SYNTHESIS AND PHOTOCHEMICAL PROPERTIES OF AROMATIC DIAZO-PHOSPHONIUM SALTS

The phosphonium salts I-VI were synthesized which have potential appli cations in communication technologies, for example as photoresist mate rials. All these compounds show a broad absorption maximum in the rang e between 310 and 350 nm, depending on the nature of the substituent a ttached to the aromatic ring. The molar absorption coefficients were d etermined to be in the range from 10 000 to 15 500 1 mol(-1) cm(-1). T heir photochemical behaviour in solution was investigated by means of UV spectroscopy and compared with other photoreactive compounds contai ning the azo group. The quantum efficiency for the investigated compou nds was found to be in the range from 0.009% to 0.026% at 308 nm, whic h is about two magnitudes smaller than that of pentazadienes or triaze nes. Absorption difference (Delta A) plots of the experiments indicate basically a one-step decay with no significant amount of intermediate products on the observed time scale. (C) 1997 Elsevier Science S.A.