Divalent ytterbium complex YbL(ONNO)(THF)2 (L(ONNO)= Me2NCH2CH2N(CH2-2-O-3,5-C6H2(tBu)2)2) (I) has first been found to serve as a catalyst for addition of amines to nitriles to give monosubstituted N-arylamidine in moderate to good yields. The aromatic amines and nitriles showed better activity. The outcome of the addition reaction was greatly affected by the structure of divalent ytterbium complexes. The reaction mechanism was proposed and the benzonitrile-coordinated divalent ytterbium phenoxide Yb(OAr)2(C6H5CN)(THF)2 (Ar = 2,6-ditBu-4-MeC6H3) was isolated as one of the intermediates.
