Yu. L. Slovokhotov

Synthesis and structure of polynuclear carbonylphosphine clusters of palladium

Abstract Reductive condensation of Pd(OAc)2 in dioxane in the presence of CO and PR3 (R = Et, Bun) with addition of CF3COOH leads to the formation of decanuclear Pd10(μ3-CO)4(μ2-CO)8(PBun3)6 (I) and Pd10(CO)14(PBun3) (II) at Pd(OAc)2:PR3 molar ratios of 1:4–1:10 and 1:1.5–1:2.5, respectively. The use of CH3COOH instead of CF3COOH results in tetranuclear clusters Pd4(CO)5(PR3)4 (III) and Pd4(μ2-CO)6(PBun3) (IV). I ⇌ III and III → IV transformations occur in organic media. The structures of I (space group P21/n, Z = λMo, 12125 independent reflections, R = 0.047) and IV (Pz:3, Z = λMo, 3254 reflections, R = 0.098) were established by X-Ray diffractions analysis. Cluster I is a 10-vertex Pd10 polyhedron, an octahedron with four unsymmetrically centered non-adjacent faces. The average PdPd distances in the octahedron are 2.825 A, in the eight short Pdoct.Pdcap. bonds with the “equatorial” Pd atoms of the inner octahedron, bridged by the μ2-CO ligands, are 2.709 A, and in the four elongated (without bridging CO groups) bonds with the apical Pd atoms of the octahedron are 3.300–3.422 A. The PBun3 ligands are coordinated to the apical Pd atoms and the capping atoms (PdP 2.291–2.324 A). Cluster IV is tetrahedral, with the CO ligands symmetrically bridged; PdPd 2.778–2.817; PdP 2.232–2.291; PdC 2.06 A (average).

X-ray crystal structure of a distorted tetrahedral cluster in the salt [(Ph3P)4Au4N]+ BF4−. Geometrical indication of stable electronic configurations in post-transition metal complexes and the magic number 18-e in centred gold clusters

According to an X-ray investigation (−120°C, λ(Mo-Kα), 6815 reflections, space group P21/c, Z = 4, R = 0.068), the cation of the tetraaurated ammonium salt [(Ph3PAu)4N]+ BF4− can be considered as a distorted tetrahedral Au4(N) cluster built up of four linearly coordinated Au atoms with an interstitial N atom (AuAu 3.012–3.504 A, AuN 1.93–2.10 A). On the basis of the structural data on 14-, 16- and 18-electron mononuclear post-transition metal complexes, the magic number of 18 skeletal electrons can be suggested for [AunLn − 1]m+ clusters with an interstitial Au atom and a quasi-spherical peripheral Aun − 1 polyhedron.

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.

Distortion of “tetrahedral” C3v coordination in the R3CO moiety due to the reduction of molecular symmetry: X-ray,. conformational, and quantum-chemical study

Abstract Distortions of the ideal configuration of the R3AX moiety in R3AXR′ type molecules are established by X-ray diffraction (R, R′ = organic substituent, A  element of maingroups IV or V of the periodic table, X = non-linearly coordinated O, S or N atom): the RAX bond angle (φ) in the transoid RAXR′ moiety is essentially smaller than the tetrahedral value of 109.5°. Decrease of the φ angle in Me3COME (I) and Me3COOCMe3 (II) molecules was obtained in molecular mechanic (φI = 103.9°, φΠ = 106.5°) and CNDO/2 (φI = 105.2°, φΠ = 104.3°) calculations and substantiated by the low-temperature X-ray study. The effect of symmetric coordination distortion has evidently, an electronic nature and is also observed in planar trigonal, trigonal-bipyramidal and octahedral environments.

Characteristic structural features of post-transition metal cyclopentadienyl derivatives : I. Tetraphenylcyclopentadienyl(triphenylphosphine)-gold(I) (Ph4HC5AuPPh3)

Abstract The gold(I) complex of tetraphenylcyclopentadiene, Ph4C5HAuPPh3 (I), has been obtained for the first time by interaction both between Ph4C5H2 and [(AuPPh3)3O]+BF4− and between Ph4HC5Li and Ph3PAuCl. The structure of I was determined by an X-ray crystal analysis (3913 reflections, R = 0.049). Crystals of I are monoclinic, at −120°C a 13.303(2), b = 12.951(2), c = 21.117(4) A, β = 96.60(1)°, Z = 4, space group P21/c. An unusual feature was found in the interaction of the Au atom with the Cp ring, viz. a coordination intermediate between η1(σ) and η3. In accordance with PMR spectroscopy data, complex I, unlike other η1-cyclopentadienyl compounds of monovalent gold, is a stereochemically rigid system with a fixed fragment.

A high-nuclear carbonylphosphine cluster of palladium, Pd23(CO)22(PEt3)10

Abstract Reactions of palladium derivatives in combination with phosphine ligands make possible the production of new species of high nuclearity. Here both the production and further characterization of a new high-nuclear cluster, Pd 23 (CO) 22 (PEt 3 ) 10 is described.

Synthesis and x-ray structure of 10-vertex palladium carbonylphosphine cluster with minimal PBun3 content

Abstract Synthesis of the carbohylphosphine cluster Pd10(CO)14(PBun3)4 (I), a product of substitution of two PBun3 ligands by terminal CO groups in the Pd10(CO)12(PBun3)6 cluster II, was carried out, and the structure of I (λ Mo, 3200 reflections, R = 0.098) was established by X-ray analysis. The Pd10 polyhedron is a four-capped octahedron with unsymmetrical caps. The average Pd—Pd distances in the inner octahedron are 2.824 A and PdPoct—Pdcap are 2.706 A, 3.149, 3.172 A (two independent molecules). The steric effects in molecles I and II, and their influence on the stability of the cluster are discussed.

Characteristic structural features of cyclopentadienyl derivatives of post-transition metals : II. Synthesis and structure of tris(triphenylphosphinegold)tetraphenylcyclopentadiene tetrafluoroborate

Abstract The trinuclear cationic complex [Ph 4 C 5 (AuPPh 3 ) 3 + [BF 4 ] - (I) obtained by interaction of C 5 HPh 4 AuPPh 3 or Ph 4 C 5 (AuPPh 3 ) 2 with [AuPPh 3 + [BF 4 ] - in THF was studied by X-ray diffraction. In the presence of benzene, triclinic crystals of the solvate [Ph 4 C 5 (AuPPh 3 ) 3 ] + [BF 4 ] - · 2 C 6 H 6 are formed, a = 12.845(6), b = 16.042(8), c = 22.642(11) A, α = 86.62(4), β = 77.51(4), γ = 76.05(4)°, space group P 1 , Z = 2, 9494 reflections with I > 2σ (λ(Mo- K α ), θ/2θ scan, 2θ R = 0.054. The complex represents a diaurated cation of tetraphenylcyclopentadienyl(triphenylphosphine)gold, containing a triangular Au 2 C fragment (AuAu 2.820(1) A) which is bonded to the third Au atom (AuAu 3.021(1) A), coordinated to the cyclopentadienyl ligand by a bond intermediate between η 1 (σ) and η 3 (AuC 2.21(2), 2.60(2) and 2.71(2) A).

Use of [(η-C5R5)M]+ fragments (M = Fe, R = H; M = Ru, R = H, Me) for synthesis of cationic cluster. X-Ray structure of [RuRh3(η-C5Me5)(η-C5H5)3(μ3-CO)3]PF6

Abstract Tetrahedral cationic cluster [MRH3(η-C5R5)(η-C5H5)3(μ3-CO)3]PF6 (M = Fe, R = H; M = Ru, R = H, Me) were synthesized by reaction of [Fe(η-C5H5)(η-Arene)]PF6 or [Ru(η-C5R5)(MeCN)3]PF6 with Rh3(η-C5H5)3(μ-CO)3. Their structure was confirmed by IR and NMR spectroscopy as well as by an X-ray diffraction study of [RuRh3(η-C5Me5)(η-C5H5)3(μ3-CO)3]PF6.

Synthesis of heteronuclear carbonyl-carbide clysters of transition metals via vertex replacement in a metal polyhedron. X-ray crystal structures of the bimetallic tetragonal-pyramidal [Fe4CoC(CO)14]− and the trimetallic octahedral Fe4CoRhC(CO)16 clusters

Abstract The successive degradation of the closo -octahedral iron carbonyl clusters with an interstitial C atom and addition of the metal carbonyl unit of different metal atoms to the resultant nido-tetragonal-pyramidal clusters lead to replacement at the vertex of octahedrons resulting in the bimetallic [Fe 5 CoC(CO) 16 ] − (I) and [Fe 4 CoC(CO) 14 ] − (II) anions as well as trimetallic Fe 4 CoRhC(CO) 16 (III) and [Fe 4 CoPdC(CO) 15 ] − (IV) clusters. An X-ray investigation of II and III revealed the nido-tetragonalpyramidal cluster structure in II with the Co atom in the basal face and in III the octahedral cluster structure with a cis-arrangement of the Co and Rh heteroatoms. The Co atom in II and the Co and Rh atoms in III are disordered over the pairs of stereochemically equivalent vertices of the metal polyhedron inside the ordered ligand polyhedron.