title: V4S9Br4: a novel high-spin vanadium cluster thiobromide with square-planar metal core.
abstract: The novel vanadium thiobromide, V4S9Br4, with a square-planar metal cluster core was synthesized and characterized by single-crystal X-ray diffraction, measurements of magnetic properties and the heat capacity, and DFT calculations of the electronic structure. At the room temperature, the compound displays paramagnetic properties with an independent spin on each V atom and with a weak exchange constant (J approximately 10 cm(-1)). The paramagnetic state is transformed into a low-spin state (AF-type ordering) at low temperatures. This change is accompanied by a heat-capacity anomaly. The observed magnetic and heat-capacity anomalies can be explained by the thermal excitation of electrons on the closely spaced molecular energy levels in the presence of the Jahn-Teller effect.
authors.affiliation: Nikolaev Institute of Inorganic Chemistry and Boreskov Institute of Catalysis, Russian Academy of Sciences, 3, Academician Lavrentiev Avenue, 630090 Novosibirsk, Russia.
authors.forename: Yuri V
authors.initials: YV
authors.lastname: Mironov
authors.forename: Spartak S
authors.initials: SS
authors.lastname: Yarovoi
authors.forename: Dmitry Y
authors.initials: DY
authors.lastname: Naumov
authors.forename: Svetlana G
authors.initials: SG
authors.lastname: Kozlova
authors.forename: Vladimir N
authors.initials: VN
authors.lastname: Ikorsky
authors.forename: Reinhard K
authors.initials: RK
authors.lastname: Kremer
authors.forename: Arndt
authors.initials: A
authors.lastname: Simon
authors.forename: Vladimir E
authors.initials: VE
authors.lastname: Fedorov