Can MP(P)₄ Compounds Form Complexes with C₆₀?

Pages 91-97 

Aleksey E. Kuznetsov

DOI: https://doi.org/10.6000/1929-5030.2017.06.03.1

Published: 01 November 2017

Abstract: Numerous complexes between versatile derivatives of metalloporphyrins MP (with M being Mn, Co, Ni, Cu, Zn and Fe) and C₆₀ 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 C₆₀, we computationally investigated possibility of the complex formation between two MP(P)₄ species, ZnP(P)₄ and NiP(P)₄, and C₆₀ without any linkers, using the CAM-B3LYP/6-31G* approach, both in the gas phase and with implicit effects from C₆H₆. We found that the binding energies in the MP(P)₄-C₆₀ complexes for these twoMP(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-C₆₀ complex whereas NiP(P)₄ inside the NiP(P)₄-C₆₀ complex essentially retained its bowl-like shape. Thus, we showed the possibility of the formation of complexes between MP(P)₄ species and C₆₀ without any linkers and showed dependence of the complex stability on the transition metal M. Further investigations are in progress.

Keyword: Porphyrin-fullerene complexes, tetraphosphorus-metalloporphyrins, DFT, binding energies, NBO charges.

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