Syntheses and characterization of hybrid bi- and multidentate tellurium ligands derived from N,N-dimethylbenzylamine: Coordination behavior of bis[2-((dimethylamino)methyl)phenyl] telluride with chromium pentacarbonyl

Article abstract of DOI:10.1021/om00010a043

A range of bi- and multidentate tellurium ligands containing both Te and N donor atoms have been synthesized and characterized by multinuclear NMR (¹H, ¹³C, ¹²⁵Te), MS, and single-crystal X-ray diffraction studies. Bidentate ligand 2-NMe₂CH₂C₆H₄TeMe (4) was obtained from the reaction of 2-NMe₂CH₂C₆H₄TeLi (3) with MeI. The reaction, in addition to the expected telluride 4, afforded the novel 2-NMe₂CH₂C₆H₄TeI (5) and the tridentate ligand (2-NMe₂CH₂C₆H₄)₂Te (6) in poor yields. The compound is monomeric with weak intermolecular contacts between the Te and iodine atoms from adjacent molecules. Alternatively, ligand 6 has been obtained by the reaction of 2-NMe₂CH₂C₆H₄Li (2) and TeI₂, and its bonding capabilities have been evaluated. Ligand 6 displaces the THF ligand in Cr(CO)₅THF to give the complex Cr(CO)₅(2-NMe₂CH₂C₆H ₄)₂Te (13) in which the ligand is bonded only through Te. Reaction of 6 with Cr(CH₃CN)₃(CO)₃ also gives the same complex 13. Structures of the free ligand and its complex have been determined. Ligand 6 crystallizes in monoclinic space group P2₁/n with a = 10.2310(10) ?, b = 5.6110(10) ?, c = 32.010(3) ?, β = 97.13°(1), V = 1823.4(4) ?³, Z = 4, D_c = 1.443 mg/m³ (Mo Kα radiation at 293(2) K). The Te atom is pyramidal, and the Cr-Te distance of 2.6665 (9) ? is the shortest known. The bidentate ligand 2-NMe₂CH₂C₆H₄TePh (7) has been similarly obtained from 2 by reaction with PhTeBr. Oxidative workup of 3 afforded the ditelluride (2-NMe₂CH₂C₆H₄)₂Te ₂ (8). Reaction of 8 with diazomethane gave the telluroether ligand (2-NMe₂CH₂C₆H₄Te)₂CH ₂ (9). Other multidentate ligands of the type (2-NMe₂CH₂C₆H₄Te)₂E (10-12) (E = (CH₂)₃, S, Se) were obtained by the reaction of Br(CH₂)₃Br, S, and Se with 3, respectively.