445252-50-6Relevant academic research and scientific papers
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
Faust, Ruediger,Ott, Sascha
, p. 1946 - 1953 (2002)
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.
