Synthesis and reactivity of an 2-azabutadiene-based π-conjugated dithioether: Formation of a N,S-ligated molybdenum chelate complex and C,N,S-pincer complexes of palladium and platinum

Nucleophilic attack of sodium isopropylthiolate on 4,4-dichloro-1,1-diphenyl-2-azabuta-1,3-diene [Cl2Cdouble bond; length as m-dashC(H)–Ndouble bond; length as m-dashCPh2}] (1) affords the 2-azabutadiene derivative [(i-PrS)2Cdouble bond; length as m-dashC(H)–Ndouble bond; length as m-dashCPh2] (2). Upon irradiation of Mo(CO)6 in THF in the presence of 2, the chelate complex cis-[(OC)4Mo{(i-PrS)2Cdouble bond; length as m-dashC(H)–Ndouble bond; length as m-dashCPh2}] (3) is obtained. Coordination on Mo occurs through the imine nitrogen and a thioether group. Polydentate dithioether 2 acts as N,C,S-pincer ligand after orthometallation reaction with Pd(II) or Pt(II). The molecular structures of 2 and (C,N,S)-[(i-PrS)2Cdouble bond; length as m-dashC(H)–Ndouble bond; length as m-dashC(Ph)C6H4)PtCl] (4b) have been determined by X-ray diffraction studies.