STRUCTURAL CHARACTERISTICS OF 3-COORDINATE ARYLHALIDE TELLURIUM(II) COMPLEXES WITH CHALCOGEN LIGANDS - SYNTHESIS, SPECTROSCOPIC CHARACTERIZATION AND X-RAY STRUCTURAL STUDIES OF HYLBENZOTHIAZOLE-2(3H)-SELONE]PHENYLTELLURIUM(II), RIS(DIMETHYLAMINO)PHOSPHANESELENIDE]-TELLURIUM(II) AND TRIS(DIMETHYLAMINO)PHOSPHANESULFIDE

The three title compounds have been synthesized and their structures s olved by means of conventional X-ray crystallographic methods. The cry stals of lbenzothiazole-2(3H)-selone]phenyltellurium(II)(I) are monocl inic; at 143K a=9.728(1), b=19.192(4), c=17.099(3)Angstrom, beta=105.1 2(1)degrees, Z=8, space group P2(1)/c. The crystals of tris(dimethylam ino)phosphaneselenide]tellurium(II) (II) (II) are monoclinic; at 293K a=9.718(2), b=17.043(3), c=11.983(2)Angstrom, beta=105.83(3)degrees, Z =4, space group P2(1)/c. The crystals of tris(dimethylamino)phosphanes ulfide (III) are monoclinic; at 143 K a=8.347(2), b=11.369(2), c=11.26 0(2)Angstrom, beta=92.94(3)degrees, Z=4, space group P2,ln. Final R va lues are 0.035, 0.036 and 0.034, respectively. Compounds I and II repr esent T-shaped complexes of Te-II containing an almost linear Br-Te-Se group with Te-Br and Te-Se bond lengths of 2.744-2.836(1) and 2.694-2 .744(1)Angstrom, respectively. The Te-C bond lengths lie in the range 2.110-2.123(5)Angstrom. The trans-influence of the chalcogen ligands a bove and related ligands are discussed and suggested to be a function of the ability of the ligands to accept positive charge from the centr al tellurium(II) atom. Ligands of the type tris(dialkylamino)phosphane chalcogenide possess a unique nitrogen atom whose hybridization change s from sp(3) towards sp(2) upon complexation. This unique N atom is al ways found to form a M-chalcogen-P-N torsion angle near 0 (or 180 degr ees) upon complexation. This is related to the delocalization of posit ive charge discussed above. A preliminary deformation electron density study of III supports this, and also indicates that the hybridization of phosphorus in these ligands differs from sp(3). NMR and IR spectra of the compounds are discussed.