Di- and linear tri-nuclear carbonyl ruthenium clusters containing asymmetrically bridging 2,7-disubstituted naphthyridines
Abstract
The diruthenium(I) complex cis-[Ru2(bmnapy)2(CO)4]1 was prepared by reaction of 2-benzylamino-7-methyl-1,8-naphthyridine (Hbmnapy) with [Ru3(CO)12] in benzene. The N1,N2 co-ordination mode of the bridging ligands is supplemented by N8 as an axial donor atom. In contrast, the analogous reaction with 7-methyl-1,8-naphthyridin-2-one (Hmonapy) or the corresponding 5-methyl-7-phenyl derivative (Hmopnapy) afforded the respective trinuclear clusters cis-[Ru3(monapy)2(CO)6]2 and cis-[Ru3(mopnapy)2(CO)6]3, which exhibit three-atom chains with 46 valence electrons. X-Ray structural analyses demonstrate that the Ru–Ru bond distance remains effectively unchanged on going from the Ru2 unit in 1[2.707(1)Å] to the Ru3 sequence in 3[average 2.701(2)Å], for which an Ru–Ru–Ru angle of 168.6(3)° is observed.