SYNTHESIS, STRUCTURE AND EPR-SPECTRA OF (NBU4)(2)[(OH2)BR4RENREBR4NREBR4(OH2)]

The reaction of (NBu4)[ReNBr4] with BBr3 in CH2Cl2 gives purple crysta ls of (NBu4)(2)[(OH2) Br4ReNReBr4NReBr4(OH2) ]. The centrosymmetric co mplex anion is formed by three ReBr4 units which are linked by two asy mmetric nitrido bridges with Re-N distances of 1.69(2) and 2.00(2) Ang strom. The coordination spheres of the terminal Re atoms are completed by water ligands. The EPR spectra of the trimer suggest a d(2)-d(1)-d (2) sequence for the Re atoms. The g, A(Re) and A(Br) tensor component s deviate from those of [ReNBr4](-) and indicate an increase in the Re -Br covalency. (C) 1998 Elsevier Science S.A. All rights reserved.