Photochromic indoline spiropyrans with carbohydrazide substituents in the pyrano[2,3-f]chromene moiety of the molecule have been synthesized. These compounds exhibit inochromic properties and are chromogenic ("naked-eye") and fluorogenic chemosensors for lanthanide cations.

A computer search for new photoactive compounds among indoline spiropyrans of coumarin series was carried out using DFT B3LYP/6-31G(d,p) method. Based on the data obtained, the spiropyrans containing a formylcoumarin fragment annulated to the 2H-pyran ring and possessing photochromic properties were synthesized. The structure and photochromism of these compounds were studied by 1H NMR, IR, and UV/Vis spectroscopy. The introduction of a formyl group into the coumarin moiety of spiropyrans led to a bathochromic shift of the long wavelength absorption maxima of merocyanine isomers, as well as to a considerable increase in their lifetime.

Chemical and electrochemical syntheses of the zinc(II) and cadmium(II) complexes with the tetradentate Schiff base (H 2 L), the condensation product of 2- N -tosylaminobenzaldehyde with diaminodipropylamine, are carried out. The structures, compositions, and properties of the synthesized metal complexes are studied by elemental analyses, IR spectroscopy, 1 H NMR, UV spectroscopy, X-ray absorption spectroscopy, and quantum-chemical calculations. The structure of the cadmium(II) complex is determined by X-ray diffraction analysis (CIF file CCDC no. 1446393). The cadmium(II) and zinc(II) complexes exhibit luminescence in a CH 2 Cl 2 solution in the blue spectral range (λ PL = 425–428 nm) with the photoluminescence quantum yields ϕ = 0.20 and 0.75, respectively.

Indolinospiropyrans containing coumarin moiety annulated to the 2H-pyran ring at the 6,5-position exhibit positive photochromism under normal conditions and are characterized by exceptionally high values of colorability. Both strong electron donating and electron withdrawing 5-R substituents in the indoline moiety provide for the noticeable decrease of colorability. Negative solvatochromism of merocyanine isomers of the synthesized spiropyrans indicates their dipolar structure which is manifested by the reduction of the rate constants of recyclization upon increasing solvent polarity. (C) 2016 Elsevier B.V. All rights reserved.

Indoline spiropyrans containing a formylcoumarin moiety annulated to the 2H-pyran ring at the 6,5-position have been synthesized, and their structure and photochromism have been studied. It has been shown that the synthesized compounds exhibit better spectral-kinetic and photochromic properties as compared with other coumarin spiropyrans.

Synthesis of new asymmetric bis-spiropyrans of indoline series based on 6,8-diformyl-5,7-dihydroxy-4-methylcoumarin was realized. Depending on the nature of the substituents in positions 1 and 5 of the indoline moiety the derived compounds may exist in solution in the spiro or merocyanine forms, or as a tautomeric mixture of these forms. UV irradiation of the cyclic forms leads to photocoloring associated with re-opening of one or both of the spiro moieties. The wide variability of spectral kinetic properties of bis-spiropyrans upon fluorescence of photoinduced forms allows one to consider them as molecular switches having absorptive and fluorescent signal functions with the possibility of practical application.

1-Alkyl-2-(2-tosylaminophenyl)-5-aminobenzimidazole and related zinc complexes are synthesized. The structure of the complex with zinc pivalate is determined by X-ray diffraction analysis. The fluorescence with the anomalous Stokes shift of the benzimidazole ligand system in solution is transformed into the fluorescence with the normal Stokes shift upon complex formation due to blocking the mechanism of intramolecular proton transfer in the excited state or upon the transition to the crystalline state formed by zwitterionic forms that are generated due to the proton transfer from the sulfonamide group to the amino group.

Chemical and electrochemical syntheses of zinc(II) and cadmium(II) complexes based on tetradentate Schiff bases (H2L1 and H2L2) resulting from condensation of 2-tosylaminobenzaldehyde with 3,6-dioxa-1,8-octanediamine or 4,9-dioxa-1,12-dodecanediamine were performed. The structure, composition, and properties of the complexes were studied by elemental analysis, IR, 1H NMR, and UV spectroscopy, X-ray absorption spectroscopy, and X-ray diffraction. The zinc(II) and cadmium(II) complexes luminesce in a DMF solution in the blue spectral region (λPL = 425–433 nm), the photoluminescence quantum yield φ being 0.25–0.30. Multilayer zinc(II)- and cadmium(II)-based electroluminescent structures with green-blue emission of the exciplex nature were fabricated.