M. I. Rybinskaya

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.

Arenetricarbonyl-molybdenum and -tungsten complexes

Abstract A preparative method is described for the synthesis of arenetricarbonyl-molybdenum complexes from tripyridinemolybdenum tricarbonyl and boron trifluoride etherate in the presence of arene. A series of compounds unavailable by the direct procedure [heating of Mo(CO)6, with arene] was prepared. In case of 1,4-diphenylbutadiene and tolane these two methods were found to give different results. 1,4-Diphenylbutadiene and Py3Mo(CO)3 in the presence of BF3 · O(C2H5)2 produce mono- and bi-nuclear arenemolybdenum tricarbonyl complexes, while Mo(CO)6 affords bis(diphenylbutadiene)molybdenum dicarbonyl as the main product on heating. Unlike other arenes, tolane and Py3Mo(CO)3 yield tritolanemolybdenum carbonyl besides tolanemolybdenum tricarbonyl, whereas the direct procedure led to no arenetricarbonylmolybdenum complexes. The compounds obtained were identified by elemental analysis and IR.

On the problem of the stabilization of α-metallocenylcarbocation. Synthesis, properties and crystal structure of [C5Me5OsC5Me4CH2+]BPh4−·CH2Cl2

Abstract The compound, [C 5 Me 5 O sC 5 Me 4 C H 2 + ]BPh 4 ·CH 2 Cl 2 , has been prepared by the reaction of C 5 Me 5 OsC 5 Me 4 CH 2 OH with NaBPh 4 in acetic acid. The Os… C + distance of 2.244 A and the inclination angle (β) of 41.8° of the exocyclic C(1)C(2) bond to the Cp-plane found by single-crystal X-ray diffraction study (the crystal was grown from a Et 2 O/CH 2 Cl 2 (mixture) suggest that there is a covalent OsC bond. Thus the C α (2) atom loses its carbenium character, the positive charge being localized mainly around the metal atom which in this case plays a role of the specific onium center. It has been shown that in nonamethylmetallocenylcarbonium ions the role of direct interaction with the metal atom in the stabilization of α-carbenium cationic center increases in the order Fe

σ,π-Binuclear complexes of transition metals coordinated to the monoolefin

Abstract σ-Vinyl derivatives of iron, tungsten, or rhenium react with iron nonacarbonyl to produce σ,π-binuclear complexes of the metals in which the presence of metal-metal bonds is very dependent on the nature of the metal. That the formation of the complexes containing a metal-metal bond does not necessarily involve the presence of an electron-withdrawing group attached to the vinyl ligand has been demonstrated for the σ-vinyl derivatives of iron, although it has been shown that for such bonding to be observed the double bond in the σ-derivative should be adjacent to the iron.

A new preparative route to cationic arene complexes of ruthenium(II), rhodhium(III) and iridium(III)

The cationic arene complexes [Ru(η-arene)(η-arene)]Y2 and [M(η-C5Me5(η-arene)]Y2 (M = Rh, Ir; Y = BF4, PF4, PF6) were prepared by direct exchange of chloride ligands in dimers [Ru(η-arene)Cl2]2 and [M(η-C5Me5)]2 for arenes by refluxing in trifluoroacetic acid. The triple chloride-bridged complexes [Ru2(η-arene)2 Cl3]Y and [M2(η-C5Me5)2Cl3]Y were obtained by reaction of these dimers with acids.

Crystal and molecular structure of the salt [C5Me5RuC5Me4︹CH2]+BPh4−·CH2CI2

The Ru...CH2 distance of 2.270Ain the cation of the salt [C5Me5RuC5Me4CH2]+BPh−4·CH2Cl2 investigated by means of an X-ray diffraction study, is slightly longer than the Os...CH2 distance of 2.244Ain the osmium analogue. The inclination angle of the exocyclic bond in the ruthenium complex (40.3°) is somewhat smaller than in the osmium compound (41.8°). The results reported, and those obtained previously, support the suggestion that the stabilization of the α-carbocationic centre increases along the series Fe « Ru < Os.

Acylation of iron carbonyl complexes of unsaturated aldehydes and ketones

Abstract The acylation of some iron carbonyl complexes of α, β-unsaturated aldehydes and ketones by (MeCO)+BF4− has been investigated and the structure of the salts obtained is discussed on the basis of IR and PMR spectra. Some chemical reactions of the cationic complexes have been studied and they were found to display high reactivity towards nucleophilic reagents.

Synthesis and spectral study of chelate alkenylarenedicarbonyl complexes of Cr, Mo and W

Abstract Irradiation of alkenylarene tricarbonyl-chromium, -molybdenum, and -tungsten compounds in which the double bond is separated from the arene moiety by a two- or three-atom bridge results in intramolecular cyclization to give stable chelate alkenylarenedicarbonylmetal complexes. Chelate complexes containing four-atom bridges have low stabilities, and those with monoatomic bridges were not formed at all. Irradiation of styrenetricarbonyl-chromium and -molybdenum leads to dinuclear tricarbonylmetal—dicarbonylmetal complexes. The chelate complexes obtained have been studied by IR, proton NMR, and 13C NMR spectroscopy. The electron density distributions and the stereochemistry of the complexes are discussed. With nonsymmetric arenes, diastereoisomers are formed; the predominant isomers have been isolated in the pure form. According to the proton NMR data the double bond in alkenylarenechromium chelates is parallel of nearly parallel to the arene ring plane.

Synthesis and crystal structure of nonamethylruthenocenylcarbenium hexafluorophosphate

Abstract The hitherto unknown functional derivatives of decamethylruthenocene (I), viz. (C 5 Me 5 )RuC 5 Me 4 CHO (II), and C 5 Me 5 RuC 5 Me 4 CH 2 OH (III) have been synthesized. The interaction of III with acids results in C 5 Me 5 RuC 5 Me 4 CH 2 + X − (IV, X = BF 4 , PF 6 ) which contain the carbocationic center stabilized by direct interaction with the Ru atom. NMR and X-ray structural data for the salt IV (X = PF 6 ) indicate the strong Ru ⋯ C + interaction (the Ru ⋯ C + distance is 2.603 A).

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.