Heteroleptic ytterbium(II) complexes supported by a bulky beta-diketiminato ligand.

Heteroleptic beta-diketiminatoytterbium(ii) complexes [{Yb(L)(mu-I)(thf)}(2)] [: L = {N(Ar*)C(Me)}(2)CH = L(1), : L = {N(SiMe(3))C(Ph)}(2)CH = L(2); Ar* = C(6)H(3)(i)Pr(2)-2,6] were prepared by a salt elimination [from YbI(2)(thf)(2) and KL] or by a ligand redistribution [from YbI(2)(thf)(2) and YbL(2)] reaction. Complexes and were convenient precursors to some new Yb(ii) heteroleptic compounds. Thus, reaction of and with KN(SiMe(3))(2) yielded the mononuclear amido compounds [Yb(L){N(SiMe(3))(2)}(thf)] (: L = L(1) and : L = L(2)). Similarly, with K{N(H)Ar*} gave [Yb(L(1)){N(H)Ar*}(thf)] (). Complex was also obtained via a protolytic reaction of [Yb{N(SiMe(3))(2)}(2)(thf)(2)] with HL(1) at an elevated temperature. Treatment of with slightly less than a stoichiometric amount of K{CH(SiMe(3))(2)} afforded [Yb(L(1)){CH(SiMe(3))(2)}(thf)] (), while using even a small excess of the alkyl reagent resulted in the deprotonation of the beta-diketiminato ligand and the formation of the known dimer [{Yb(L(3))(thf)}(2)] [, L(3) = N[combining macron](Ar*)C(Me)C(H)C(C[combining macron]H(2))N(Ar*)]. Compounds or reacted with KCPh(3) in thf yielding [Yb(L(1)){eta(5)-C(6)H(5)CPh(2)}(thf)] () or [Yb(CPh(3))(2)(thf)(2)] (), respectively; the latter has two differently coordinated CPh(3) ligands. The molecular structures of 1, 2, 4, 5, 6, 8 and 9 were determined by X-ray diffraction.