New Molecular Complexes of Fullerenes C60 and C70 with Tetraphenylporphyrins [M(tpp)], in which M=H2, Mn, Co, Cu, Zn, and FeCl

Abstract

New molecular complexes of fullerenes C60 and C70 with tetraphenylporphyrins [M(tpp)] in which M-H2, MnII, CoII, CuII, ZnII and Fe(III)Cl, have been synthesised. Crystal structures of two C60 complexes with H2TPP, which differ only in the number of benzene solvated molecules, and C60 and C70 complexes with [Cu(tpp)] have been studied. The fullerene molecules form a honeycomb motif in H2TPP.2C60. 3C6H6, puckered graphite-like layers in H2TPP.2C60.4C6H6, zigzag chains in [Cu(tpp)].C70.1.5C7H8.0.5C2HCl3 and columns in [Cu(tpp)]2.C60. H2TPP has van der Waals contacts with C60 through nitrogen atoms and phenyl groups. Copper atoms of the [Cu(tpp)] molecules are weakly coordinated with C70, but form no shortened contacts with C60. The formation of molecular complexes with fullerenes affects the ESR spectra of [M(tpp)] (M = Mn, Co and Cu). [Mn(tpp)] in the complex with C70 lowers its spin state from S = 5/2 to S = 1/2, whereas [Co(tpp)] and [Cu(tpp)] change the constants of hyperfine interaction. ESR, IR, UV-visible and X-ray photoelectron spectroscopic data show no noticeable charge transfer from the porphyrinate to the fullerene molecules.

Supramolecular Fullerene-Porphyrin Chemistry. Fullerene Complexation by Metalated “Jaws Porphyrin” Hosts

“…44 A similar warping of macrocycles is observed in fullerene complexes with metalloporphyrazines 28 and other metallo-tetraphenylporphyrins. 23 Second, the Cu‚‚‚C distances are relatively long (2.83 and 3.06 Å to a 6:6 ring juncture), and the copper atom is not drawn out of the porphyrin plane toward the fullerene. In fact, the Cu atom protrudes out of the porphyrin plane in the opposite direction (0.024 Å from the mean N 4 plane) because of the overall doming and asymmetric warping of the porphyrin.…”

“…More examples followed, [19][20][21][22][23][24][25] and fullerenes are attracted to other flat π surfaces. 13,[26][27][28] The curved to flat π-π attraction has been analyzed by molecular mechanics modeling and shown to be largely the result of van der Waals dispersion forces.…”

Extending supramolecular fullerene-porphyrin chemistry to pillared metal-organic frameworks

“…This is the expected result of maximizing van der Waals contact. It is observed in the discrete supramolecular chemistry of jaws porphyrin (27,28) and cocrystallate structures (24,39).…”

Fullerene−Porphyrin Constructs

“…7 Almost any free-base porphyrin or metalloporphyrin (or like macrocycle) can be cocrystallized with almost any fullerene (or derivatized fullerene) from comixed solutions. [8][9][10][11][12][13] Representative examples are illustrated by H 2 TPP‚ C 60 ‚3toluene (H 2 TPP ) tetraphenylporphyrin) and 2Co-(OEP)‚C 60 ‚CHCl 3 (OEP ) dianion of octaethylporphyrin). As shown in Figures 2 and 3, the structures often adopt an alternating zigzag motif.…”

“…NIR absorption bands attributed to porphyrin-to-fullerene charge-transfer bands have been observed in solid spectra of porphyrinfullerene cocrystallates. 12 Near-edge X-ray absorption fine structure (NEXAFS) measurements on a Zn porphyrin-C 60 film show decreased porphyrin C1s and N1s binding energies relative to uncomplexed porphyrin. 33 This has been interpreted in terms of charge transfer from the fullerene to the metalloporphyrin.…”