Aluminum Complexes Incorporating Bulky Nitrogen and Sulfur Donor Ligands

The synthesis and structures of aluminum complexes incorporating bulky thioamidate (RC(NR')S-), thioureido (R'HNC(NR')S-), and amidinate (RC(NR')2-) ligands are described. The reaction of AlMe3 with AdN=C=S (Ad = 1-adamantyl) affords the insertion product {MeC(NAd)S}AlMe2 (1), which binds 1 equiv of AlMe3 to generate {MeC(NAd)S}AlMeAlMe3 (2). The alkane elimination reaction of AlMe3 and N,N'-disubstituted thiourea derivatives, (R'HN)2C=S, affords thioureido complexes {R'HNC(NR')S}AlMe2 (3a, R' = Ad; 3b, R' = Ar = 2,6-iPr2-Ph). Carbodiimides, R'N=C=NR', react with AlMe3 to afford acetamidinate compounds {MeC(NR')2}AlMe2 (4a, R' = Ad; 4b, R' = Ar). Sequential addition of tBuLi and AlX2Cl (X = Cl, Me) to R'N=C=NR' affords pivamidinate compounds {tBuC(NR')2}AlCl2 (5b, R' = Ar) and {tBuC(NR')2}AlMe2 (6a, R' = Ad; 6b, R' = Ar). Complexes 1, 3a, 6a, and 6b have been characterized by X-ray crystallography.