SYNTHESIS AND STRUCTURE OF NB-2(MU(2)-SE-2)(2)(TE2I6)(2)

Compound Nb-2(mu(2)-Se-2)(Te2I6)(2) was obtained in high yield by high -temperature reaction (500 degrees C) of the dinuclear cluster complex Nb-2(mu(2)-Se-2)(2)I-4 with Te and I-2 in a 1:4:4 ratio. The structur e of Nb2Se4Te4I12 has been determined by single-crystal X-ray diffract ion. It is characterized by the presence of isolated molecules of [Nb- 2(mu(2)-Se-2)(2)(Te2I6)(2)]. The inner skeleton is formed by a dinucle ar [Nb-2(mu(2)-Se-2)(2)](4+) fragment with a Nb-Nb distance of 2.926(2 ) Angstrom; the Se-Se distances are 2.310(2) and 2.311(2) Angstrom. Ea ch Nb atom is ligated (formally) by Te2I62- ligands. The terminal Te-I distances in the Te2I62- ligands range from 2.735(2) to 2.786(2) Angs trom. The bridging Te-I distances are rather long, ranging from 3.175( 1) to 3.261(2) Angstrom. Copyright (C) 1997 Elsevier Science Ltd.