Amplified Optical Nonlinearity in a Self-Assembled Double-Strand Conjugated Porphyrin Polymer Ladder
作者:Thomas E. O. Screen、Jonathan R. G. Thorne、Robert G. Denning、David G. Bucknall、Harry L. Anderson
DOI:10.1021/ja026205k
日期:2002.8.1
butadiyne-linked conjugated zinc porphyrin polymer in chloroform results in self-assembly of a double-strand ladder complex. Excess ligand causes this duplex to dissociate into single strands. These binding processes were elucidated by near-IR and NMR titrations, as well as by gel permeation chromatography and small-angle neutron scattering. Ladder-making and -breaking are highly cooperative, with Hill coefficients
将 4,4'-联吡啶添加到氯仿中的内消旋丁二炔连接的共轭锌卟啉聚合物溶液中,导致双链梯形复合物的自组装。过量的配体导致该双链体解离成单链。这些结合过程通过近红外和核磁共振滴定,以及凝胶渗透色谱和小角中子散射来阐明。造梯和破梯协作性很强,希尔系数分别为 3.0 和 3.7。梯子的自组装将 pi 系统保持在平面构象中,增强共轭,导致 Q 带的红移和增强。正如在 1064 nm 处的简并四波混合测量所揭示的那样,每个大环的三阶磁化率的实部和虚部都通过梯形形成放大。在该波长下,双链聚合物复合物具有 |chi(3)xyyx| = 6.0 x 10-17 m2 V-2 每个大环,而在相同条件下单链聚合物为 6.6 x 10-18 m2 V-2。