Syntheses, structures, and coordination of diborylbipyridines and bipyridinediborates

Article abstract of DOI:10.1002/(sici)1099-0682(199903)1999:3<393::aid-ejic393>3.0.co;2-5

6,6'-Bis(diethylboryl)-2,2'-bipyridine (1a) was obtained in low yield by in situ deprotonation of 2,2'-bipyridine in the presence of diethyl(methoxy)borane. 6,6'-Dilithio-2,2'-bipyridine reacts with various alkoxyboranes leading to bipyridinediborates 2 in good yields. The derivatives 2b and 2c allow the formation of the free diborylbipyridines 1b and 1c. The coordination properties of the diboryl-bipyridines as tetra- functional donor-acceptor compounds have been used for the formation of the copper complex 4 and of the adduct 5 which is built from diborylbipyridine and a dihydroxydiboroxan derivative. The composition of the products follows from spectroscopic data and from X-ray structure analyses for 2f, 4, and 5.