Torsional potentials and conformational structures in the halogen substituted molecules HOCCH2X,HOCCHX2, XOCCH2X,XOCCHX2, XH2CCOCH3, X2HCCOCH3, (XH2C)2CO, (X2HC)2CO,and (X3C)2CO (X = Cl,Br) as determined by molecular-mechanics calculations

Parameter values of the non-blonded atom⋯atom interaction Br⋯OC have been established from gas-phase data. Conformational energies, structures, torsional barrier heights and torsional force constants of the title compounds have been estimated. For BrOCCH₂Br, (Cl₃C)₂CO and (ClH₂C)₂CO the calculated results are compared with gas-phase observations. It is suggested that hexachloroacetone ought to be reinvestigated by electron diffraction.     

Glass-forming region and structure in SiS2Li2SLiX (X = Br,I)

The glass-forming region in the SiS₂Li₂SLiX (X = Br, I) system, as determined by X-ray diffraction, has been extended to higher lithium content by the use of a direct liquid nitrogen quench. The base glass, 0.4SiS₂0.6Li₂S, was synthesized and doping up to 0.28SiS₂0.42Li₂S0.30LiBr and 0.24SiS₂0.36Li₂S0.40LiI was achieved. The properties of these glasses are compared to the glasses formed by previously reported quenching methods.Vibrational assignments have been made from infrared investigation of the glasses using FT-IR. The basic glass network consists of SiS₄ tetrahedra while the addition of Li₂S as a network modifier produced nonbridging sulfur. Doping with lithium halide did not significantly change the glass network, i.e., no changes in IR peak positions were observed. However, the higher lithium ion concentration resulted in higher mobility and ionic conduction.     

Sn(II)―X和Sn(IV)―X (X=O,S, N,C, P,As, Se,Te, F,Cl, Br,I)键价参数

基于剑桥晶体数据库中同配配合物的Sn(Ⅱ)―X和Sn(Ⅳ)―X(X=O,S,N,C,P,As,Se,Te,F,Cl,Br,I)键长数据,采用键价参数B=0.037nm拟合得到Sn(Ⅱ)―X和Sn(Ⅳ)―X的键价参数R0,这样拟合的经验参数R0中有一些是首次推出.本文所报道的Sn(Ⅱ)―O键基于B=0.037nm的R0值(0.1956nm)可适用于多数Sn(Ⅱ)呈各种配位数时的氧化态指定,而文献报道的B=0.055nm和R0=0.1859nm主要对于低配位的情况能取得Sn(Ⅱ)原子价态指定的较好结果.本研究证明,进一步研究键价参数对键价和(BVS)计算至关重要的那些可能的因素实乃当务之急.     

(Me3Sn)2SbSb(SnMe3)2, 1∞-verknüpfte SbSb-Hanteln in einem thermochromen Distiban mit Schweratomgerüst

Single crystals of the thermochromic distibane (Me₃Sn)₄Sb₂ (1) are obtained by irradiation of (Me₃Sn)₃Sb with sunlight. The crystal structure of 1 is reported as linear chains of distibane molecules in trans conformation with Sb ⋯ Sb contacts of 389 ppm. Diffuse reflexion spectra of 1 in the solid state and in solution demonstrate thermochromic effect. The Raman spectrum of solid 1 exhibits strong absorption at 162 cm⁻¹ for ν(Sb₂).     

The vibrational spectra of (CH3)3MCCCCM(CH3)3, with M = C,Si, Ge,or Sn

Infrared spectra from 200 to 4000 cm⁻¹ and Raman spectra from 80 to 4000 cm⁻¹ have been recorded for the molecules (CH₃)₃MCCCCM(CH₃)₃ with M = C, Si, Ge, or Sn. Solid samples and solutions in several solvents have been used. Assignments of the fundamentals were made on the assumption of D_3d symmetry, which proved quite satisfactory. In all, 140 of the 188 spectroscopically-active fundamentals for the four molecules have been assigned.The in-phase CC stretch is 115–135 cm⁻¹ higher than the out-of-phase one. This is in sharp contrast to cumulated double bonds, where the in-phase stretch is roughly half the out-of-phase one. A rationalization of this is given.     

Synthesis,Characterization and Crystal Structure of (PhCH2)2Sn(S2CENt2) and (PhCH2)2Sn(S2CNC4H8)2

Two new dibenzyltin bisditiocarbamates(PhCH2)2 Sn(S2CNEt2)2(1) and (PhCH2)2 Sn(S2CNC4H8)2(2) were synthesized by the reaction of dibenzyltin dichloride with dithiocarbamates and characterized by elemental analysis ,IR,^1H NMR and MS spectra.The crystal structures were determined by X-ray single crystal diffraction analysis.In both complexes,the tin atom is six-coordinated in a distorted octahedral configuration.In the crystals of 1,the molecular packing in unit cell reveals that the two adjacent molecules are symmetrically linked to each other in dimers by two Sn S interactions of 0.3816nm.In the crystals of 2,the molecules are packed in the unit cell in one-dimensional chain structure linked by weaker intermolecular S S conmtacts.     

The reaction of Sn[CH(SiMe3)2]2 with ethyne: formation of (HCC)Sn[CH(SiMe3)2]2(μ-trans-CHCH)Sn[CH-(SiMe3)2]2(CHCH2)

The reaction of Sn[CH(SiMe₃)₂]₂ and ethyne at ambient temperature affords a mixture of products, from which the title compound has been separated and identified by IR, ¹H, and ¹³C NMR spectroscopy.     

Synthesis,chemical and biological properties of &{Pt[S(CH2)3Cl]2}6 and Pt[C6H3(oCH2CH  CH2)(p-CH3)]2

PtCl₄²⁻ with the ligand HS(CH₂)₃Cl affords a linear polymer which is converted into the hexamer title compound by heating in xylene in the presence of a small amount of dimethylsulphoxide. The hexamer undergoes Cl substitution upon reaction with NaBr or NaI. From the reaction of PtCl₂ with the Grignard reagent of o-allyl-p-methyl-chlorobenzene is obtained the monomer complex Pt[C₆H₃(CH₂CH  CH₂-o) (CH₃p)]₂. The biological properties of the complexes as inhibitors of DNA, RNA and protein synthesis has been evaluated.     

Sn(Ⅱ)-X和Sn(Ⅳ)-X (X=O,S,N,C,P,As,Se,Te,F,Cl,Br,I)键价参数

基于剑桥晶体数据库中同配配合物的Sn(Ⅱ)-X和Sn(Ⅳ)-X (X=O,S,N,C,P,As,Se,Te,F,Cl,Br,I)键长数据,采用键价参数B=0.037 nm拟合得到Sn(Ⅱ)-X和Sn(Ⅳ)-X的键价参数R0,这样拟合的经验参数R0中有一些是首次推出.本文所报道的Sn(Ⅱ)-O键基于B=0.037 nm的R0值(0.1956 nm)可适用于多数Sn(Ⅱ)呈各种配位数时的氧化态指定,而文献报道的B=0.055 nm和R0=0.1859 nm主要对于低配位的情况能取得Sn(Ⅱ)原子价态指定的较好结果.本研究证明,进一步研究键价参数对键价和(BVS)计算至关重要的那些可能的因素实乃当务之急.     

Reactivity of [M(CO)3(NN)(thioureas)] (M = Mo,W; NN = 2,2′bipyridine, 1,10-phenanthroline) complexes towards systems with mercury-halides bonds. Trimetallic compounds with XMHgM′X (M′ = Mo,W; X = Cl,Br, I) bondings

New heterotrimetallic complexes were isolated by reaction of M(CO)₃(NN)L (M = Mo, W; NN = bipy, phen; L = thioureas) either with HgX₂ (X = Cl, Br, I) giving complexes of the formula [M(CO)₃(NN)(X)]₂Hg or with M′(CO)₃(NN′)(Cl)(HgCl) (M′ = Mo, W; NN′ = bipy, phen) producing compounds of the type (Cl)(NN)(CO)₃MHgM′(CO)₃(NN′)(Cl). These new photosensitive substances were characterized through IR spectroscopy and conductivity measurements. Structures involving XMHgM′X bonding are proposed and the reactions are discussed in terms of an insertion of the fragment M(CO)₃(NN) into the HgX bonds.     

Über gemischte bindungen in der IV. hauptgruppe: III. Octaphenylpropan-analoga Ph3SnSiPh2SnPh3 und Ph3SnGePh2SnPh3, korrelation zwischen geminalen NMR-kopplungen 2J(SnMSn) und nicht-bindenden Sn⋯Sn-abständen

Reaction of Ph₃SnLi with Ph₂SiCl₂ or Ph₂GeCl₂ at −78°C in THF yields (Ph₃Sn)₂SiPh₂ (1) and (Ph₃Sn)₂GePh₂ (2). The crystal structure of 1 (R = 0.075) exhibits SnSi distances of 257.2(4) and 257.9(5) pm, an SnSiSn angle of 118.5(2)°, and a central C₃SnSiC₂SnC₃ molecular skeleton with symmetry close to C₂. The geminal NMR coupling ²J(¹¹⁹Sn ⋯ ¹¹⁹Sn) in 1, and in a tri-, tetra- and pentastannane series shows a linear correlation to their respective non-bonded d(Sn ⋯ Sn) distances (I(t-Bu₂Sn)₄I: 20 Hz/496 pm; 1: 724 Hz/443 pm).     

Density functional study of S(N) 2 substitution reactions for CH(3) Cl + CX(1) X(2•-) (X(1) X(2) = HH, HF, HCl, HBr, HI, FF, ClCl, BrBr, and II)

A systematic investigation on the S_N2 displacement reactions of nine carbene radical anions toward the substrate CH₃Cl has been theoretically carried out using the popular density functional theory functional BHandHLYP level with different basis sets 6‐31+G (d, p)/relativistic effective core potential (RECP), 6‐311++G (d, p)/RECP, and aug‐cc‐pVTZ/RECP. The studied models are CX¹X^2?? + CH₃Cl → X²X¹CH₃C^? + Cl^?, with CX¹X^2?? = CH₂^??, CHF^??, CHCl^??, CHBr^??, CHI^??, CF₂^??, CCl₂^??, CBr₂^??, and CI₂^??. The main results are proposed as follows: (a) Based on natural bond orbital (NBO), proton affinity (PA), and ionization energy (IE) analysis, reactant CH₂^?? should be a strongest base among the anion‐containing species (CX¹X^2??) and so more favorable nucleophile. (b) Regardless of frontside attacking pathway or backside one, the S_N2 reaction starts at an identical precomplex whose formation with no barrier. (c) The back‐S_N2 pathway is much more preferred than the front‐S_N2 one in terms of the energy gaps [ΔE(front)?ΔE(back)], steric demand, NBO population analysis. Thus, the back‐S_N2 reaction was discussed in detail. On the one hand, based on the energy barriers (ΔE and ΔE) analysis, we have strongly affirmed that the stabilization of back attacking transition states (b‐TSs) presents increase in the order: b‐TS‐CI₂ < b‐TS‐CBr₂ < b‐TS‐CCl₂ < b‐TS‐CHI < b‐TS‐CHBr < b‐TS‐CHCl < b‐TS‐CF₂ < b‐TS‐CHF < b‐TS‐CH₂. On the other hand, depended on discussions of the correlations of ΔE with influence factors (PA, IE, bond order, and ΔE), we have explored how and to what extent they affect the reactions. Moreover, we have predicted that the less size of substitution (α‐atom) required for the gas‐phase reaction with α‐nucleophile is related to the α‐effect and estimated that the reaction with the stronger PA nucleophile, holding the lighter substituted atom, corresponds to the greater exothermicity given out from reactants to products. © 2012 Wiley Periodicals, Inc. J Comput Chem, 2012     

Tantalum dicyclopentadienyl hydrides containing the TaSn σ-bond. Crystal and molecular structure of (η5-C5H5)2TaH2Sn(CH3)Cl2

Interaction of Cp₂TaH₃ (Cp = η⁵-C₅H₅) with Me_nSnCl_4-n (n = 0–2) in benzene leads to heterometallic complexes with the composition Cp₂TaH₂(SnMe_nCl_3-n). The complex Cp₂TaH₂(SnMe₂Cl) can be obtained only when the HCl eliminated is fixed with triethylamine. The Mössbauer, IR and ¹H NMR spectroscopy data show that these compounds have a symmetrical structure with two terminal TaH bonds and a central TaSn σ-bond. The Cp₂TaH₂(SnMeCl₂) complex was studied by X-ray analysis. The crystals of this compound are rhombic with the unit cell parameters a 7.7361(1), b 10.552(1), c 16.943(3) Å, space group P_cmn, R = 0.0264, R_w = 0.0278. The molecule Cp₂TaH₂(SnMeCl₂) possesses a mirror symmetry plane which passes through the centers of the Cp cycles and the Ta, Sn, and C atoms of the methyl group: d(TaSn) 2.752(1), d(Ta-H) 1.61(10) Å. On the basis of spectroscopic and structural data the TaSn bond is concluded to have increased s character.     

The excess enthalpies of liquid GaGeTe and GaSnTe alloys

The excess enthalpies of the liquid alloys GaGeTe and GaSnTe were measured in a heat-flow calorimeter at 1203 K. The enthalpy surface in the ternary space in both systems is characterized by a valley stretching from the exothermic minimum in the GaTe system to the minima of the GeTe and SnTe systems. The minima in the ternary systems were found in this valley, i.e. on the sections Ga₂Te₃-GeTe and Ga₂Te₃-SnTe. A comparison of the experimental data with those calculated from the excess enthalpies of the constituent binaries with the aid of the Bonnier model, reveals only small deviations. A preliminary investigation was made into the ternary phase diagram of GaSnTe. This system contains the two quasibinary sections Ga₂Te₃-SnTe, GaTe-SnTe and the ternary compound Ga₆SnTe₁₀. The previously reported compounds Ga₂SnTe₃ and GaSnTe₂ do not exist.     

Syntheses,structures and characterization of the tetranuclear tin(IV) oxysulfide clusters ( n -Bu4N)2[Sn4(μ4-O)S5(edt)2X2] (X=Cl,Br) (edt=1,2-ethanedithiolate)

During attempts to prepare cubane-like clusters from the precursor (Bu₄N)₂[Sn₃S₄(edt)₃] (edt?=?1,2-ethanedithiolate), two new tetranuclear tin(IV) oxysulfide clusters, (Bu₄N)₂ [Sn₄(μ₄-O)S₅(edt)₂Cl₂] (1) and (Bu₄N)₂[Sn₄(μ₄-O)S₅(edt)₂Br₂] (2) were unexpectedly obtained by reaction of (Bu₄N)₂[Sn₃S₄(edt)₃] with SnX₂ (X?=?Cl,?Br). X-ray crystal structure analyses show that the two compounds possess an isostructural anionic cluster with a highly distorted tetrahedral metal skeleton. The two compounds have been characterized spectroscopically.     

Complexes of the type Mo2(O2CR)2X2(LL) In which the bidentate phosphine ligands LL Straddle the MoMo bond

The reactions of Mo₂(O₂CCH₃)₂Cl₂(PPh₃)₂ with the bidentate phosphine ligands Ph₂PCH₂CH₂PPh₂(dppe), Ph₂PCHCHPPh₂(dppee) and o-C₆H₄(PPh₂)₂(dppbe) yield purple complexes of the stoichiometry Mo₂(O₂CCH₃)₂X₂(LL) in which the acetate ligands are believed to be cis and the LL ligands bridge the dimolybdenum core so that their P atoms are anti to one another. The relationship of these complexes to the previously reported complex Mo₂(O₂CCH₃)₂Cl₂(dppm), where dppm = Ph₂PCH₂PPh₂, is discussed. These complexes have been characterized on the basis of their electrochemical redox properties, and electronic absorption and NMR (¹H and ³¹P{¹H}) spectral measurements.     

Ab initio quantum chemical studies of the electronic properties of the hydrogen bonded N2HF,N2HCl, (HCN)2 and NH3HCN complexes

The results of ab initio self-consistent field (SCF) and configuration interaction (CI) calculations on the hydrogen bonded N₂HF, N₂HCl, (HCN)₂ and NH₃HCN complexes, using basis sets that range from double-zeta plus polarization to triple-zeta plus double polarization, are reported. The primary objective of this work has been to calculate the changes in the dipole moments and the electric field gradients (EFGs) at the quadrupolar ¹⁴N, ²H and ³⁵Cl nuclei that are induced by H-bonding. Since the interpretation of the H-bond induced shifts requires a knowledge of the molecular dynamics in weakly H-bonded molecular complexes such as those studied in the present work, we have taken into account the effects of vibrational averaging on both the EFGs and dipole moments utilizing harmonic intermolecular force fields that were generated using ab initio SCF methods. The results of these calculations are compared with the corresponding experimental quantities that are obtained from the microwave spectra of these complexes.     

The system YPO4Ca3(PO4)2Ca2P2O7

The ternary system YPO₄Ca₃(PO₄)₂Ca₂P₂O₇ has been investigated by differential thermal analysis, powder X-ray diffraction, and microscopy in reflected light. Its phase diagram and isothermal section at room temperature have been determined. The system contains only one double phosphate which is formed at the 1:1 molar ratio YPO₄:Ca₃(PO₄)₂, i.e., Ca₃Y(PO₄)₃.