Centro de Química - Vila Real, Universidade de Trás-os-Montes e Alto Douro, 5001-801, Vila Real, Portugal.
Photochem Photobiol Sci. 2011 Aug;10(8):1346-54. doi: 10.1039/c1pp05067b. Epub 2011 Jun 27.
A new set of photochromic hindered benzo- and naphtho[1,3]oxazines with fast switching speed between the closed and open form were synthesised. Laser excitation of these uncoloured molecules (with ∼10 ns FWHM pulses) leads to the cleavage of the C-O bond and opening of the oxazine ring in less than 20 ns, generating a thermally unstable coloured zwitterionic species that reverts in few nanoseconds to the initial oxazine closed form. For these derivatives a detailed spectroscopic and photophysical study was undertaken involving measurements of absorption and phosphorescence spectra, phosphorescence quantum yields (ϕ(Ph)), phosphorescence lifetimes (τ(Ph)), triplet energies (E(T)), singlet oxygen (ϕ(Δ)) and ring opening photoreaction (ϕ) quantum yields, reisomerization kinetics and the zwitterionic form lifetime. A remarkable solvent effect on the lifetime of the photogenerated species was observed.
一组新的光致变色受阻苯并和萘并[1,3]恶嗪，在闭环和开环形式之间具有快速的切换速度，被合成了。这些无色分子的激光激发（具有 ∼10 ns FWHM 脉冲）导致 C-O 键的断裂和恶嗪环在不到 20 ns 内打开，生成热不稳定的有色两性离子物种，在几纳秒内返回到初始的恶嗪闭环形式。对于这些衍生物，进行了详细的光谱和光物理研究，包括吸收和磷光光谱、磷光量子产率（ϕ(Ph)）、磷光寿命（τ(Ph)）、三重态能量（E(T)）、单线态氧（ϕ(Δ)）和开环光反应（ϕ）量子产率、重排动力学和两性离子形式寿命的测量。观察到光致生物质的寿命对溶剂有显著的影响。
