I. A. Lobanova

Syntheses, structures, and electroconductivity of bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) and bis(methylenedithio)tetrathiafulvalene (BMDT-TTF) salts with cobalt 8,8′-dichloro-3,3′-bis(1,2-dicarbollide)

Radical cation salts of bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) and bis(methylenedithio)tetrathiafulvalene (BMDT-TTF) with the 8,8′-dichloro derivative of cobalt bis(1,2-dicarbollide) (BEDT-TTF)2[8,8′-Cl2-3,3′-Co(1,2-C2B9H10)2] (1) and (BMDT-TTF)4[8,8′-Cl2-3,3′-Co(1,2-C2B9H10)2] (2) were synthesized and their crystal structures and electrocon-ducting properties were determined. The synthesized radical cation salts are semiconductors with the conductivity σ293 = 1.5 and 2.0 Ohm−1 cm−1, respectively. A decrease in the size of the substituent in a series of (BEDT-TTF)2[8,8′-X2-3,3′-Co(1,2-C2B9H10)2] and (BMDT-TTF)4[8,8′-X2-3,3′-Co(1,2-C2B9H10)2] (X = I, Br, Cl) results in the compression of the anion sublattice of the crystal and compaction of the radical cation packing of the conducting layer, which, in turn, increases the conductivity of the crystals.

Mercury derivatives of exo-nido-ruthenacarborane

Abstract Symmetrical mercury derivative of exo - nido -ruthenacarborane was prepared by two routes: mercuration of exo - nido -5,6,10-[Cl(Ph 3 P) 2 Ru]-5,6,10-(μ-H) 3 -10-H-7,8-C 2 B 9 H 8 ( 1 ) and interaction of Ru(PPh 3 ) 3 Cl 2 with [10,10′-Hg-(7,8-C 2 B 9 H 11 ) 2 ]Cs 2 . Using o -carboran-9-ylmercury trifluoroacetate for mercuration of 1 leads to an unsymmetrical mercury compound with 9- o -carboranyl and exo - nido -ruthenacarboranyl ligands: 5′,6′,10′- exo - nido -[Cl(Ph 3 P) 2 Ru]-5′,6′,10′-(μ-H) 3 -10′-(1,2-C 2 B 10 H 11 Hg-9)-7′,8′-C 2 B 9 H 8 ( 4 ). The same compound was prepared by the action of Ru(PPh 3 ) 3 Cl 2 on [9,10′-Hg-(1,2-C 2 B 10 H 11 )(7′,8′-C 2 B 9 H 11 )]Cs ( 5 ). Both types of new compounds were obtained as a mixture of cis / trans isomers which were separated and characterized by elemental analysis and NMR spectra. The X-ray structure of trans -5′,6′,10′- exo - nido -[Cl(Ph 3 P) 2 Ru]-5′,6′,10′-(μ-H) 3 -10′-(1,2-C 2 B 10 H 11 Hg-9)-7′,8′-C 2 B 9 H 8 ( 4b ) was determined.

Metallotropic rearrangement of η5-fluoroenyltricarbonyl-manganese in acid media

Abstract Using IR and PMR spectroscopy, it has been shown that on addition of trifluoroacetic acid to (η 5 -C 13 H 9 )Mn(CO) 3 in CH 2 Cl 2 solution protonation of position 9 of the fluorenyl ligand takes place with simultaneous migration of the metal atom onto the six-membered ring of the fluorenyl ligand, forming of [(η 6 -C 13 H 10 )Mn(CO) 3 ] + .

Electrophilic substitution in eleven-vertex metallacarborane 1,2,4-CpCoC2B8H10

Bromination and mercuration of cobaltacarborane 1,2,4-CpCoC2B8H10 were investigated. Mercuration under mild conditions (Hg(OCOCF3)2 in CH2Cl2) afforded the only monomercurated complex containing the mercury atom at position 6. Bromination gave rise to 3-mono-, 6-mono-, or 6,9-disubstituted derivatives depending on the reaction conditions. The mercurated derivative was studied by the X-ray diffraction method.

Synthesis, structure, and properties of a new bifunctional radical cation salt with ferracarborane anion: (BEDT-TTF)2[8,8´-Cl2-3,3´-Fe(1,2-C2B9H10)2]

A new radical cation salt of bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) with iron(III) bis(1,2-dicarbollide) 8,8´-dichloro derivatives, that is (BEDT-TTF)2[8,8´-Cl2-3,3´-Fe-(1,2-C2B9H10)2], was synthesized. Its electroconducting and magnetic characteristics were studied, molecular and crystal structures were determined. The electroconductivity of crystals at room temperature was σ293 ~5 Ω–1 cm–1, which is close to the corresponding value for the salt of cobalt bis(1,2-dicarbollide) dichloro derivative and is considerably higher than the electroconductivity of a similar salt of unsubstituted iron bis(1,2-dicarbollide). The measurements of magnetic susceptibility at 2—300 K showed that this salt is paramagnetic.

New boron-containing 2′-deoxyadenosines

Conjugates of polyhedral boron hydrides with deoxyadenosine were synthesized by the opening of cyclic oxonium derivatives of closo-dodecaborate and cobalt bis(1,2-dicarbollide) with 2′-deoxyadenosine derivatives containing a nucleophilic group in the substituent at C(8). Biological studies of the derivatives obtained for cytotoxicity revealed that the derivatives based on closo-dodecaborate did not exhibit cytotoxicity. The conjugates obtained can be used in further biological trials as potential agents for boron neutron capture therapy of cancer.

Electrophilic substitution reactions of ferracarborane 3-(η5-Cp)-4-SMe2-3,1,2-FeC2B9H10

Mercuration and bromination reactions of ferracarborane 3-(η5-Cp)-4-SMe2-3,1,2-FeC2B9H10 (1) were investigated. Mercuration of 1 under mild conditions (mercury trifluoroacetate in dichloromethane) results in 8-monosubstituted mercury derivative as the only reaction product. Depending on the reaction conditions, bromination of 1 results in 8-mono- or 7,8-disubstituted bromo derivatives. The structures of the monomercury and dibromo derivatives of 1 were established by X-ray analysis.

Synthesis of new charge-compensated cobalt bis(1,2-dicarbollide) derivatives

New hetero-substituted charge-compensated cobalt bis(1,2-dicarbollide) derivatives were synthesized by the reaction of 8,8′-μ-iodo-3-commo-3-cobalta-bis(1,2-dicarba-closo-dodecaborane) [8,8′-μ-I-3,3′-Co(1,2-C2B9H10)2] with 1,4-thioxane, pyridine N-oxide, and tetrahydropyran. X-ray diffraction studies showed that the 8′-iodo-8-(pyridiniumoxy)eucosahydro-1,1′,2,2′-tetracarba-3-commo-cobalta-closo-tricosaborate molecule has the gauche-conformation (the substituents are turned with respect to each other by 69.2°). The positive charge is predominantly localized on the N(Py) atom.

Reaction of exo-nido-ruthenacarborane [Cl(Ph3P)2Ru]-5,6,10-(μ-H)3-10-H-7,8-C2B9H8 with bromine

The reaction of bromine with exo-nido-ruthenacarborane [Cl(Ph3P)2Ru]-5,6,10-(μ-H)3-10-H-7,8-C2B9H8 (1) led to the replacement of the chlorine atom by the bromine atom in the octahedral environment of the ruthenium atom rather than to the substitution in the carborane cage. The structure of [Br(Ph3P)2Ru]-5,6,10-(μ-H)3-10-H-7,8-C2B9H8 was established by NMR and IR spectroscopy and X-ray diffraction analysis.

Synthesis of 1,4-disubstituted 1,2,3-triazoles based on cobalt bis(1,2-dicarbollide)

An approach to the synthesis of new 1,4-disubstituted 1,2,3-triazoles, in which one or both substituents contain the cobalt bis(1,2-dicarbollide) fragment, was suggested based on the 1,3-dipolar cycloaddition of azides to alkynes catalyzed by copper(I) compounds. The reaction of cobalt bis(1,2-dicarbollide) azido derivatives with different terminal acetylenes led to 1,2,3-triazoles with the [((CH2)2X(CH2)2O-C2B9H10)Co(C2B9H11)] (X = O or CH2) substituent at position 1 and the organic substituent at position 4. The [3+2] cycloaddition reaction of cobalt bis(1,2-dicarbollide) alkynyl derivatives with methyl azidoacetate furnished isomeric 1,4-disubstituted 1,2,3-triazoles with the metallacarborane fragment at position 4. 1,2,3-Triazole with metallacarborane substituents at positions 1 and 4 containing 36 boron atoms was also synthesized.