Gennadii V. Shilov

The M(dddt)2 family of conducting complexes: [Ni(dddt)2]3(AuBr2)2, the first quasi-two-dimensional metal stable down to at least 1.3 K

The first stable molecular metal, [Ni(dddt)2]3(AuBr2)2, among the M(dddt)2 family of conducting charge-transfer salts has been prepared and its crystal structure has been solved by X-ray analysis. The origin of the metallic conductivity of [Ni(dddt)2]3(AuBr2)2 as well as the stability of this salt with respect to metal-to-insulator transitions is explained on the basis of tight-binding band structure calculations.

A complex of buckminsterfullerene with sulfur, C602S8: synthesis and crystal structure

The C60·2S8 complex was prepared by reaction of buckminsterfullerene C60 with sulfur in trichloroethylene and its single-crystal X-ray structure was studied at room temperature. Crystals of this compound are monoclinic, space groupC 2/c, a=20.90(1),b=21.10(1),c=10.537(9) Å, β=111.29(7)°,Z=4,dcalc=1.89 g·cm−3. The crystal structure of the C60·2S8 complex consists of packed fullerene molecules that form hexagonal channels along thec axis with eight-membered crown-shaped S8 cyclic molecules inside the channels. The distances between the centers of neighboring fullerene molecules are 10.036(7), 10.636(7), and 10.537(9) Å. Each C60 molecule is linked to eight S8 molecules with ten shortened intermolecular contacts C...S 3.41(1)–3.52(2) Å. The average values of the C=C and C-C bond lengths are 1.32(3) and 1.47(3) Å, which attest to a significant degree of localization of electron density in the c60 molecule.

Nitrosyl iron complexes with enhanced NO donating ability: synthesis, structure and properties of a new type of salt with the DNIC cations [Fe(SC(NH2)2)2(NO)2]+

Novel nitrosyl iron complexes [Fe(SC(NH2)2)2(NO)2]2SO4·H2O(I) and [Fe(SC(NH2)2)2(NO)2]2[Fe2(S2O3)2(NO)4](II) have been synthesized via the reactions of FeSO4 and Na2[Fe2(S2O3)2(NO)4], respectively, with acidic solutions of thiocarbamide in water. The structure and properties of I and II were studied using X-ray analysis, Mossbauer, IR, and EPR spectroscopy and amperometry. Both complexes are characterized by a prolonged NO generation without additional activation in aqueous anaerobic solutions, similar to the organic NO donor diethylene triamine; however, they are more effective: at pH 7 the NO amount is ∼32.6 and ∼31.8 nM mol−1 of the complex for I and II, respectively. The obtained results show feasibility for the synthesis of water-soluble hybrid nitrosyl NO-generating complexes, which contain the NO groups both in the cationic and anionic sublattices and provide the control of the NO release kinetics.

Unexpected formation of chiral single crystals of {NH(n-C3H7)3[MnIICrIII(C2O4)3]}, A 2D oxalate-based material

In an attempt to obtain chiral single crystals of a two-dimensional (2D) bimetallic oxalate-based material by enantioselective auto-assembling of Mn2+ and (rac)-[Cr(C2O4)3]3− templated by the optically active complex (+)-(Rp)-[1-CH2(n-C3H7)3-2-CH3(C5H3)Fe(C5H5)]+, we obtained the unexpected 2D network species {NH(n-C3H7)3[MnCr(C2O4)3]}. X-ray diffraction determination of the structure reveals that the complex crystallizes in the enantiomorphous space group P63. The interlayer spacing of 7.93u2009Åu2009is the lowest found so far for 2D, bimetallic, oxalate-bridged compounds.

Crystal and molecular structures of new fullerides, (Ph4P)2C60Hal (Hal=Br or I) and (Ph4As)2C60Cl

New air-stable fullerides, (Ph4P)2C60Hal (Hal=Br or I) and (Ph4As)2C60Cl, were synthesized, and their crystal structure were determined. A comparative crystal-chemical analysis of the fullerides under study demonstrated that they are isostructural, described by the general formula (Ph4X)2C60Hal (X=P or As, and Hal=Cl, Br, or I), and crystallize in the triclinic system. The C60− and Hal− anions occupy special centrosymmetric positions. The (Ph4P)+ and (Ph4As)+ cations occupy general positions. The principal parameters of the molecular structures are reported.

Some structural features of the conducting layer in the radical cation [Pt(dddt)2]2FeCl4 salt

Abstract The crystal structure and electrical conductivity of the cation metal complex [Pt(dddt)2]2FeCl4 are reported. The main characteristic feature of the crystal structure of [Pt(dddt)2]2FeCl4 is the absence of radical cation stacks in the conducting layer and the strong dimerization of the [ Pt(dddt) 2 ] 1 2+ cations.

New molecular metals based on BEDO radical cation salts with the square planar Ni(CN)42− anion

Two new radical cation salts based on bis(ethylenedioxy)tetrathiafulvalene (BEDO) with the square planar Ni(CN)42− anion, (BEDO)4Ni(CN)4·4CH3CN (1) and (BEDO)5Ni(CN)4·3C2H4(OH)2 n (2), were synthesized by electrocrystallization. The X-ray structural analysis, electrical transport and magnetotransport properties as well as the calculated Fermi surfaces are presented and discussed. Both salts show metallic properties down to 4.2 K. The nature of the Fermi surface of both salts is discussed and compared with those of other β″ type BEDO salts. On the basis of this comparison it is suggested that salt 2 is a likely candidate to exhibit magnetic breakdown and quantum interference effects in the magnetoresistance. It is shown that salt 1 exhibits unconventional magnetotransport behavior.

Crystal structure of a new molecular complex of fullerene with tetramethyltetraselenafulvalene: C60·TMTSF·2CS2

A new molecular complex of fullerene with tetramethyltetraselenafulvalene (TMTSF), C60·TMTSF·2CS2, (1) was synthesized. The structure and composition of the complex were established by X-ray diffraction analysis. The crystals of C60·C10H12Se4·2CS2 are monoclinic:a=15.407(2),b=12.934(2),c=12.026(2) Å β=108.39(3)°,V=2274.1(6) Å3, space groupCm, Z=2,dcalc=1.929 g cm−3,R=0.047. The crystal structure of 1 consists of layers. Layers formed by fullerene and CS2 molecules alternate with layers of TMTSF molecules. Peculiarities of the crystal structure of 1 are the nonplanar conformation of TMTSF molecules and the absence of shortened C…C contacts between adjacent fullerenes molecules. The energy of intermolecular TMTSF…C60 interactions in the crystal was estimated.

Synthesis and photochromic properties of 4-[2-(anthracen-9-yl)-5-methyloxazolyl] fulgide

New photochromic fulgide, viz., 4-{1-[2-(anthracen-9-yl)-5-methyloxazol-4-yl]ethylidene}-3-isopropylidenetetrahydrofuran-2,5-dione, with fluorescent properties was synthesized. Studies by electronic, IR, and 1H NMR spectroscopy and X-ray diffraction demonstrated that this fulgide exists in the Z form. Light irradiation of its solutions at a wavelength of 365 nm causes Z/E isomerization giving rise to the thermally stable cyclic form. The latter is transformed into the starting E isomer under light irradiation at λ = 436 nm.

Electronic and steric effect manifestations in the structure of 9-Azidoacridine

The crystal structure of 9-azidoacridine (9AA) was determined by X-ray structure analysis (the compound crystallizes in the rhombic system). The crystallographically independent fragment of the structure of 9AA was found to contain two molecules. Both molecules were nonplanar, and the azido group was displaced out of the acridine nucleus plane by 34.6° (molecule A) and 28.6° (molecule B). The barriers to azido group rotations about the C-N bond were calculated by the semiempirical PM3 and nonempirical DFT B3LYP quantum-chemical methods. According to the B3LYP/6-31G* calculations, the structures with the azido group situated in the acridine nucleus plane and perpendicularly to this plane are 0.21 and 1.66 kcal/mol, respectively, higher in energy than the completely optimized structure, in which the dihedral angle between the azido group and acridine nucleus planes is 32°. The PM3 method overestimates the steric strain energy of 9AA and underestimates the energy of azido group conjugation with the acridine nucleus compared with B3LYP calculations.