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The geometrical and electronic structures of the CrO and CrO clusters are computed using density functional theory with a generalized gradient approximation in the range of 1 ≤ n ≤ 14. Local total spin magnetic moments, polarizabilities, binding energies per atom, and energies of abstraction of O and O are computed for both series along with electron affinities of the neutrals and vertical detachment energies of the anions. In the lowest total energies states of CrO, CrO, CrO, CrO, CrO, CrO, and CrO, total spin magnetic moments of the Cr atoms are quite large and antiferromagnetically coupled. In the rest of the series, at least one of the Cr atoms has no spin-magnetic moment at all. The computed vertical electron-detachment energies of the CrO are in good agreement with experimental values obtained in the 1 ≤ n ≤ 7 range. All neutral CrO possess electron affinities larger than the electron affinities of halogen atoms when n > 6 and are thus superhalogens. It is found that the neutrals and anions are stable with respect to the abstraction of an O atom in the whole range of n considered, whereas both neutrals and anions became unstable toward the loss of O for n > 7. The polarizability per atom decreases sharply when n moves from one to four and then remains nearly constant for larger n values in both series. The largest members in both series, CrO and CrO, possess the geometrical structures of the Cr(O) type by analogy with monochromium Cr(O).

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A new photochromic spiropyran of the indoline series, containing a quinoline fragment, has been synthesized. The photochromic properties of the spiropyran and its iodomethylate have been studied. 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.Investigation of ultrathin pressed microcrystalline samples of salts of spiropyrans and spiroxazines with N-methylated pyranopyridine rings [6,11,12] showed that at constant UV irradiation (365 nm) they are colored reversibly with the development of a broad absorption band between 500 and 650 nm, as was also observed in solution. The photochromic conversions are reversible and monocrystals survive some tens of cycles before structural and spectral changes. To establish the features of the molecular and crystal structure which provide reversible photochromic conversions of salts of spiropyrans under crystal packing conditions we carried out the synthesis and systemic investigation of the structure of new salts of various classes of spiropyrans [5,6,12,13].

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