The di- and tetraalkynyl biphenyls 3 and 5 have been synthesized from the t
etrabromo derivative 1 by using Pd-catalyzed cross-coupling reactions. The
reaction of 3 or 5 with cis-[RuCl2(dppe)(2)] (8) affords vinylidene rutheni
um complexes, which were deprotonated with Et3N to give the terminal sigma
-alkynylruthenium derivatives 9-12. The reaction of 3 or 5 with [Ru(CO)ClH(
PPh3)(3)] (13) gave the corresponding di-a-alkenyl ruthenium complexes 14 a
nd 15.