title: Synthesis and structure of Ta4S9Br8. An emergent family of early transition metal chalcogenide clusters.
abstract: Single crystals of Ta4S9Br8 are obtained by heating Ta, S, and Br2 at 400 degrees C in a 4.0:9.0:4.0 molar ratio in a 44% yield. The structure was determined by X-ray analysis and consists of molecular clusters [Ta4(mu4-S)(mu-S2)4Br8]. The tantalum atoms form a square with long Ta...Ta distances (3.30 angstroms), with four S2 ligands bridging the Ta-Ta edges and one capping the square. Each Ta atom has two terminal bromine atoms. The compound is diamagnetic and has only two electrons for metal-metal bonding. IR and Raman spectral studies with the use of 34S allow to identify characteristic vibrations S-S (537 cm(-1)) and Ta4-mu4-S (407 cm(-1)). The compound is soluble in CH3CN, giving a dark-red solution with a characteristic electronic spectrum, which was assigned on the base of DFT calculations. ESI-MS spectra of the solutions show formation of [[Ta4S9Br8]Br]- associates.
authors.affiliation: Nikolaev Institute of Inorganic Chemistry, Russian Academy of Sciences, pr. Lavrentyeva 3, Novosibirsk 630090, Russia. caeser@che.nsk.su
authors.forename: Maxim N
authors.initials: MN
authors.lastname: Sokolov
authors.forename: Artem L
authors.initials: AL
authors.lastname: Gushchin
authors.forename: Pavel A
authors.initials: PA
authors.lastname: Abramov
authors.forename: Alexandr V
authors.initials: AV
authors.lastname: Virovets
authors.forename: Eugenia V
authors.initials: EV
authors.lastname: Peresypkina
authors.forename: Svetlana G
authors.initials: SG
authors.lastname: Kozlova
authors.forename: Boris A
authors.initials: BA
authors.lastname: Kolesov
authors.forename: Cristian
authors.initials: C
authors.lastname: Vicent
authors.forename: Vladimir P
authors.initials: VP
authors.lastname: Fedin