SYNTHESIS, CHARACTERIZATION, AND CRYSTAL-STRUCTURE OF NEUTRAL RHENIUM(V) COMPLEXES WITH S-SUBSTITUTED N2S2 LIGANDS

A series of neutral rhenium(V) oxo complexes was synthesized by the re action of ReOBr4- with diamino-thiol-thioether ligands of the type (RS C(CH3)(2)CH2NH(o-C6H4)NHCH2C(CH3)(2)SH. The complexes were characteriz ed by IR, UV/visible, and H-1 and C-13 NMR spectroscopy and by fast-at om-bombardment mass spectroscopy. The single-crystal X-ray structure d etermination on two of the complexes, where R = CH2CH=CH2 and CH2CH2CH 3, showed them to consist of a square pyramidal (ReON2S2)-O-V core. eO [CH2=CHCH2SC(CH3)(2)CH2N(o-C6H4)NCH2C(CH3)(2)S], C17H25N2OS2Re, crysta llizes in the monoclinic space group P2(1)/a with a = 17.899(3) Angstr om, b = 13.910(1) Angstrom, c = 15.936(1) Angstrom, beta = 104.70(1)de grees, Z = 8, D-calc = 1.813 g cm(-3), and mu(Cu K alpha) = 139.8 cm(- 1). The propyl complex, C17H27N2OS2Re, crystallizes in the monoclinic space group P2(1)/a with a = 18.076(1) Angstrom, b = 13.920(1) Angstro m, c = 15.994(1) Angstrom, beta = 105.09(1)degrees, Z = 8, D-calc = 1. 797 g cm(-3), and mu(Cu K alpha) = 138.0 cm(-1). The combination of th e steric and electronic effects of the aromatic ring fused to the back bone of the N-C-C-N ligand and the S-substitution result in deprotonat ion of both amine nitrogens and coplanarity of the base of the square pyramidal complex.