Emel Ermiş

Studies on the electronic absorption spectra of some monoazo derivatives.

The electronic absorption spectra of a series of azo dye compounds containing -Cl, -SO3H and -OH groups were recorded in twenty one solvents with different polarities. The solvents were selected to cover a wide range of parameters (refractive index, dielectric constant and hydrogen bonding ability). Solvent-induced effect on the maximum absorption band frequencies of azo dye compounds are described in terms of solute-solvent interactions. Multiple linear regression equation for νmax was performed using polarizability-polarity parameters and Kamlet-Taft solvatochromic parameters. The results help to assign the solvent-solute interactions and the solvatochromic potential of the investigated compounds. It is concluded that the electronic of the substituent and hydrogen bonding acceptor ability of the solvents are the major factors to the interaction in solutions.

9-Benzyl-9H-carbazole.

The asymmetric unit of the title compound, C19H15N, contains two crystallographically independent molecules. In both molecules, the planar carbazole moieties [maximum deviations = 0.037 (4) and 0.042 (3) Å] are oriented with respect to the adjacent benzene rings, at dihedral angles of 85.29 (8) and 89.89 (7)°, respectively. In the crystal structure, weak C—H⋯π interactions are observed involving the carbazole rings.

11-Butyl-3-meth-oxy-11H-benzo[a]carbazole.

The title compound, C21H21NO, consists of a carbazole skeleton with a methoxybenzene ring fused to the carbazole, and a butyl group attached to the carbazole N atom. The carbazole skeleton is nearly planar [maximum deviation = 0.078 (2) Å], and it is oriented at a dihedral angle of 4.22 (4)° with respect to the adjacent methoxybenzene ring.

Bis(μ-4-methyl­benzoato-κ2O:O′)bis­[aqua­(4-methyl­benzoato-κ2O,O′)zinc(II)]–bis­(μ-4-methyl­benzoato-κ2O:O′)bis­[(4-methyl­benzoato-κO)(nicotinamide-κN)zinc(II)]–water (1/1/2)

The crystal structure of the title compound, [Zn2(C8H7O2)4(H2O)2]·[Zn2(C8H7O2)4(C6H6N2O)2]·2H2O, consists of two kinds of dinuclear ZnII complexes (complex A and complex B) and uncoordinated water molecules. In complex A, [Zn2(C8H7O2)4(H2O)2], each Zn cation is chelated by a 4-methylbenzoate (PMB) anion and coordinated by a water molecule, and is further bridged by two PMB anions in a trigonal-bipyramidal geometry. In complex B, [Zn2(C8H7O2)4(C6H6N2O)2], each ZnII cation is coordinated by a monodentate PMB anion and one nicotinamide (NA) ligand, and is further bridged by two PMB anions in a tetrahedral geometry. Weak intra-molecular π–π stacking between adjacent benzene rings is observed in complex B, the centroid–centroid distance being 3.710 (2) Å. Extensive O—H⋯O and N—H⋯O hydrogen bonding and weak C—H⋯O hydrogen bonding is present in the crystal structure. The crystal studied was a racemic twin; the minor twin component refined to 38%.

3,3'-Dimethyl-4,4'-(hexane-1,6-di-yl)bis-[1H-1,2,4-triazol-5(4H)-one].

The title compound, C12H20N6O2, has a centre of symmetry. The molecule consists of two triazole rings joined by an aliphatic –(CH2)6– chain. The crystal structure is stabilized by intermolecular N—H⋯O hydrogen bonds and by π–π stacking interactions between the triazole rings of inversion-related molecules [centroid–centroid distance = 3.277 (8) Å].

Diaqua­bis(4-methyl­benzoato-κO)bis­(nicotinamide-κN1)nickel(II)

The title NiII complex, [Ni(C8H7O2)2(C6H6N2O)2(H2O)2], is centrosymmetric with the Ni atom located on an inversion center. The molecule contains two 4-methylbenzoate (PMB) and two nicotinamide (NA) ligands and two coordinated water molecules, all ligands being monodentate. The four O atoms in the equatorial plane around the Ni atom form a slightly distorted square-planar arrangement, while the slightly distorted octahedral coordination is completed by the two N atoms of the NA ligands in the axial positions. The dihedral angle between the carboxylate group and the adjacent benzene ring is 26.15 (10)°, while the pyridine and benzene rings are oriented at a dihedral angle of 87.81 (4)°. In the crystal structure, intermolecular O—H⋯O and N—H⋯O hydrogen bonds link the molecules into a three-dimensional network. The π–π contact between the benzene rings [centroid–centroid distance = 3.896 (1) Å] may further stabilize the crystal structure. A weak C—H⋯π interaction involving the pyridine ring also occurs.

4-[2-(2,2-Dimethyl-4,6-dioxo-1,3-dioxan-5-yl-idene)hydrazin-1-yl]benzo-nitrile.

In the title compound, C(13)H(11)N(3)O(4), the dioxane ring adopts an envelope conformation with the C atom bonded to the dimethyl group in the flap position [deviation = 0.613 (1) Å]. The nitrile group and the attached benzene ring are roughly coplanar [maximum deviation = 0.087 (1) Å]. An intra-molecular N-H⋯O hydrogen bond involving the hydrazinyl group generates an S(6) ring. The N-N and C-N bond lengths indicate that the compound may be a mixture of the azo and hydrazone tautomeric forms but the presence of the N-bound H atom supports the hydrazone form. The crystal structure is stabilized by weak inter-molecular C-H⋯O, C-H⋯N and C-H⋯π inter-actions.