Ferromagnetism and its photo-induced effect in 2D iron mixed-valence complex coupled with photochromic spiropyran

Photo-and thermochromic spiranes. 29. New photochromic indolinospiropyrans containing a quinoline fragment

“…Features of the molecular structure of the compounds were determined by X-ray structural investigations. It was established that the pyridopyran fragments of the cations in the crystal of the iodomethylate salt, unlike those in the crystal of the neutral spiropyran, emerge from 2 1 -stacks, disposed jointly with I -ions, which causes their higher mobility and aids the course of reversible photoconversions on UV irradiation in solution.Keywords: indolinospiropyran, quinoline fragment, X-ray structural analysis, photochromism.The synthesis of spiropyran salts (SP + X -), the investigation of their molecular, crystal structure, and photochromic conversions in the solid phase has caused immense interest [2][3][4][5][6][7] in the design of new polyfunctional materials based on them, combining in one crystal lattice several beneficial properties (photoswitching nonlinear optical properties [8] or photomagnetism [9]) and raising the prospect of using crystalline hybrids in miniature electronic instruments.Photochromic conversions of neutral spiropyrans, linked with cleavage of the C spiro -O bond and subsequent isomerization of the molecule, require a large open space and consequently is extremely hindered in crystals by the total packing in the lattice. As a rule the neutral spiropyrans in monocrystals and microcrystalline powders under stationary radiation conditions do not display photocoloration caused by the formation of open photomerocyanine structures [10], as was observed in solution or in the amorphous state.…”

“…The synthesis of spiropyran salts (SP + X -), the investigation of their molecular, crystal structure, and photochromic conversions in the solid phase has caused immense interest [2][3][4][5][6][7] in the design of new polyfunctional materials based on them, combining in one crystal lattice several beneficial properties (photoswitching nonlinear optical properties [8] or photomagnetism [9]) and raising the prospect of using crystalline hybrids in miniature electronic instruments.…”

“…Each of these fragments is nonplanar. The indoline fragment has a bend at the N (1) -C (3) line of ϕ = 32.8° in compound 3 and ϕ = 29.2° in compound 4 (angle between the planes N (1) -C (23') -C (3) and N (1) -C (3) -C (8) -C (9) ). The N (1) and C (3) atoms are positioned in the plane of the benzene ring of the indoline fragment.…”

Photo- and thermochromic spiranes. 31.* Photochromic cationic spiropyrans with a pyridinium fragment in the aliphatic side chain*2

“…The major effect of introducing a quaternized pyridinium fragment into the benzopyran part of the spiropyran entails a significant decrease in the rate of thermal relaxation processes.Keywords: cationic indolinospiropyrans, pyridinium fragment, photochromism, electronic absorption spectroscopy.Photochromic organic molecules, some of which are spiropyrans and spirooxazines, have recently been the subject of intensive research due to the use of these compounds in optical recording and data transformation systems, sensors, optical electronics, optical bioelectronics, and transport systems [2-5].However, the limit to improving the characteristics of monofunctional materials has now been reached and attention is being directed toward the development of hybrid polyfunctional materials holding promise for application in molecular electronics.A possible solution of this problem lies in the creation of hybrid polyfunctional materials, which combine structural units responsible for different physicochemical properties such as photochromism and magnetism [6][7][8][9], photochromism and conductivity [10,11], electrical and magnetic properties [12], and optical dichroism and magnetism [13]. A systematic study of both the structure and properties of such units and the feasibility of their combination into a single crystal lattice is required for the development of such materials from molecular units differing in their chemical nature, the investigation of the interaction of such units on each other, and methods for the modification of the properties of the separate units to impart desired properties to the hybrid materials.…”

“…A possible solution of this problem lies in the creation of hybrid polyfunctional materials, which combine structural units responsible for different physicochemical properties such as photochromism and magnetism [6][7][8][9], photochromism and conductivity [10,11], electrical and magnetic properties [12], and optical dichroism and magnetism [13]. A systematic study of both the structure and properties of such units and the feasibility of their combination into a single crystal lattice is required for the development of such materials from molecular units differing in their chemical nature, the investigation of the interaction of such units on each other, and methods for the modification of the properties of the separate units to impart desired properties to the hybrid materials.…”