Synthesis, Structures, and Characterization of Dimeric Neutral Dithiolato‐Bridged Tungsten Complexes

Abstract

The quadruply bridged bimetallic dithiolato complex [(Cp*W)2(µ‐S)2(µ,η2‐S2CH2)] (3) and the open‐cage triple‐decker complex [(Cp*W)2(µ‐S)(µ‐η4:η4‐B2H2S2)] (2) have been prepared by treatment of CS2 with in situ generated [(Cp*W)2(B2H6)2] (1) obtained by the reaction of [Cp*WCl4] with [LiBH4·thf]. The solid‐state X‐ray diffraction structures of these complexes show the presence of doubly bridging η2‐S2B2H2 and η2‐S2CH2 ligands with a short W–W bond. While many dimolybdenum–sulfur compounds are known, examples of the tungsten–dithilato complexes are relatively few, and in this respect, the isolation of [(Cp*W)2(µ‐S)2(µ,η2‐S2CH2)] represents a rare example of this type. Electronic‐structure analysis, on the grounds of density functional theory (DFT), together with X‐ray diffraction studies, has rationalized the presence of short W–W and B–B bonds. Large HOMO–LUMO gaps have been observed for both compounds, which is consistent with their thermodynamic stability. All of the compounds have been characterized by mass spectrometry, IR spectroscopy, and 1H NMR, 11B NMR, and 13C NMR spectroscopy in solution, and the structural architectures have been unambiguously established by X‐ray diffraction crystallographic analysis.