A Versatile Bis-Porphyrin Tweezer Host for the Assembly of Noncovalent Photoactive Architectures: A Photophysical Characterization of the Tweezers and Their Association with Porphyrins and Other Guests
作者:Lucia Flamigni、Anna Maria Talarico、Barbara Ventura、Regis Rein、Nathalie Solladié
DOI:10.1002/chem.200500789
日期:2006.1.11
bis(Zn(II)-porphyrin) tweezer host with anthracene components as apex and side-arms has been synthesized. Mono- (pyridine) and bidentate (4,4'-bipyridine) guests were used as models for single and double axial coordination inside the cavity, respectively. A series of dipyridylporphyrin guests with different substitution patterns and excited-state energy levels have association constants with the tweezers that are
合成了以蒽组分为先端和侧臂的双(Zn(II)-卟啉)镊子主体。单(吡啶)和双齿(4,4'-联吡啶)客体分别用作腔内单轴和双轴配位的模型。一系列具有不同取代模式和激发态能级的二吡啶基卟啉客体与镊子的缔合常数约为10(6)M(-1),表明与腔内部的络合。仅在腔体发生严重变形(使咬合张开约30%)时,才会发生这种络合。这种特性,加上通过绕单键旋转减少咬合距离的能力,使得这些卟啉镊子成为迄今为止报道的最通用的镊子之一,调整咬合距离大约在5到20埃之间。能量传递到三卟啉复合物中的游离碱客体几乎是定量的(95-98%),转移速率与以降低取向因子为特征的Forster机制一致。