Synthesis and Photophysical Properties of New Chromium(III) Complexes of N-Derivatized 1,4,8,11-Tetraazacyclotetradecane Ligands <i>cis</i>-[Cr(1,8-R<sub>2</sub>cyclam)Cl<sub>2</sub>]Cl, Where R Is a Pendant Chromophore. Exclusive Formation of the <i>cis</i> Isomer
作者:Frank DeRosa、Xianhui Bu、Peter C. Ford
DOI:10.1021/ic0300870
日期:2003.6.1
Several new chromium(III) complexes have been synthesized utilizing derivatives of the macrocyclic ligand cyclam (1,4,8,11-tetraazacyclotetradecane) with various N-substituted chromophores in the 1 and 8 positions (1,8-R(2)cyclam) where R = CH(3), CH(2)Ph, CH(2)Nph (Nph = naphthyl), and CH(2)Anth (Anth = anthracyl). X-ray crystal structures were determined for all four complexes, and these are formed
利用大环配体cyclam(1,4,8,11-四氮杂环十四烷)的衍生物与在1和8位(1,8-R(2)cyclam的各种N-取代的生色团)合成了几种新的铬(III)配合物),其中R = CH(3),CH(2)Ph,CH(2)Nph(Nph =萘基)和CH(2)Anth(Anth =蒽环)。确定所有四个络合物的X射线晶体结构,并且它们仅以顺式构型形成,其中两个叔胺在配位体的“铰链”位置(即,沿着折叠轴)。结果,在比未取代的Cr(cyclam)Cl(2)(+)离子进行顺式反式异构化所需的力更大得多的条件下,顺式异构体似乎对异构化呈惰性。光物理研究表明,发射仅发生在以金属为中心的配体场双峰激发态下,而不管初始激发是进入四方配体场带还是悬垂发色团的pi-pi谱带。因此,悬垂生色团的激发导致有效的分子内能量转移到以金属为中心的配体场激发态。