Spectral kinetic characteristics of the photoisomerization products of naphthylmethylideneiminospironaphthopyran induced by photolysis at different wavelengths
作者:P. P. Levin、N. L. Zaichenko、A. I. Shienok、L. S. Kol’tsova、I. R. Mardaleishvili、A. S. Tatikolov
DOI:10.1007/s11172-012-0078-6
日期:2012.3
The spectral kinetic characteristics of intermediates generated by photolysis with light at the wavelengths 337 and 430 or 470 nm of the photobifunctional compound (PBC), 1,3-dihydro-5-(2-hydroxy-1-naphthylmethylideneimino)-1,3,3-trimethylspiro[2H-indole-2,3-[3H]-naphtho[2,1-b]pyran], whose molecule combines the spironaphthopyran and hydroxyazomethine fragments, and also parameters of model compounds, viz., naphthylmethylideneimine and spironaphthopyran, were studied in methanol and toluene. The relative quantum yields of formation of different intermediates of PBC were measured relatively to model compounds, namely, trans-keto isomer formed due to cis-trans-isomerization and prototropic equiliration in the azomethine fragment, and in the merocyanine form generated by spiro bond opening. It was found that the photolysis of the PBC with light at the wavelengths λ = 430 or 470 nm nearly no produces the merocyanine form, whereas the relative yield of the trans-keto tautomer is ∼0.6. For PBC photolysis at λ = 337 nm, the yield of the merocyanine form is ∼0.2 and the yield of the trans-keto isomer decreases substantially (≤0.2). The solvent nature affects the kinetic behavior of the system. The consistency of the isomerization and proton transfer processes is discussed.
在波长为 337 和 430 或 470 纳米的光下光解 1,3-二氢-5-(2-羟基-1-萘亚甲基亚氨基)-1,3,3-三甲基螺[2H-吲哚-2,3-[3H]-萘并[2,1-b]吡喃]光功能化合物 (PBC)所产生的中间产物的光谱动力学特性、1,3-二氢-5-(2-羟基-1-萘亚甲基亚氨基)-1,3,3-三甲基螺[2H-吲哚-2,3-[3H]-萘并[2,1-b]吡喃],其分子结合了螺萘并吡喃和羟基氮甲基片段。,在甲醇和甲苯中研究了萘亚甲基亚胺和螺萘并吡喃的参数。相对于模型化合物,测量了形成 PBC 不同中间体的相对量子产率,即偶氮亚甲基片段中顺反异构和原向平衡形成的反式酮异构体,以及螺键打开产生的美蓝形式。研究发现,波长为 λ = 430 或 470 纳米的光对 PBC 进行光解时,几乎不产生美花氨酸形式,而反式酮同系物的相对产率为 0.6。在 λ = 337 纳米波长下进行 PBC 光解时,美拉德菁形式的产率为∼0.2,反式酮异构体的产率大幅下降(≤0.2)。溶剂性质会影响体系的动力学行为。讨论了异构化和质子转移过程的一致性。