Two pairs of 1: 2 neutral trans mononuclear transition-metal (M = Ni(II) and Cu(II)) complexes of pyridine-2,4-dione and quinoline-2,4-dione based heterocyclic dyes have been structurally and spectrally characterized and compared herein. X-ray single-crystal diffraction analyses of four complexes, namely trans-[Ni(La)2(DMF)2] (1), trans-[Cu(La)2(DMF)2] (2), trans-[Ni(Lb)2(DMF)2] (3) and trans-[...

The fabrication of an optical biosensor by using stacked films where 3-methyl-2-benzothiazolinone hydrazone (MBTH) was immobilized in a hybrid nafion/sol-gelsilicate film and laccase in a chitosan film for the detection of phenolic compounds wasdescribed. Quinone and/or phenoxy radical product from the enzymatic oxidation ofphenolic compounds was allowed to couple with MBTH to form a colored az...

A series of substituted 8-arylazo 7-hydroxy 4-methyl coumarin (4a-4g) were synthesized and in-vitro evaluation for their preliminary antibacterial activities against E.coli, Staphylococcus aurous, Bacillus subtilis and Pseudomonas aeroginosa were carried out by agar-well diffusion method. Initially, the diazotized primary aryl amines, 3a-3g were synthesized and followed by coupling with 7-hydro...

Abstract Tautomerism is one of the most important phenomena to consider when designing biologically active molecules. In this work, we use NMR spectroscopy, IR, and X-ray analysis as well quantum-chemical calculations in gas phase a solvent study tautomerism 1- (2-, 3- 4-pyridinecarbonyl)-4-substituted thiosemicarbazide derivatives. The tautomer containing both carbonyl thione groups turned out...

A novel alkyl chain-functionalized manganese complex with dioxolene ligands shows a bimodal three-membered valence tautomerism, one of which synchronizes with a cooperative solid-melt phase transition and the other occurs in the melt noncooperatively.

We report a state-of-the-art spectroscopic study of an archetypical barbaralone, conclusively revealing the valence tautomerism phenomena for this bistable molecular system. The two distinct 1- and 5-substituted tautomers have been isolated in supersonic expansion first time successfully characterized by high-resolution rotational spectroscopy. This work provides irrefutable experimental eviden...

The glyceraldehyde conversion in terms of dehydration, keto-enol tautomerism, and retro-aldol reaction has been discussed by means of ab initio density functional theory calculation to elucidate the catalytic water molecule influence on the pathways. The optimized structures of reactants, products, and transition state structure on the glyceraldehyde conversion pathways were fully optimized wit...

Technical iodine was found to catalyze the condensation between 2-aminobenzohydrazide (1) and some aldehydes and ketones in absolute ethanol under mild conditions to afford hydrazone and quinazoline derivatives, respectively. Condensation of 1 with terephthalaldehyde (2) in 1 : 1 molar ratios afforded the hydrazone 3, while hydrazone 4 was formed on using a double molar ratio of 1. On the other...

The V(V) atom in the title complex, [V(C(14)H(8)BrClN(2)O(2))(CH(3)O)O(CH(3)OH)], is six-coordinated by one phenolate O, one imine N and one enolic O atom of the hydrazone ligand, one oxide O atom, one methanol O atom and one methoxide O atom in a distorted octa-hedral geometry. The dihedral angle between the two benzene rings of the hydrazone ligand is 13.2 (3)°. The deviation of the V atom to...

Schiff base condensation of benzil bis(hydrazone) with formaldehyde, acetone and benzaldehyde and its nickel(II) complexes were synthesised. Preparation of the free ligands was accomplished by refluxing benzil with hydrazine derivatives in 1:10 mole ratios in ethylene glycol. The spectral characterisation of hydrazone based 14-membered octaaza macrocyclic complexes of nickel(II) was undertaken....