UV-induced photoreaction pathways of salicylic acid: Identification of the fourth stable conformer and ketoketene–water complex

UV Laser-Induced Photodecomposition of Matrix-Isolated Salicylhydroxamic Acid: Identification of New Isocyanate Complexes

Photochemical reactions of salicylhydroxamic acid were induced using tunable UV laser radiation followed by FTIR spectroscopy. Four pairs of co-products were experimentally found to appear in the photolysis: C6H4(OH)NCO⋯H2O (1), C6H4(OH)C(O)N⋯H2O (2), C6H4(OH)2⋯HNCO (3), and C6H4(OH)NHOH⋯CO (4). The comparison of the theoretical spectra with the experimental ones allowed us to determine the structures of the complexes formed in the matrices. The mechanisms of the reaction channels leading to the formation of the photoproducts were proposed. It was concluded that the first step in the formation of the complexes (1), (2), and (3) was the scission of the N-O bond, whereas the creation of complex (4) was due to cleavage of the C-N bond.

Synthesis, characterization and the nonlinear optical properties of newly synthesized 4-((1,3-dioxo-1-phenylbutan-2-yl)diazenyl)benzenesulfonamide

The dye of azo compound is prepared by coupling reaction of dizonium salt of sulfanilamide with benzoylacetone. The product is characterized by FTIR spectroscopy, Mass spectroscopy and ¹H NMR spectroscopy. The geometries of the synthesized dye is optimized using B3LYP method and 6-31G (d,p) basis sets. Nonlinear optical properties are investigated theoretically by calculation of some quantum chemical descriptors using the DFT/B3LYP method with a 6-31G(d,p) basis set in comparison with urea as a standard. The UV-visible spectrum of synthesized azo dye are calculated using TD-DFT with B3LYP/6-31G(d,p) level. The nonlinear refractive index of the prepared dye is calculated via the diffraction ring patterns and Z-scan techniques using 473 nm visible, continuous wave laser light. The diffraction ring patterns are numerically simulated using the Fresnel-Kirchhoff theory with reasonable agreements. The property of optical limiting of the azo dye is tested.

Three is company: dual intramolecular hydrogen-bond enabled carboxylic acid active in ring-opening polymerization

Dual intramolecular H-bonding made weak Brønsted acid an active catalyst in cationic ring-opening polymerizations.