Interaction of Curved and Flat Molecular Surfaces. The Structures of Crystalline Compounds Composed of Fullerene (C₆₀, C₆₀O, C₇₀, and C₁₂₀O) and Metal Octaethylporphyrin Units

Abstract

Solutions of C60, C60O, or C70 and metal complexes of octaethylporphyrin (OEPH2) yield crystals that contain both the fullerene and the porphyrin. The structures of C60·2CoII(OEP)·CHCl3, C60·2ZnII(OEP)·CHCl3, and C60O·2CoII(OEP)·CHCl3 are isomorphous and contain an ordered C60 cage surrounded by two MII(OEP) units. Although there is no covalent bond between the fullerene and porphyrin components, the separation between these units is shorter than normal van der Waals contact. Crystals of C70·CoII(OEP)·C6H6·CHCl3, C70·NiII(OEP)·C6H6·CHCl3, and C70·CuII(OEP)·C6H6·CHCl3 are also isomorphous with an ordered fullerene, but have only one porphyrin/fullerene contact. Crystalline C60·ClFeIII(OEP)·CHCl3 lacks the close face-to-face porphyrin/porphyrin contact that is common to all of the other structures reported here but retains the intimate contact between the porphyrin and the fullerene. In (C120O)·CoII(OEP)·0.6C6H6·0.4CHCl3 the fullerene dimer is enclosed by two CoII(OEP) moieties. Unfortunately disorder in the fullerene portion obscures details of the geometry of the bridging region between the fullerenes.

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).…”

Peculiarities of C60.− Coordination to Cobalt(II) Octaethylporphyrin in Ionic Multicomponent Complexes: Observation of the Reversible Formation of CoC(C60−) Coordination Bonds

“…[1,2] Fullerenes were shown to cocrystallize with metal octaethyl-and tetraarylporphyrins. [3][4][5][6][7] For some of these cocrystals, weak metal-carbon(fullerene) bonding was found. For example, cobalt(ii) octaethylporphyrin (Co II OEP), cobalt(ii) tetraphenylporphyrin (Co II TPP), and ironA C H T U N G T R E N N U N G (iii) tetraphenylporphyrin form complexes with C 60 with M···CA C H T U N G T R E N N U N G (C 60 ) contacts with lengths of 2.67-2.71, 2.63-3.11, and 2.69-2.70 , respectively.…”

“…For example, cobalt(ii) octaethylporphyrin (Co II OEP), cobalt(ii) tetraphenylporphyrin (Co II TPP), and ironA C H T U N G T R E N N U N G (iii) tetraphenylporphyrin form complexes with C 60 with M···CA C H T U N G T R E N N U N G (C 60 ) contacts with lengths of 2.67-2.71, 2.63-3.11, and 2.69-2.70 , respectively. [3][4][5][6] These contacts are noticeA C H T U N G T R E N N U N G ably shorter than the sum of the van der Waals radii of metal (M) and C atoms (> 3.1 ), but are essentially longer than the length of a strong MÀC bond, for example, in alkylco-A C H T U N G T R E N N U N G balamins (1.99-2.03 [8] ). Nevertheless, this bonding orders the fullerene molecules in the complexes with metal octaethylporphyrins, and allows the molecular structures of some fulA C H T U N G T R E N N U N G lerene derivatives and endometallofullerenes to be studied.…”

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

“…The unexpectedly close approach of a curved surface to the center of a flat surface was originally recognized in the x-ray crystal structure of a fullerene-porphyrin conjugate (23). Subsequent cocrystallization studies of fullerenes with porphyrins (or metalloporphyrins) established the generality of the phenomenon (24,25), and discrete complexes of fullerenes in bisporphyrin (26) or ''jaws porphyrin'' hosts (27,28) have illustrated the supramolecular chemistry principles involved. The interaction is primarily van der Waals in nature (24) but is influenced by a summation of other weak forces.…”