Synthesis and structural characterization of polymeric dimethylaluminum phenylthiolate

The reaction of trimethylaluminum with thiophenol forms the compound [Me2Al(μ-SPh)]n in good yield. The compound has been characterized by 1H, 13C and variable-temperature NMR (VT-NMR) spectroscopy, mass spectroscopy, and by cryoscopic molecular-weight determination. The solid-state structure has been determined by single-crystal X-ray crystallography and was assigned to the monoclinic space group Pc (no. 7) with cell constants a=9.2499(12), b=7.1344(10), c=7.1947(11) Å, β=100.328(3)° and Z=2. The refinement converged with R1=7.24% (wR2=15.4%) for 581 (I≥2σ(I)) observed reflections and was described in terms of an infinite chain polymer with phenyl thiol groups and dimethylaluminum groups alternating. The average Al–S distance is 2.36 Å. VT-NMR shows that the compound exhibits some fluxional behavior, which affects the ortho protons of the phenyl ring. Cryoscopic molecular-weight measurements show that the aggregation state is a function of concentration, and it has been proposed that two species, dimer and trimer, exist in solution.