Mixed Ruthenium–Iridium Carbonyl Cluster Complexes. Synthesis of the Anions [Ru3Ir2(CO)14]2− and [Ru3Ir2(CO)14H]− and Crystal Structures of Their [tetraphenylphosphonium]+ Salts

The reaction of Ru₃(CO)₁₂ and [Ir(CO)₄]^- (as [PPh₄]⁺ or [N(PPh₃)₂]⁺ salts) yields the anion [Ru₃Ir₂(CO)₁₄]^2- (1) which has been found to derive from the intermediate [Ru₃Ir(CO)₁₃]^- anion. Treatment of (1) with acids gives the conjugated hydrido species [Ru₃Ir₂(CO)₁₄H]^- (2). The two anions were characterized by single-crystal X-ray diffraction of their [PPh₄]⁺ salts. [PPh₄]₂[Ru₃Ir₂(CO)₁₄]: space group C2/c, Z=4, a=22.121(5) Å, b=10.546(5) Å, c=25.931(5) Å, =103.870(5)°, R=0.052 and R_w=0.130 for 3128 independent reflections with I>2(I ). [PPh₄][Ru₃Ir₂(CO)₁₄H]: space group P2₁/c, Z=8, a=22.833(5) Å, b=13.893(5) Å, c=25.810(5) Å, =92.650(5)°, R=0.070 and R_w=0.150 for 12141 independent reflections with I>2(I). Both anions 1 and 2 have a trigonal bipyramidal metal frame. There are two independent anions in the asymmetric unit of 2 differing in their ligand stereochemistry.     

Crystal Structure of a Novel Phosphorane (C30H27N3O12P4)with Three P-P Bonds

1　INTRODUCTIONInrecentyears,therehasbeenmuchinterestinphosphoranescontainingonlyonephosphorus-phosphorusbondandthestructuresofmostofthesecompoundshavebeenidentifiedbyX-raycrystallography[1～6].In1990,anewtypeofphosphoraneinvolvingtwoP-Pbondswassuccessfullysynthesized[7],butthecrystalstructurewasnotdetermined.Wehavesuccessfullysynthesizedthenovelphosphorane3bear-ingthreeP-Pbonds.Hereitscrystalstructureisreported.2　EXPERIMENTAL2.1　PreparationAllprocedureswereperformedunderN2atmos…     

Oxidative coupling of radicals in reactions of compounds of tervalent iodine with trimethylsilyl(phenyl) acetylene

Reactions of trimethylsily](phenyl)acetyleiie with aryl and alkyl difluoroiodides give coupling products of substituents in high yields.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 1022–1023, April, 1996.     

Synthesis, structure, and reaction of tricoordinate stibine and tetracoordinate stiboranide

Tricoordinate stibine 1 and tetracoordinate stiboranide 2a were synthesized by utilizing SbCl₃. The structure of 2a was confirmed by X-ray analysis. The interconversion between 1 and 2 could be achieved by BrNEt₄ and NaH or BuLi. The pentacoordinate apicophilic stiborane 6 was prepared from 1. Due to steric repulsion between the TIP group and the aromatic ring, the C1-Sb-C2 angle of 6b was narrowed by 4.4° compared to that of 6a by X-ray analysis.     

Crystal Structure of 2-Germatranylmethyl-N-(4'-methylphenyl) succinimide

1INrnODUCTIONItiswell-knownthatitaconicacidderivativesandgermatraneshavemanybioac-tivitiest1.23.lnordertoinvestigatethestructureandantitumoractivitiesofnewger-maniumcompounds,wesynthesizedaseriesofpolycycliccompoundsbythereactionoftrichlorogermanewith2-succinimidesor2-methylenesuccinamicacids[3i.Aspartofthiswork,n0wwereP0rtinthispaPerthecrystalstructureofthetitlec0mpound.2EXPERIMENTAL2-Germatranylmethyl-N-(4'-methylphenyl)succinimidewassynthesizedasacolourlesscrystal,anditsstructureh…     

Sequential Nucleophilic Substitution of Phosphorus Trichloride with Alcohols in a Continuous-Flow Reactor and Consideration of a Mechanism for Reduced Over-reaction through the Addition of Imidazole

We demonstrate a sequential nucleophilic substitution of highly electrophilic and inexpensive phosphorus trichloride with three different alcohols in a continuous-flow reactor. A variety of alcohols including ones that contained acid- and/or basic-labile functionalities were rapidly reacted. A over nucleophilic substitution that occurred during reaction of the second alcohol was suppressed by the addition of imidazole. Density functional theory calculations of the sequential nucleophilic substitutions of alcohols were performed both with and without imidazole, and Berry pseudorotation was suggested as a rate-limiting step in both cases. Herein, we discuss the reasons for the decreased selectivity in the absence of imidazole as well as those for improved selectivity in the presence of imidazole during the second nucleophilic substitution.     

FREE RADICAL RING OPENING POLYMERIZATION OF CYCLIC ACRYLATES

Cyclic acrylates, 2,2- dimethyl-5-methylene-1 , 3-dioxolan-4 -one and 2- phenyl-5-methylene-1,3-dioxolan-4-one, were synthesized successfully. The monomers were characterized by ~1H NMR, ~(13)C NMR, IR and elemental analysis or HRMS. Polymerization of the monomers were carried out at 120℃with di-t-butylperoxide as initiator. The polymers were studied by ~1H NMR, ~(13)C NMR, UV and hydrolysis. The molecular weights of the resulting polymers were estimated by viscosity measurement and the extent of ring opening was estimated also by ~1H NMR and hydrolysis of the polymers and further confirmed by UV spectra.     

Synthesis and Crystal Structure of Fe（aapo）2Cl3 （aapo=2—Acetylamino Pyridine N—Oxide

1INTRODUCTIONComplexesofpyridineN-oxideligandshavereceivedmoreandmoreattention,andwehavereportedsomeofthemcontainingadonorsubstituteatthe2-positioninanattempttobroadentherangeofpyridineN-oxidecomplexes[1,2].MostcrystalstructuresofpyridineN-oxidesreportedareaboutdivalenttransitionmetalionsM(Ⅱ)[1～4],withonlyaveryfewontrivalenttransitionmetalionsM(Ⅲ)[5].Asthecontinuingworkofsystematicresearch,herewewillpresentthesynthesisandstructureofthetitlecompound.Toourknowledge,itisthefirstexamplet…     

Bis-(2-diphenylphosphinoethyl)cyclopentadienylchlorolutetium: synthesis and dynamic behavior in solution

The new biscyclopentadienyl lutetium complex (⁵:¹-C₅H₄CH₂CH₂PPh₂)₂LuCl was synthesized by the reaction of LuCl₃(THF)₃ with lithium (2-diphenylphosphinoethyl)cyclopentadienide. Its behavior in solution was investigated by dynamic NMR spectroscopy. It was shown that the coordination of both phosphino groups to the lutetium center is retained over the whole temperature range studied. The barrier to pseudo-rotation for the trigonal bipyramid, which governs the intramolecular dynamics of this complex, was determined.     

Berry pseudorotation mechanism for the interpretation of the 19F NMR spectrum in PF5 by ab initio molecular dynamics simulations.

For the first time, theoretical evidence that confirms the importance of the Berry pseudorotation process in the interpretation of the 19F NMR spectrum of phosphorus pentafluoride (PF5) is presented. Ab initio molecular dynamics simulations have been performed to generate a large number of configurations used for NMR parameter computations at the density functional theory level. Two different temperatures were set to highlight the effect of pseudorotation process on the NMR spectrum. Average 19F chemical shifts and spin-spin coupling constants calculated for the five fluorine atoms converge towards the NMR equivalence of the five atoms when the Berry pseudorotation mechanism is accounted for.     

Comparison of Si_n~+ and Ge_n~+(n=2―15) Cationic Structures

We designed and optimized a large number of the isomers of Si12+ at the level of density functional theory (DFT)-B3LYP/6-311++G(d) using the Gaussian 03 software package. An unambiguous structure of the Si12+ cluster is presented, whose IR spectrum agrees well with the experiment result. The most stable geometric structures of Gen+(n=2―15) clusters were determined by the all-electron PBE/DND method in DMol3 of the Material Studio Package, and compared with those of the corresponding Sin+ geometries. Most st...     

Highly Strained Metallocenophanes: Synthesis and Ring-Opening of Sulfur-, Selenium- and Boron- Bridged [1]Ferrocenophanes

Abstract

The limits of cyclopentadienyl ring-tilting in [l]ferrocenophanes are explored with the incorporation of group 16 elements and a first row element. In this paper the synthesis and ring-opening polymerisation (ROP) behaviour of highly strained chalcogen-and boron- bridged [l]ferrocenophanes will be described.     

金/巯基环肽单层膜的循环伏安和交流阻抗初步研究

用电化学方法初步研究了巯基环肽的在金基底上形成的吸附层,结果表明硫基环肽（CPCBC）可以在金表面形成成具有一定覆盖度的吸附膜;与烷基硫醇单层膜不同的是,该吸附膜十分松散。我们初步认为巯基环肽分子采用“直立式吸附”并且巯基环肽分子结构的复杂性是造成吸附膜松散的原因。     

Synthesis and crystal structure of a mixed-ligand compound di-n-butyl(4-chlorobenzoxy)(4-chlorobenzohydroxamato)tin(IV)

Reaction of dibutyltin dichloride with 4-chlorobenzohydroxamic acid and 4-chlorobenzoic acid in 1:1:1 stoichiometry yields the new title compound di-n-butyl(4-chlorobenzoxy)(4-chlorobenzohydroxamato)tin(IV) 1, which had been characterized by IR and ¹H, ¹³C, ¹¹⁹Sn NMR. Single X-ray crystal structure analysis has been determined for 1, which crystallizes as the five-coordinate mixed-ligand dibutyltin(IV) complex containing both monodentate and bidentate ligands. The crystal structure of the compound reveals that the tin atom adopts distorted trigonal bipyramidal geometry with the Bu groups trans to each other. The C-Sn-C angle is 145.9(3)°, and the Sn-O bonds are 2.083(4) and 2.158(4) Å in one ligand and 2.242(4) Å in the other. An unusual feature of the structure is the presence of a kind of intermolecular hydrogen bonding which serves to stabilize the crystal structure.     

环酮及其衍生物的光化学反应研究进展

综述了环酮及其衍生物的光化学反应的有机进展.较详细地介绍了单环酮、芳香酮、二元酮和二元环酮的光氧化反应、光还原反应、光偶联反应,尤其是对非增感光氧化反应、潜手性酮的不对称光还原反应以及激光在有机光化学反应中的应用也进行了介绍.     

环状膦酸酯的合成及其质谱特征

本文研究了环状膦酸酯的合成方法，通过三种方法合成了十五个具有各种烷基结构的六元和七元环膦酸酯，并对这十五个化合物质谱作了分析和归纳，得出了一些有助于鉴定这类膦酸酯的质谱特征。     

PE AND UV SPECTRA OF LINEAR AND CYCLIC POLYSILANES AND ASSIGNMENT BY AB INITIO CALCULATIONS

Abstract

Ab initio calculations have been performed on linear and cyclic polysilanes including permethylsubstituted compounds. Koopmans' approximation was used for assigning experimentally obtained PE and UV spectra. The PE spectrum of octamethylcyclotetrasilane and the UV spectra of cyclopenta and cyclohexasilane are presented for the first time.     

MnO2电极的循环伏安光电化学测量

用循环伏安法的光电化学现场测量研究了γ-MnO_2在充放电过程中的电化学和光电化学性质, γ-MnO_2本身的光电流为正值, 在阴极还原过程中光电流不断减小, 由正值变为负值。说明γ-MnO_2是n型半导体, 阴极还原过程相当于对γ-MnO_2进行了p型掺杂。