Efficient Synthesis of 1,2‐Bis(2,2′‐bipyridinyl)ethane and 1,2‐bis(1,10‐phenanthrolinyl)ethane ligands by oxidative coupling of the corresponding monomeric methylene carbanions

Several dimeric 1,2‐bis (2,2′‐bipyridinyl)ethane (1,2,6,7, and 9 and 1,2‐bis(1,10‐phenanthrolinyl)) ethane (3,4, and 5) ligands have been synthesized in high yield by oxidative coupling of the corresponding monomeric methylene carbanions using as oxidating agents Br 2 , I 2 , and 1,2‐dibromoethane. The structure of the compounds obtained from three tetramethyl‐2,2′‐bipyridines and one tetramethyl‐1,10‐phenanthroline have been assigned on the basis of their 1 H‐NMR spectra. The electronic absorption and emission properties of these new ligands are reported. They display intense fluorescence spectra.