Solid state quantum yield determination of a novel base photogenerator

The photoefficiency of a new class of base photogenerating materials, based on the photoremoval of the α,α-dimethyl-3,5-dimethoxybenzyloxycarbonyl (Ddz) group from masked amine-type bases, was investigated. The solid state quantum yield for the photogeneration of cyclohexylamine from its corresponding Ddz carbamate was evaluated at 280 nm using a number of quantitative IR methods. A value of 0.10 was found using the optimal method involving a comparison of the intensities of a strong IR reference band solely associated with the polymer matrix with the decreasing carbonyl absorption of the Ddz substrate. Comparable quantum yields were also found by using an intense band associated with the Ddz-masked amine, thus indicating the overall applicability and reliability of the method provided that careful choice of the reference band was made. The value of the quantum efficiency for the photodeprotection of Ddz-masked amines is sufficiently high for practical applications requiring the use of photogenerated base.