Syntheses and characterization of di- and mono-thiocyanato germanium (IV) complexes with 5,14-dihydro-6,8,15,17-tetramethyldibenzo[b,i][1,4,8,11]tetraazacyclotetra decine

摘要

By controlling the molar ratio of Ge(tmtaa)Cl-2 and NH4SCN at 1:2 and 1:1 in CH3OH (H(2)tmtaa = 5,14-dihydro-6,8,15,17-tetramethyldibenzo[b,i] [1,4,8,11]tetraazacyclotetradecine), two kinds of germanium(IV) complexes, Ge(tmtaa)(NCS)(2) (1) and Ge(tmtaa)(Cl)(NCS) (2), were prepared and characterized by IR, UV, mass and NMR spectra as well as DSC measurements. In the IR spectrum of 1, two C=N stretching bands of NCS groups were observed at 2073 and 2043 cm(-1), while in the IR spectrum of 2, only one C=N stretching band of a NCS group appeared at 2110 cm(-1). The crystal structure of a trans six-coordinate tmtaa complex of germanium in the +IV oxidation state is reported. X-ray single crystal analysis of 1 reveals that it adopts a six-coordinate geometry in which two NCS groups are in trans positions, The bond lengths of Ge-N between the central germanium and NCS groups are 1.996(6) and 2.031(6) Angstrom. They are longer than those between the central metal and nitrogen atoms of tmtaa (1.926 Angstrom). (C) 2002 Elsevier Science Ltd. All rights reserved. [References: 25]