Influence of different transition metals in phthalocyanines on their interaction energies with volatile organic compounds: an experimental and computational study.

Experimental partition coefficients were determined for a series of volatile organic compounds (VOCs) (acetonitrile, n-butylamine, n-octane tetrachloroethene, and toluene) for the interaction with 2,3,9,10,16,17,23,24-octakis(octyloxy)-phthalocyaninato complexes, PcM(OR)(8), with varying central metal atoms [M=H(2) (metal-free), Ni, Pd, Cu, Zn]. Large partition coefficients for toluene were observed in the case of the nickel and palladium phthalocyanines, whereas for the corresponding zinc-containing compound, interaction with n-butylamine resulted in a high value for the partition coefficient. Interaction energies for model coordination complexes were obtained at the ab initio LMP2/ LACVP* level of theory. The interaction of various small volatiles with the various PcM(OR)(8) compounds was studied using the PM3 semiempirical Hamiltonian. Large values for interaction energies correspond to particularly strong partition coefficients, suggesting that coordination of the volatiles to the central metal dominates over the often discussed pi-system stacking at the PcM(OR)(8)'s.