Acetylene-substituted pyrazino[2,3-f][1,10]phenanthrolines and their Ru(ii) complexes: syntheses, electronic properties and an exploration of their suitability as building blocks for metal-coordinated dehydroannulenes
作者:Rüdiger Faust、Sascha Ott
DOI:10.1039/b110660k
日期:2002.4.26
Aryl- and silyl-terminated 6,7-dialkynylpyrazino[2,3-f][1,10]phenanthrolines (pyzphen) have been prepared by the condensation of [1,10]phenanthroline-5,6-diamine with appropriately functionalised dialkynyl-1,2-diones. These new ligands were used as chelators in the formation of the corresponding [Ru(bpy)2(pyzphen)]·2PF6 and [Ru(phen)2(pyzphen)]·2PF6 complexes. The terminally free diethynyl [Ru(bpy)2(pyzphen)] complex, obtained by protodesilylation of a silyl-protected precursor, was shown to be amenable to oxidative acetylene hetero-coupling reactions with arylacetylenes and allowed the preparation of the corresponding butadiynyl-substituted derivatives. Homo-coupling reactions of the terminally free diethynyl [Ru(bpy)2(pyzphen)] complex to produce cyclic dehydroannulene-arrays were successful, but furnished an inseparable mixture of compounds of at least two different ring sizes. The photophysical
and electrochemical properties of both the free ligands and their Ru(II)-complexes are clearly modified by the presence of the alkynyl substituents. In comparison with non-acetylenic model compounds it was established that acetylene substitution induces bathochromically shifted electronic absorptions and emissions to various degrees in ligands and complexes, leads to increased luminescence lifetimes and quantum yields of the ruthenium pyzphen complexes, and renders the acetylenic ligands and their complexes more susceptible to electrochemical reduction.
终端为芳基和硅基的6,7-二炔基吡咯啉[2,3-f][1,10]菲啰啉(pyzphen)是通过将[1,10]菲啰啉-5,6-二胺与适当功能化的二炔基-1,2-二酮缩合而制备的。这些新配体作为螯合剂,用于形成相应的[Ru(bpy)2(pyzphen)]·2PF6和[Ru(phen)2(pyzphen)]·2PF6复合物。通过对硅基保护前体进行去硅化反应获得的终端自由的二炔基[Ru(bpy)2(pyzphen)]复合物,显示出能够与芳基炔烃进行氧化乙炔异聚合反应,从而制备了相应的丁炔基取代衍生物。终端自由的二炔基[Ru(bpy)2(pyzphen)]复合物的异聚反应成功地产生了环状脱氢环烷烃阵列,但得到的化合物为至少两种不同环大小的不可分离混合物。自由配体及其Ru(II)复合物的光物理和电化学性质明显受到炔基取代基的影响。与非炔基模型化合物相比,结果表明,炔基取代会在配体和复合物中以不同程度引起电子吸收和发射的红移,增加了锆吡咯啉复合物的发光寿命和量子产率,并使炔基配体及其复合物对电化学还原更为敏感。