NW palladium complexes of cyclopropenylidenes of the type of trans-ClIPd(CPl(Py-Xl have been synthesized, where CP is di-t-butylcyclopropenyiidene or bis~dlisopropylamino)cyclopropenylidene, and Py-X is I-substrtuted pyridines (X -H, CH3, CNl. The complexes revealed high catalytic activity tovard the cycloreversion of quadricyclane (~1 to norbornadiene (NED).
Sased on a detailed kinetic study, it is concluded that liberataon of Py-X is prerequisite for the metal to interact vith Q. The rate of the reaction obeys a rate expression dtNBDl/dt = kcatlcatllf2(Ql. The apparent catalytic activity (kCdtl can be related to the catalytic activity ik*) of the coordinatively unsaturated species C13Pd(CPl and the dissociation constant (Kl for pyridine liberation by kcatk"Kl/3. The values k* and K are discussed in relation to the nature of ligands. Molecular rearrangements of highly strained compound6 catalyzed by transition-metal complexes have attracted considerable attention during last two decades.' Recently, in connection with the importance of light energy storage system based on photochemical formation of strained molecules special cautzons have been foCUSed on the catalysis of tranaltron-metal complexes for exotharmic valence isomerizstions of the kind of molecules , especially for quadricyclane fpl to norbornadiene (NBD).' In