电荷转移配合物薄膜制备方法和结构表征的研究进展

回顾了与Langmuir-Blodgett(LB)技术有关的电荷转移配合物薄膜的各类制备方法、结构表征结果,并比较了制备方法对薄膜结构的影响.例如,将LB膜C18H37TCNQ(电子受体)插入到电子给体3,3’,5,5’-tetramethylbenzidine(四甲基联苯胺, TMB)的石油醚溶液中进行掺杂,制备了TMB•C18H37TCNQ电荷转移配合物薄膜.在这种薄膜中,给体和受体以面对面的方式堆积,两者的环平面与基片平面接近垂直.而采用硬脂酸和C18H37TCNQ的混合LB膜通过类似的掺杂路线制备的TMB•C18H37TCNQ薄膜的结构发生了一些变化,例如其长的烃链C18H37更加垂直于基片平面.通过比较以前的各种实验结果可以得出以下结论:电荷转移配合物的结构可以通过制备方法得到控制.

A Review for the Preparation and Structural Characterization of Thin Films of Charge-Transfer Complexes

Four methods to prepare thin films of charge-transfer complexes have been reviewed and the structural characterization of the related CT films was studied. In the LB films of the complex of N,N,N’,N’-tetramethylbenzidine (N-TMB) and 2-octadecyl-7,7,8,8- tetracyanoquinodimethane (C18H37TCNQ), the chromophore planes for both C18H37TCNQ and N-TMB are nearly parallel to the substrate surface while the hydrocarbon chain is considerably tilted with respect to the substrate normal. By dipping the mixed LB films of stearic acid and C18H37TCNQ into a petroleum ether solution of 3,3’,5,5’-tetramethylbenzidine(TMB), the thin films of charge-transfer complex can also be formed. In that case, the chromophore plane of TMB is nearly perpendicular to the substrate surface with its long axis lying on the substrate. If dipping LB films of pure C18H37TCNQ into a petroleum ether solution of TMB, we can also obtain the thin films of TMB•C18H37TCNQ and the orientation of the chromophore plane of TMB keeps nearly unchanged compared with the CT complexe thin films prepared from mixed LB films. The orientation of the hydrocarbon chain of the CT complexes, however, depends on the preparation methods undoubtedly.