Alexander R. Kudinov

Extremely Efficient Alkane Oxidation by a New Catalytic Reagent H2O2/Os3(CO)12/Pyridine

Triosmium dodecacarbonyl catalyzes a very efficient oxidation of alkanes by H(2)O(2) in MeCN to afford alkyl hydroperoxides (primary products) as well as alcohols and ketones (aldehydes) at 60 degrees C if pyridine is added in a low concentration. Turnover numbers attain 60,000, and turnover frequencies are up to 24,000 h(-1).

Synthesis of the first 30-electron triple-decker complexes of the iron group metals with cyclopentadienyl ligands. X-Ray structure of [(η-C5H5)Ru(μ,η-C5Me5) Ru(η-C5Me5)]PF6

The first 30-electron triple-decker complexes of the iron group metals [(η-C5R5)M(μ,η-C5Me5)M′(η-C5Me5)]PF6 were synthesized by reaction of [Fe(η-C5H5)(η-C6H6)]PF6 or [Ru(η-C5R5)(MeCN)3]PF6 (R = H, Me) with decamethylmetallocenes M′(η-C5Me5)2 (M′= Fe, Ru, Os). The pentamethylcyclopentadienyl ligand η-bonded to both metal atoms is the middle deck in these sandwich compounds. Their structure was confirmed by 1H and 13C{1H} NMR spectroscopy as well as by an X-ray diffraction study of [(η-C5H5)Ru(μ,η-C5Me5)Ru(η- C5Me5)]PF6.

Dicationic triple-decker complexes with a bridging boratabenzene ligand

Abstract New dicationic triple-decker complexes with a bridging boratabenzene ligand [Cp*Fe(μ-η:η-C 5 H 5 BMe)ML]X 2 (ML=CoCp*, 6 (CF 3 SO 3 ) 2 ; RhCp, 7 (BF 4 ) 2 ; IrCp, 8 (CF 3 SO 3 ) 2 ; Ru(η-C 6 H 6 ), 9 (CF 3 SO 3 ) 2 ; Ru(η-C 6 H 3 Me 3 -1,3,5), 10 (CF 3 SO 3 ) 2 ; Ru(η-C 6 Me 6 ), 11 (CF 3 SO 3 ) 2 ) were synthesized by stacking reactions of Cp*Fe(η-C 5 H 5 BMe) ( 2 ) with the corresponding half-sandwich fragments [ML] 2+ . The structure of 10 (CF 3 SO 3 ) 2 was determined by X-ray diffraction study.

Synthesis and structure of rhodium complexes with monoanionic carborane ligand [9-SMe2-7,8-C2B9H10]−

Abstract (Rhodacarborane)halide complexes [(η-9-SMe 2 -7,8-C 2 B 9 H 10 )RhX 2 ] 2 ( 4a : X=Cl; 4b : X=Br; 4c : X=I), which are analogous to [Cp*RhX 2 ] 2 , were synthesized by reaction of (η-9-SMe 2 -7,8-C 2 B 9 H 10 )Rh(cod) (cod=1,5-cyclooctadiene) with HX. Compounds 4 were used to prepare several sandwich and half-sandwich complexes containing (η-9-SMe 2 -7,8-C 2 B 9 H 10 )Rh fragment. 2e-Ligands destroy the dimeric structure of 4 to give the adducts (η-9-SMe 2 -7,8-C 2 B 9 H 10 )RhLX 2 , exemplified by preparation of (η-9-SMe 2 -7,8-C 2 B 9 H 10 )Rh(CO)I 2 and (η-9-SMe 2 -7,8-C 2 B 9 H 10 )Rh(PPh 3 )Cl 2 . The reaction of 4a with dppe in the presence of TlBF 4 affords the cationic complex [(η-9-SMe 2 -7,8-C 2 B 9 H 10 )Rh(dppe)Cl]BF 4 ( 7 BF 4 ). Sandwich complexes [(η-9-SMe 2 -7,8-C 2 B 9 H 10 )Rh(η-C 5 R 5 )]CF 3 SO 3 ( 11a CF 3 SO 3 : R=H; 11b CF 3 SO 3 : R=Me) were obtained by abstracting chloride from 4a by CF 3 SO 3 Ag with subsequent treatment with C 5 R 5 H. Complex 11b PF 6 was prepared by reaction of [Cp*RhCl 2 ] 2 with Na[9-SMe 2 -7,8-C 2 B 9 H 10 ]. Complex (η-9-SMe 2 -7,8-C 2 B 9 H 10 )Rh(η-7,8-C 2 B 9 H 11 ), containing two carborane ligands, was obtained by reaction of 4a with Tl[Tl(η-7,8-C 2 B 9 H 11 )]. Structures of 7 BF 4 and 11b PF 6 were confirmed by X-ray diffraction study.

Iron- and Ruthenium-Containing Triple-Decker Complexes with a Central Pentaphospholyl Ligand − X-ray Structures of [(η-C5H5)Fe(μ-η:η-P5)Ru(η-C5Me5)]PF6 and [(η-C5Me5)Ru(μ-η:η-P5)Ru(η-C5Me5)]PF6

Triple-decker cationic complexes with a central pentaphospholyl (pentaphosphacyclopentadienyl) ligand [Cp*M(μ-η:η-P5)M′(η-C5R5)]+ (3b: M = M′ = Fe, R = Me; 4a: M = Ru, M′ = Fe, R = H; 4b: M = Fe, M′ = Ru, R = H; 4c: M = Fe, M′ = Ru, R = Me; 5a: M = M′ = Ru, R = H; 5b: M = M′ = Ru, R = Me) were synthesized by exploitation of the stacking reactions of pentaphosphametallocenes Cp*M(η-P5) (1: M = Fe; 2: M = Ru) with half-sandwich fragments [(η-C5R5)M′]+. They were isolated as salts with BF4− or PF6− anions, and the structures of 4aPF6 and 5bPF6 were determined by X-ray diffraction. Triple-decker complexes with a central pentaphospholyl ligand are less reactive in nucleophilic degradation reactions than analogous complexes with C4Me4P and Cp* ligands in the bridging position. Only 4a and the previously known analogue 3a (M = M′ = Fe, R = H), containing the CpFe fragment, are nucleophilically destroyed by MeCN and NaI. The electrochemical properties of 2, 3a, 3b, 4a−c, 5a and 5b and the related cobalt-containing complexes [(η-C4Me4)Co(μ-η:η-P5)MCp*]+ (6: M = Fe; 7: M = Ru) were investigated. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)

Simple Synthesis of Ruthenium π Complexes of Aromatic Amino Acids and Small Peptides

The interaction of [Ru(eta(6)-C(10)H(8))(Cp)](+) (Cp=C(5)H(5)) with aromatic amino acids (L-phenylalanine, L-tyrosine, L-tryptophane, D-phenylglycine, and L-threo-3-phenylserine) under visible-light irradiation gives the corresponding [Ru(eta(6)-amino acid)(Cp)](+) complexes in near-quantitative yield. The reaction proceeds in air at room temperature in water and tolerates the presence of non-aromatic amino acids (except those which are sulfur containing), monosaccharides, and nucleotides. The complex [Ru(eta(6)-C(10)H(8))(Cp)](+) was also used for selective labeling of Tyr and Phe residues of small peptides, namely, angiotensin I and II derivatives.

Synthesis of slipped triple- and tetra-decker cationic ruthenium complexes with the μ, η5 : η6-indenyl ligand. X-Ray structure of [(η-C5H5)Ru(μ, η5 : η6-C9H7-Ru(η-C5Me5)]PF6

Abstract Slipped triple-decker complexes with a central indenyl ligand [(η-C 5 R 5 )Ru(μ, η 5 : η-C 9 H 7 )Ru(η 6 -C 5 R′ 5 )]PF 6 (R, R′ = H, Me) were prepared by interaction of Ru(η-C 5 R 5 )(η 5 -C 9 H 7 ) or Ru(η-C 5 Me 5 )(η 6 -C 9 H 7 ) with [Ru(η-C 5 H 5 )(MeCN) 3 ]PF 6 or [Ru(η-C 5 Me 5 )(MeCN) 5 ]PF 6 . The same reaction leads in the case of bis(η 5 -indenyl)ruthenium to the slipped triple-decker complexes [(η-C 5 R 5 )Ru(μ, η 6 : η 5 -C 9 H 7 )Ru(η 5 -C 9 H 7 )]PF 6 (R = H, Me) as well as to the tetra-decker complexes [(η-C 5 R 5 )Ru(μ, η 6 : η 5 -C 9 H 7 )Ru(μ, η 5 : η 6 -C 9 H 7 )Ru(η-C 5 R′ 5 )](PF 6 ) 2 (R, R′ = H, Me). The structure of the complexes was confirmed by 1 H and 13 C{ 1 H} NMR spectroscopy. An X-ray diffraction study of [(η-C 5 H 5 )Ru(μ, η 5 : η 6 -C 9 H 7 )Ru(η-C 5 Me 5 )]PF 6 provided supporting evidence.

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.

(Tetramethylcyclobutadiene)cobalt Complexes − Syntheses of Tris(ligand) Derivatives and Structures of [(C4Me4)Co(CO)3]BF4 and [(C4Me4)Co(NCMe)3]PF6

Photolysis of [Cb*Co(C6H6)]PF6] (6) (Cb* = C4Me4) in acetonitrile solution produces the red solvento complex [Cb* Co(NCMe)3]PF6 (8) in quantitative yield. Alternatively, heating of the acetonitrile solution to reflux temperature may effect the displacement of the benzene ligand. Photolysis of 6 in liquid ammonia gives [Cb*Co(NH3)3]PF6 (9). Compound 8 is substitution-labile and reacts with a wide variety of Lewis bases to produce substitution products [Cb*CoL3]PF6 with L = P(OMe)3 (10), py (11), CNtBu (12), and the related compound (NEt4)2[Cb*Co(CN)3] (13). Thermal reaction of [Cb*Co(CO)3]BF4 (7) with PMe3 takes place spontaneously at ambient temperature and produces the monosubstitution product [Cb*Co(CO)2(PMe3)]BF4 (14), while irradiation combined with a purging stream of N2 effects an exhaustive decarbonylation and affords [Cb*Co(PMe3)3]BF4 (16). Irradiation of 7 in acetonitrile produces mixtures of the mono- and disubstitution products; if a purging stream of N2 is applied, [Cb*Co(CO)(NCMe)2]BF4 (18) is formed with a small admixture of [Cb*Co(NCMe)3]BF4. The iodide Cb*CoI(CO)2 reacts with 2,2′-bipyridine to produce the monocarbonyl complex [Cb*Co(CO)(bipy)]I (15). Single-crystal structure determinations of [Cb*Co(CO)3]BF4 (7) with Co−Cb(ring plane) 1.777(2) A (av.) and of [Cb*Co(NCMe)3]PF6 (8) with Co−Cb(ring plane) 1.68(1) A (av.) are reported. Synthetic procedures for the preparation of [Cb*Co(CO)3]BF4 (7), Cb*CoI(CO)2 (2), and [Cb*Co(C6H6)]PF6 (6) are also given. An electrochemical study of the compounds 8, 10−13, and 16 reveals chemically fully reversible oxidation reactions. Hard σ-donor ligands (CN−, py, NCMe) stabilize the corresponding 17e species much more so than soft donor ligands [PMe3, CNtBu, and P(OMe)3]. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)

New triple-decker complexes prepared by the stacking reactions of cationic metallofragments with sandwich compounds

The results of our recent studies devoted to the synthesis of cationic triple-decker complexes are summarized. The stacking reactions of cationic metallofragments with sand-with compounds can be used as a general method for the synthesis of these complexes. This method was used for the preparation of 30- and 34-electron cationic triple-decker complexes containing cyclopentadienyl and pentaphospholyl ligands in the bridging position and carbocycles CnHn (n=4–7) and carboranes as terminal ligands.