Habibe Tezcan

The synthesis and spectral properties determination of 3-substituted phenyl-1,5-diphenylformazans

Abstract In this study novel 3-substituted-phenyl-1,5-diphenylformazans were synhesised with –CH 3 , –OCH 3 , –OH and –Br groups at o -, m - and p -positions. Their structures were elucidated with 1 H-NMR, 13 C-NMR and IR spectroscopy. Their UV–vis spectra indicated that their λ max showed a shift amount of which was dependent upon the type and position of the substituent on the ring. There was a good correlation between these shifts and Hammet substituent coefficients.

Substituent effects on the spectral properties of some 3-substituted formazans

Abstract In this study, 3-substitutedphenyl-1.5-diphenylformazans were synthesized with –NO 2 and –COOH groups in the o -, m- and p- positions of the 3-phenyl ring. Their structures were elucidated from elemental analysis, 1 H NMR, 13 C NMR and IR spectra. The dependence of λ max upon the type of the substituents and their positions on the phenyl ring was investigated using UV–vis spectra. It was observed that there was a shift of λ max towards the blue region with the electron withdrawing –NO 2 and –COOH groups. The size of this chemical shift (Δ λ max ) was dependent upon the type and position of the substituent on the 3-phenyl ring. A linear relation was obtained between the substituent effect and the Hammett substituent coefficients.

Synthesis, spectroscopy, and quantum-chemical calculations on 1-substituted phenyl-3,5-diphenylformazans

In this study 1-substituted phenyl-3,5-diphenylformazans were synthesized from benzaldehyde-N-phenylhydrazone and appropriate phenyldiazonium salts having CH(3), Br, and Cl at the o-, m-, and p-positions of 1-phenyl ring. Their structures were determined by infrared and ultraviolet-visible spectra. Bathochromic effect in accordance with the electron-donating effect of CH(3), Br, and Cl group and its magnitude were dependent upon type and position of substituent on the ring. The ground-state geometries and absorption wavelengths for 1-phenyl substituted formazans were studied with density functional theory and time-dependent density functional theory. The calculations were carried out by using PBE1PBE functional with 6-311G(2d,2p) basis set for lambda(max) of the UV-vis spectra for the studied formazans. A good agreement was obtained between the experimental and computed values.

Spectral and electrochemical behavior of 1-[(NO2, COOH)-substituted phenyl]-3,5-diphenylformazans

Abstract1-[(NO2, COOH)-substituted phenyl]-3,5-diphenylformazans were synthesized. The compounds were characterized by infrared (IR), ultraviolet–visible (UV–vis), 1H nuclear magnetic resonance (NMR), 13C NMR spectra, elemental analysis, and cyclic voltammetry. From the UV–vis spectra of substituted formazans it was seen that λmax values were shorter than the λmax value of unsubstituted formazan. It was observed that the shift values were dependent on the type and position of the substituents. A correlation between Hammett substituent coefficients and λmax values was obtained. The oxidation peak potentials of substituted formazans were found more anodic than that of unsubstituted formazan. The oxidation mechanism was a single step for the NO2-substituted formazans, and two steps for COOH-substituted formazans.Graphical abstract

Synthesis, Crystal Structure, and Spectroscopic Studies of N-(4-Bromobenzylidene)-N′-(2-Pyridyl) Hydrazine Schiff Base Molecule

A new Schiff base complex N-(4-bromobenzylidene)-N′-(2-pyridyl) hydrazine, C12H10N3Br, has been synthesized and characterized by elemental analyses, mass, 1H NMR, ultraviolet–visible (UV–VIS), and IR spectroscopy and single-crystal X-ray determination. The p-Br-benzene and pyridine rings are almost planar and the dihedral angle between the planes is 11.1(3)°. The crystal structure is stabilized by intermolecular N‒H…N‒Py hydrogen bonding interaction. X-ray diffraction analyses show that N-(4-bromobenzylidene)-N′-(2-pyridyl) hydrazine Schiff base molecule crystallizes in the monoclinic system, P21/c space group, a = 5.611(5) Å, b = 19.566(5) Å, c = 10.715(5) Å, β = 98.766(5)°, and V = 1162.60(12) Å3.

Synthesis, spectral analysis, structural elucidation and quantum chemical studies of (E)-methyl-4-((2-phenylhydrazono) methyl)benzoate

The title compound, (E)-methyl-4-[(2-phenylhydrazono)methyl]benzoate, (I), (C15H14N2O2), has been synthesized by condensation reaction of methyl-4-formylbenzoate and phenylhydrazine. The compound has been characterized by elemental analysis, IR, (1)H NMR, (13)C NMR, UV-Vis spectroscopies and single crystal X-ray diffraction techniques. Optimized molecular structure, harmonic vibrational frequencies, (1)H and (13)C NMR chemical shifts have been investigated by B3LYP/6-31G(d,p) method using density functional theory (DFT). Global chemical reactivity descriptors, natural population analysis (NPA), thermodynamic and non-linear optical (NLO) properties have also been studied. The energetic behavior of the compound has been examined in solvent media using the integral equation formalism polarizable continuum model (IEF-PCM).

N-(4-Nitro­benzyl­idene)-N′-phenyl­hydrazine

Molecules of the title compound (alternative name: p-nitrobenzaldehyde phenylhydrazone), C(13)H(11)N(3)O(2), adopt an E configuration about the azomethine C=N double bond. Molecules are approximately planar and the dihedral angle between the planes of the phenyl rings is 11.62 (9) degrees. Hydrogen bonding links molecules related by 4(2) screw axes to form helices with a pitch of 7.7186 (8) A.

N-(4-Methoxybenzylidene)-N'-(2-pyridyl)hydrazine.

Molecules of the title compound (alternative name p-methoxybenzaldehyde 2-pyridylhydrazone), C(13)H(13)N(3)O, adopt an E configuration about the azomethine C=N double bond. Molecules are almost planar, the dihedral angle between the pyridine and methoxyphenyl rings being only 6.19 (12) degrees. Pairwise N-H.N hydrogen bonds [R(2)(2)(8) in graph-set notation] link centrosymmetrically related molecules into discrete pairs.