Oxidative Cleavage of C=S and P=S Bonds at an Al I Center: Preparation of Terminally Bound Aluminum Sulfides

Abstract The treatment of cyclic thioureas with the aluminum(I) compound NacNacAl ( 1 ; NacNac=[ArNC(Me)CHC(Me)NAr] − , Ar=2,6‐Pr i 2 C 6 H 3 ) resulted in oxidative cleavage of the C=S bond and the formation of 3 and 5 , the first monomeric aluminum complexes with an Al=S double bond stabilized by N‐heterocyclic carbenes. Compound 1 also reacted with triphenylphosphine sulfide in a similar manner, which resulted in cleavage of the P=S bond and production of the adduct [NacNacAl=S(S=PPh 3 )] ( 8 ). The Al=S double bond in 3 can react with phenyl isothiocyanate to furnish the cycloaddition product 9 and zwitterion 10 as a result of coupling between the liberated carbene and PhN=C=S. All novel complexes were characterized by multinuclear NMR spectroscopy, and the structures of 5 , 9 , and 10 were confirmed by X‐ray diffraction analysis. The nature of the Al=S bond in 5 was also probed by DFT calculations.