Gallium and Indium Complexes of Bis(amino thiol) (N(2)S(2)) Ligands

Three methods have been developed to prepare gallium and indium complexes of three tetradentate N(2)S(2) ligands of the general formula M(N(2)S(2))R (M = Ga, In; R = Cl, Br, SCN, O(2)CC(6)H(5)-O,O'). The ancillary ligand (Cl, SCN, O(2)CC(6)H(5)-O,O') was varied with the tetradentate ligand BAT-TM. X-ray crystallography shows that the coordination geometry about the d(10) metal ion is influenced by the steric requirements of the ligands. X-ray crystallography of four molecules results in the following data: GaCl(BAT-TM) (1), formula = C(10)H(22)ClGaN(2)S(2), space group = Pnma, a = 12.387(4) Å, b = 21.116(6) Å, c = 5.986(2) Å, V = 1565.8(9) Å(3), Z = 4; InCl(BAT-TM) (2), formula = C(10)H(22)ClInN(2)S(2), space group = Pnma, a = 12.968(9) Å, b = 29.29(1) Å, c = 5.866(2) Å, V = 1620(2) Å(3), Z = 4; InNCS(BAT-TM) (3), formula = C(11)H(24)ClInN(3)S(3), space group = Pbca, a = 11.812(3) Å, b = 11.679(3) Å, c = 24.238(9) Å, V = 3449.7 (17) Å(3), Z = 8; In(O,O'-O(2)CC(6)H(5))(BAT-TM) (4), formula = C(19)H(29)O(2)InN(2)S(2), space group = P2(1)/n, a = 10.783(2) Å, b = 18.708(4) Å, c = 12.335(4) Å, V = 2321.7(9) Å(3), Z = 4. Proton NMR studies show that the complexes are stable in solution; in polar solvents such as acetonitrile, for certain molecules, two metal-ligand complexes are observed. Similarly, two metal-ligand complexes are seen in NMR data taken in 80% acetonitrile/20% D(2)O (pD = 4.6) mixture. HPLC studies (acetonitrile/50 mM sodium acetate, pH = 4.6) show that the lipophilicity of the ligand determines the retention time of the complex.