A. A. Kamyshova

Gas-phase formation of mono- and dications from iron-subgroup decamethylmetallocenes and their calculation by the density functional method

Abstract The possibility of forming mono- [C 5 Me 5 MC 5 Me 4 CH 2 ] + ( 1 ) and dications [1,2(CH 2 ) 2 C 5 Me 3 MC 5 Me 5 ] 2+ ( 2 ) and 1,1′-[M(C 5 Me 4 CH 2 ) 2 ] 2+ ( 3 ) starting from iron subgroup decamethylmetallocenes (Fe ( a ), Ru ( b ), Os ( c )) was studied using electron-impact mass-spectrometry. The peaks of both single ( M + ) and doubly charged ( M 2+ ) molecular ions are present in the mass-spectra of all compounds studied. The basic fragmentation patterns are the elimination of one ( M + ) and two atoms of hydrogen ( M 2+ ) to give the corresponding mono- ( 1 ) and dications ( 2 and/or 3 ). The density-functional method was used for ab initio calculations of the geometry and total energies of cations 1 and 2 and the anti , syn , and gauche conformers of 3 for comparison with the dication [1,3-(CH 2 ) 2 C 5 Me 3 MC 5 Me 5 ] 2+ ( 2b ′). The calculation data for monocations 1a – c are in a good agreement with the results of X-ray analysis of these cations except for the MCH 2 interatomic distances and angles α , which are presumed to be most sensitive to phase changes. The relative order of stabilities of the mono- and dications was as follows: F

Generation of [1,2-(CH2)2C5Me3MC5Me4CH2-1′]3+ (M=Ru, Os) trications and determination of their structures by comparing NMR-spectra with density-functional method calculations

Abstract A general method for generating [1,2-(CH 2 ) 2 C 5 Me 3 MC 5 Me 4 CH 2 ] 3+ trications, where M=Ru ( 4a ) and Os ( 4b ) , from the salts of monocations [C 5 Me 5 MC 5 Me 4 CH 2 ] + An − ( 1a , b , An − =BF 4 ) by the action of dioxygen in a solution CF 3 SO 3 H superacid is presented. The energy characteristics of 4a and 4b have been calculated. NMR-spectra have been registered and analyzed. Conclusions received from NMR data for solutions of trications were compared with DFT calculation results of them in the gaseous phase.

UV photolysis of protonated ruthenium and osmium decamethylmetallocenes as a new method for synthesis of the metallonium cations Open image in new window

Decamethylmetallocenes Cp*2M (M=Ru, Os) in the presence, of acids (CF3CO2H, CF3SO3H) give thepprotonation products [Cp*2MH]+An−. Broad-band UV photolysis of their solutions results in the formation of the salts of onium cations. A preparative procedure for the synthesis of these salts has been developed. Hydrolysis of the salts gives the carbinol Cp*MC5Me4CH2OH.

Preparation of stable α-(nonamethylmetallocenyl)-α-hydroxycarbocations and their transformations

Abstract It has been shown that the structure of α-(nonamethylmetallocenyl)-α-hydroxycarbocations (M = Fe, Ru, Os), prepared by protonation of formylnonamethylmetallocenes with HBF4 and CF3COOH, depends on the nature of the metal and anion and is determined by the relative basicities. The Fe-containing salts have an open fulvenoid structure with an interionic hydrogen bond O-H … X irrespective of the nature of anion (X = BF4−, CF3COO−). The Ru- and Os-containing salts, in which the metal atoms are more basic than Fe, have, in the case of the weakly basic BF4− anion, a cyclic structure with an intramolecular M … HO hydrogen bond, while in the case of the more basic X = F− or CF3COO− anions they are transformed to the open fulvenoid structure with an interionic hydrogen bond OH … X, the structure of which has been established by an X-ray diffraction study of C 5 Me 5 RuMe 4 C + H − OH … F − . When the Fe-containing salts are kept in polar solvents or stored in the solid state for a long time they are entirely converted into paramagnetic salts of formylnonamethylferrocenium, the structure of which was confirmed by the oxidation of formylnonamethylferrocene using AgBF4.

Single-, double-, and triple-charged cations based on iron-subgroup decamethylmetallocenes

Methods for the synthesis and structures of metallocenylmethyl cations are considered using stable permethyl derivatives as examples. The simplest and most convenient procedure for the preparation of mono-, di-, and trications involves oxidation of permethylmetallocenes (M = Ru or Os) with oxygen in the presence of strong protic acids. Based on the results of physicochemical studies (X-ray diffraction analysis, 1H and 13C NMR spectroscopy) and quantum-chemical calculations (density functional theory), a resonance hybrid with contributions of the metallonium (onium), carbocationic, and fulvene structures was proposed for the description of the structures of these cations.

Reduction of (1,3-diformylindenyl)cyclopentadienylruthenium derivatives

The reduction of the (1,3-diformylindenyl)cyclopentadienylruthenium derivatives {η5-1,3-(CHO)2C9H5}RuCp (Cp = C5H5), {η5-1,3-(CHO)2C9H5}RuCp* (Cp* = C5Me5), and {η5-1,3-(CHO)2C9H5}RuCpF (CpF = C5Me4CF3) with NaBH4 or LiAlH4 under mild conditions affords the [1,3-bis(hydroxymethyl)indenyl]cyclopentadienylruthenium complexes {η5-1,3-(CH2OH)2C9H5}RuCp, {η5-1,3-(CH2OH)2C9H5}RuCp*, and {η5-1,3-(CH2OH)2C9H5}-RuCpF, respectively, in good yields.