Synthesis and characterization of novel chiral ortho-tellurated complexes derived from [(S)-1-(dimethylamino)ethyl]benzene: crystal and molecular structure of {2-[(S)-1-(dimethylamino)ethyl]phenyl}tellurium trichloride

Abstract

Novel chiral ortho-tellurated compounds of the types ArTeX3, ArTeX, and ArMeTeX2 (X = Cl, Br, diethyldithiocarbamate) in which the Ar group is (S)-2-Me2NCH(Me)C6H4, have been synthesized by the organolithium route. The derivatives were characterized by H-1 NMR, C-13 NMR, IR, specific rotation, and MS techniques. The room-temperature and variable-temperature NMR (H-1 and C-13) studies indicate that a strong intramolecular Te...N coordination renders the tellurium atom in ArTeX3 and ArMeTeX2 pentacoordinate and in ArTeX tricoordinate. The optical purity of the complexes has been determined with the use of a chiral shift reagent. The crystal structure of [(S)-2-MeNCH(Me)C6H4]TeCl3 (6) has been determined. The crystals form in the trigonal space group P3(2) with a = 11.814 (2) angstrom, c = 8.532 (10) angstrom, and Z = 3; R = 2.12% for 847 observed reflections. The complex is monomeric with weak association between Te and a neighboring chlorine.