Several tellurometalates of the general formula [MTe7]n- (n = 2, 3) have been isolated as salts of organic cations by reaction of suitable metal sources with polytelluride solutions in DMF. The [HgTe7]2- anion has the same structure in both the NEt4+ and the PPh4+ salts except for a minor change in the ligand conformation. The [AgTe7]3- and [HgTe7]2- anions contain metal atoms coordinated in trigonal-planar fashion to η3-Te74- ligands. The central Te atom of an η3-Te74- ligand is coordinated to the metal atom and to two Te atoms in a "T"-shaped geometry consistent with a hypervalent 10 e- center. The planar [AuTe7]3- anion may best be described as possessing a square-planar AuIII atom coordinated to an η3-Te54- ligand and to an η1-Te22- ligand. The reaction of [NEt4]n[MTe7] (M = Hg, n = 2; M = Au, n = 3) with the activated acetylene dimethyl acetylenedicarboxylate (DMAD) has yielded the products [NEt4]n[M(Te2C2(COOCH 3)2)2] (M = Hg, n = 2; M = Au, n = 1). The metal atoms are coordinated to two Te(COOCH3)C=C(COOCH3)Te2- ligands, for M = Hg in a distorted tetrahedral fashion and for M = Au in a square-planar fashion.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Inorganic Chemistry