Crystallographic evidence of hexacoordination at phosphorus via intramolecular coordination of donor groups on phosphane and phosphane sulphide

The X-ray structure analysis of bis(8-dimethylamino-l-naphthyl)phenylphosphane (3) and of the corresponding sulphide 4 has revealed hexacoordination at phosphorus in both cases, the N … P separations being less than the sum of the van der Waal radii. Furthermore, in both cases the overall geometry corresponds to a distorted bicapped tetrahedron. The optimum geometry calculated for 4 via the program developed by Autodesk (MM + method) suggests that the structure of the molecule is a function not only of steric requirements but also of electronic effects.     

高折光指数光学树脂的合成——相转移法合成不饱和硫醇酯单体的条件控制

采用正常的低温相转移催化（ＰＴＣ）和反滴碱溶液ＰＴＣ法分别合成了含硫双烯ＭＥＳＤＭＡ和单烯ＭＥＰＳＭＡ．１Ｈ ＮＭＲ分析证明ＭＥＳ中的杂质主要是由原料ＴＤＧ引入的．对含单个巯基的ＭＥＰＳ的正常ＰＴＣ酯化接枝双键，因存在巯基和不饱和双键的加成反应而导致失败．作者最终得到了折光指数在１６２５以上的ＭＥＳＤＭＡ／ＭＥＰＳＭＡ共聚物．     

四核钴羰基簇合物Co4(CO)8(μ-CO)2(μ4-PSR)2的合成和晶体结构

The title compounds Co4(CO)8(μ-CO)2 (μ4-PSR) [R=-CH3, -C2H5, -C(CH3)3,-(CHa)4CH3] were synthesized by the reaction of Co2(CO)8 with RSPCl2. They were characterized by IR, 1HNMR, elemental analysis. The crystal and molecular structure of Co4(Co)8(μ-CO)2 (μ4-PSC2H5) has been determined by single crystal diffraction method. Crystal data: monoclinic, space group P21 /c, with a=8-445(3), 6=8.562(3), c= 17.125(6)Å, β=104.26 (3)' 9 V=1200.1Å3, Z=2, Dc=1.937gcm-3. Its molecular structure contains an octahedral Co4P2 skeleton which consists of a rectangular four cobalt atoms core and the Co4 core is capped above and below by two quadruply bridging PSR ligands.     

Synthesis of poly(2,5-dimethylphenylene sulfide) through oxidative polymerization of sulfur chloride with p-xylene

Poly(2,5-dimethylphenylene sulfide) was prepared by oxidative polymerization of sulfur chloride with p-xylene using 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) as an oxidizing agent. The reaction proceeded efficiently under atmospheric pressure and at room temperature. The polymer formed had a high melting temperature and linear structure which was confirmed by spectroscopies. The effects of reaction time, solvent, temperature and oxidizing agent on polymerization are also discussed.     

Perturbative solution of the RPA equation. An application to the calculation of rotational strengths

The RPA equation is solved by perturbation in Møller-Plesset (MP) and Epstein-Nesbet (EN) partitions, which are first compared on a specific example. To still accelerate the faster one (EN), a third scheme is proposed, which involves preliminary diagonalization within a limited subset , followed by usual EN perturbation between and the rest of the whole configuration space. Criteria for the choice of are given.     

Neue neutrale und kationische Mono‐Aziridin‐Komplexe des Typs [CpMn(CO)2Az], [CpCr(NO)2Az]+ und [(Ph3P)(CO)4ReAz]+ über CO‐, Hydrid‐ und Chlorid‐Abspaltungsreaktionen

Novel Neutral and Cationic Mono‐Aziridine Complexes of the Type [CpMn(CO)₂Az], [CpCr(NO)₂Az]⁺, and [(Ph₃P)(CO)₄ReAz]⁺ via CO‐, Hydride‐, and Chloride‐Elimination Reactions The monoaziridine complexes 1 — 5 are obtained by three differently induced substitution reactions. The photolytically induced CO substitution reaction of [CpMn(CO)₃] with 2, 2‐dimethylaziridine leads to the neutral N‐coordinate aziridine complex [Cp(CO)₂Mn{$\overline{N(H)CMe₂C}$ H₂}] ( 1 ). The protonation of [(Ph₃P)(CO)₄ReH] with CF₃SO₃H and consecutive treatment with 2, 2‐dimethylaziridine or 2‐ethylaziridine gives the salt‐like aziridine complexes [(Ph₃P)(CO)₄Re{$\overline{N(H)CMe₂C}$ H₂}](CF₃SO₃) ( 2 ) or [(Ph₃P)(CO)₄Re{ H₂}](CF₃SO₃) ( 3 ) by hydride elimination reactions. The like‐wise salt‐like complexes [Cp(NO)₂Cr{$\overline{N(H)CMe₂C}$ H₂}](BF₄) ( 4 ) and [Cp(NO)₂Cr{ H₂}](CF₃SO₃) ( 5 ) are synthesized from [CpCr(NO)₂Cl] by chloride elimination with AgX (X = BF₄, CF₃SO₃) in the presence of 2, 2‐dimethylaziridine or 2‐ethylaziridine, respectively. As a result of X‐ray structure analyses, the metal atoms are trigonal pyramidally ( 1, 4, 5 ) or octahedrally ( 2, 3 , cis‐position) configurated; the intact three‐membered rings coordinate through the distorted tetrahedrally configurated N atoms. All compounds 1‐5 are stable with respect to the directed thermal alkene elimination to give the corresponding nitrene complexes; the IR, ¹H‐ and ¹³C{¹H}‐NMR, and MS spectra are reported and discussed.     

Oxorhenium(V)‐ and Tricarbonylrhenium(I) Complexes with Substituted Pyrazoles as Products of the Degradation of Hydrotrispyrazolylborates

Hydrotris(3, 5‐dimethylpyrazol‐1‐yl)borate and hydrotris(3‐phenylpyrazol‐1‐yl)borate decompose during reactions with [ReOCl₃(PPh₃)₂] and [NEt₄]₂[Re(CO)₃Br₃], respectively. The generated pyrazole ligands form complexes with the rhenium(V) oxo and the rhenium(I ) tricarbonyl cores. X‐ray crystal structures of the oxo‐bridged dimer [Cl(PPh₃)(O)Re(μ‐O)(μ‐Me₂pz)₂Re(O)(HMe₂pz)Cl] ( 1 ) and [Re(CO)₃(HPhpz)₂(Phpz)] ( 2 ) (HMe₂pz = 3, 5‐dimethylpyrazole, HPhpz = 3‐phenylpyrazole) show that the substituted pyrazoles can readily deprotonate and act as monodentate or bridging anionic ligands. Re‐N bond lengths between 2.09 and 2.14Å have been observed for the bridging and between 2.12 and 2.23Å for the terminal pyrazole ligands.     

Products of Ag+, Cu+ and Cu2+ Ion Implantation in the Surface of Polycrystalline Cadmium Sulfide as Photocatalysts for the Oxidation–Reduction Reaction of Methylene Blue with Formaldehyde

Semiconductor–semiconductor and molecule (molecular ion)–semiconductor products are formed upon the implantation of Ag⁺, Cu⁺, and Cu²⁺ ions in the CdS surface. Possible mechanisms were examined for their photocatalytic action in the reduction of methylene blue.     

Mixed-metal cluster chemistry. 26 . Proclivity for “all-terminal” or “plane-of-bridging-carbonyls” ligand disposition in tungsten-triiridium clusters

Reaction of WH(CO)₃(η-C₅Me₅) with IrCl(CO)₂(4-H₂NC₆H₄Me) affords WIr₃(μ-CO)₃(CO)₈(η-C₅Me₅) in low yield. A structural study reveals a WIr₂-centred plane of bridging carbonyls, in contrast to the crystal structure of WIr₃(CO)₁₁(η-C₅H₅) (all-terminal carbonyl distribution). DFT calculations reveal an increasing proclivity to adopt an all-terminal CO disposition for clusters MIr₃(CO)₁₁(η-C₅H₅) in the gas phase on proceeding from M=Cr to Mo and then W, consistent with structural studies in the solid state for which the tungsten-containing cluster is the only all-terminal example. Increasing electron donation from the ligands in the tungsten system (either from phosphine substitution or cyclopentadienyl permethylation) suffices to impose a plane of bridging carbonyls in the ground state structure. ¹³C NMR fluxionality studies reveal that CO exchange mechanism(s) for WIr₃(CO)₁₁(η-C₅H₅) and the related tetrahedral cluster W₂Ir₂(CO)₁₀(η-C₅H₅)₂ are very fast and involve all carbonyls on the clusters. DFT calculations on MIr₃(CO)₁₁(η-C₅H₅) (M=Cr, Mo) substantiate a ‘merry-go-round’ mechanism for carbonyl scrambling in these systems, a result which is consistent with the scrambling behaviour seen in the NMR fluxionality studies on the W-containing congener.     

Synthesis and electrochemistry of Group 6 tetracarbonyl (N,N′-bis(ferrocenylmethylene)ethylenediamine)metal(0) complexes

Thermal substitution reaction of Cr(CO)₄(η^2:2-1,5-cyclooctadiene), Mo(CO)₄(η^2:2-norbornadiene), and W(CO)₅(η²-bis(trimethylsilyl)ethyne) with N,N′-bis(ferrocenylmethylene)ethylenediamine (bfeda) yields M(CO)₄(bfeda) complexes which could be isolated from the reaction solution and characterized by elemental analysis, MS, IR, and NMR spectroscopy. In the case of tungsten, W(CO)₅(bfeda) is formed as intermediate and then undergoes the ring closure reaction yielding the ultimate product W(CO)₄(bfeda). The electrochemical behavior of the M(CO)₄(bfeda) complexes was studied by using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) in dichloromethane with tetrabutylammonium tetrafluoroborate as electrolyte. Constant potential electrolysis of the complexes was performed successively at their peak potentials at 0 °C in their CH₂Cl₂ solution and the electrolysis was followed by in situ recording the electronic absorption spectra in every 5 mC. In the electrolysis of Cr(CO)₄(bfeda), the central Cr(0) is oxidized first and electrolysis continues with oxidations of two ferrocenyl groups until the end of totally three moles of electron passage per mole of complex. In the electrolysis of Mo(CO)₄(bfeda) and W(CO)₄(bfeda) the first oxidation occurs on the central atom forming a short-lived species which undergoes an intramolecular one-electron transfer and is reduced back to M(0) while one of the ferrocene units is oxidized to the ferrocenium cation at the same time. This indicates that the electron is transferred from iron to the central metal atom.