Mono- and polynuclear Co^II complexes with 2-hydroxy-6- methylpyridine

The reaction of 2-hydroxy-6-methylpyridine with Co(NO3)2·6H2O or Co(F3CSO3)2·6H2O in the absence of a deprotonating agent produces the mononuclear complexes Co(HL)4(NO3)2 or Co(HL)4(F3CSO3)2 (HL is 6-methyl-2-pyridone), respectively. In the presence of triethylamine, the reaction affords the trinuclear complex Co3(HL)2(L)4(NO3)2 or the heptanuclear dicationic complex [Co7L12]·(F3CSO3)2·4MeCN in the case of cobalt nitrate or cobalt trifluoromethanesulfonate, respectively. When HL is deficient, the replacement of the trimethylacetate anions in polymeric cobalt pivalate [Co(OH)n(OOCCMe3)2−n]x gives rise to the hexanuclear complex Co6(μ3-OH)2(η2,μ3-L)2(μ-OOCCMe3)8(HOOCCMe3)4, whereas the HLCo6(μ3-OH)(η2,μ3-L)3(η2,μ-L) (μ3-L)(μ3-OOCCMe3)(μ-OOCCMe3)4(η2-OOCCMe3) complex is generated when HL is present in excess. The structures of the reaction products were established by X-ray diffraction.