É. G. Perevalova

Tris(triphenylphosphinegold)oxonium salts

Abstract The oxonium salts (Ph3PAu)3O+X- where X-  BF4-, CF3COO-, MnO4- have been prepared. These salts are formed from coordinatively unsaturated Ph3PAu+ cations in alkaline or acid media. An X-ray study of (Ph3PAu)3O+BF4- indicates that the oxonium ions are dimeric in the crystalline form. The fragment (Ph3PAu)3O has a pyramidal structure: the oxygen atom is outside the Au3 plane.

A new type of organogold compound

Organogold complexes of the type [R(AuPPh3)2]+BF−4 (I) containing a univalent gold atom and an AuAu fragment have been synthesised. They are formed by the interaction of RAuPPH3 with tetrafluoroboric acid or organomercury mercury compounds with CH3AuPPh3 and HBF4. Their structures have been identified through 1H NMR, 31P NMR, IR, UV (and X-ray for [C5H5 - FeC5C5H4(AuPPh3)2]+BF−4). When acted upon by nucleophilic reagents, the complexes liberate the cation AuPPh3+. Organometallic compounds promote an exchange of organic ligands.

Syntheses of organogold(1+) compounds by direct auration

Abstract Organogold(1+) compounds have been synthesized by direct auration of cyclopentadiene, cyanoacetic ester and malonitrile with (Ph 3 PAu) 3 O + BF 4 − . An X-ray structural study (λ Mo, 5062 reflections, R = 0.039) of bis(triphenylphosphinegold)malonitrile has been carried out (monoclinic, a = 12.055(6), b = 14.086(5), c = 20.466(12) A, β = 90.32(4)°, space group P 2 1 / c , Z = 4). The AuAu bond length is 2.912(1) A.

New organogold complexes: tetraphenylcyclopentadiene derivatives

Abstract Mono- and diaurated derivatives of tetraphenylcyclopentadiene, Ph4C5HAu-PPh3 and Ph4C5(AuPPh3)2, have been obtained by auration of tetraphenylcyclopentadiene with tris(triphenylphophinegold)oxonium tetrafluoroborate. Under the action of [Ph3,PAu]+BF4− both mono- and diaurated derivatives form the trinuclear cationic complex [Ph4C5(AuPPh3)3]+BF4−, which is converted into Ph4C5(AuPPh3)2 when treated with nucleophiles. The structure of Ph4C5HAuPPh3 and [Ph4C5(AuPPh3)3]+BF4− was established by IR, UV, PMR spectral and X-ray structural studies. Ph4C5HAuPPh3 has a CAu bond and additional coordination of Au with two neighboring carbon atoms of the five-membered ring; the structure is non-fluxional. The complex [Ph4C5(AuPPh3)3]+BF4− includes rather rare structural moieties: a three-membered carbometal cycle AuCAu , three gold atoms linked to each other, AuAuAu, and univalent gold coordinated with three carbon atoms of the Ph4C5 ring.

Synthesis and structure of dimeric metallocene derivatives of transition metals of groups IV and V. Crystal and molecular structures of (η5:η5-C10H8)(C5H5)2Nb2(μ-H)(μ-OEt) and (η5:η5-C10H8)(C5H5)2Ti2(μ-H)(μ-Cl)

Abstract Reduction of Cp 2 MCl 2 (M = Nb and Ti) with potassium in toluene yields binuclear fulvalene complexes (η 5 :η 5 -C 10 H 8 )(C 5 H 5 ) 2 Nb 2 (μ-H)(μ-Cl) (IIa) and (η 5 :η 5 -C 10 H 8 )(C 5 H 5 ) 2 Ti 2 (μ-H)(μ-Cl) (III). Treatment of IIa with KOR gives (η 5 :η 5 -C 10 H 8 )(C 5 H 5 ) 2 Nb 2 (μ-H)(μ-OR) (IIb, R = CH 3 ; IIc, R = C 2 H 5 ) X-ray structural investigations of complexes IIc (4593 reflections, R = 0.041) and III (2951 reflections, R = 0.042) show similar geometric structures, NbNb 3.136(1) A (IIc), TiTi 3.126(1) A (III), MCp 2.04 A (IIc) and 2.04 A (III), bond angles NbONb 94.6°, TiClTi 77.6°, dihedral angles Cp/Cp in the metal sandwiches 135.2° (IIc) and 137.3° (III) and the bending angle of the fulvalene ligand 15.6° in both IIc and III.

Binuclear and mononuclear di-η5-cyclopentadienylniobium chemistry: a new insight. Crystal and molecular structure of [Cp2NbH2]−[Na · benzo-15-crown-5]+

Abstract A mononuclear di-η 5 -cyclopentadienylniobium complex Cp 2 NbH 2 Na (I) has been found to be a by-product of the reaction of Cp 2 NbCl 2 with NaH, the principal products being (η 5 : η 1 -C 5 H 4 ) 2 Cp 2 Nb 2 H 2 ) 2 (II) in THF and (η 5 : η 5 -C 5 H 4 C 5 H 4 )Cp 2 -Nb 2 (η-H) 2 (III) in DME. Cp 2 NbH 2 Na wasalso obtained by reaction of Cp 2 NbH 3 or the mixture of Cp 2 NbBH 4 + Et 3 N with NaH. Crystal and molecular structure of [Cp 2 NbH 2 ] − [Na · NbH 2 − [Na · B15C5] + (Ia) (B15C5 = benzo-15-crown-5) was established by an X-ray diffraction study (4208 reflections, R = 0.022; monoclinic, at −120° C, a 17.345(3), b 11.742(3), c 22.965(5) A, β 98.52(1)°, Z = 8 space group C 2/ c ). The structural data indicate substantial ionic character of the (Cp 2 NgH 2 ) − … (Na · B15C5) + interaction in the solid.

Synthesis and chemical properties of μ-hydrido-μ-halogenodicyclopentadienylfulvalenediniobium

Bis-niobocene (η5 : η1-C5H4)2Nb2H2 when treated with organic halides, e.g. C4H9Cl, C6H5CH2Cl, CCl4, CHCl3, CH3I and C2H5Br gives quantitatively new fulvalene complexes (η5 : η5-C10H8)(C5H5)2Nb2(μ-Hal). The complex (η5 :η5)-C10H8)(C5H5)2Nb2(μ-H)(μ-Cl) readily exchanges its bridging chlorine atom for methoxy and ethoxy groups or a hydride ligand. Reaction with water gives a diamagnetic compound, for which the structure (η5 : η5-C10H8)(C5H5)2(Cl)2Nb2(μ-O) is proposed. A new method for the synthesis of bis-niobocene through interaction of (C5H5)2NbCl2 with NaH in THF was found. It is shown that in DME the same reaction between (C5H5)2NbCl2 and NaH gives an isomeric fulvalene complex (η5 : η5-C10H8)(C5H5)2Nb2(μ-H)2 instead.

Synthesis and crystal structure of bis(triphenylphosphine)gold tricyanomethanide, [(PPh3)2Au]+ [C(CN)3]−

Abstract A new unusual transformation of tetracyanoethylene (TCE) into a tri-cyanomethanide anion [C(CN)3]− has been found. This transformation occurs as a result of action of tris(triphenylphosphinegold)oxonium tetrafluoroborate [O(AuPPh3)3]+BF4− on TCE or its donor-acceptor complexes with toluene and 2.4-dihydro-1.3-diphenylcyclopenta(b)indene, to give [(PPh32Au]+[C(CN)3]− (I). The X-ray diffraction study of I (20°, λMo-Ka, 1569 reflections, space group C2/c, Z = 4, R = 0.0296) has revealed that the cations [Au(PPh3)2]+ occupy specific positions in the inversion centres and the anions [C(CN)3− are located on the ‘2’ axes. No. Au…N interaction in I has been found. Complex I has been characterized by 1H and 31P NMR and IR spectroscopy. The conductivity of I in CH3OH-CH3CN solutions has been measured.

Characteristic structural features of cyclopentadienyl derivatives of post-transition metals: III. Synthesis and structure of fluorenyl (triphenylphosphine) gold(I)☆

Abstract The fluorenyl gold derivative C 13 H 9 AuPPh 3 (I) was obtained by fluorene auration with the complex [(AuPPh 3 ) 3 O] + BF 4 − or interaction of C 13 H 9 Li or C 13 H 9 Na with ClAuPPh 3 . An X-ray structure study of I (−120°C, λ Mo, 8192 reflections, space group P 2 1 / c , Z = 12, R = 0.024) shows that the Au atom in I has η 1 coordination. Moreover, the structure of three geometrically different, crystallographically independent molecules of I in crystal indicates limited structural nonrigidity, i.e. pendular motion” of the AuPPh 3 group at the sp 3 -hydridized carbon atom of the fluorenyl ligand. The PMR spectral characteristics of I are typical of stereochemically rigid σ-organic gold(I) derivatives.

Mono- and di-cationic species of a [1,1-dimercurio]ferrocenophane bisdimethylaminomethyl derivative

Abstract Oxidation of iron atoms in a neutral ferrocenophane with two ferrocene moieties and two mercury atoms, C 5 H 4 FeC 5 H 3 (CH 2 NMe 2 )HgC 5 H 4 FeC 5 H 3 (CH 2 NMe 2 )Hg , gives corresponding mono- and di-cationic species. Ferrocenium, substituted ferrocenium salts and TCNQ were chosen as oxidizing agents. Electronic absorption and Mossbauer spectra of the oxidized species are discussed.