SYNTHESIS, STRUCTURE, AND MAGNETIC-PROPER TIES OF [CRCL(-MU-CL)(TMEDA)](2)

The title complex [CrCl(mu-Cl))(TMEDA)](2) (1) is obtained in an equim olar reaction of CrCl2(THF) with TMEDA in high yield. 1 crystallises i n the monoclinic space group P2(1)/c with a = 843.2(2), b = 1109.(2), c = 1147.4(3)pm, beta = 102.99(2)degrees and Z = 2. The molecular stru cture of 1 contains two, slightly distorted quadratic pyramidal CrL(5) -subunits, which are linked via two unsymmetrical Cl-bridges. The mu-C l-functions take the apical position of one and a basal position of th e second CrL(5)-unit, wherein the apical Cr-Cl bond (277.6(1) pm) is d estinctly longer than the basal Cr-Cl bond (240.6(1)pm). The terminal Cr-Cl bond is still shorter (237.5(1) pm). The Cr...Cr distance is far beyond any bonding interaction. This is confirmed by means of magneti c susceptibility measurements, which show four unpaired electrons per Cr centre; however, a small antiferromagnetic coupling of J/k = -7.3 K can be calculated. This coupling is suggested to be originated by a 9 0 degrees-sigma-superexchange via the asymmetric mu-Cl functions.