Synthesis and Study of Three Novel Macrocyclic Selena[<i>n</i>]ferrocenophanes Containing a Naphthalene Unit

Three novel macrocyclic ligands, L1–L3, in which a ferrocene unit and a fluorescent moiety are linked to polyselena rings have been designed and prepared from 1,1′-bis­(3-bromopropylseleno)­ferrocene. Reaction of L with [M­(NCMe)4]­(PF6)2 (M = Pd and Pt) led to complexes [ML]­(PF6)2 (M = Pd and Pt). Crystal structure analysis revealed that after complexation, the macrocyclic ligand adopts the unusual c,c,c conformation due to intramolecular C–H···π interactions from the hydrogen atoms of ferrocene moieties to the naphthalene ring. Electrochemical studies showed that in [ML]­(PF6)2 (M = Pd and Pt) the half-wave potential of the 1,1′-ferrocenediyl group shifts to much more positive potentials due to electron density withdrawn from Se donor atoms. Electrochemical and optical measurements were used to calculate HOMO and LUMO levels as well as HOMO–LUMO band gaps. Results were compared and correlated with the differences in molecular structures.本研究设计并合成了三种新型大环配体L1~L3，该类配体将二茂铁（ferrocene）单元与荧光基团连接至多硒环结构，其合成原料为1,1'-双(3-溴丙基硒代)二茂铁。将配体L与[M(乙腈(NCMe))4](PF6)2（M=钯Pd、铂Pt）反应，得到配合物[ML](PF6)2（M=Pd、Pt）。晶体结构分析表明，配位后该大环配体因二茂铁单元的氢原子与萘环之间存在分子内C-H···π相互作用，呈现出罕见的c,c,c构象。电化学研究显示，在配合物[ML](PF6)2（M=Pd、Pt）中，1,1'-二茂铁二基基团的半波电位向更正电势方向大幅偏移，这是由于硒给体原子抽离了体系的电子密度。通过电化学与光学测试，计算得到了最高占据分子轨道（Highest Occupied Molecular Orbital, HOMO）、最低未占据分子轨道（Lowest Unoccupied Molecular Orbital, LUMO）能级以及HOMO-LUMO能带隙，并将测试结果与分子结构差异进行对比与关联分析。