Synthesis of a Naphthalene-Bridged Bis(guanidinato)ytterbium(II) Complex and an Unexpected Pathway in Its Reaction with CH3CN, p-CIC6H4CH2CN, and Ph2CHCN

A novel binuclear ytterbium(II) complex supported by a naphthalene-bridged bis(guanidinate) ligand, [Yb(mu-L)(THF)](2) (1; L = 1,8-C10H6{NC(N'Pr)(NH'Pr)}(2)), was synthesized by the reduction reaction of [Yb(L)Cl(THF)(2)] with Na/K alloy in THF and structurally characterized. The reactions of 1 with CH3CN and p-ClC6H4CH2CN resulted in the formation of the corresponding binuclear (crotononitrileamido)ytterbium(III) complexes [Yb(L)(mu-(N,N')-N(H)C(Me)=C(H)C N)(THF)](2) (2) and [Yb(L)-(mu(N,N')-N(H)C(CH2C6H4-p-Cl)=C(C6H4-p-Cl)C N)-(THF)](2) (3) via metalation of the nitrile, followed by insertion of a second nitrile molecule. Treatment of 1 with the bulkier Ph2CHCN afforded the mononuclear (keteniminato)ytterbium-(III) complex [Yb(L)(N=C=CPh2)(THE)(2)] (4) by deprotonation of Ph2CHCN. The molecular structures of 2-4 have been determined.