Me_3NO存在下Ir_4(CO)_(11)L(L=CO,PPh_3)的CO取代反应动力学研究

刊用FT-IR和UV技术跟踪反应进程,研究了在Me_3NO存在下Ir_4(CO)_(12)和Ir_4(CO)_(11)PPh_3分别在CHCl_3—C_2H_5OH和CHCl_3溶剂中取代羰基反应的动力学与机理。结果表明反应遵循二级速率定律:r=k_2[Me_3NO][配合物]。该速率方程与缔合机理相一致。将Ir_4(CO)_(11)L和Os_3(CO)_(11)L(L=CO,PPh_3)体系的动力学结果相比较,着重讨论了桥基因素对反应活性的影响。     

Theoretical studies on Ru(fppz)_2(CO)L (L=N-heterocyclic ligand):Electronic structure,absorption,phosphorescence,and solvatochromism

A series of ruthenium(II) complexes Ru(fppz)2(CO)L [fppz = 3-trifluoromethyl-5(2-pyridyl)pyrazole; L = pyridine (1), 4-dimethylaminopyridine (2), 4-cyanopyridine (3)] were designed and investigated theo-retically to explore their electronic structures, absorption, and emissions as well as the solvatochrom-ism. The singlet ground state and triplet excited state geometries were fully optimized at the B3LYP/LANL2DZ and CIS/LANL2DZ level, respectively. The HOMO of 1-3 is composed of dyz(Ru) atom and π(fppz). The LUMO of 1 and 2 is dominantly contributed by π*(fppz) orbital, but that of 3 is con-tributed by π*(L). Absorption and phosphorescence in vacuo, C6H12, and CH3CN media were calculated using the TD-DFT level of theory with the PCM model based on the optimized ground and excited state geometries, respectively. The lowest-lying absorption of 1 and 2 at 387 and 391 nm is attributed to {[dyz(Ru) π(fppz)] → [π*(fppz)]} transition, but that of 3 at 479 nm is assigned to {[dyz(Ru) π(fppz)] → [π*(L)]} transition. The phosphorescence of 1 and 2 at 436 and 438 nm originates from 3{[dyz(Ru) π(fppz)] [π*(fppz)]} excited state, while that of 3 at 606 nm is from 3{[dyz(Ru) π(fppz)] [π*(L)]} excited state. The calculation results showed that the absorption and emission transition character can be changed from MLCT/ILCT to MLCT/LLCT transition by altering the substituent on the L ligand. The phosphorescence of 1 and 2 does not have solvatochromism, but that of 3 at 606 nm (vacuo), 584 nm (C6H12), and 541 nm (CH3CN) is strongly dependent on the solvent polarity, so introducing elec-tron-withdrawing group on ligand L will induce remarkable solvatochromism.     

Phosphine-centred resolution of (η4-diene)Fe(CO)3 complexes: (η4-tropone)Fe(CO)2L and (η4-isoprene)Fe(CO)2L [L = (+)-(neomenthyl)PPh2]

(η⁴-Tropone)Fe(CO)₃ and (η⁴-isoprene)Fe(CO)₃ form separable diastereoisomers on substitution of CO by (+)-(neomenthyl)PPh₂. In the tropone complex, diastereoisomer interconversion occurs by a 1,3-metal shift. The absolute configuration of the isoprene complex has been determined crystallographically.     

Perfluoromethyl-element-liganden: XXXVI. Chrom-, molybdän- und wolframkomplexe des typs M(CO)5L und M(CO)4L2 mit mercaptophosphan-liganden

The coordinating properties of the ligands L¹ (= MeP(SMe)₂) and L² (= CF₃P(SMe)₂) have been studied by synthesis and spectroscopic investigations (IR, NMR, MS) of their chromium, molybednum and tungsten complexes M(CO)₅L (M = Cr, Mo, W, L¹: 1–3; L²: 4–6 and M(CO)₄L₂ (L¹: 7–9; L²: 10–12. Complexes 1–6 are obtained by indirect photochemical substitution via M(CO)₅THF, compounds 7–12 by replacement of norbornadiene (NBD) in M(CO)₄NBD. Spectroscopic data [η(CO), Δδ] support the σ-donor/π-acceptor model of the MP bonds and the influence of mesomeric besides inductive and steric effects.     

(Ph3P)2,Co(CO)2Cl和(dppe-P,P)2CO(CO)+的分子轨道研究

本文对(PH3P)2, Co(CO)2Cl和(dppe-P,P)2CO(CO)+(dppe=Ph2CH2CH2PPh2)五配位C2O对称性模型化合物进行了分轨道研究, 结果表明, 钴的3d轨道很少参与成键, 钴的4s, 4P与配体的S,P轨道通过形式上的二电子三中心键和二电子二中心键的相互作用构成五配位, 此外, 还解释了这两种化合物不同稳定性的原因。     

Metal-stabilized carbanions IX. The influence of metal basicity on the η6 ⇄ η5 Haptotropic equilibrium of (fluorenyl)-Cr-(CO)2L anions (L = CO,P(OPh),3, PPh3, P(n-Bu)3)

The (fluorene)Cr(CO)₂L complexes (L = CO, P(OPh)₃, PPh₃, P(n-Bu)₃) have been synthesized and metallated with KH in THF to form the corresponding η⁶-anions, which in turn equilibrate at room temperature with the η⁵-hapto isomers. All theses species have been fully characterized by ¹³C and ³¹P NMR spectroscopy. The rate of metallation, the reduction potential, the IR carbonyl stretching frequencies, and the η⁶ ⇄ η⁵ haptotropic equilibrium are strongly influcned by the nature of L.     

The reactions of [MI2(CO)3(NCMe)2] (M = Mo or W) with one equivalent of L (L = pyridine or substituted pyridines) to give [WI2(CO)3(NCMe)L] and [M(μ-I)I(CO)3L]2

The complexes [MI₂(CO)₃(NCMe)₂] (M = Mo or W) react with one equivalent of L in CH₂Cl₂ at room temperature to give initially the mononuclear seven-coordinate complexes [MI₂(CO)₃(NCMe)L] which have been isolated for M = W; L = 3Cl-py, 3Br-py, 4Cl-py and 4Br-py. These compounds dimerise to give the iodidebridged dimers [M(μ-I)I(CO)₃L]₂ by displacement of acetonitrile. When M = Mo; L = 3Cl-py, 3Br-py, 4Cl-py and 4Br-py, and when M = Mo and W; L = py, 2Me-py (for M = W only), 4Me-py, 3,5-Me₂-py, 2Cl-py and 2Br-py, only the dimeric complexes have been isolated. The ease of dimerisation of [MI₂(CO)₃(NCMe)L] is discussed in terms of the steric and electronic effects of the substituted pyridines.     

一类[Os(II)(CO)3(tfa)(L)](L=O^O,O^N,N^N)配合物的结构和光谱特征

采用密度泛函理论以及B3LYP方法和单激发组态相互作用(CIS)方法分别优化了一系列[Os(II)(CO)3(tfa)(L)](tfa为三氟乙酸; L=O^O(1), O^N(2), N^N(3), 其中O^O为六氟乙酰丙酮, O^N为羟基喹啉, N^N为3-(三氟甲基)-5-(2-吡啶基)吡唑)配合物的基态和激发态结构. 利用含时密度泛函理论(TD-DFT)结合极化连续溶剂化模型(PCM)计算了配合物在CH2Cl2溶液中的吸收和发射光谱. 研究结果表明, 优化得到的几何结构参数和相应的实验值符合得非常好, 激发态几何构型相对基态变化较小, 这与实验上观察到的较小的斯托克斯频移现象一致. 配合物1-3的最低能吸收分别在342、431和329 nm, 其磷光发射分别在521、638 和488 nm. 配合物1-3的最高占据分子轨道和最低空轨道主要表现为L配体的π和π*轨道特征, 所以它们的最低能吸收归属于π-π*电荷跃迁, 并混有少量的金属到配体的电荷跃迁(MLCT)和配体之间电荷跃迁(LLCT)微扰, 且其高能吸收也表现为配体内部(IL)和配体间(LL)的电荷跃迁. 此外, 它们的磷光发射和吸收有相似的跃迁特征.     

Oxidative addition reactions TO Cp′Co(CO)L (Cp′ = C5H4CH3; L = CO,PPh3 and tetracyanoethylene) with XCN (X = Br,I)

Oxidative addition of XCN (X = Br, I) to Cp′Co(CO)L (L = CO, PPh₃) leads to the formation of Cp′CoL(CN)X. The complexes C′_pCoTCNE(L) do not react with XCN.     

Synthesis and Crystal Structure of (L)2W(CO)4·CH3COCH3 (L = 1-Phenacylimidazole)

The reaction of 1-phenacylimidazole with W(CO)6 in a 1:1 molar ratio under irra- diation with a high-pressure Hg lamp mainly yielded the title compound (C29H26N4O7W, Mr = 726.39), which is of orthorhombic, space group Pbca with a = 27.665(4), b = 7.7807(12), c = 27.803(4) (A), V = 5984.8(16) (A)3, Z = 8, Dc = 1.612 g/cm3, λ(MoKα) = 0.71073 (A), μ = .3.911 mm-1, F(000) = 2864, R = 0.0583 and wR = 0.1502 for 3356 observed reflections (I > 2σ(I)). The crystal structural analysis indicates that in the coordination geometry of tungsten, 1-phenacylimidazole acts as a monodentate ligand and two imidazole ligands locate in a cis-position.     

SYNTHESES AND CRYSTAL STRUCTURE OF [Et_4N]{Mo(CO)_5L}(L=I~-,SPh~-)

<正> Crystal of [Et4N][Mo(CO)5I](1) (Mr = 493. 15) is tetragonal with space group P4/n, a =b==9. 374(2) ,c=10. 545(2)(?), V=926. 5(?)3, Z = 2, F(000) = 480, Dc=1. 77g/cm3and μ = 23. 6cm-1. R = 0. 040, Rw = 0.043 for 374 observed reflections. Crystal of [Et4N][Mb(CO)5(SPh)] (2) is orthorhombic ith space group Pbam, a= 15. 230(3), b = 18. 389(10), c=8. 172(3)(?), V=2288. 6 (?)3, Z = 4, Dc=1. 38gcm3, μ = 6.7cm-1.R = 0. 043, Rw = 0. 042 for 1621 observed reflections. Complexes 1 and 2 possess the same geometry. The Mo atom is octahe-drally coordinated with obvious trans drrdct, all the Mo -C bond lengths are shorter obviously and the C - O bond are longer than those of Mo(CO)6.     

Syntheses,crystal structures,and electrochemical studies of Fe2(CO)6(μ-PPh2)(μ-L) (L = OH,OPPh2, PPh2)

Reaction of Fe₃(CO)₁₂ and Ph₂PH in the presence of Et₃N in THF at 0?°C immediately forms Fe₂(CO)₆(μ-PPh₂)(μ-OH) (1), Fe₂(CO)₆(μ-PPh₂)(μ-k²O,P-OPPh₂) (2), and Fe₂(CO)₆(μ-PPh₂)₂ (3) in yields of 25, 14, and 19%, respectively. Experiments confirm that Et₃N shortens the reaction time. The absence of O₂ hinders the formation of 2. The presence of H₂O can increase the yield of 1. Their structures have been determined by X-ray crystallography and the complexes have been completely characterized by EA, IR, and ¹H, ¹³C, ³¹P NMR. Electrochemical studies reveal that they exhibit catalytic H₂-producing activities.     

Carbonylmetall-verbindungen des bis(di-t-butylphosphino)schwefeldiimids: Bildung von zweikernkomplexen S{NPtBu2[MLn]}2 (MLn = Cr(CO)5), Mo(CO)5, W(CO)5, Fe(CO)4) und chelatkomplexen S(NPtBu2)2M(CO)4 (M = Cr,Mo, W). Kristall- und molekülstruktur von S(NPtBu2)2Cr(CO)4

The reaction of bis(di-t-butylphosphino) sulphur diimide, S(NP^tBu₂)₂ (1) ¹, with coordinatively unsaturated 16-electron complex fragments [M(CO)₅] leads to both binuclear 1 : 2 adducts S{NP^tBu₂[M(CO)₅]}₂ (M = Cr (2B), Mo (3B) and W (4B)) and mononuclear chelate complexes S(NP^tBu₂)₂M(CO)₄ (M = Cr (2C), Mo (3C) and W (4C)). A binuclear compound S{NP^tBu₂[Fe(CO)₄]}₂ (5B) is obtained from the reaction of 1 with Fe₂(CO)₉. The new complexes which all contain the intact sulphyr diimide 1 are characterized on the basis of their infrared, ¹H, ¹³C and ³¹P NMR spectra. An X-ray structure analysis of S(NP^tBu₂)₂Cr(CO)₄ (2C) reveals a distorted octahedral coordination sphere around the central chromium atom and an almost planar but twisted six-membered Cr(PN)₂S heterocycle with angles of 91.98(2)° at chromium (P(1)CrP(2)) and 124.6(1)° at sulphur (N(1)SN(2)).     

Synthesis and Crystal Structure of (L)_2W(CO)_4·CH_3COCH_3 (L=1-Phenacylimidazole)

1 INTRODUCTION Due to their variability in binding modes, five- membered heterocyclic ligands such as pyrazole[1] and 1,2,4-triazole[2] have been drawn much attention. Consequently, there are numerous reports on their derivatives. Imidazoles resemble pyrazoles, and they are isomeric five-membered heterocyclic molecules containing two nitrogen atoms. Furthermore, imida- zole is also a ring component of adenine and purine, one of the most versatile binding sites in biological systems, so th…     

Übergangsmetallcarbin-komplexe: LXXXV. Strukturuntersuchungen der reaktionsprodukte von trans-Br(CO)2L2LCNEt2 (L2 = 2,2′-bipyridyl, 1,10-phenanthrolin) mit den organylanionen [(CO)5MEPh2]− (M = Cr,Mo, W; E = P,As, Sb)

The reaction of trans-Br(CO)₂L₂WCNEt₂ (L₂ = 2,2′-bipyridyl (2,2′-bipy), 1,10-phenanthroline (ophen)) with organyl anions of Main Group V elements coordinated to a pentacarbonylmetal fragment of the general formula [(CO)₅MEPh₂]⁻ (M = Cr, Mo, W; E = P, As, Sb) leads, by substitution of the bromine ligand, to new neutral diethylaminocarbyne complexes of the type (CO)₅MEPh₂(CO)₂L₂-WCNEt₂ (M = Cr, Mo, W; E = P, As, Sb; L₂ = 2,2′-bipy, ophen) which contain a heavier element of Main Group V in a bridging position between two transition metals. Spectroscopic investigations at low temperatures show that the bridged complexes exist as a mixture of cis and trans isomers, with the thermodynamic equilibrium favouring the cis complexes. Temperature dependent NMR spectra indicate a dynamic process in which the chelating ligand L₂ (L₂ = 2,2′-bipy, ophen) switches between two cis and two cis / trans positions, relative to the carbyne ligand, and causes a rapid interconversion of the two stereoisomers at room temperature.     

Cluster synthesis. 42. The synthesis and crystal and molecular structures of the sulfur-bridged platinum-ruthenium carbonyl cluster compounds PtRu3(CO)9 L(PPh3)(μ3-S)2 (L=CO,PPh3) and PtRu4(CO)12(PPh3)(μ4-S)2

Two new mixed metal cluster complexes PtRu₃(CO)₁₀(PPh₃)(₃-S)₂,3 14% yield and PtRu₃(CO)₉(PPh₃)₂(₃-S)₂,4 23% yield were obtained from the reaction of Ru₃(CO)₉(₃-S)₂,1 with Pt(PPh₃)₂(C₂H₄) at 0°C. The cluster of4 consists of a spiked triangle of four metal atoms with two triply bridging sulfido ligands. The reaction of Ru₄(CO)₁₁(₄-S)₂,2 with Pt(PPh₃)₂(C₂H₄) yielded the expanded mixed-metal cluster complex PtRu₄(CO)₁₂(PPh₃)(₄-S)₂,5 in 12% yield. The structure of the cluster5 can be described as a pentagonal bipyramid of five metal atoms and two sulfido ligands with one metal-metal bond missing. Compounds4 and5 were characterized by a single-crystal X-ray diffraction analyses.     

磷光配合物(L)Re(CO)3Cl(L=α,α-diamine)的电化学性质和电子能级

通过循环伏安法对磷光发光材料(L)Re(CO)3Cl(L=α,α-diamine)系列配合物的电化学性质进行了研究.结合电子吸收、荧光光谱和量子化学计算确定了其能级结构,考察了二胺配体的取代基修饰对能级结构影响的规律.(L)Re(CO)3Cl系列配合物表现为单一的氧化(正电位方向)和多步还原(负电位方向)过程,分别反映了Re—Cl的杂化轨道组成的HOMO能级和二胺配体的π*轨道组成的LUMO能级的结构.与光谱数据比较发现,(L)Re(CO)3Cl配合物电化学数据主要反映的是三重态电子能级结构.     

cis-[Pt(NH3)2(L)]2+/+ (L = Cl, H2O, NH3) binding to purines and CO: does pi-back-donation play a role?

The ability of cis-[Pt(NH(3))(2)(L)](2+/+), a molecular fragment of the anticancer drug cisplatin, to bind to purines and CO by pi-back-donation from Pt to the ligand was examined computationally. Optimized geometries and computed vibrational frequencies suggest that cis-[Pt(NH(3))(2)(L)](2+/+) (L = Cl, H(2)O, NH(3)) is a poor pi-donor and that pi-back-donation does not play an important role for Pt(II)-ligand interactions in general.