Synthesis and study of hexanuclear molybdenum clusters containing thiolate ligands

Four hexanuclear molybdenum chloride cluster complexes containing terminal thiolate ligands have been synthesized and fully characterized. (Bu4N)(2)[Mo6Cl8(SEt)(6)] was prepared by reacting Na-2[Mo6Cl8(OMe)(6)] with an excess of ethanethiol in refluxing tetrahydrofuran. (PPN)(2)[Mo6Cl8(SBu)(6)], (Bu4N)(2)[Mo6Cl8(SBn)(6)], and (Bu4N)(2)[Mo6Cl8(SNC8H6)(6)] (C8H6NS- = 3-indolylthiolate) were subsequently prepared in the reaction of [Mo6Cl8(SEt)(6)](2-) with an excess of HSR (R = Bu, Bn or 3-indolyl). Single crystal X-ray diffraction analyses were performed on two of these complexes: (PPN)(2)[Mo6Cl8(SEt)(6)]center dot Et2O, crystallizes in the triclinic space group P (1) over bar with a = 12.3894(11), b = 13.7651(12), c = 15.0974(13), alpha = 103.975(2), beta = 99.690(2), gamma = 98.062(2), and Z = 1; (PPh3Me)(2)(Mo6Cl8(SBn)(6)]center dot 2NO(2)CH(3), also crystallizes in the P (1) over bar space group with a = 12.1574(16), b = 13.4441(17), c = 14.2132(18), alpha = 89.654(2), beta = 88.365(2), gamma = 71.179(2), and Z = 1. Our studies demonstrate that [Mo6Cl8(SEt)(6)](2-) displays luminescent properties and that the same complex undergoes substitution reactions with different thiols, as well as reaction with electrophilic reagents such as Mel.