L. E. Vinogradova

Synthesis of 5,10,15,20-tetra[3-(o- andm-carboranyl)butyl]porphyrins containing the C−B σ-bond

Abstract5,10,15,20-Tetra[3-(o- andm-carboranyl)butyl]porphyrins containing carborane groups bonded to alkyl substituents of the porphyrin cycle by the C−B σ-bond were obtained by condensation of 4-(o- andm-carboran-9-yl)pentanals with pyrrole.

Synthesis ofo-andm-carborane derivatives of [2,2]paracyclophane and abnormal Clemmensen reduction of ketones of the [2,2]paracyclophane and carborane series

Methods for the synthesis of [2,2]paracyclophane derivatives containingo- andm-carboranyl substituents in position 4, separated from the [2,2]paracyclophane system by one or two C atoms (alcohols and ketones) were developed. The Clemmensen reduction of a number of ketones of the [2,2]paracyclophane ando-carbonane series occurs abnormally. The reduction of 1-benzoyl-o-carboranes to the corresponding alcohols by zinc in ethanol in a neutral medium was performed for the first time.

Synthesis of difunctional 1,4-dimethyl-1,4-disilacyclohexanes

Transformations of HVinSiCl2, HVinSi(Me)Cl, HVinSi(Me)Ph, and HVinSi(Me)NEt2 in the presence of Pt catalyst were studied. In dilute solutions, the reaction gave a mixture of structural and stereoisomers of five- and six-membered disilacyclanes, resulting from intramolecular cyclization of the initially formed linear dimer. In the case of methyl(phenyl)disilacyclane, the structural isomers were separated andtrans-1,4-dimethyl-1,4-diphenyl-1,4-disilacyclohexane was isolated. The reaction of this product with HCl in the presence of AlCl3 followed by hydrolysis resulted in the synthesis oftrans-1,4-dichloro- andtrans-1,4-dihydroxy-1,4-dimethyl-1,4-disilacyclohexanes. The structures of the structural and stereoisomers synthesized were confirmed by1H,13C, and29Si NMR and IR spectroscopies and mass spectrometry.

Study of the mutual effect of the carborane nucleus and the benzene ring by the method of ultraviolet and Raman spectroscopy

1. We obtained the UV absorption spectra of 1-phenyl-o-carborane, 3-phenyl-o-carborane, 1-phenyl-m-carborane, 1,2-diphenyl-o-carborane, 1,7-diphenyl-m-carborane, and also the cesium salt of phenyldi-carbaundecarborane (13) in the 210–340 nm region. 2. The integral intensity of the ∼1600 cm−1 line in the Raman spectra of solutions of 1-phenyl-o-carborane, 1,2-diphenyl-o-carborane, 1-phenyl-m-carborane, and benzotrifluoride in CH2Cl2 was measured. 3. The effect of the carborane nucleus on the UV absorption band of the benzene ring in the 240–280 nm region is expressed in a slight shift of the maximum, with the retention of a distinct vibrational structure and an increase in the molar absorption coefficient up to several hundred units. In contrast, in the UV spectrum of [C6H5CB9H10CH]−Cs+ the intensity of the same band reaches 7700; the vibrational structure is smoothed out completely. 4. On the basis of the UV spectra and the intensities in the Raman spectra of the phenylcarboranes it was concluded that conjugation of the benzene ring with carborane nuclei is absent, and that conjugation with the dicarbaundecarborane (13) anion exists.

VIBRATIONAL STUDY OF ROTATIONAL ISOMERISM IN DIALKYLDICHLOROSILANES CL2SIR2 (R = BUN, HEXN)

IR and Raman spectra of Cl2SiR2 (R=Hexn (1), Bun (2)) in liquid, glassy, and polycrystalline states were investigated. In the liquid and glassy states, rotational isomerism about the Si−C and C−C bonds takes place, the compounds being mixtures of conformers. In the crystalline state, only one, the most stable conformer (all-trans in relation to the C−C bonds), persists. Compound2, in contrast to1, was found to crystallize on cooling with great difficulty.

Investigation of the vibrational spectra of carbaphosphaboranes and carbaarsaboranes

1. The IR and Raman spectra of o-, m-, and p-carbaphosphaboranes (CPB) and carbaarsaboranes (CAB), as well as the IR spectra of C-deuterated m-CPB and m-CAB, were obtained in the region of 250–4000 cm−1. 2. The positions and integral intensities of the IR bands corresponding to the valence vibrations of CH were measured. 3. The C-H bond of CPB and CAB, just as in carboranes, is capable of giving a hydrogen bond, the enthalpy of formation of which with dimethyl sulfoxide is ∼2–3 kcal/mole.

ORGANOMETALLIC HYDRIDES AS REACTANTS IN FULLERENE CHEMISTRY. INTERACTION OF C60 AND C70 FULLERENES WITH HIR(CO)(PPH3)3

The iridium hydride complex HIr(CO)(PPh3)3 reacts with fullerenes C60 and C70 yielding (η2-Cn)IrH(CO)(PPh3)2 (n = 60, 70) complexes. Their composition, configuration, and the position of the double bond coordinated with the metal atom in the fullerene moiety have been established by IR studies (comparison with deuterated analogs), and1H and31P NMR spectroscopy.

Vibrational spectra of o-, m-, and p-carboranes B10H10C2H2 and their B-decachloro-substitution products

1. Complete vibrational spectra have been obtained for the icosohedral carboranes O- and M-B10H10C2H2 and O-, M-, and p-B10Cl10C2H2, and certain frequencies identified. 2. The spectra of these compounds proved to be more simple than could have been anticipated from an application of the selection rules for the symmetries in question. It is suggested that certain vibrations in these molecules follow the higher effective A12X12-I symmetry of the hypothetical icosahedron.

IR spectroscopic study of the reaction of dihydroxyorganocyclosiloxanes with 2,2-dimethyl-1-oxa-2-silacyclohexane

The reaction of various mono- and dihydroxyorganocyclosiloxanes with 2,2-dimethyl-1-oxa-2-silacyclohexane was studied by IR spectroscopy. A series of new bis[dimethyl(hydroxybutyl)siloxy] organocyclosiloxanes were obtained.

Infrared spectroscopic study of proton-donor capacity of ch bonds of C- and B-ethynylcarboranes

Conclusions1.In the B- and C-ethynylcarboranes the ethynyl CH bond has a greater proton-donor capacity than the carborane CH bond.2.The insertionof an ethynyl group into the carborane nucleus hardly changes the proton-donor capacity of the carborane CH bond when compared with the unsubstituted carboranes.3.The carboranyl group increases the proton-donor capacity of the acetylenic CH bond when compared with butylacetylene, in which connection this effect decreases in the order 1->2-, 3->9-carboranyl groups, i.e., with decrease in the electron-acceptor effect of the carboranyl group.