Synthesis and structural characterization of 2-mercapto-1-tert-butylimidazole and its Group 12 metal derivatives (HmimtBu)2MBr2 (M = Zn, Cd, Hg)

2-Mercapto-1-tert-butylimidazole (Hmim^tBu) and its Group 12 metal complexes (Hmim^tBu)₂ MBr₂ (M = Zn, Cd, Hg) have been readily prepared and structurally characterized. Whereas the former displays a dimeric structure in the solid state with two S H–N interactions linking each pair of molecules, the four-coordinate complexes exhibit distorted tetrahedral geometries with the S–M–S angles in the range 103.2–135.2. The average M–Br bond lengths are 2.401, 2.567, and 2.688 Å for M = Zn, Cd, and Hg, respectively, and the corresponding average M–S bond distances are 2.350, 2.540, and 2.467 Å. The average C–S bond length for all the complexes (1.72 Å) is only ca. 0.02 Å longer than the corresponding value in the free ligand. Hmim^tBu is orthorhombic, space group Pbca, a = 10.1571(5) Å, b = 9.7906(5) Å, c = 17.6616(9) Å, V = 1756.34(15) ų, Z = 8; (Hmim^tBu)₂ZnBr₂ is monoclinic, space group C2/c, a = 17.187(3) Å, b = 8.9908(17) Å, c = 15.560(3) Å, = 117.206(3), V = 2138.3(7) ų, Z = 4; (Hmim^tBu)₂CdBr₂ is triclinic, space group P , a = 7.4625(6) Å, b = 9.6149(9) Å, c = 31.020(3) Å, = 93.485(2), = 94.579(2), = 103.872(2), V = 2146.6(3) ų, Z = 4; (Hmim^tBu)₂HgBr₂ is monoclinic, space group P2₁/c, a = 6.8908(6) Å, b = 10.2397(9) Å, c = 29.859(3) Å, = 94.364(2), V = 2100.7(3) ų, Z = 4.