Redefining the Coordination Geometry and Reactivity of Guanidinate Complexes by Covalently Linking the Guanidinate Ligands. Synthesis and Reactivity of [RN{NH(R)}CN(CH₂)₂NC{NH(R)}NR]M(CH₂Ph)₂ (R = iPr; M = Ti, Zr)

Reaction of the new biguanidine ( i Pr)HN{NH( i Pr)}CN(CH 2 ) 2 NC{NH( i Pr)}N( i Pr)H ( 1 ) with M(CH 2 Ph) 4 affords the hydrocarbyl complexes [ i PrN{NH( i Pr)}CN(CH 2 ) 2 NC{NH( i Pr)}N i Pr]M(CH 2 Ph) 2 ([L 4 Pr ]M(CH 2 Ph) 4; M = Ti ( 2 ), Zr ( 3 )). Structure determinations of 2 and 3 and the reactivity of 3 with 2,6-dimethylphenyl isocyanide indicate that the linked guanidinate ligand system provides a more open metal coordination sphere than do the unlinked analogues.