对此给予了解释.     

金和银氮杂环卡宾原子簇化合物的合成结构与细胞毒性研究

由[Ag₃L₂(CH₃CN)₂](PF₆)₃(1,L=bis(N-pyridylimidazoliumyl)methane)通过金属转移反应合成了含有氮杂环卡宾配体的金银混合原子簇化合物,[Au₂AgL₂(CH₃CN)₂](PF₆)₃(2)和[Au₄AgL₄](PF₆)₅(3),用X-射线单晶衍射确定了2和3的晶体结构。化合物1和2结构相同,3个金属原子三角形排列。化合物3中5个金属原子呈链状排列,其中银原子居于中间。这些化合物在室温下分别在417,415和457 cm^-1处表现荧光。用MTT实验方法研究了对HuH7,C6和A375肿瘤细胞的毒性,其毒性顺序为1>2>3与这些化合物中银含量顺序相一致。     

喹啉-8-甲醛缩4-甲基氨基硫脲Ni(Ⅱ)/Zn(Ⅱ)/Cd(Ⅱ)/Cu(Ⅱ)配合物的合成、结构和DNA结合性质

合成并通过单晶衍射、元素分析、红外光谱表征了配合物[NiL₂]·2CH₃OH（1）,[ZnL₂]·CH₃OH（2）,[CdL₂]·CH₃CH₂OH（3）和[Cu₂L₂Cl₂]（4）（HL为喹啉-8-甲醛缩4-甲基氨基硫脲）。单晶衍射结果表明,配合物1~3结构相似,中心金属离子与来自2个硫醇化脱质子配体L^-的4个N原子和2个S原子配位,采取扭曲的八面体配位构型。而配合物4中Cu（Ⅱ）离子与1个中性配体HL和3个氯离子配位,其中2个氯离子为μ²桥联。荧光光谱结果表明,所有配合物,尤其是4与DNA的相互作用能力明显强于配体。     

喹啉-8-甲醛缩4-甲基氨基硫脲Ni(Ⅱ)/Zn(Ⅱ)/Cd(Ⅱ)/Cu(Ⅱ)配合物的合成、结构和DNA结合性质

合成并通过单晶衍射、元素分析、红外光谱表征了配合物[NiL₂]·2CH₃OH（1）,[ZnL₂]·CH₃OH（2）,[CdL₂]·CH₃CH₂OH（3）和[Cu₂L₂Cl₂]（4）（HL为喹啉-8-甲醛缩4-甲基氨基硫脲）。单晶衍射结果表明,配合物1~3结构相似,中心金属离子与来自2个硫醇化脱质子配体L^-的4个N原子和2个S原子配位,采取扭曲的八面体配位构型。而配合物4中Cu（Ⅱ）离子与1个中性配体HL和3个氯离子配位,其中2个氯离子为μ²桥联。荧光光谱结果表明,所有配合物,尤其是4与DNA的相互作用能力明显强于配体。     

双胺配体[K2(L)(THF)2](L=[Ph2Si(NAr)2]2-, Ar=2,6-iPr2C6H3)构筑的两个低价稀土镱化合物

以双胺类配体[K₂(L)(THF)₂] (1)(L=[Ph₂Si(NAr)₂]^2-, Ar=2,6-ⁱPr₂C₆H₃)与二价稀土YbI₂(THF)₂的交换反应得到2个不同类型的化合物[Yb(L)(THF)₃] (2)和{Yb(L)₂[K(THF)₂]₂} (3)。对化合物进行X-射线单晶结构解析, 核磁共振和元素分析表征。研究结果表明:化合物2中, 通过1个双齿含氮配体和3个中性THF分子配位, 以五配位模式稳定二价镱稀土中心。而化合物3中二价稀土镱是与2个螯合胺类配体配位, 以共平面、四配位模式稳定其金属中心。K⁺恰好在配体的2个苯环之间, 形成独特的三明治结构, 有助于化合物的稳定。     

基于6-羟基-2-吡啶基膦酸配体的铜配合物的合成、结构及磁性

在水热条件下, 以6-羟基-2-吡啶基膦酸为主配体, 4, 4'-联吡啶(bpy)及1, 2-二(4-吡啶基)乙烯(bpe)为桥联配体, 合成了2个铜膦酸配位聚合物[Cu₃(L)₂(bpy)₂(H₂O)₂]·2H₂O (1), [Cu₃(L)₂(bpy)₂(H₂O)₃]·2H₂O (2)。配合物1中, Cu²⁺离子由膦酸配体连接成一条链, 该链由bpy桥联成二维层, 层与层之间通过氢键作用构成三维结构。配合物2与配合物1是同构的, 桥联配体是bpe。磁性研究表明, 配合物1与2中铜离子之间存在反铁磁性耦合。     

Synthesis,Characterization, and X‐ray Crystal Structure of Macrocyclic Nickel/Iron/Sulfur Cluster Complexes

A series of macrocyclic Ni/Fe/S cluster complexes were synthesized and structurally characterized. The macrocyclic type of (diphosphine)Ni‐bridged double butterfly Fe/S complexes [μ‐SCH₂CH₂OCH₂CH₂S‐μ][(μ‐S=CS)Fe₂(CO)₆]₂‐[Ni(diphosphine)] ( 1 – 3 ; diphosphine = dppe, dppv, dppb) were prepared by treatment of the dianion [{μ‐SCH₂CH₂OCH₂CH₂S‐μ}{(μ‐CO)Fe₂(CO)₆}₂]^2–, generated in situ from Fe₃(CO)₁₂, Et₃N, and HSCH₂CH₂OCH₂CH₂SH with excess CS₂ followed by treatment of the resulting dianion [{μ‐SCH₂CH₂OCH₂CH₂S‐μ}{(μ‐SC=S)Fe₂(CO)₆}₂]^2– with (diphosphine)NiCl₂. The three complexes 1 – 3 were characterized by elemental analysis and IR, ¹H NMR, and ³¹P NMR spectroscopy. In addition, the molecular structures of 2 and 3 were established by X‐ray crystallography.     

Ligand‐Stabilized and Atomically Precise Gold Nanocluster Catalysis: A Case Study for Correlating Fundamental Electronic Properties with Catalysis

We present results from our investigations into correlating the styrene‐oxidation catalysis of atomically precise mixed‐ligand biicosahedral‐structure [Au₂₅(PPh₃)₁₀(SC₁₂H₂₅)₅Cl₂]²⁺ (Au₂₅‐bi) and thiol‐stabilized icosahedral core–shell‐structure [Au₂₅(SCH₂CH₂Ph)₁₈]^? (Au₂₅‐i) clusters with their electronic and atomic structure by using a combination of synchrotron radiation‐based X‐ray absorption fine‐structure spectroscopy (XAFS) and ultraviolet photoemission spectroscopy (UPS). Compared to bulk Au, XAFS revealed low Au–Au coordination, Au? Au bond contraction and higher d‐band vacancies in both the ligand‐stabilized Au clusters. The ligands were found not only to act as colloidal stabilizers, but also as d‐band electron acceptor for Au atoms. Au₂₅‐bi clusters have a higher first‐shell Au coordination number than Au₂₅‐i, whereas Au₂₅‐bi and Au₂₅‐i clusters have the same number of Au atoms. The UPS revealed a trend of narrower d‐band width, with apparent d‐band spin–orbit splitting and higher binding energy of d‐band center position for Au₂₅‐bi and Au₂₅‐i. We propose that the differences in their d‐band unoccupied state population are likely to be responsible for differences in their catalytic activity and selectivity. The findings reported herein help to understand the catalysis of atomically precise ligand‐stabilized metal clusters by correlating their atomic or electronic properties with catalytic activity.     

Two thiourea‐containing gold(I) complexes

The crystal structures of two salts of bis­(thio­urea)­gold(I) complexes, namely bis­(thio­urea‐κS)­gold(I) chloride, [Au(CH₄N₂S)₂]Cl, (I), and bis­[bis­(thio­urea‐κS)­gold(I)] sulfate, [Au(CH₄N₂S)₂]₂SO₄, (II), have been determined. The chloride salt, (I), is isomorphous with the corresponding bromide salt, although there are differences in the bonding. The Au^I ion is located on an inversion centre and coordinated by two symmetry‐related thio­urea ligands through the lone pairs on their S atoms [Au—S 2.278 (2) Å and Au—S—C 105.3 (2)°]. The sulfate salt, (II), crystallizes with four independent [Au(CH₄N₂S)₂]⁺ cations per asymmetric unit, all with nearly linear S—Au—S bonding. The cations in (II) have similar conformations to that found for (I). The Au—S distances range from 2.276 (3) to 2.287 (3) Å and the Au—S—C angles from 173.5 (1) to 177.7 (1)°. These data are relevant in interpreting different electrochemical processes where gold–thio­urea species are formed.     

Quantum-chemical study of the effect of ligands on the structure and properties of gold clusters

The structures of [Au₄(dpmp)₂X₂]²⁺clusters, where Х =–C≡CH,–СН₃,–SCH₃,–F,–Cl,–Br,–I, dpmp is bis((diphenylphosphino)methyl)(phenyl)phosphine, are calculated at the level of density functional theory with the PBE functional and a modified Dirac–Coulomb–Breit Hamiltonian in an all-electron basis set (Λ). Using the example of [Au₄(dpmp)₂(С≡CС₆Н₅)₂]²⁺, the interatomic distances and bond angles calculated by means of PBE0/LANL2DZ, TPSS/LANL2DZ, TPSSh/LANL2DZ, and PBE/Λ are compared to X-ray crystallography data. It is shown that PBE/Λ yields the most accurate calculation of the geometrical parameters of this cluster. The ligand effect on the electronic stability of a cluster and the stability in reactions of decomposition into different fragments is studied, along with the capability of ligand exchange. Stability is predicted for [Au₄(dpmp)₂F₂]²⁺ and [Au₄(dpmp)₂(SCH₃)₂]²⁺, while [Au₄(dpmp)₂I₂]²⁺ cluster is unstable and its decomposes into two identical fragments is supposed.

     

Structural characteristics of 2-halo-1,3,2-dithiarsenic compounds and tris-(pentafluorophenylthio)-arsen

The combination of various dithiols and AsX₃ (X = F, Cl) produces the series of cyclized halo-arsenic dithiolate compounds: 2-chloro-1,3,2-dithiarsolane [AsCl(SCH₂CH₂S)] (1), 2-iodo-1,3,2-dithiarsolane [AsI(SCH₂CH₂S)] (2), 2-chloro-1,3,2-dithiarsenane [AsCl(SCH₂CH₂CH₂S)] (3), 2-iodo-1,3,2-dithiarsenane [AsI(SCH₂CH₂CH₂S)] (4), 3-chloro-4H,7H-5,6-benz-1,3,2-dithiarsepine [AsCl(SCH₂)₂(C₆H₄)] (5), 1,2-bis-dithiarsolan-2-ylmercapto-ethane [As₂(SCH₂CH₂S)₂(SCH₂CH₂S)] (6) and tris-(pentafluorophenylthio)-arsen [As(SC₆F₅)₃] (7). The geometry around As for these compounds is best described as trigonal pyramidal with varying degrees of distortion. Compound 1 crystallizes in two polymorphic forms with similar structural parameters. The compounds have been characterized by IR, ¹H, ¹⁹F, and ¹³C NMR, X-ray crystallography and GC-MS.     

Formation,Expansion, and Interconversion of Metallarings in a Sulfur‐Bridged AuICoIII Coordination System

A novel Au^ICo^III coordination system that is derived from the newly prepared [Co(D ‐nmp)₂]⁻ ( 1 ⁻; D ‐nmp=N‐methyl‐D ‐penicillaminate) and a gold(I) precursor Au^I is reported. Complex 1 ⁻ acts as a sulfur‐donating metallaligand and reacts with the gold(I) precursor to give [Au₂Co₂(D ‐nmp)₄] ( 2 ), which has an eight‐membered Au^I₂Co^III₂ metallaring. Treatment of 2 with [Au₂(dppe)₂]²⁺ (dppe=1,2‐bis(diphenylphosphino)ethane) leads to the formation of [Au₄Co₂(dppe)₂(D ‐nmp)₄]²⁺ ( 3 ²⁺), which consists of an 18‐membered Au^I₄Co^III₂ metallaring that accommodates a tetrahedral anion (BF₄⁻, ClO₄⁻, ReO₄⁻). In solution, the metallaring structure of 3 ²⁺ is readily interconvertible with the nine‐membered Au^I₂Co^III metallaring structure of [Au₂Co(dppe)(D ‐nmp)₂]⁺ ( 4 ⁺); this process depends on external factors, such as solvent, concentration, and nature of the counteranion. These results reveal the lability of the Au S and Au P bonds, which is essential for metallaring expansion and contraction.     

Cluster Build-up Reactions using Di-gold Cationic Fragments: Synthesis and Structural Characterization of [Os7(CO)19(Au2dppm)]

The reaction of the di-gold cation [Au₂(dppx)]²⁺ with the heptanuclear cluster dianion [Os₇(CO)₂₀]^2– affords the mixed metal cluster [Os₇(CO)₂₀{Au₂(dppx)}] (x=m (1), e (2), b (3)). On standing, in solution, this complex undergoes decarbonylation to give the cluster [Os₇(CO)₁₉{Au₂(dppx)}] (x=m (4), e (5), b (6)). The complexes have been characterised spectroscopically, and an X-ray structure determination of the dppm derivative shows that it contains a metal core based on an Os₇ edge-bridged bicapped tetrahedron with the two ₃-Au atoms capping adjacent triangular Os₃ faces of the central tetrahedron. In an analogous reaction, the carbido anion [Os₇(H)C(CO)₁₉]^– affords the neutral cluster [Os₇C(CO)₁₉{Au₂(dppm)}] (7) when treated with [Au₂(dppm)]²⁺ in the presence of base.     

Formation,Expansion, and Interconversion of Metallarings in a Sulfur‐Bridged AuICoIII Coordination System

A novel Au^ICo^III coordination system that is derived from the newly prepared [Co(D ‐nmp)₂]^? ( 1 ^?; D ‐nmp=N‐methyl‐D ‐penicillaminate) and a gold(I) precursor Au^I is reported. Complex 1 ^? acts as a sulfur‐donating metallaligand and reacts with the gold(I) precursor to give [Au₂Co₂(D ‐nmp)₄] ( 2 ), which has an eight‐membered Au^I₂Co^III₂ metallaring. Treatment of 2 with [Au₂(dppe)₂]²⁺ (dppe=1,2‐bis(diphenylphosphino)ethane) leads to the formation of [Au₄Co₂(dppe)₂(D ‐nmp)₄]²⁺ ( 3 ²⁺), which consists of an 18‐membered Au^I₄Co^III₂ metallaring that accommodates a tetrahedral anion (BF₄^?, ClO₄^?, ReO₄^?). In solution, the metallaring structure of 3 ²⁺ is readily interconvertible with the nine‐membered Au^I₂Co^III metallaring structure of [Au₂Co(dppe)(D ‐nmp)₂]⁺ ( 4 ⁺); this process depends on external factors, such as solvent, concentration, and nature of the counteranion. These results reveal the lability of the Au? S and Au? P bonds, which is essential for metallaring expansion and contraction.     

A theoretical study of the activation of methane by Gold(III) homoleptic complexes

The density functional theory method with the PBE functional, SBK pseudopotential, and extended basis sets was used to study the reaction between methane and gold(III) homoleptic complexes, namely, [AuX₄]^? (X = Cl, Br, I, H, CN, NH₂, OH, CH₃, and SH), [Au(X(CY)₂X)₂]^? (X = S, Y = H; X = Y = O), Au₂Cl₆, [Au(X₂(CY))₂]⁺ (X = S, Y = NH₂; X = O, Y = H), and [Au(acac)₂]⁺, with the formation of electrophic substitution products. The activation of methane under mild conditions was found to be uncharacteristic of anionic and neutral complexes. According to calculations of cationic oxygen-containing complexes, the formation of methane complexes is possible in their reactions with methane. The energy barrier to this reaction noticeably decreases because of the activation of the C-H bond in this complex. The heat effects vary widely depending on the nature of the ligand. There is, however, no obvious correlation between their values and the activation energy of the reaction.