Complexes of M3S44+ (M = Mo, W) with chiral alpha-hydroxy and aminoacids: Synthesis, structure and solution studies

Abstract

New complexes of triangular clusters M3S44+ (M=Mo, W) with incomplete cuboidal metal–chalcogenide framework bearing chiral α-hydroxy and amino acids have been prepared. l-lactic acid (H2lac), l-mandelic acid (H2man), and l-alanine (Hala) react with [W3S4Br4(PPh3)3] in 1:1 ratio to yield, respectively, monosubstituted complexes [W3S4(PPh3)3Br3(Hlac)(CH3CN)] (1), [W3S4(PPh3)3Br3(Hman)(CH3CN)] (2), and [W3S4(PPh3)3Br3(Hala)(CH3CN)]Br (3). In the presence of base [Mo3S4Cl4(PPh3)3] gives trisubstituted complexes [Mo3S4(PPh3)3(Hlac)2(lac)] (4) and [Mo3S4(PPh3)3(Hman)3]Cl (5). Circular dichroism studies of 4 indicate chirality transfer from the ligand to the Mo3S44+ cluster core. These complexes incorporate Cu+ with the formation of corresponding {M3CuS4}5+ cuboidal derivatives. NMR and ESI-MS studies of solution behavior are presented.