A Comprehensive Experimental and Theoretical Study on the [{(η5-C5H5)2Zr[P(µ-PNEt2)2P(NEt2)2P]}]2O Crystalline System.

The structure of tetraphosphetane zirconium complex C52H100N8OP10Zr21 was determined by single crystal X-ray diffraction analysis. The crystal belongs to the monoclinic system, space group P21/c, with a = 19.6452(14), b = 17.8701(12), c = 20.7963(14)Å, α = γ = 90°, ß = 112.953(7)°, V = 6722.7(8)Å3, Z = 4. The electronic structure of the organometallic complex has been characterized within the framework of Quantum Chemical Topology. The topology of the Electron Localization Function (ELF) and the electron density according to the Quantum Theory of Atoms in Molecules (QTAIM) show no covalent bonds involving the Zr atom, but rather dative, coordinate interactions between the metal and the ligands. This is the first reported case of a Zr complex stabilized by an oxide anion, anionic cyclopentadienyl ligands and rare tetraphosphetane anions.

Experimental and Theoretical Mechanistic Study on the Thermal Decomposition of 3,3-diphenyl-4-(trichloromethyl)-5-nitropyrazoline.

The present paper is a continuation of comprehensive study regarding to synthesis and properties of pyrazoles and their derivatives. In its framework an experimental and theoretical studies of thermal decomposition of the 3,3-diphenyl-4-(trichloromethyl)-5-nitropyrazoline were performed. It was found, that the decompositions of the mentioned pyrazoline system in the solution and at the melted state proceed via completely different molecular mechanisms. These mechanisms have been explained in the framework of the Molecular Electron Density Theory (MEDT) with the computational level of B3LYP/6-31G(d). A Bonding Evolution Theory (BET) examination of dehydrochlorination of the 3,3-diphenyl-4-(trichloromethyl)-5-nitropyrazoline permits elucidation of the molecular mechanism. It was found, that on the contrary for most known HCl extrusion processes in solution, this reaction is realised via single-step mechanism.

Regiospecific formation of the nitromethyl-substituted 3-phenyl-4,5-dihydroisoxazole via [3 + 2] cycloaddition.

ABSTRACT: 5-(Nitromethyl)-3-phenyl-4,5-dihydroisoxazole was obtained as a product of a high-yielding [3 + 2] cycloaddition reaction of in situ-generated benzonitrile N-oxide and 3-nitroprop-1-ene. For the first time, the regiochemistry of this reaction was unambiguously proven by X-ray structural analysis. The quantum-chemical calculation performed at the M06-2X/6-31G(d) (PCM) theoretical level affords a basis for explaining the course of reaction as well as the nature of transition states. Next, further DFT calculations together with spectral data shed light on structural aspects of the product.

Novel synthesis scheme and in vitro antimicrobial evaluation of a panel of (E)-2-aryl-1-cyano-1-nitroethenes.

Drug resistance has become a major concern in the field of infection management, therefore searching for new antibacterial agents is getting more challenging. Our study presents an optimized and eco-friendly synthesis scheme for a panel of nitroalkenes bearing various functional groups in the aromatic moiety and bromine or cyano substituents in 1 position of nitrovinyl moiety. The presence of nitrolefine group outside the ring minimalizes genotoxic properties while conjugation of aryl group with nitrovinyl moiety increases stability of the compounds. Then our research focused on evaluation of biological properties of such obtained (E)-2-aryl-1-cyano-1-nitroethenes. As they exhibit strong bacteriostatic and bactericidal activities against reference bacteria and yeast species with no detectable cytotoxicity towards cultured human HepG2 and HaCaT cells, they could be promising candidates for the replacement of traditional nitrofurane-containing antibacterial drugs. Nevertheless, validation of the obtained data in an in vivo model and additional safety studies on mutagenicity are still required.

Chlorido(η-cyclo-penta-dien-yl)[(4a,4b,8a,9,9a-η)-fluoren-yl](fluorenyl-κC)zirconium(IV) toluene solvate.

In the title compound, [Zr(C(5)H(5))(C(13)H(9))(2)Cl]·C(7)H(8), the Zr(IV) atom is coordinated by a Cl atom, a cyclo-penta-dienyl (Cp) ligand [Zr-centroid (Cp) = 2.199 (3) Å] and two fluorenyl ligands (Fl) [Zr-centroid (Fl) = 2.273 (2) Šand Zr-CH from fluorenyl = 2.355 (2) Å] in a distorted tetra-gonal geometry. The dihedral angles between the mean planes of the fluorenyl ring systems and the Cp ring are 36.62 (6)° for the η(1)-coordinated fluorenyl and 52.85 (6)° for the η(5)-coordinated fluorenyl, while the dihedral angle between the mean planes of the two fluorenyl ring systems is 76.18 (7)°.

2,4-Bis[bis(diisopropyl-amino)-phos-phanyl]-1,2,3,4-tetra-phospha-bicyclo[1.1.0]butane.

The title compound, C(24)H(56)N(4)P(6) or ((i)Pr(2)N)(2)P-P(4)-P(N(i)Pr(2))(2), adopts a butterfly structure, with planar environments for the N atoms and pyramidal environments for the P atoms. The structure studied has a 15% twin component that is related by a twofold rotation about [100].