Bleaching of Bis[1-(4-dimethylaminophenyl)-2-phenylethanedithione]nickel(0) in Polymer Solution and Polymer Matrix

Abstract

Abstract Bis[1-(4-dimethylaminophenyl)-2-phenylethanedithione]nickel(0) (BDN), a Q-switch dye for neodymium lasers, bleached in polymer matrix such as poly(butyl methacrylate). To elucidate the bleaching mechanism, the effect of water-soluble polymer added to dimethyl sulfoxide (DMSO) solution of BDN on the bleaching rate was investigated. BDN was reduced by a water-soluble polymer such as poly(vinyl alcohol) (PVA), starch, and cyclodextrin (CD) in DMSO. BDN bleached in DMSO solution with PVA and bleaching rate depended on the saponification number of PVA. BDN was also bleached by adding CD to DMSO solution. From the concentration dependence of CD on BDN bleaching rate, it was presumed that the vicinity of Ni of BDN is not included in β- and γ-CD, but is included in α-CD. For avoiding reduction of BDN by CD, 2,4,5-tri-O-methoxy-β-cyclodextrin (T-β-CD) was examined. BDN was not reduced by an inclusion complex of BDN with T-β-CD. The storage life of Q-switch with matrices of poly(butyl methacrylate) and polystyrene was determined. The Q-switch with polystyrene matrix having transmittance of 70.0% is expected to have transmittance of 70.4% after strage for 10 years at 25 °C.