Magnetic and Structural Studies of Vanadium Arene Complexes
作者:Victoria Beck、Andrew R. Cowley、Dermot O'Hare
DOI:10.1021/om0497442
日期:2004.8.1
The temperature dependence of the solid-state magnetic susceptibility for the paramagnetic V(l) complexes trans-(CPV)(2)(mu-eta(6):eta(6)-C6H6) (1) and CpV(eta(6)-C6H6) (2) has been investigated. Complex 1 obeys the Curie-Weiss law over the temperature range 10-300 K with mu(eff) = 4.81 mu(B) and Theta = -18.8 K. The high-temperature moment is consistent with the presence of a total of four unpaired electrons derived from two low-spin V(I) d(4) metal centers in an S = 2 configuration. However, at ca. 9 K the magnetic susceptibility displays a broad maximum. This magnetic behavior may be modeled over the full temperature range (4-300 K) using the Heisenberg intracluster magnetic exchange expression for an S-1 = S-2 = 1 system with g = 2.37, Theta = -12.3 K, and J = -2.64 cm(-1). Complex 2 obeys the Curie-Weiss law over the temperature range 5-300 K, with mu(eff) =.2.86 mu(B) and Theta = -5.0 K. The X-ray structure of 2 (P2(1)/a, a = 10.7842(4) Angstrom, b = 7.8233(4) Angstrom, c = 11.2017(5) Angstrom, beta = 113.830(2)degrees at 150 K, Z = 4) has been determined. Crystals of 2 undergo a reversible phase transition to a new monoclinic cell with a' approximate to (a + c)/2, b' approximate to b, c' approximate to (c - a)/2 over the temperature range 290-270 K.
The first triple-decker sandwich with a bridging benzene ring
作者:Alan W. Duff、Klaus Jonas、Richard Goddard、Hans Juergen Kraus、Carl Krueger
DOI:10.1021/ja00354a050
日期:1983.8
Reactive organometallic compounds from metallocenes
作者:K. Jonas
DOI:10.1351/pac198456010063
日期:1984.1.1
be covered include the synthesis of (C5H5)Co(C2H4)2 and its application as a catalyst precursor for the cobalt-catalysed alkyne cyclooligarrization and the cotrimerization of alkynes and nitriles. Also reported are the alkali metal cobaltates MA[Co (C2H4)4] and MA[Co (cod)2] (MA = alkali metal) which can be used as starting materials for the preparation of new catalysts for the hydrogenation of olefins