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Synthesis and photochemical degradation of copper(II) ortho-azidobenzoate

“…The TLC of the photolysis products of the aqua complex demonstrated that, at low radiation doses (irradiation time of 15-60 s), only two reaction products were formed: a light green spot due to copper(II) anthranilate with R f = 0 and a violet spot due to the chelate complex with R f = 0.47. The areas of these spots increased with radiation dose, and the spot area of the chelate complex was much greater than the spot area of copper(II) anthranilate; that is, the process of photodehydration occurs much more rapidly than the degradation of the azido group with the formation of the amino group [3,4]. A comparison between the absorption curves of copper(II) anthranilate (Fig.…”

“…The photochemical properties of aromatic azides depend on the nature of the organic radical (the positions and properties of substituents on the aromatic ring), as well as on the nature of surrounding molecules (solvent and various additives in solution and the relative arrangement of molecules in a crystalline, amorphous, or adsorbed state) [1][2][3][4]. Moreover, the azido group, which has lone electron pairs on nitrogen atoms [5], as well as other nitrogen-containing groups (amino, azo, and nitrilo) [6][7][8][9][10], can form coordination compounds with transition metals.…”

“…The yield was 65% on a theoretical basis. The melting temperature of ortho-azidobenzoic acid is 144°ë [3] The dissolution of the aqua complex in these solvents also resulted in the formation of the chelate.…”

Direct Observation of Unstable Reaction Intermediates by Acid‐Base Complex Formation

“…The difference of 0.026 may indicate the existence of the 2‐carboxyphenylnitrene intermediate, the existence of which is assumed from the ESR measurements. Recently, based on the UV and IR spectra of crystalline samples of 2‐azidobenzoic acid, it was reported that the heterocyclic ring of 2,1‐benzisoxazolone was produced by the singlet arylnitrene and the dimer, 2,2′‐dicarboxyazobenzene, was produced by the triplet arylnitrene . Because the produced nitreno group was too far from the neighboring nitreno in the crystal structure, it was not dimerized into 2,2′‐dicarboxyazobenzene, but rather retained its single‐crystal form after intersystem crossing from the singlet to triplet states.…”

Synthesis of 2,1-benzisoxazole-3(1H)-ones by base-mediated photochemical N–O bond-forming cyclization of 2-azidobenzoic acids

“…For the preparative synthesis of 2,1-benzisoxazoles, in addition to the traditional method based on the reductive heterocyclization of ortho -substituted nitro compounds [ 17 – 21 ], two other routes are available: the annulation of nitroso compounds [ 22 – 23 ] and the thermal [ 24 ], catalytic [ 25 – 27 ] or photochemical cyclization of aryl azides [ 28 – 31 ].…”