Stepwise construction and destruction of nickel thiolate Ni3 cluster revealed by mass spectrometry and crystallography

Abstract

Trinuclear nickel thiolate cluster [Ni3(μ3-S)(L)3]NO3 (HL = (1-methyl-1H-benzo[d]imidazol-2-yl)methanethiol) (1) has been synthesized from Ni(NO3)2·6H2O and HL at solvothermal condition at 80 °C using methanol as solvent. It has been characterized by X-ray single crystal diffraction, elemental analysis, electrospray ionization mass spectrometry (ESI-MS), and thermogravimetric analysis. The stability of the cluster in methanol is reflected by the fact that the molecular ion peak of [Ni3(μ3-S)(mbms)3]+ is dominant in ESI-MS. Furthermore, the release of H2S from 1 was observed at elevated in source energy condition and in tandem mass spectrometry. The H2S fragment was also detected during the destruction of 1 by thermogravimetric analysis combined with mass spectrometry (TG-MS). Key fragments [NiLS]+ and [Ni2L2]+ were percepted in solution by ESI-MS during the reaction, which have also been detected at elevated in source energy condition. A plausible stepwise assembly process including [NiL]+ to the mixture of [NiLS]+ and [Ni2L2]+ which then combined to give the product [Ni3L3S]+ was proposed.