Dmitri V. Konarev

New molecular complexes of fullerenes C60 and C70 with tetraphenylporphyrins [M(tpp)], in which M=H2, Mn, Co, Cu, Zn, and FeCl.

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.

Molecular complexes of C60 with tetrasulfur tetranitride

Compounds C60(S4N4)2−x(C6H6)x (1a-d) withx=0.67 (a), 1.0 (b), 1.1 (c), and 1.2 (d), in which isomorphous replacement of S4N4 with benzene takes place, were obtained by the reaction of fullerence C60 with tetrasulfur tetranitride in benzene. Complexes C60·S4N4 (2) and C60(S4N4)2 (3) containing no solvent were isolated from toluene. The compositions of the compounds were established by elemental and thermogravimetric analyses. The data of IR and X-ray photoelectron (XP) spectroscopies show that in the complexes studied the transfer of electron density occurs mainly from the nitrogen atoms of S4N4.

NEW COMPLEX OF FULLERENE WITH AN ORGANIC DONOR : (C60)2.TPDP.(CS2)

The discovery of superconductivity characterized by high temperatures of the superconducting transition in M{sub 3}C{sub 60} salts (M is an alkali metal) and the discovery of ferromagnetic properties in TDAE{center_dot}C{sub 60} salts have awakened considerable interest in studying compounds of C{sub 60} with organic donors. The use of these donors opens up broad possibilities for the synthesis of substances with various packings of C{sub 60} in the crystal, which finally determines different properties of these compounds. At present, molecular complexes of fullerene with various donors including S- and Te-containing derivatives of tetrathiafulvalene have been prepared. The authors synthesized the first charge transfer complex of C{sub 60} with 2,2`,6,6`-tetraphenyldipyranylidene (TPDP) as the donor, (C{sub 60}){sub 2}{center_dot}TPDP{center_dot}(CS{sub 2}){sub 4}.

The molecular structure of high-spin (S = 5/2) manganese(II) phthalocyanine in tetrabutylammonium bromido(phthalocyaninato)manganese(II).

The title complex salt, (C16H36N)[MnBr(C32H16N8)] or (TBA)[Mn(II)Br(Pc)] (TBA is tetrabutylammonium and Pc is phthalocyaninate), has been obtained as single crystals by the diffusion technique and its crystal structure was determined using X-ray diffraction. The high-spin (S = 5/2) [Mn(II)Br(Pc)](-) macrocycle has a concave conformation, with an average equatorial Mn-N(Pc) bond length of 2.1187 (19) Å, an axial Mn-Br bond length of 2.5493 (7) Å and with the Mn(II) cation displaced out of the 24-atom Pc plane by 0.894 (2) Å. The geometry of the Mn(II)N4 fragment in [Mn(II)Br(Pc)](-) is similar to that of the high-spin (S = 5/2) manganese(II) tetraphenylporphyrin (TPP) in [Mn(II)(1-MeIm)(TPP)] (1-MeIm is 1-methylimidazole).

Synthesis and crystal structure of a new molecular complex of fullerene C70, 4BNDY·3C70·4C6H6 (BNDY is binaphtho[1,8-d,e]-1,3-dithiin-2-ylidene)

A new C70-based molecular complex 4BNDY·3C70·4C6H6 (1) (BNDY is binaphtho[1,8-d.e]-1,3-dithiin-2-ylidene) was prepared, and its full X-ray diffraction study at room temperature was performed. The C70 molecules in crystal 1 are ordered in different ways, and their ordering depends on van der Waals interactions between them and nonplanar BNDY molecules in the boat conformation. The neighboring BNDY molecules in the structure are bound to each other by π-π interactions.

Synthesis, Structure, and Properties of the Fullerene C60 Salt of Crystal Violet, (CV+)(C60.−)⋅0.5 C6H4Cl2, which Contained Closely Packed Zigzagged C60.− Chains

The reduction of fullerene C60 by zinc dust in the presence of crystal violet cations (CV(+) ) yielded a deep-blue solution, from which crystals of (CV(+) )(C60 (.-) )⋅0.5 C6 H4 Cl2 (1) were obtained by slow mixing with n-hexane. The salt contained isolated, closely packed zigzagged chains that were composed of C60 (.-) radical anions with a uniform interfullerene center-to-center distance of 9.98 Å. In spite of the close proximity of the fullerenes, they did not dimerize, owing to spatial separation by the phenyl substituents of CV(+) . The room-temperature conductivity of compound 1 was 3×10(-2)  S cm(-1) along the fullerene chains. The salt exhibited semiconducting behavior, with an activation energy of Ea =167 meV. Spins localized on C60 (.-) were antiferromagnetically coupled within the fullerene chains, with a Weiss temperature of -19 K without long-range magnetic ordering down to 1.9 K.

Dielectric properties of C60 molecular complexes

The permittivity ɛ of the molecular complexes (BTX)C60CS2, (DAN)C60(C6H6)3, and (S4N4)1.2C60(C6H6)0.8 has been studied at 100 MHz. A maximum has been observed to appear in the temperature dependence ɛ(T) at T≈90 K, which can be assigned to freezing of the orientational disorder. A region of anomalous growth of ɛ with decreasing temperature has been found in the low-temperature range T≤25 K, this feature being apparently sensitive to the actual packing pattern of C60 spheres in the molecular complex.