Tri-, bi- and mononuclear rhodium complexes with the anionic polydentate ligands 1,8-naphthyridine-2-one and 5,7-dimethyl-1,8-naphthyridine-2-one

Abstract

The complexes of the general formula [{Rh(R 2Onapy)(diolefin)} x] (diolefin=cod, tfb, nbd; Onapy =1,8-naphthyridine-2-one) are prepared by reaction of [{RhCl(diolefin)} 2] with HR 2Onapy and potassium hydroxide; complexes with substituted R 2Onapy are mononuclear and those with Onapy are either mono- or binuclear. Both react with carbon monoxide to give [{Rh(μ-R 2Onapy)(CO) 2} 2] (R= H, Me). Reactions of these tetracarbonyl complexes with the species [Rh(CO) 2(Me 2CO) x] + or with [Rh(CO)+(PPh 3) 2(Me 2CO)] ClO 4 give the trinuclear complexes [Rh 3(μ 3-R 2Onapy) 2(CO) 6] ClO 4 and [Rh 3(μ3-R 2Onapy) 2(CO) 4(PPh 3) 2]ClO 4, respectively. The former reacts with diolefins to give the complexes [Rh 3(μ 3-R 2Onapy) 2,(CO) 2(diolefin) 2]ClO 4(diolefin =cod, tfb, nbd). The bi- and trinuclear complexes are deeply-coloured solids which display a strong band in the visible region indicative of intramolecular metal-metal interaction.