Single-Crystal X-ray Diffraction Studies of Solvated Crystals of C60 Reveal the Intermolecular Interactions between the Component Molecules.

The solid-state structures of seven solvates of C60 (C60·4tetrachloroethylene, C60·2tetrachloroethylene, C60·3benzene, C60· n-pentane, C60·diethyl ether, C60·chlorobenzene, and C60·benzene·dichloromethane) were determined by single-crystal X-ray diffraction at low temperature. At 90 K, the fullerene and solvate components are generally well-ordered and do not show the orientational disorder that plagues similar structures determined at room temperature. Interactions between the solvate molecules and the fullerene and between adjacent C60 molecules were examined and analyzed. Van der Waals and weak charge-transfer interactions are important to help to organize the individual components in these structures. The weak Lewis acid behavior of C60, such as when it cocrystallizes with diethyl ether or chlorinated solvents, is apparent. In addition, π-stacking interactions are prevalent. The solvates of C60 reported here were frequently obtained from attempts to cocrystallize C60 with another chemical compound. Although the desired cocrystals were never formed, the unincorporated molecules influenced solvate formation.

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 [C(60)(N(CH(2)CH(2))(2)N)] and the fullero[60]pyrrolidine [C(60)(CH(2)N(CH(3))CH(2))], have been prepared and characterized by X-ray crystallography. The polymeric structure of {[C(60)(N(CH(2)CH(2))(2)N)][Ag(O(2)CCF(3))](2)}.CS(2) 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 eta(2)-bonds to carbon atoms in different regions of the fullerene cage, and there is one close Ag-Ag contact (3.1657(7) A) as well. These chains are further cross-linked by bridging trifluoroacetate ions. The structure of {[C(60)(CH(2)N(CH(3))CH(2))]Ag(NO(3))}.0.25CH(3)OH 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 eta(1)-fashion for one chain and in distorted eta(2)-fashion in the other. Additionally, each Ag(I) ion is bonded to two oxygen atoms from two bridging nitrate ions. On the other hand, [C(60)(N(CH(2)CH(2))(2)N)](2)Ag(NO(3)).0.5CH(3)OH.CH(2)Cl(2) is a simple coordination complex with two very large ligands attached to Ag(I). Coordination of Ag(I) to C(60) produces much smaller alterations to the fullerene geometry than does coordination of Pt(0)(PPh(3))(2) or Ir(I)(CO)Cl(PPh(3))(2) groups.

A distorted tetrahedral metal oxide cluster inside an icosahedral carbon cage. Synthesis, isolation, and structural characterization of Sc4(mu3-O)2@Ih-C80.

The remarkably large cluster Sc4(mu3-O)2 has been obtained trapped inside an Ih-C80 cage by conducting the vaporization of graphite rods doped with copper(II) nitrate and scandium(III) oxide in an electric arc under a low pressure helium atmosphere with an added flow of air. The product has been isolated by chromatography and identified by high-resolution mass spectrometry. The structure of Sc4(mu3-O)2@Ih-C80 has been determined by X-ray crystallography on a crystal of Sc4(mu3-O)2@Ih-C80.NiII(OEP).2(C6H6). The Sc4(mu3-O)2 unit consists of a distorted tetrahedron of scandium atoms with oxygen atoms bridging two of its faces. The Sc-Sc distances range from 2.946(7) to 3.379(7) A.

Internal and external factors in the structural organization in cocrystals of the mixed-metal endohedrals (GdSc2N@Ih-C80, Gd2ScN@Ih-C80, and TbSc2N@Ih-C80) and nickel(II) octaethylporphyrin.

Structural characterizations of three new mixed-metal endohedrals, GdSc 2N@ I h -C80, Gd 2ScN@ I h -C80, and TbSc 2@ I h -C80, have been obtained by single-crystal X-ray diffraction on GdSc 2N@ I h -C80 x Ni (II)(OEP) x 2C 6H 6, Gd 2ScN@ I h -C 80 x Ni(II)(OEP) x 2C6H6, and TbSc 2N@ I h -C80 x Ni (II)(OEP) x 2C6H6. All three have I h -C 80 cages and planar MM' 2N units. The central nitride ion is positioned further from the larger Gd3+ or Tb3+ ions and closer to the smaller Sc3+ ions. The MM' 2N units show a remarkable degree of orientational order in these and related compounds in which the endohedral fullerene is cocrystallized with a metalloporphyrin. The MM' 2N units are oriented perpendicularly to the porphyrin plane and aligned along one of the N-Ni-N axes of the porphyrin. The smaller Sc3+ ions show a marked preference to lie near the porphyrin plane. The larger Gd3+ or Tb3+ ions assume positions further from the plane of the porphyrin. The roles of dipole forces and electrostatic forces in ordering these cocrystals of endohedral fullerenes and metalloporphyrins are considered.

New egg-shaped fullerenes: non-isolated pentagon structures of Tm3N@C(s)(51 365)-C84 and Gd3N@C(s)(51 365)-C84.

Although there are 51 568 non-IPR and 24 IPR structures for C84, the egg-shaped endohedral fullerenes Tm3N@C(s)(51 365)-C84 and Gd3N@C(s)(51 365)-C84 utilize the same non-IPR cage structure as found initially for Tb3N@C(s)(51 365)-C84.

Adventures in crystallization. Crystalline salts containing one, two, or even three chemically distinct cations obtained from solutions of [(cyclohexyl isocyanide)(4)Rh(I)]+.

By judicious selection of crystallization conditions, it has been possible to obtain the salts of a common building block, [(RNC)4Rh(I)]+, in single-crystal form suitable for X-ray diffraction. Salts that contain a single type of cation include deep green [(C6H11NC)12Rh(I)3](SbF6)3, deep green [(C6H11NC)12Rh(I)3](AsF6)3, and straw yellow [(C6H11NC)8Rh(II)2Cl2](BF4)2 (in addition to the previously isolated trimeric deep green [(i-PrNC)12RhI3]Cl3 x 4.5 H2O, monomeric, [(C6H11NC)4 Rh(I)](BPh4), and [(i-PrNC)4Rh(I)](BPh4) (both yellow), and red, dimeric [(C6H11NC)8Rh(I)2]Cl2 x 0.5C6H6 x 2H2O). Ordered crystals of [(C6H11NC)12Rh(I)3](SbF6)3 contain linear Rh3 units, while those of [(C6H11NC)12Rh(I)3](AsF6)3 show disorder which is consistent with the presence of linear or bent Rh3 units. The formation of green [(C6H11NC)12Rh(V/III)3Cl2][(C6H11NC)12Rh(I)3]Cl6, and brown [(C6H11NC)12Rh(V/III)3Cl2][(C6H11NC)8Rh(I)2][(C6H11NC)4RhI]Cl6 x 16H2O x 3C6H6 along with unidentified red-brown cubes from an air-exposed solution of [(C6H11NC)4Rh(I)]Cl is reported. As their formulas indicate, green [(C6H11NC)12Rh(V/III)3Cl2][(C6H11NC)12Rh(I)3]Cl6, and brown [(C6H11NC)12Rh(V/III)3Cl2][(C6H11NC)8Rh(I)2][(C6H11NC)8Rh(I)]Cl6 x 16H2O x 3C6H6 contain two or three chemically distinct cations, respectively, but again are built from a common precursor, [(C6H11NC)4Rh(I)]+.

Sc3N@C78: encapsulated cluster regiocontrol of adduct docking on an ellipsoidal metallofullerene sphere.

The first N-tritylpyrrolidino derivatives of D(3h) (78:5) Sc(3)N@C(78) were successfully synthesized and isolated. The addition sites for the two nearly equivalent kinetic monoadducts 1a and 1b are across two different 6,6 junction sites on the Sc(3)N@C(78) cage that are offset from the horizontal plane defined by the Sc(3)N cluster. The adducts were characterized by NMR experiments, DFT calculations and X-ray crystallographic analysis of Sc(3)N@C(78) derivative 1a. A unique finding of this study is the regiocontrol of adduct docking by the internal Sc(3)N cluster.

"Open rather than closed" malonate methano-fullerene derivatives. The formation of methanofulleroid adducts of Y3N@C80.

Cycloaddition of bromomalonates to Y3N@C80 unexpectedly gave rise to fulleroid derivatives with unusually high stability. Complete characterization of these derivatives is described including X-ray crystallography, 1H NMR, 13C NMR, HMQC, UV-visible, HPLC, MALDI-MS, and electrochemistry. Density functional theory calculations are also presented, which provide a rationale for the formation of the fulleroid and reveal the underlying thermodynamic basis for their stability.

X-Ray crystallographic and EPR spectroscopic characterization of a pyrrolidine adduct of Y3N@C80.

Crystallographic data for the pyrrolidine adduct Y3N@C80C4H9N x 2.5CS2 reveals a slightly pyramidalized Y3N unit with idealized mirror symmetry that straddles the site of addition but does not directly interact with the addend.