Preparation and characterisation of C60(ferrocene)2

Abstract

c6() cocrystallises with ferrocene t o give black C60(ferrocene)2, which contains discrete CEO and ferrocene molecules; the ferrocene does not reduce CeO, but the structure appears t o be stabilised as a result of weak intermolecular cha rg e-t ra nsfer i nte ractions.Buckminsterfullene (c60) is a molecular building block, which can be used to prepare new materials with interesting properties.1-3 It behaves as a mild oxidising agent, displaying six reversible one-electron reductions in solution,4 and may be described as a partly delocalised electrophilic poly-alkene. As an electron acceptor, c 6 0 can be expected to interact with electron-donors (D) to form either charge-transfer complexes, C60Dn, or charge-separated systems, [C,.-][D+],,. The extent of charge separation has important bearing on the preparation of molecular conductors and soft ferromagnets.235 Discrete c 6 0 molecules have been successfully incorporated into novel ionic and molecular materials. For example, alkali metal 'salts', C60Mn (n = 3, 4, 6) have been prepared and (n = 3) display high temperature superconductivity.2 c 6 0 is an ideal guest for a-, por y-cyclodextrin [especially the latter, with which it forms a water-soluble, encapsulated complex, Cm(y-cyclodextrin)2] .6 Analogous behaviour was not observed with the larger oblate spheroidal fullerene, C70. c 6 0 also cocrystallises with 1 ,Chydroquinone to yield a solid, formulated as C60( 1,4-hydroq~inone)3,~ which consists of a polymeric hydrogen-bonded lattice containing large cavities occupied by the c 6 0 molecules. The stability of this compound is

Phase changes and chemical reactions in molecular crystals

“…The stable conformation of the ferrocene molecule is thus eclipsed, in agreement with the results from an early gas-phase electron-diffraction study (Haaland & Nilsson, 1968), and not staggered, as usually depicted in textbooks. The same eclipsed conformation has recently turned up in the C6o(ferrocene) 2 cocrystal (Crane, Hitchcock, Kroto, Taylor & Walton, 1992) -an unexpected corroboration! Ferrocene can thus adopt three different crystal structures.…”

Metal-chelating capacities attached to fullerenes

“…Best known in this class are the alkalimetal fullerides which are already superconducting at relatively high temperatures [6]. In metal-complex fullerene cocrystallites, the interaction between the fullerene and the metal complexes is fundamentally van der Waals, such as observed in C 60 (ferrocene) 2 [7] and cocrystallates of teraarylporphyrins with C 60 [8]. Furthermore, C 60 is often described as an electron deficient polyolefin, capable of forming coordination bonds to transition metals.…”

Solid state 13C and 1H MAS NMR investigations of C60(ferrocene‒d10)2 complex

“…The C 60 (ferrocene-d 10 ) 2 complex [7] was prepared from C 60 (99.99%) [8] and ferrocene-d 10 [9] according to the procedure described elsewhere [2]. As a result, 95% of protons has been exchanged with deuterium in ferrocene-d 10 .…”

“…2a) is due to the two crystallographically unequivalent sites of the ferrocene in the compound. An X-ray study has reported [7], that the compound has a triclinic symmetry P1 where the C 60 molecule lies in the crystallographic inversion centre (Fig. 1).…”