Bipyridines, substituted

BiphenyIyImagnesium iodide, 46, 94 2,2 -Bipyeidine, 46, S 2,2 -Bipyridines, substituted, from al-kylpyridines, 46, 9... 

Complete chlorination of 4,4 -bipyridine to octachloro-4,4 -bipyridine is accomplished by vapor-phase chlorination at 555°C. Mono-, di-, tri-, and tetrachloro-4,4 -bipyridines substituted at the positions ortho to the nitrogen atoms are obtained at lower temperatures. 2,6-Dihydroxy-3-cyano-4,4 -bipyridine gives 2,5,6-trichloro-3-cyano-4,4 -bipyridine on reaction with phosphorus chlorides, ring substitution accompanying replacement... 

Fig. 2.1.4. Bis(2,2 -bipyridine)-substituted BINOL 10 and its dimeric and trimeric dinuclear metal complex.

Because bipyridines substituted at the 3 and 3 positions exhibit a large steric repulsion between substituents while in the cis configuration,27 they bind metals more weakly and form strained, nonplanar structures.28 However, a series of 3,3 -disubstituted bipyridines were coordinated to ruthenium, and it was demonstrated that molecular distortions could be used to advantage in modulating physical properties of the resulting complexes.29... 

The ring opening of bitriazolopyridines, (15), with the addition of various reagents leads to the formation of 6,6 -disubstituted bpys.54,55 Bipyridines substituted with a secondary alcohol, an ester linkage, and a ketone were synthesized using sulfuric acid, acetic acid, and selenium dioxide, respectively (Scheme 8).54... 

Stable free radicals are employed in a variety of studies requiring spin labels, MRI, antioxidants, or magnetic materials. Elongated ethynyl-bridged radicals 7 and 10 based on pyridine- and bipyridine-substituted nitronyl nitroxide (NTT) radicals are also prepared by... 

A pH-sensitive microelectrochemical transistor [288] is based on the pH dependence of the reduction potential of a 4,4 -bipyridine-substituted polypyrrole. At a fixed gate voltage, file source-drain current is pH-dependent, as a result of the reversible protonation of the bipyridinium group. 

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