Victor N. Khrustalev

Remarkable Ligand Effect in Ni- and Pd-Catalyzed Bisthiolation and Bisselenation of Terminal Alkynes: Solving the Problem of Stereoselective Dialkyldichalcogenide Addition to the CC Bond

We have developed two new catalytic systems based on Ni and Pd complexes to solve the challenging problem of dialkyldichalcogenide (Alk2E2; E=S, Se) addition to alkynes. A comparative study of two catalytic systems-Ni/PMe2Ph and Pd/PCy2Ph-has revealed that the Ni catalyst is superior with respect to high catalytic activity and more general scope relative to the Pd system. A novel synthetic methodology was developed for the preparation of (Z)-bis(alkylthio)alkenes and (Z)-bis(alkylseleno)alkenes from terminal alkynes with excellent stereoselectivity and high yields.

Photo–Thermal Haptotropism in Cyclopentadienylcobalt Complexes of Linear Phenylenes: Intercyclobutadiene Metal Migration†

An attractive strategy for achieving solar–thermal energy conversion is to harvest sunlight in the form of activated chemical bonds through photoisomerization of a suitable molecule that can release, on demand, such stored and transportable energy by thermal reversal to its original form. When such reversible isomerizations entail significant topological alterations, they provide blueprints for eliciting further functions, for example in switches, machines, datastorage, sensors, and other devices. Because of their expanded tunability and generally favourable electronic absorption regimes, organometallic complexes are advantageous in this respect, yet have remained relatively unexplored. Among them, topologically simplest are metallohaptotropic arrays in which a single metal moiety photomigrates, thermally reversibly, to a higher-energy position along a fused p framework, without the assistance of additives. Only two such systems are known, [Mo(PMe3)3] complexes of indole and quinazoline, discovered as part of a study focusing on catalytic hydrogenations of heterocycles. We report 1) the photothermal reversibility of {CpCo} complexes of linear phenylenes by a novel mode of haptotropism, namely, h:h from one cyclobutadiene ring to another (Scheme 1); 2) the first X-ray structures of metalated linear phenylenes, illustrating the aromatization of the ligand on

From small structural modifications to adjustment of structurally dependent properties: 1-methyl-3,5-bis[(E)-2-thienylidene]-4-piperidone and 3,5-bis[(E)-5-bromo-2-thienylidene]-1-methyl-4-piperidone.

The molecules of the title compounds, C(16)H(15)NOS(2), (I), and C(16)H(13)Br(2)NOS(2), (II), are E,E-isomers and consist of an extensive conjugated system, which determines their molecular geometries. Compound (I) crystallizes in the monoclinic space group P2(1)/c. It has one thiophene ring disordered over two positions, with a minor component contribution of 0.100 (3). Compound (II) crystallizes in the noncentrosymmetric orthorhombic space group Pca2(1) with two independent molecules in the unit cell. These molecules are related by a noncrystallographic pseudo-inversion center and possess very similar geometries. The crystal packings of (I) and (II) have a topologically common structural motif, viz. stacks along the b axis, in which the molecules are bound by weak C-H...O hydrogen bonds. The noncentrosymmetric packing of (II) is governed by attractive intermolecular Br...Br and Br...N interactions, which are also responsible for the very high density of (II) (1.861 Mg m(-3)).

Crystal structure of methyl (3RS,4SR,4aRS,11aRS,11bSR)-5-oxo-3,4,4a,5,7,8,9,10,11,11a-deca-hydro-3,11b-ep-oxy-azepino[2,1-a]iso-indole-4-carboxyl-ate.

The title compound, C15H19NO4, is the a product of the esterification of the corresponding carbonic acid with methanol. The molecule comprises a fused tetracyclic system containing three five-membered rings (2-pyrrolidinone, tetrahydrofuran and dihydrofuran) and one seven-membered ring (azepane). The five-membered rings have the usual envelope conformations, with the quaternary C atom being the flap atom for the 2-pyrrolidinone ring, and the ether O atom being the common flap atom for the remaining rings. The seven-membered azepane ring adopts a chair conformation with the methine and middle methylene C atoms lying above and below the mean plane defined by the remaining five atoms. The carboxylate substituent is rotated by 77.56u2005(5)° with respect to the base plane of the tetrahydrofuran ring. In the crystal, the molecules are bound by weak C—H⋯O hydrogen-bonding interactions into puckered layers parallel to (001).

Racemic and Enantiopure Forms of 3‐Ethyl‐3‐Phenylpyrrolidin‐2‐One Adopt Very Different Crystal Structures

3-Ethyl-3-phenylpyrrolidin-2-one (EPP) is an experimental anticonvulsant based on the newly proposed α-substituted amide group pharmacophore. These compounds show robust activity in animal models of drug-resistant epilepsy and are thus promising for clinical development. In order to understand pharmaceutically relevant properties of such compounds, we are conducting an extensive investigation of their structures in the solid state. In this article, we report chiral high-performance liquid chromatography (HPLC) separation, determination of absolute configuration of enantiomers, and crystal structures of EPP. Preparative resolution of EPP enantiomers by chiral HPLC was accomplished on the Chiralcel OJ stationary phase in the polar-organic mode. Using a combination of electronic CD spectroscopy and anomalous dispersion of X-rays we established that the first-eluted enantiomer corresponds to (+)-(R)-EPP, while the second-eluted enantiomer corresponds to (-)-(S)-EPP. We also demonstrated that, in the crystalline state, enantiopure and racemic forms of this anticonvulsant have considerable differences in their supramolecular organization and patterns of hydrogen bonding. These stereospecific structural differences can be related to the differences in melting points and, correspondingly, solubility and bioavailability.

Crystal structure of cyclo-tris­(μ-3,4,5,6-tetra­fluoro-o-phenyl­ene-κ2C1:C2)trimercury–tetra­cyano­ethyl­ene (1/1)

The crystal structure and thermal properties of a mixed-stack donor–acceptor complex of trimeric perfluoro-o-phenylene mercury with tetracyanoethylene in an 1:1 ratio were studied by X-ray diffraction and TGA methods.

Monohalogenated ferrocenes C(5)H(5)FeC(5)H(4)X (X = Cl, Br and I) and a second polymorph of C(5)H(5)FeC(5)H(4)I.

The structures of the three title monosubstituted ferrocenes, namely 1-chloroferrocene, [Fe(C(5)H(5))(C(5)H(4)Cl)], (I), 1-bromoferrocene, [Fe(C(5)H(5))(C(5)H(4)Br)], (II), and 1-iodoferrocene, [Fe(C(5)H(5))(C(5)H(4)I)], (III), were determined at 100 K. The chloro- and bromoferrocenes are isomorphous crystals. The new triclinic polymorph [space group P-1, Z = 4, T = 100 K, V = 943.8 (4) A(3)] of iodoferrocene, (III), and the previously reported monoclinic polymorph of (III) [Laus, Wurst & Schottenberger (2005). Z. Kristallogr. New Cryst. Struct. 220, 229-230; space group Pc, Z = 4, T = 100 K, V = 924.9 A(3)] were obtained by crystallization from ethanolic solutions at 253 and 303 K, respectively. All four phases contain two independent molecules in the unit cell. The relative orientations of the cyclopentadienyl (Cp) rings are eclipsed and staggered in the independent molecules of (I) and (II), while (III) demonstrates only an eclipsed conformation. The triclinic and monoclinic polymorphs of (III) contain nonbonded intermolecular I...I contacts, causing different packing modes. In the triclinic form of (III), the molecules are arranged in zigzag tetramers, while in the monoclinic form the molecules are arranged in zigzag chains along the a axis. Crystallographic data for (III), along with the computed lattice energies of the two polymorphs, suggest that the monoclinic form is more stable.

Monohalogenated ferrocenes C5H5FeC5H4X (X = Cl, Br and I) and a second polymorph of C5H5FeC5H4I

The structures of the three title monosubstituted ferrocenes, namely 1-chloroferrocene, [Fe(C(5)H(5))(C(5)H(4)Cl)], (I), 1-bromoferrocene, [Fe(C(5)H(5))(C(5)H(4)Br)], (II), and 1-iodoferrocene, [Fe(C(5)H(5))(C(5)H(4)I)], (III), were determined at 100 K. The chloro- and bromoferrocenes are isomorphous crystals. The new triclinic polymorph [space group P-1, Z = 4, T = 100 K, V = 943.8 (4) A(3)] of iodoferrocene, (III), and the previously reported monoclinic polymorph of (III) [Laus, Wurst & Schottenberger (2005). Z. Kristallogr. New Cryst. Struct. 220, 229-230; space group Pc, Z = 4, T = 100 K, V = 924.9 A(3)] were obtained by crystallization from ethanolic solutions at 253 and 303 K, respectively. All four phases contain two independent molecules in the unit cell. The relative orientations of the cyclopentadienyl (Cp) rings are eclipsed and staggered in the independent molecules of (I) and (II), while (III) demonstrates only an eclipsed conformation. The triclinic and monoclinic polymorphs of (III) contain nonbonded intermolecular I...I contacts, causing different packing modes. In the triclinic form of (III), the molecules are arranged in zigzag tetramers, while in the monoclinic form the molecules are arranged in zigzag chains along the a axis. Crystallographic data for (III), along with the computed lattice energies of the two polymorphs, suggest that the monoclinic form is more stable.