Interactions of metalloporphyrins as donors with the electron acceptors C60, tetracyanoquinomethane (TCNQ) and trinitrofluorenylidenemalonitrile

Crystals of C-60.Pt-II(OEP).2(C6H6), TCNQ.Cu-II(OEP), TCNQ.H-2(OEP), TCNQ.2Cu(II)(OEP), TCNQ.2Zn(II)(OEP) and TNFM.Co-II(OEP) [OEP is the dianion of octaethylporphyrin, TCNQ is 7,7,8,8-tetracyanoquinodimethane, TNFM is (2,4,7-trinitrofluorenylidene)malonitrile] have been obtained by diffusion of a solution of the porphyrin as donor into a solution of the respective acceptor molecule. The structure of C-60.Pt-II(OEP).2(C6H6) consists of an ordered C-60 cage nestled against the platinum porphyrin which makes close face-to-face contact with another Pt-II(OEP) molecule. In contrast, there are no close face-to-face contacts between porphyrins in the crystal structures of TCNQ.Cu-II(OEP), TCNQ.H-2(OEP), and TNFM.Co-II(OEP). These compounds consist of classical donor-acceptor stacks of interleaved porphyrin and TCNQ or TNFM molecules with separations of ca. 3.3 Angstrom between adjacent molecules. However with TCNQ.2Cu(II)(OEP) and TCNQ.2Zn(II)(OEP) the structures involve TCNQ (A) and M-II(OEP) (D) molecules that crystallize in stacks with a DDA(DDA)(n)DDA arrangement. Within these stacks there are pairwise contacts between M-II(OEP) molecules and these pairs are compared to those found in C-60.Pt-II(OEP).2(C6H6) and related fullerene-containing crystals.