Bipyridines, fluoro derivatives

In an extensive investigation of the behavior of halogeno-pyridines and -quinolines towards potassium amide in liquid ammonia, tendencies to react according to the hetaryne type and other mechanisms were compared. The following results may be mentioned. 3-Fluoropyridine does not react via 3,4-pyridyne, but yields fluoro derivatives of 4,4 - and 2,4 -bipyridine. 3,6-Dibromopyridine is converted first into 6-bromo-3,4-pyridyne and not into 6-amino-3-bromopyridine. 2-Bromoquinoline yields 2-methylquinazoline together with 2-aminoquinohne. ... 

A mixture of silver(I) fluoride and 2,2 -bipyridine replaces chlorine with fluorine in 1-chloro-octane in 86% yield after 45 minutes at 130°C.28 Some heterocyclic polychloro derivatives are also fluorinatcd by silver(I) fluoride. Thus, perfluoro(2,3,4,5-tetrahydropyridine) (1) and per-fluoro(3,4-dihydro-2//-pyrrole) are prepared from 2,2,6-trichloro-3,3,4,4,5,5-hexafluoro-2,3.4,5-tetrahydropyridine and 2,2,5-trichloro-3,3,4.4-tetrafluoro-3,4-dihydro-2//-pyrrole by reaction with silver(l) fluoride at room temperature.31 Since the fluorination of 2,2,5-trichloro-3,3,4,4-tetrafluoro-3,4-dihydro-2//-pyrrole with silver(l) fluoride is slow, recycling is necessary.31... 

The application of the Horrock and Sudnick equation to the terbium complex of ligand 6, reveals that only one water molecule is still coordinated to the complexed cation. Consequently, the lifetime (t = 1.5 sec) and the luminescence quantum yield (< > = 0.2) of this complex are very high and make it attractive for applications as luminescent probes in time-resolved fluoro-immunoassays (TR-FIA). " In order to lurther improve the luminescence properties of these ligands by increasing their molar absorbitivities (e) we have synthesized calix[4]arenes (e.g. 7) with four bipyridines or phenantrolines at the lower rim. A significant increase in the value of e of these derivatives has been... 

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