Synthesis of ferrocenylacetylide derivatives of gold-ruthenium and gold-osmium clusters. Crystal structures of M3(AuPPh3)(C≡CFc)(CO)9 (M=Ru or Os; Fc is ferrocenyl)

The synthesis and crystal structures of the clusters M₃(AuPPh₃)(C≡CFc)(CO)₉ (M=Ru,3a; or M=Os,3b) are described. Compound3a was synthesized by deprotonation of Ru₃H(C≡CFc)(CO)₉ under the action of KOH/EtOH followed by treatment of the anionic complex [Ru₃(C≡CFc)(CO)₉]⁻ with chloro(triphenylphosphine)gold. Compound3b was prepared by the reaction of Os₃(CO)₁₀(NCMe)₂ with FcC≡CAuPPh₃, which was synthesized by the reaction of FcC≡CNa with ClAuPPh₃. The pentanuclear cluster Ru₄(AuPPh₃)(C≡CFc)(CO)₁₂ (4a), which was prepared by the reaction of3a with Ru₃(CO)₁₂, was characterized by spectral methods. Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1295–1299, July, 2000.     

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

The trinuclear cationic complex [Ph₄C₅(AuPPh₃)₃⁺[BF₄]^- (I) obtained by interaction of C₅HPh₄AuPPh₃ or Ph₄C₅(AuPPh₃)₂ with [AuPPh₃⁺[BF₄]^- in THF was studied by X-ray diffraction. In the presence of benzene, triclinic crystals of the solvate [Ph₄C₅(AuPPh₃)₃]⁺[BF₄]^-· 2 C₆H₆ are formed, a = 12.845(6), b = 16.042(8), c = 22.642(11) Å, α = 86.62(4), β = 77.51(4), γ = 76.05(4)°, space group P$\text{1}$, Z = 2, 9494 reflections with I > 2σ (λ(Mo-K_α), θ/2θ scan, 2θ < 46°), with absorption correction R = 0.054. The complex represents a diaurated cation of tetraphenylcyclopentadienyl(triphenylphosphine)gold, containing a triangular Au₂C fragment (AuAu 2.820(1) Å) which is bonded to the third Au atom (AuAu 3.021(1) Å), coordinated to the cyclopentadienyl ligand by a bond intermediate between η¹(σ) and η³ (AuC 2.21(2), 2.60(2) and 2.71(2) Å).     

Hypercoordinated compounds of gold(I)

Mono- and binuclear gold(I) derivatives ofortho-substituted diphenyl ether, C₆H₅OC₆H₄AuPPh₃ and O(C₆H₄)₂(AuPPh₃)₂, were prepared by the reaction of the 2,2'-dilithium derivative of diphenyl ether with ClAuPPh₃. X-Ray structural study has shown that these compounds contain secondary intramolecular bonds between the gold and oxygen atoms. The interaction of C₆H₅OC₆H₄AuPPh₃ with (AuPPh₃)BF₄ affords the [C₆H₅OC₆H₄(AuPPh₃)₂]BF₄ cationic complex. The latter reacts with PPh₃ to give the starting C₆H₅OC₆H₄AuPPh₃ complex.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 729–736, April, 1994.The authors wish to thank A. L. Blyumenfel'd for recording³¹P NMR spectra, D. V. Zagorevskii and K. V. Kazakov who obtained mass spectra, and Yu.L. Slovokhotov who carried out the EXSAFS study.The study described in the present paper was partly supported by the International Scientific Fund, grant N Ch. 002479.     

Quantum chemical study of C—H bond activation in methane molecule by AuIII aqua chloride complexes

The mechanism of the reactions of methane with the gold(III) complexes [AuCl_x(H₂O)_{4− x} ]^3−x (x = 2, 3, or 4) was studied by the DFT/PBE method with the SBK basis set. High activation barriers obtained for the reactions of [AuCl₄]⁻ and [Au(H₂O)Cl₃] with methane suggest these reactions cannot proceed under mild conditions. The reaction of the [Au(H₂O)₂Cl₂]⁺ complex with methane has a rather low energy barrier and proceeds through the formation of an intermediate complex. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 191–201, February, 2006.     

Über Tris[(trialkylphosphan)gold(I)]oxonium-tetrafluoroborate und Tris[(triphenylphosphan)gold(I)]sulfonium-tetrafluoroborat

On Tris[(trialkylphosphine)gold(I)]oxonium Tetrafluoroborates and Tris[(triphenylphosphine)gold(I)]sulfonium Tetrafluoroborate [Et₃PAu]⁺BF, obtained from Et₃PAuCl and AgBF₄ in tetrahydrofuran, reacts with KOH (molar ratio 3:1) to give the oxonium salt [(Et₃P)Au]₃O⁺BF ( 1 ). The homologous [^t(Bu₃P)Au]₃O⁺BF ( 2 ) is generated similarly from ^tBu₃PAuCl and Ag₂O in the presence of NaBF₄ in THF. The composition and identity of these two first tris[(tri alkyl phosphine)gold(I)]oxonium salts have been confirmed by analytical and spectroscopic data. The compounds are useful aurating agents. From the corresponding triphenylphosphine complex and (Me₃Si)₂S quantitative yields of the sulfonium salt [(Ph₃P)Au]₃S⁺BF ( 3 ) are obtained. Its crystal structure features monomeric cations, and in these small Au? S? Au angles indicate significant metal-metal bonding.     

Auration of ruthenocene: synthesis and molecular structure of mono- and diaurated derivatives

Ruthenocene, like ferrocene, reacts with (Ph₃PAu)₃O⁺BF₄ ^– to afford agem-diaurated derivative CpRuC₅H₄(AuPPh₃)₂ ⁺BF₄ ^–, which is converted into CpRuC₅H₄AuPPh₃ when treated with PPh₃. X-ray structural analysis revealed substantial Ru-Au interaction in the diaurated derivative.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1335–1337, July, 1994.This work was supported by the Russian Foundation for Basic Research (projects 03-93-5827 and 03-93-18559).     

Dynamic and electrooptical properties of FH…F and FH…N hydrogen bridges

The dynamic and electrooptical parameters of the hydrogen bridges in (HF)₂, FH…FCD₃, FH…NCH, and FH…NCCH₃ complexes were calculated by the MINDO/3 method. Relationships between these parameters have been found. These parameters for the F−H…Y bridges mainly coincide with the relationships previously established for the hydrogen O−H…Y bridges. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1067–1069, May, 1997.     

Synthesis and photophysical properties of luminescent mononuclear and dinuclear gold(I) complexes with ethynyl-substituted phenanthrolines

A novel asymmetric dinuclear gold(I) complex with 3,6-diethynylphenanthroline, 3,6-bis{(PPh₃)–Au–C≡C}₂-phen, has been synthesized from Au(PPh₃)Cl (PPh₃ = triphenylphosphine) and 3,6-diethynyl-1,10-phenanthroline. The asymmetrical dinuclear gold(I) complex, 3,6-bis{(PPh₃)–Au–C≡C}₂-phen, demonstrated a weak phosphorescence assignable to the metal-perturbed ³ π–π* transition in the long wavelength region compared to an intense emission of the symmetrical dinuclear complex with 3,8-diethynylphenanthroline, 3,8-bis{(PPh₃)–Au–C≡C}₂-phen. A similar tendency of phosphorescent bands for the mononuclear gold(I) complexes with 5-ethynylphenanthroline, 5-{(PPh₃)–Au–C≡C}-phen, and 3-ethynylphenanthroline, 3-{(PPh₃)–Au–C≡C}-phen was observed. The absorption bands assignable to the π–π*(C≡Cphen) transition and phosphorescent emission assignable to the metal-perturbed ³ π–π* transition for these four gold(I) complexes were reasonably consistent with the results calculated by DFT and TD-DFT.     

Secondary interactions in the crystal structure of heterovalent 5,7,12,14-tetramethyl-1,4,8,11-tetraazacyclotetradeca-4,6,11,13-tetraenatogold(III) dibromoaurite(I)

The complex [Au(C₁₄H₂₂N₄)][AuBr₂] with two types of gold atoms (Au(III) and Au(I)) was obtained. In the cation 5,7,12,14-tetramethyl-1,4,8,11-tetraazacyclotetradeca-4,6,11,13-tetraenatogold(III), the Au atom is coordinated by four N atoms of the tetraazamacrocyclic amide ligand to make up a distorted square. The dibromoaurite(I) anion is linear. The conformation and packing of the structure is determined and stabilized by weak intermolecular hydrogen bonds C-H…Br and C-H…Au, an aurophilic interaction Au(I)…Au(III), and coordination bonds Au…N.     

Potential surface topology of a butene—gold atom system in the ground state

Quantum chemical modeling of but-1-ene isomerization to cis-but-2-ene and trans-but-2-ene in the presence of a gold atom has been carried out in the framework of the density functional theory with an extended basis set, the PBE functional, and a pseudopotential with relativistic corrections included. Two possible mechanisms have been considered, viz., with the formation of an intermediate σ-complex with one C(sp²)—Au bond and with gold insertion into the C—H bond. In the former case, the calculated energy barriers to two isomerization stages are higher than 30 kcal mol⁻¹. In the latter case, the reaction involves three stages and proceeds via a metal hydride complex with low barriers. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1330–1337, July, 2008.     

Oxygen Electroreduction Performance of Ultrasmall Gold Nanoclusters

Ultrasmall gold nanoclusters consisting of 2-4 Au atoms were synthesized and their performance in electrocatalytic oxygen reduction reactions (ORR) was examined. These clusters were synthesized by exposing AuPPh₃Cl to the aqueous ammonia medium for one week. Electrospray ionization mass spectrometry (ESI-MS), X-ray absorption fine structure (XAFS), and X-ray photoelectron spectroscopy (XPS) analyses indicate that the as-synthesized gold clusters (abbreviated as Au_x) consist of 2-4 Au atoms coordinated by the triphenylphosphine, hydroxyl, and adsorbed oxygen ligands. A glassy carbon disk electrode loaded with the Au_x clusters (Au_x/GC) was characterized by the cyclic and linear-sweep voltammetry for ORR. The cyclic voltammogram vs. RHE shows the onset potential of 0.87 V, and the kinetic parameters of J_K at 0.47 V and the electron-transfer number per oxygen molecule were calculated to be 14.28 mA/cm² and 3.96 via the Koutecky-Levich equations, respectively.     

A novel mononuclear gold(I) complex: Synthesis and x-ray structure of [Au{P(C6H5)3}3][SiF5] · 1.5 CH2Cl2

Tris(triphenylphosphine)gold(I)-pentafluorosilicate(IV) ([Au{P(C₆H₅)₃}₃][SiF₅]) was prepared and the structure was determined by single crystal x-ray diffraction. The complex crystallizes in the triclinic space group P1 (No. 2). The lattice constants are a = 14.634(2) Å, b = 17.180(2) Å, c = 22.212(3) Å, α = 86.48(1)°, β = 78.95(1)°, γ = 83.99(1)°. Number of molecules per cell: Z = 4. The gold atoms are coordinated to three triphenylphosphine ligands to form the trigonal planar cation [Au{P(C₆H₅)₃}₃]⁺. Separated from the cation is the [SiF₅]^? anion which is regular trigonal bipyramidal coordinated. No interactions between the fluorine atoms and the gold atoms were observed.     

Hydrogen bond CH…O in a methanolic solution of hydrogen chloride

The existence of a hydrogen bond in which a methyl group of the (MeOH)₂H⁺ ion acts as a proton donor is examined. The fundamental vibration frequencies of this ion were calculated for different numbers and strengths of CH…O bonds. The atomic charges in neutral ((MeOH) _n ,n=1–4) and protonated ((MeOH) _m H⁺,m=2–6) associates of methanol molecules were also calculated. The experimentally observed decrease in the v(CH) vibration frequencies of the (MeOH)₂H⁺ ion to 2890 cm⁻¹ and 2760 cm⁻¹ is attributable to the fact that each methyl group of the ion is involved in formation of two CH…O bonds with strength of −12.5 kJ mol⁻¹. The proton-donating ability of the CH bond depends on the charge on its H atom; however, it does not correlate with the dipole moment of this bond. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 306–312, February, 1999.     

Hypercoordinated gold(i) compounds

Cyclic organogold complex, containing an Au...Au bond, was prepared by reaction of Ph₃PAu(o-C₆H₄)CH₂(C₆H₄-o)AuPPh₃ with dppe. The length of the carbon bridge of the diphosphine ligand, optimal for formation of the Au...Au bond, was preliminarily determined using molecular simulation. The structure of the complex obtained was determined by X-ray diffraction analysis and by MS,¹H NMR, and³¹P NMR.For Communication 2, seeRuss. Chem. Bull., 1994,43, 1063.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2032–2034, October, 1995.The authors wish to thank P. V. Petrovskii for recording NMR spectra and D. V. Zagorevskii and K. V. Kazakov for recording mass spectrum.The work was carried out with financial support from the International Science Foundation (Grant MDV 000).     

Gold(III) amine complexes in aqueous alkali solutions

The gold(III) 1,3-diaminopropane complex [Au(1,3-pn)(1,3-pn-H)]Cl₂ has been synthesized. Its dissociation constant has been determined: Au(1,3-pn)₂³⁺ = Au(1,3-pn-H)²⁺ + H⁺, logK _a1 = −7.03 ± 0.05 (I = 0.1 mol/L NaClO₄). Considerable spectral changes are observed for strong alkali solutions (pH 11–14) containing the monoamido forms of the gold(III) ethylenediamine, 1,3-diaminopropane, and diethylenetriamine complexes (Au(en)(en-H)²⁺, Au(1,3-pn)(1,3-pn-H)²⁺, Au(dien-H)OH⁺). These changes are attributed to the formation of the diamido species Au(en-H)₂⁺, Au(1,3-pn-H)₂⁺, and Au(dien-2H)OH⁰. The dissociation constants of the monoamido complexes have been determined: Au(en)(en-H)²⁺ (logK _a2 = −10.9 ± 0.1 at I = 0.001–0.01 mol/L NaCl); Au(1,3-pn)(1,3-pn-H)²⁺ (logK _a2 = −11.3 ± 0.1 at I = 0.1 mol/L NaCl); Au(dien-H)OH⁺ (logK _a2 = −12.4 ± 0.1 at I = 0.1 mol/L NaCl).     

Synthesis, structure, and thermal transformations of double complex salts [Au(C4H13N3)Cl][MCl6]· nH2O (M = Ir, Pt; n = 0–2)

Double complex salts [Au(C₄H₁₃N₃)Cl][MCl₆]·nH₂O (M = Ir, Pt; n = 0–2) were synthesized. According to X-ray diffraction data, compounds with n = 1.5 are isostructural; the crystal structure is composed of the complex cations [Au(dien)Cl]²⁺ (dien is diethylenetriamine), the complex anions [MCl₆]²⁻, and water molecules of crystallization. Thermolysis of the double complex salts under hydrogen and helium was studied. The formation of nonequilibrium solid solutions based on Ir in the Au-Ir system and based on Pt in the Au-Pt system was demonstrated. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 416–421, March, 2006.     

Some Tris[(triorganophosphine)gold(I)]-oxonium and -Organoimonium Tetrafluoroborates with Bulky Substituents

Tris{[tri(2-methylphenyl)phosphine]gold(I)}-, tris{[tri(2,4,6-trimethylphenyl)phosphine]gold(I)}- and tris{[tri(cyclohexyl)phosphine]gold(I)}-oxonium tetra-fluoroborate ( 1?3 ) have been prepared from the corresponding (phosphine)gold(I) chlorides, silver oxide, and sodium tetrafluoroborate in acetone. These oxonium salts are excellent aurating agents for primary amines. Thus in the reaction with 1, t -butylamine ^tBuNH₂ and aniline PhNH₂ are readily converted into the tri nuclear imino complexes {[(2-MeC₆H₄)₃P]Au}₃N^tBu⁺BF₄^? ( 4 ) and {[(2-MeC₆H₄)₃P]Au}₃NPh⁺BF ( 5 ) in high yields. With 3 , both aniline and 8-amino-quinoline also give the tri nuclear complexes, i.e. {[(c-C₆H₁₁)₃P]Au}₃ NPh⁺BF ( 6 ) and {[(c-C₆H₁₁)₃P]Au}₃N(C₉H₆N)⁺BF ( 7 ). Auration of aniline with the most sterically hindered reagent 2 yields only the bi nuclear complex {[2,4,6-Me₃C₆H₂)₃P] · Au}₂N(Ph)H⁺BF ( 8 ). The reagents 1?3 and the Products 4 – 8 have been characterized by analytical and NMR spectroscopic data, and the crystal structures of compounds 4 and 6 have been determined by single crystal x-ray diffraction. In the cations of 4 , a triangle of gold atoms with short Au — Au contacts [3.036(1), 3.107(1), and 3.214(1) Å] forms a steep pyramid with the nitrogen atom, in which the angles Au? N? Au are all much smaller than the tetrahedral standard of 109.7°: 94.8(4), 98.1(4), and 103.0(4)°. This triangular Au₃ unit is staggered relative to the three methyl groups of the ^tBu substituent at nitrogen. The results for 6 are similar [Au — Au: 3.037(1), 3.071(1), and 3.222(1) Å; Au? N? Au: 95.3(3), 96.5(3), and 103.6(3)°]. Variable temperature NMR studies of compounds 3 and 8 show hindered rotation of the mesityl groups about the P? C bonds of the ligands originating from the steric congestion within each tertiary phosphine.     

Protonation of the acyclic tetraaza metallocomplex of gold(III) [Au(C9H19N4)]2+ in aqueous solution. Synthesis and crystal and molecular structure of [Au(C9H20N4)](H5O2)(ClO4)4

Protonation equilibrium has been studied for the acyclic gold(III) tetraaza metallocomplex [AuB]²⁺ [B = N, N′-bis(2-aminoethyl)-2,4-pentanediiminato(1−)] in aqueous solution. The synthetic procedure is described. The crystal and molecular structure of the protonated form of the [AuHB](H₅O₂)(ClO₄)₄ complex has been determined. Monoclinic crystals with unit cell dimensions a = 11.964(2) Å, b = 13.789(3) Å, c = 15.496(3) Å, β = 109.00(3)°, V = 2417.1(8) ų, Z = 4, ρcalc = 2.243 g/cm³, space group P2₁/n. The structure is built of nearly planar [Au(C₉H₂₀N₄)]³⁺ complex cations, (H₅O₂)⁺ cations, and [ClO₄]⁻ anions. The gold atom coordinates four nitrogen atoms of the ligand, forming a square plane. The six-membered chelate ring of the ligand is protonated at the central β-carbon atom and contains imine C=N bonds. The oxygen atoms of the perchlorate ions are hydrogen bonded to the (H₅O₂)⁺ dihydroxonium ion and to the nitrogen atoms of the NH₂ groups of the [AuHB]³⁺ cation. Original Russian Text Copyright ? 2005 by V. A. Afanasieva, L. A. Glinskaya, R. F. Klevtsova, and I. V. Mironov __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 46, No. 5, pp. 909–915, September–October, 2005.     

Heterometallic “butterfly” cluster [Fe3(CO)9(μ3-OBut)Au(PPh3)]

Alkylation of the [Fe₃(μ₃-O)(CO)₉]²⁻ dianion withtert-butyl iodide afforded the [Fe₃(μ₃OBu¹)(CO)₉]⁻ monoanion. The reaction of the latter with Au(PPh₃)Cl in the presence of TIBF₄ yielded the new heterometallic “butterfly” cluster [Fe₃(CO)₉(μ₃-OBu^t)Au(PPh₃)]. According to the X-ray data, both clusters synthesized contain the unchanged Fe₃(μ₃-O) fragment of the initial dianion. The addition of the Au(PPh₃) fragment to the monoanion occurred in such a way as to minimize steric changes. As a result, a “turned inside out” heterometallic “butterfly”, which contains the μ₃-O ligand on the outside rather than on the inside, was obtained. The dihedral angle characterizing the “butterfly” is 151°. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1779–1783, September, 1999.     

Compounds of hypercoordinated gold(i)

A binuclear organic derivative of gold(i) with diphenylmethane CH₂(C₆H₄)₂(AuPPh₃)₂ has been prepared by the reaction of 2,2-dilithiumdiphenylmethane with ClAuPPh₃. X-ray analysis of this compound revealed a transoid conformation of the molecule with agostic bonds between the gold atoms and methylene hydrogens. The complex was characterized by IR,¹H and³¹P NMR, and mass spectral data.For Report 1 seeRuss. Chem. Bull., 1994,43, 681.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1125–1130, June, 1994.This work was performed with partial financial support from the International Science Foundation (Project No. MDV 000).