Synthesis of a tripalladium cluster containing an η1:η2:η2-bridging butadienyl ligand stabilized by a zwitterionic structure
摘要:
An eta(1)-butadienyl complex [{trans-eta(1)-CH2=C(Me)C=CH2}Pd(PPh3)(2)Cl] (1) reacted with [(mu-eta(2):eta(2)-1,3-butadiene)Pd-2(PPh3)(mu-Cl)Cl] (2) to result in displacement of the diene ligand of 2 accompanied by exchange of PPh3 of 1 with Cl anion of 2 producing a butadienyl tripalladium cluster [{(mu-CH2=C(Me)C=CH2)Pd(PPh3)Cl-2}.{Pd-2(PPh3)(2)(mu-Cl)}] (3) stabilized by the zwitterionic structure in moderate yield. The X-ray structure analysis of 3 revealed rigid binding of [Pd-3(PPh3)(2)(mu-Cl)](+) and[{CH2=C(Me)C=CH2}Pd(PPh3)Cl-2](-) through the pi-bond coordination of the butadienyl group to the dipalladium cation.