Preparation and Structural Characterization of the Bis[bis(trimethyl-silyl)amido]chalcogenides of Selenium and Tellurium

Abstract

The new compounds Se[N(SiMe3)2]a2n d Te[N(SiMe3)2]h2a ve been prepared in relatively good yields and their crystal structures determined by X-ray crystallography at low temperature. The p. compound crystallizes in the monoclinic system, space group C2/c, with Z = 4 and unit cell dimensions u = 1705.4 (3) pm, b = 642.2 (2) pm, c = 21 16.7 (4) pm, and j3 = 108.19 (2)O. The Te compound crystallizes in the triclinic system, space group Pi, with Z = 2 and unit cell dimensions a = 903.9 (3) pm, b = I 1 11.7 (4) pm, c = 1241.0 (4) pm, CY = 88.67 (2)O, 0 = 73.68 (3)O, and y = 69.10 (2)’. The crystals of both compounds consist of isolated Ch[N(SiMe3)J2 (Ch = Se, Te) molecules containing V-shaped ChN2 units with Se-N distances of 186.9 (2) pm and Te-N distances of 205.3 (2) and 204.5 (2) pm. The NChN bond angles were found to be 108.0 ( I ) and 105.8 ( 1 ) O for the Se and Te compounds, respectively. No significant intermolecular Ch-N interactions were found in the two compounds, but an intermolecular Te-Te distance of 377 pm, substantially less than the corresponding van der Waals distance, is present in the Te compound.