铜－吡啶类络合物模拟漆酶催化漆酚氧化聚合成膜的红外光谱分析

IR ANALYSIS OF THE OXIDATIVE POL YMERIZATION OF URUSHIOL TO COATING CATALYZED BY CUPRIC COMPLEXES WITH PYRIDINES AS MODELS OF LACCASE

用红外光谱研究了Ｃｕ－ｐｙ、Ｃｕ－ＰＶＰｙ和Ｃｕ－ＱＰＶＰｙ催化漆酚氧化聚合交联过程。漆酚氧化聚合阶段的共同特征是：１．漆酚酿吸收峰１６５２ｃｒｎ￣－１先涨后落；２．共轭双烯吸收峰９８２和９４５ｃｍ￣－１逐渐减弱，而共轭三烯吸收峰９９２ｃｍ￣－１和芳醚吸收峰１２１５ｃｍ￣－１却逐步增强；３．苯环三取代吸收峰８３０、７６５ｃｍ￣－１都有所减弱，苯环四取代吸收峰８７５和８０５ｃｍ￣－１出现；４．苯环骨架吸收峰１６２０、１５９２ｃｍ￣－１之间的界限缩小甚至消失。到了漆膜的实于阶段，漆酚酿吸收峰１６５２ｃｍ￣－１再度兴起，但９９２ｃｍ￣－１吸收峰却由涨转落，其他吸收峰也有变化。以上光谱变化表明这３种催化剂都模拟了漆酶的催化作用。在Ｃｕ－ＰＶＰｙ催化漆酚氧化聚合阶段，发现孤立双键吸收峰３００８ｃｍ￣－１比共轭双烯吸收峰９８２和９４５ｃｍ￣－１消失得更早；并且从反应一开始就出现了１７１５ｃｍ｀－１羰基吸收峰。还比较了Ｃｕ－ＰＶＰｙ与Ｃｕ－ＱＰＶＰｙ催化的异同。

The oxidative polymerization and cross-linking process of urushiol catalyzed by cupric complex-es with pyridine,poly(4-vinylpyridine),and partially quaternized poly(4-vinylpyridine)by benzyl chloridewere studied by IR analysis. During oxidative polymerization of urushiol, absorption peak of urushi-olquinone at 1652 cm￣-1 enlarged at the beginning and then diminished. Absorption peaks of conjugated di-enes at 982 and 945 cm￣-1 weakened gradually,and absorption peaks of conjugated trienes at 992 cm￣-1 andthat of aromatic ethers at 1215 cm￣-1 grew by degrees. Absorption peaks of trisubstituted benzene at 830and 765 cm￣-1 also declined,and those of tetrasubstituted benzene at 875 and 805 cm￣-1 appeared.Theboundary valley between both absorption peaks at 1620 and at 1592 cm￣-1 which are attributed to benzeneskeleton reduced or even disappeared. During the solidifying stage,absorption peak of urushiolquinone at1652 cm￣-1 rose again, and that at 992 cm￣-1 changed from enlarging to diminishing. These changes in IRspectra showed that above-mentioned three catalysts simulated the catalytical action of laccase.It was found that absorption peak of carbonyl at 1715 cm￣-1 appeared at the beginning of the reactionand that of isolated double bond at 3008 cm￣-1 disappeared earlier than absorption peaks of conjugated di-enes at 982 and 945 cm￣-1. In addition,differences and similarities between Cu-PVPy and Cu-QPVPy werediscussed.