Formation of Crystalline Polymers from the Reaction of Amine-Functionalized C₆₀ with Silver Salts

Three new crystalline compounds of Ag(I) with fullerene-containing ligands, the piperidine adduct [C60(N(CH2CH2)2N)] and the fullero[60]pyrrolidine [C60(CH2N(CH3)CH2)], have been prepared and characterized by X-ray crystallography. The polymeric structure of {[C60(N(CH2CH2)2N)][Ag(O2CCF3)]2}·CS2 consists of linear chains composed of two distinct molecules of the functionalized fullerene, with four Ag(I) ions attached to the four nitrogen atoms and four bridging trifluoroacetate ions. Two of the four Ag(I) ions form η2-bonds to carbon atoms in different regions of the fullerene cage, and there is one close Ag−Ag contact (3.1657(7) Å) as well. These chains are further cross-linked by bridging trifluoroacetate ions. The structure of {[C60(CH2N(CH3)CH2)]Ag(NO3)}·0.25CH3OH involves two similar polymeric chains in which Ag(I) ions bind to the nitrogen atom of one N-methyl-3,4-fullero[60]pyrrolidine ligand and to a carbon atom of another N-methyl-3,4-fullero[60]pyrrolidine in η1-fashion for one chain and in distorted η2-fashion in the other. Additionally, each Ag(I) ion is bonded to two oxygen atoms from two bridging nitrate ions. On the other hand, [C60(N(CH2CH2)2N)]2Ag(NO3)·0.5CH3OH·CH2Cl2 is a simple coordination complex with two very large ligands attached to Ag(I). Coordination of Ag(I) to C60 produces much smaller alterations to the fullerene geometry than does coordination of Pt0(PPh3)2 or IrI(CO)Cl(PPh3)2 groups.