Synthesis, Structure, Gas-Phase Reactivity, and Catalytic Relevance of Trinuclear Mo3S4 Clusters Bearing Terminal Hydroxo and Hydrosulfido Groups

Abstract

Molybdenum(IV) hydroxo [Mo3S4(dmpe)3(OH)3]+ (1+) and hydrosulfido [Mo3S4(dmpe)3(SH)3]+ (2+) [dmpe = 1,2-bis(dimethylphosphanyl)ethane] trimetallic cuboidal cluster complexes have been isolated in high yields by treating their chloride precursors with sodium hydroxide or sodium hydrosulfide, respectively. The crystal structures of [1]BPh4 and [2]PF6 confirm that –QH (Q = O, S) groups are coordinated to metal centers. Both hydroxo and hydrosulfido Mo3S4 cluster complexes are fully characterized by spectroscopic, mass spectrometric, and X-ray techniques. A comparative study of the gas-phase dissociation of 1+ and 2+ cations using ESI tandem mass spectrometry is presented, and the results are compared with those already reported for the hydroxo tungsten analogue. The gas-phase reactivity of 1+ and 2+ species towards ethanol and 1-penthanethiol have been explored. The gas-phase-generated [Mo3S4(dmpe)2(O)(OH)]+ cation activates ethanol molecules through a similar mechanism to that proposed for its tungsten congener. The main differences in aldehyde elimination under collision-induced dissociation (CID) conditions between molybdenum and tungsten cluster sulfides are discussed.