Solid-state photochromic indoline spiropyrans bearing a formyl group at the 6′ and 8′ positions of the 2
H
-chromene moiety of the molecules were characterized. The molecular structures of ...spiropyrans were established by single-crystal X-ray diffraction. Intermolecular interactions and voids in the crystals were investigated using the CrystalExplorer17 software package. Further studies of photochromism and mechanochromism of these spiropyrans in the crystalline state are shown to be promising.
•Indoline and benzoxazine based spiropyrans were investigated by the KEMS•Monomer molecules are the main constituents of the saturated vapor•The sublimation enthalpies were found by the second law of ...thermodynamics•The formation enthalpies in the ideal gas and crystalline state were calculated
Sublimation of 1,3,3,6′-tetramethyl-8′-formyl-spiroindoline-2,2′-2H -chromene (SP-1) and 3,6′-dimethyl-8′-formyl-spiro (4-oxo-3,4-dihydro-2H-1,3-benzoxazine)-2,2′-2H -chromene (SP-2) was studied by Knudsen effusion mass spectrometry in the temperature range 309–363 K and 331–384 K, respectively. It has been shown that, in the temperature range under study, both spiropyrans are thermally stable and sublime congruently in the form of monomeric molecules. The dependences of the saturated vapor pressure (Pa) on temperature are described by the equations:
lg p (SP-1) = – (6.239±0.093)∙103∙T–1+ (15.832±0.278),
lg p (SP-2) = – (6.625±0.111)∙103∙T–1 + (15.459±0.312).
The sublimation enthalpies have been evaluated by the second law method as ΔsH°(298.15 K) = 119±5 kJ∙mol–1 (SP-1) and ΔsH°(298.15 K) = 128±5 kJ∙mol–1 (SP-2). The enthalpies of formation of spiropyran molecules in the ideal gas state, ΔfH°g(298.15 K) = 199±9 kJ∙mol–1 (SP-1) and ΔfH°g(298.15 K) = –296±10 kJ∙mol–1 (SP-2), have been calculated using isodesmic reactions method implying quantum chemical calculations. Combining the latter values with the corresponding sublimation enthalpies the enthalpies of formation for crystalline state spiropyrans were determined: ΔfH°cr(298.15 K) = 80±10 kJ∙mol–1 (SP-1) and ΔfH°cr(298.15 K) = –424±11 kJ∙mol–1 (SP-2).
Features of the crystal structure of 2-{2-(6′-bromo-1,3,3-trimethylspiroindoline-2,2′-chromene-8′-yl)ethenyl}-1,3,3-trimethyl-3
Н
-indolium perchlorate have been investigated. The studied crystals ...have been grown under different temperature conditions and using different solvent mixtures. Intermolecular interactions and cavities in the crystals have been studied using CrystalExplorer v21.5 software package.
This work deals with the study of two derivatives of spiropyrans of indoline series and α-lipoic acid, which are considered as potential photopharmacological agents with controllable biological ...activity. The structure of the compounds has been studied in detail by X-ray diffraction analysis that revealed high lability of lipoic acid fragments. To assess potential biological activity, molecular docking for the possibility of spiropyran molecule to bind to amylin protein in order to inhibit its aggregation has been performed. The results of molecular docking showed a potential increase in the affinity of spirocyclic derivatives toward this protein as compared with α-lipoic acid.
New spiropyran salts in the row of 1,3,3-trimethylspiro-indoline-2,2'-2Н-chromene are prepared and their structures are investigated. Molecular structures of obtained compounds are confirmed by X-ray ...diffraction and NMR spectroscopy. An open merocyanine isomer is found to be the most stable structure for one of these compounds.
The paper describes the preparation of a new salt spiropyran of indoline series containing vinyl-3
H
-indolium fragment in the 8' position of the 2
H
-chromene moiety and a chlorine atom in the ...benzene ring of the indoline fragment. The structure of the reaction product was studied by IR,
1
H, and
13
C NMR spectroscopy. The data of X-ray diffraction study indicate that the reaction leads to the partial exchange of the indoline hetarene fragment to provide previously described salt spiropyran containing no chlorine atom in the indoline portion of the molecule.
A new spiropyran salt in which the positive charge is localized on the nitrogen atom of the indoline moiety and the negative charge is localized on the ClO
4
−
group is synthesized. The structure of ...the compound is determined by the single crystal X-ray diffraction analysis.
The new spiropyran systems with an azomethine bridge were synthesized from a spiropyran containing aminogroup at 6′ position of the benzopyran fragment and substituted aromatic aldehydes. The ...chemical structure of compounds is confirmed by elemental analysis data, NMR (
1
H and
13
C) and IR spectroscopy. Photochemical studies revealed the presence of photochromic properties at room temperature for one of the obtained spiropyrans.
Synthesis, structure study, and photochromic properties of new salt spiropyrans of indoline series containing chlorine and bromine atoms in the 6'-position of the 2
H
-chromene moiety have been ...reported. The structure of the obtained compounds has been confirmed by
1
H NMR spectroscopy and X-ray diffraction analysis. The compounds are photochromic; the long-wavelength absorption maximum for photoinduced isomer shows a considerable hypsochromic shift, while the lifetime increases considerably as compared with the fluorine-containing analog.
