The formation of proton complexes of the photoinduced colored open form of naphthopyrans in solutions was first discovered and investigated by spectral-kinetic method. The complexes exhibit a new absorption band in the visible region, which is bathochromically shifted relative to the absorption band of the photoinduced colored open form. With an increase in the concentration of perchloric or hydrochloric acid, this long-wavelength absorption band appears immediately after the addition of acids to solutions of photochromic compounds. The protonation efficiency depends on the strength of the acids.

中文翻译：

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光致变色萘并吡喃质子化的光谱表现

首次发现并通过光谱动力学方法研究了溶液中光诱导的萘并吡喃有色开放形式的质子配合物的形成。配合物在可见光区显示出新的吸收带，该吸收带相对于光致彩色开放形式的吸收带发生了红移。随着高氯酸或盐酸浓度的增加，在向光致变色化合物的溶液中添加酸后，该长波吸收带立即出现。质子化效率取决于酸的强度。