Mixed valence gold chemistry: Stepwise oxidation of a cyclic trigold(I) complex

Oxidation of the cyclic complex Au₃(CH₃OCNCH₃)₃ by iodine or bromine produces three distinct complexes Au₃(CH₃OCNCH₃)₃X_n (_n = 2,4 or 6, X = Br or I) in which the gold atoms undergo stepwise oxidative halogen addition. The products have been characterized by elemental analysis, molecular weight determinations, proton magnetic resonance spectra and IR spectra. The complexes with n = 4 or 2 undergo spontaneous autodecomposition. In the case of Au₃(CH₃OCNCH₃)₃Br₄ this decomposition produces gold metal, Au₃(CH₃OC NCH₃)₃Br₆, methyl bromide, and methyl isocyanate in an extremely clean reaction.     

Theoretical study of reaction channels for the weakly bound complex systems created with HF,CO2, and various amines

This investigation conducted reaction channels of weakly bound complexes CO₂…HF, CO₂…HF…NH₃, CO₂…HF…NH₂CH₃, CO₂…HF…NH(CH₃)₂, and CO₂…HF…N(CH₃)₃ systems, using the Gaussian 98 package at the B3LYP/6‐311++G(3df,2pd) level. The syn‐fluoroformic acid or syn‐fluoroformic acid plus NH₃ or amine conformers are more stable than the related anti‐fluoroformic acid or anti‐fluoroformic acid plus NH₃ or amine conformers. However, the above‐mentioned weakly bound complexes are more stable than both the related syn‐ and anti‐type fluoroformic acid or acid plus NH₃ or amine conformers and their related decomposed into CO₂ + HF or CO₂ + NHR₃F (R?H, CH₃) combined molecular systems. Five reaction channels of the weakly bound complexes exist. Each channel includes weakly bound complexes and their related above‐mentioned systems. Moreover, each reaction channel contains two transition states. The transition state between the weakly bound complex and anti‐fluoroformic acid type structure (T₁₃) is significantly higher than that of internal rotation (T₂₃) between syn‐ and anti‐FCO₂H (or FCO₂H…NR₃) structures. However, the above‐mentioned T₁₃ can significantly decrease its energy by adding the third molecule NH₃ or NR₃ (R?H or CH₃). The more CH₃ that is substituted in NR₃ of the reaction channel, the lower the activation energy of the transition state in the system is affected. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005     

New cationic and anionic tetracoordinate nickel(I) complexes

Summary The preparation, structural study and chemical behaviour of new cationic, monoanionic and dianionic tetracoordinate nickel(I) complexes of the types: [NiL₄][BPh₄] (L=PPh₃, AsPh₃ or SbPh₃), [PR₄][NiX₂L₂] (X=Cl, Br or I; L=PPh₃, AsPh₃ or SbPh₃ and [PR₄]⁺=PPh₄, Ph₃PCH₂Ph or Ph₃PEt) and [PR₄]₂[NiX₃L] (X=Cl, Br or I; L=PPh₃ and [PR₄]⁺=PPh₄ or PPh₃CH₂Ph) are described.     

Boranate und Boranato-metallate. III. Boranatozinkate der Alkalimetalle

The reaction of zinc halides (ZnCl₂, ZnBr₂) or Zn(BH₄)₂ with LiBH₄ or NaBH₄ in ether or tetrahydrofurane yields LiZn(BH₄)₃, Li₂Zn(BH₄)₄ or NaZn(BH₄)₃ respectively. The latter complex is also obtained by the reaction of NaZn(OCH₃)₃ or Na₂Zn(OCH₃)₄ with diborane. Octakis(tetrahydridoborato)-trizincate K₂Zn₃(BH₄)₈ and BaZn₃(BH₄)₈ are formed by treating Zn(BH₄)₂ with KBH₄ or Ba(BH₄)₂. The ¹¹B-nmr- and ir-spectra of the new complexes are recorded and discussed in terms of double hydrogen bridge bonding of BH₄ groups to the central zinc atom.     

Perfluoralkyljod-verbindungen: das trifluormethyljoddinitrat CF3J(NO3)2

CF₃I(NO₃)₂ is formed from the reactions of CF₃IF₂ or CF₃IO with N₂O₅ as well as CF₃I with ClNO₃. During the reactions of CF₃IF₂ with N₂O₅ or CF₃I with ClNO₃ the intermediate products CF₃IF(NO₃) or CF₃ICl(NO₃) can be identified. The preparations, properties, ¹⁹F-nmr spectra and the thermal decomposition of CF₃I(NO₃)₂ are described.     

On the reactivity of less common halopseudohalogens towards metalcarbon- and metalmetal-bonded compounds

Freshly generated solutions of iodine azide (IN₃) and iodine isocyanate (INCO) in acetonitrile or carbon tetrachloride add oxidatively to tertiaryaryl derivatives of group VB elements, Ar₃M (Ar = Ph, p-tolyl, p-ClC₆H₄ or p-FC₆H₄, and M = As, Sb or Bi) and diaryltellurium(II), Ar₂Te (Ar = Ph or p-CH₃OC₆H₄) at −10°C to −5°C to give stable covalent monomeric products, Ar₃MIX and Ar₂TeIX, respectively (where X = N₃ or NCO). The mode of bonding of the pseudohalide group to M has been established by solid-state IR spectra. Ar₃MI(N₃) failed to react with CS₂ but reaction with PhNCY (Y = O or S) gave cyclic tetrazole derivatives. Contrasting behaviour was also observed in the metathetic reaction of Ar₂MIX and Ar₂TeIX with silver pseudohalides [AgX′ (X′ = NCO or NCS)]. The tetraorgano compounds, R₄M (M = Sn or Pb, and R = Ph or p-tolyl), and Bu₃SnPh failed to react with IN₃ and Bu₃SnPhINCO but IN₃ cleaved one tin-aryl bond from Ar₄Sn in the presence of AlCl₃. Addition of IN₃ and INCO across the olefinic bond of Ph₃SnCH₂CHCH₂ is preferred to tin-allyl bond cleavage. Reactions of hexaaryldileads with IN₃ and INCO under appropriate conditions proceeded with the cleavage of a PbPb bond. Parallel reactions of cyanogen halides (CNI and CNBr) resulted in the formation of corresponding triaryllead halides and pseudohalide derivatives.     

Gold(I) and Palladium(II) Complexes Containing the Functionalized Ylides Triarylphosphonium Cyanomethylide or 2-Cyanoethylide (R3P=CHR′, R′=CN,CH2CN)

The coordination properties of ylides R₃P=CHCN and R₃P=CHCH₂CN were studied. Ylide R₃P=CHCN reacts with [AuCl(tht)] (molar ratio 1 : 1, tht=tetrahydrothiophene) to give [AuCl{CH(PPh₃)CN}] ( 1 ). Dinuclear complexes [(AuL)₂{μ-C(PR₃)CN}]ClO₄⋅nH₂O (n=1, L=PPh₃, R=Ph ( 2a ) or Tol (=4-MeC₆H₄) ( 2b ); n=0, R=Tol, L=P(pmp)₃ ( 2c ; pmp=4-MeOC₆H₄ or AsPh₃ ( 2d )) are the products of reactions between phosphonium salts (R₃PCH₂CN)ClO₄ (R=Ph or Tol) and [Au(acac)L] (molar ratio 1 : 3, L=PPh₃ or P(pmp)₃; acacH=acetylacetone). The reaction of [Au(acac)PPh₃] with (Ph₃PCH₂CH₂CN)ClO₄ (Au/P 2 – 5) gives the mononuclear complex [Au{CH(PPh₃)CH₂CN}(PPh₃)]ClO₄⋅0.5 H₂O ( 3 ). Complexes 2b or 2c react with [Au(acetone)L]ClO₄ (molar ratio 1 : 1, L=PPh₃ or P(pmp)₃), prepared in situ from [AuCl(L)] and AgClO₄ in acetone, to give the corresponding trinuclear derivatives [(AuL)₂{μ₃-{C(PTol₃)CN}(AuL)}](ClO₄)₂ (L=PPh₃ ( 4a ) or P(pmp)₃ ( 4b )]. We attempted unsuccessfully to prepare single crystals of 4a or 4b or of the triflate salt [{Au(PPh₃)}₂{μ₃-{C(PTol₃)CN}(AuPPh₃)}](TfO)₂⋅H₂O ( 4a′ ), obtained by reacting 4a with 2 equiv. of KCF₃SO₃. In complexes 2 and 4 , two new types of coordination of the ylides R₃P=CHCN are present. Attempts to coordinate three AuL groups to the N-atom of (R₃PCCN)⁻ induced by aurophilicity (see A and B ) were unsuccessful. The reaction between PdCl₂ and R₃P=CHCN (molar ratio 1 : 2) gives trans-[PdCl₂{CH(PTol₃)CN}₂] ( 5 ).     

A PHOSPHORUS-31 NUCLEAR MAGNETIC RESONANCE STUDY OF TERTIARY PHOSPHINE DERIVATIVES OF GROUP VI METAL CARBONYLS. IV. SUBSTITUTED TRIARYLPHOSPHINES

Abstract

Thirty compounds of the type (ZC₆H₄)₃PM(CO)₅ where Z is 3-CH₃, 4-CH₃, 3-CH₃O, 4-CH₃O, 3-CF₃, 4-CF₃, 4-Cl, 4-F, 4-CH₃S, or 4-(CH₃) C and M is Cr, Mo, or W are reported, in addition to [4-(CH₃)₃SiC₆H₄]₃ PW(CO)₅ and [(2-CH₃C₆H₄)n(C₆H₅)3–n P] M(CO)₅ where n is 1 or 2 and M is Cr, Mo, or W. Phosphorus-31 NMR and infrared data are presented. In general, the compounds containing the more effective electron withdrawing substituents on the tertiary arylphosphines exhibit the larger ³¹P coordination chemical shifts, the higher carbonyl stretching frequencies, and the larger phosphorus-31-tungsten-183 coupling constants.     

Synthesis of Bis(tricarbonylcyclopentadienylmolybdenum)bismuth(III) Chloride and Its Reaction with Metals

Polynuclear organometallic compounds [CpMo(CO)₃]₂BiCl and [CpMo(CO)₃]BiCl₂ were prepared by reaction of bismuth with tricarbonylcyclopentadienylmolybdenum chloride in dimethyl sulfoxide (DMSO). [CpMo(CO)₃]₂BiCl is reduced with magnesium or indium in tetrahydrofuran to give bismuth, [CpMo(CO)₃]₃Bi, and magnesium or indium chloride. In the presence of DMSO, the reaction of [CpMo(CO)₃]₂BiCl with magnesium or indium yields bismuth and the organomolybdenum derivative of magnesium or lithium, respectively.     

希土化合物对离体巨噬细胞的影响

本文应用细胞培养法和单细胞阳离子测定系统研究了希土化合物以地巨噬细胞的影响，结果表明，在培养介质中ＳｍＣｌ３和Ｙｃｌ３的浓度大于１ｍｍｏｌ．ｄｍ＾－３时，有明显的细胞毒性，Ｙｃｌ３的细胞毒性大于ＳｍＣｌ３，ＳｍＣｌ３和ＹＣｌ３的细胞毒性明显大于Ｓｍ（Ａｌａ）３Ｃｌ３和Ｙ（Ａｌａ）２Ｃｌ３。希土化合物的作用使细胞（Ｃａ＾２＋ｉ）升高；毒性越大，Ｃａ＾２＋ｉ升高越甚。低浓度Ｓｍ＾３＋和Ｙ６３＋对细胞膜     

Neutral bis(pentafluorophenyl)triphenylarsinegold(III) complexes

The complexes XAu(C₆F₅)₂AsPh₃ have been prepared by substitution of chloro- or perchlorato-bis(pentafluorophenyl)triphenylarsinegold(III) with alkali or with silver salts MX (X = NO₃, CH₃COO, NO₂, CF₃COO, CN, SCN, N₃ and C₆H₅COO). Decomposition of the nitrato or acetato complex leads to C₆F₅AuAsPh₃.     

Reactions du pentachlorure de methyltungstene avec quelques coordinats du type oxo. Acces aux complexes des oxytrichlorure et dioxychlorure de methyltungstene(vi)

Stable MeWOCl₃ and MeWO₂Cl complexes were obtained in good yields by treating certain oxo-type ligands (i.e. OPR₃, OAsPh₃ or OSMe₂) either with MeWCl₅ or with MeWOCl₃, which were obtained from WCl₆ or WOCl₄ and HgCl₂.     

Monocarbonyl cationic rhodium(I) complexes

Summary The preparations and characterisation of cationic complexes of the type [Rh(CO)(MeCN)(PR₃)₂]ClO₄, [Rh(CO)L(PR₃)₂]ClO₄ (L=py or 2-MeOpy), [Rh(CO)(L-L)(PR₃)₂]ClO₄ (L-L = bipy or phen) and [Rh(CO)(PR₃)₃]ClO₄ with PR₃ = P(p-YC₆H₄)₃ (Y=Cl, F, Me or MeO) are described.     

ChemInform Abstract: Two Structure Types Based on Si6O15 Rings: Synthesis and Structural and Spectroscopic Characterization of Cs1.86K1.14DySi6O15 and Cs1.6K1.4SmSi6O15.

Single crystals of Cs_1.86K_1.14DySi₆O₁₅ (I) and Cs_1.6K_1.4SmSi₆O₁₅ (II) are grown by reaction of SmF₃ or Dy₂O₃, DyF₃, SiO₂, K₂CO₃, and Cs₂CO₃ in a MoO₃ or MoO₃/RbF flux (Pt crucible, 950 °C, 3—6 h; controlled cooling).     

Ce3Cl5[SiO4] und Ce3Cl6[PO4]: Ein chloridreiches Chloridsilicat und ‐phosphat des Cers im Vergleich

Ce₃Cl₅[SiO₄] and Ce₃Cl₆[PO₄]: A Chloride‐Rich Chloride Silicate of Cerium as Compared to the Phosphate By reacting CeCl₃ with CeO₂, cerium and SiO₂, or P₂O₅, respectively, in molar ratios of 5 : 3 : 1 : 3 or 8 : 3 : 1 : 2, respectively, in sealed evacuated silica tubes (7 d, 850 °C) colorless, rod‐shaped single crystals of Ce₃Cl₅[SiO₄] (orthorhombic, Pnma; a = 1619.7(2), b = 415.26(4), 1423.6(1) pm; Z = 4) and Ce₃Cl₆[PO₄] (hexagonal, P6₃/m; a = 1246.36(9), c = 406.93(4) pm; Z = 2) are obtained as products insensitive to air and water. Excess cerium trichloride as flux promotes crystal growth and can be rinsed off again with water after the reaction. The crystal structures are determined by discrete [SiO₄]^4– or [PO₄]^3– tetrahedra as isolated units. Both, the chloride silicate Ce₃Cl₅[SiO₄] and the chloride phosphate Ce₃Cl₆[PO₄], exhibit structural similarities to CeCl₃ (UCl₃ type), when four or three Cl^– anions are each substituted formally by one [SiO₄]^4– or [PO₄]^3– unit, respectively, in the tripled formula (Ce₃Cl₉). The coordination number for Ce³⁺ is thus raised from nine in CeCl₃ to ten in Ce₃Cl₅[SiO₄] and Ce₃Cl₆[PO₄], along with a drastic reduction of the molar volume with the transition from Ce₃Cl₉ (V_m = 186.17 cm³/mol) to Ce₃Cl₅[SiO₄] (V_m = 144.15 cm³/mol) and Ce₃Cl₆[PO₄] (V_m = 164.84 cm³/mol). The polyhedra of coordination around Ce³⁺ can be described as quadruple‐capped trigonal prisms, which in addition to seven Cl^– anions each also show another three oxygen atoms of two ortho‐silicate or ortho‐phosphate tetrahedra, respectively.     

Synthesen und Kristallstrukturanalysen von Tetraalkylphosphonium-, -arsonium- und -stiboniumtriiodiden

Syntheses and Crystal Structure Analyses of Tetraalkyl Phosphonium, Arsonium, and Stibonium Triiodides The reaction of Me₄EI (E?P, As), Me₃EtSbI, Me₂Et₂SbI, MeEt₃SbI, or Et₄SbI with I₂ in absence of solvent gives Me₄PI₃ (E?P, As), Me₃EtSbI₃, Me₂Et₂SbI₃, MeEt₃SbI₃, or Et₄SbI₃. Me₄SbI₃ is formed in a reversible reaction by addition of I₂ to (Me₄Sb)₃I₈ or by reaction of a solution of Me₄SbI in ethanol with I₂ in benzene. The crystal structures of Me₄EI₃ (E?P, Sb), and Me₃EtSbI₃ and the syntheses of the novel compounds are reported.     

Syntheses and properties of cyanamide and cyanoguanidine complexes of platinum(II). X-Ray structure of trans-[Pt(CF3)(NCNEt2)(PPh3)2][BF4]

Complexes trans-[PtX(L)(PPh₃)₂]A [1: X = CF₃; A = BF₄; L = NCNH₂, NCNMe₂, NCNEt₂, or NCNC(NH₂)₂. 2: X = Cl; A = BPh₄; L = NCNMe₂ or NCNEt₂] and cis-[PtCl(L)(PPh₃)₂][BPh₄] [3: L = NCNH₂ or NCNC(NH₂)₂], which appear to be the first cyanamide or cyanoguanidine complexes of platinum to be reported, have been prepared by treatment of trans-[PtBr(CF₃)(PPh₃)₂] (in CH₂Cl₂/acetone and in the presence of Ag[BF₄]) or of cis-[PtCl₂(PPh₃)₂] (in THF and in the presence of Na[BPh₄]), respectively, with the appropriate substrate. In KBr pellets or in solution 1 (L = NCNMe₂ or NCNEt₂) undergoes ready replacement of the organocyanamide (under the trans influence of CF₃) by bromide to regenerate trans-(PtBr(CF₃)(PPh₃)₂]. The X-ray structure of 1 (X = CF₃, A = BF₄, L = NCNEt₂) is also reported, and shows the presence of two apical intramolecular contacts of the metal with two ortho-hydrogen atoms of the phosphines, whereas the amine N atom of the diethylcyanamide is trigonal planar in the linear NCN framework with a delocalized π system.     

Regioselective Sequential Additions of Nucleophiles and Electrophiles to Perfluoroalkylfullerenes: Which Cage C Atoms Are the Most Reactive and Why?

The sequential addition of CN^? or CH₃^? and electrophiles to three perfluoroalkylfullerenes (PFAFs), C_s‐C₇₀(CF₃)₈, C₁‐C₇₀(CF₃)₁₀, and C_s‐p‐C₆₀(CF₃)₂, was carried out to determine the most reactive individual fullerene C atoms (as opposed to the most reactive C?C bonds, which has previously been studied). Each PFAF reacted with CH₃^? or CN^? to generate metastable PFAF(CN)^? or PFAF(CH₃)₂^2? species with high regioselectivity (i.e., one or two predominant isomers). They were treated with electrophiles E⁺ to generate PFAF(CN)(E) or PFAF(CH₃)₂(E)₂ derivatives, also with high regioselectivity (E⁺=CN⁺, CH₃⁺, or H⁺). All of the predominant products, characterized by mass spectrometry and ¹⁹F NMR spectroscopy, are new compounds. Some could be purified by HPLC to give single isomers. Two of them, C₇₀(CF₃)₈(CN)₂ and C₇₀(CF₃)₁₀(CH₃)₂(CN)₂, were characterized by single‐crystal X‐ray diffraction. DFT calculations were used to propose whether a particular reaction is under kinetic or thermodynamic control.     

Polymerization of substituted olefins initiated by organometallic compounds of titanium (IV)

Polymerization tests were carried out in homogeneous systems on various substituted olefins CH₂=CRZ (R = H or CH₃; Z = CN, COOR, C₆H₅ or OCOR) with compounds of titanium (IV) Ti X_4?x Y_x (X and/or Y = Cl, OR, NR₂, C₅H₅, OCH₂ CF₃, CH₃, C₆H₅ …) or with the bimetallic complex CH₃Ti(OR)₃, Al(CH₃)₃. The activity of the initiator varies with the co-ordination environment of the titanium and to a considerable extent with the functional groups linked to the olefin.     

Molybdenum(VI), (V) and (IV) complexes with chiral benzoin thiosemicarbazone

The chiral (ONS) dianionic Schiff base ligand benzoin thiosemicarbazone (H₂L) reacts with MoO₂(acac)₂ to give the polymeric complex [(MoO₂L) _n ] (1) (Type 1). The reaction of MoO₂L with pyridine (py), 3-picoline (3-pic) or 4-picoline (4-pic) gives [Mo^VIO₂LD] (D = py, 3-pic or 4-pic) (Type 1). Further, the reaction of [MoO₂L] or [MoO₂LD] with PPh₃ or reaction of [MoO₂L] with PPh₃ (plus bpy or phen, D) in the presence of donor reagents D gives [Mo^IVOL] or [Mo^IVOLD] (Type 2). On the other hand, the reaction of [MoO₂L] with hydrazides (zdhH₃) such as benzoylhydrazine (bhH₃), isonicotinoylhydrazine (inhH₃), nicotinoylhydrazine (nhH₃), salicyloylhydrazine (slhH₃) and thiosemicarbazide (tscH₃) produced non-oxo–diazenido complexes [MoL(zdh)] (Type 3). The complexes have been characterized by elemental analyses, molar conductance, magnetic moment, electronic, i.r. and e.s.r. spectroscopic measurements.