Transition metal–carbon bonds. Part XXXIV. 1H and 13C nuclear magnetic resonance studies on π-allylic–palladium complexes

Abstract

Under high resolution the ¹H n.m.r. spectra of π-allylic–palladium compounds are more complex than previously reported :e.g., the resonance of the central allylic hydrogen of [Pd₂I₂(C₃H₅)₂] consists of 15 ‘lines’. The spectra are thus interpretable as AA′BB′C patterns. Some relative signs of coupling constants in π-allylic complexes are reported for the first time. ¹³C N.m.r. spectral shifts and J(¹³C¹H) values are reported and discussed. [Pd(acac)-(1,2,3,7-cyclo-octa-2,4-dienylpalladium] is shown not to be fluxional at 25° by ¹³C n.m.r. spectroscopy.