Can MP(P)4 Compounds Form Complexes with C60

Abstract

Numerous complexes between versatile derivatives of metalloporphyrins MP (with M being Mn, Co, Ni, Cu, Zn and Fe) and C 60 have been synthesized and characterized recently. Favorable van der Waals attractions between the curved p-surface of the fullerene and the planar p-surface of MP assist in the supramolecular recognition, overcoming the necessity of matching a concave-shaped host with a convex-shaped guest structure. Recently, we reported the computational studies of the structures and electronic properties of the series of metalloporphyrins where all the four pyrrole nitrogen atoms are replaced with P-atoms, MP(P) 4 , M = Sc-Zn. Motivated by the numerous examples of the complex formation between regular planar or quasi-planar MP and C 60 , we computationally investigated possibility of the complex formation between two MP(P) 4 species, ZnP(P) 4 and NiP(P) 4 , and C 60 without any linkers, using the CAM-B3LYP/6-31G* approach, both in the gas phase and with implicit effects from C 6 H 6 . We found that the binding energies in the MP(P) 4 -C 60 complexes for these two MP(P) 4 compounds are relatively low, ca. 1-1.6 kcal/mol and ca. 5 kcal/mol for M = Zn and Ni, respectively. The ZnP(P) 4 species was found to be noticeably distorted in the ZnP(P) 4 -C 60 complex whereas NiP(P) 4 inside the NiP(P) 4 -C 60 complex essentially retained its bowl-like shape. Thus, we showed the possibility of the formation of complexes between MP(P) 4 species and C 60 without any linkers and showed dependence of the complex stability on the transition metal M. Further investigations are in progress.