BIPYRIDYLACETYLENES-1 - THE SYNTHESIS OF SOME BIPYRIDYLACETYLENES VIA THE PALLADIUM-CATALYZED COUPLING OF ACETYLENES WITH 2,2'-DIBROMOBIPYRIDYL, AND THE SINGLE-CRYSTAL X-RAY STRUCTURE OF 6,6'-BISPHENYLETHYNYL-2,2'-BIPYRIDINE

The synthesis of a series of 6,6'-diethynyl-2,2'-bipyridyls from the palladium-catalyzed coupling of 6,6'-dibromo-2,2'-bipyridine with a series of arylacetylenes is reported. The single crystal X-ray structure of 6,6'-phenylethynyl-2,2'-bipyridyl was determined. Crystal data: monoclinic, A2/a, with cell constants a = 10.0385(4), b = 9.2166(4), c = 21.4130(8) angstrom, and beta = 102.981(3)-degrees; D(calc.) = 1.226 g cm-3, Z = 4, R(f) = 0.045, S = 1.22, using 886 reflections of the 1443 unique reflections. The packing diagram indicates essentially that the molecules pack in a layered assembly with the nitrogen atoms of the dipyridyl groups on opposite sides and with a dihedral angle of 59.85(16)-degrees between the pyridyl and phenyl groups. The acetylenic bond distances are normal.