F. Gomez-de La Torre et al., Synthesis, characterization, and fluxional behaviour of binuclear palladium complexes with a half-a-frame structure, MONATS CHEM, 131(12), 2000, pp. 1267-1280
Partial removal of chloride anions from the dimer [Pd(eta (3)-2-CH3-C3H4)(m
u -Cl)](2) with AgTf(Tf = CF3SO3) followed by addition of dppm affords [Pd-
2(eta (3) -Me-C3H4)(2)(mu -Cl)(mu -dppm)]Tf (1). The substitution of Cl- by
X- (X = pz, SC6F5, S-py) using the appropriate salts yields the new deriva
tives [Pd-2(eta (3)-Me-C3H4)(2)(mu -X)(mu -dppm)]Tf (2-4). All complexes ex
hibit a dinuclear half-A-frame structure with two isomers present in soluti
on. The isomers differ in the relative orientation of the two allyl groups
(cis or trans). The isomer interconversion was studied by variable temperat
ure H-1 NMR spectroscopy. The molecular structures of 2 and 4 were solved b
y X-ray diffraction studies. A distorted boat conformation of the seven- or
six-membered metallacycle was found in both cases.