Dinuclear Cobalt(II) Complexes with Various Dinucleating Ligands and Their Dioxygen Complexes

Various types of dinuclear cobalt(II) complexes, [Co2L(CH3COO)2]ClO4, [Co2L(CH3COO)](ClO4)2, [CO2L(OH)](ClO4)2, [Co2L(C3H3N2)]ClO4)2(C3H3N2−)=pyrazolate), and [CO2LX2](ClO4)n, were prepared, where HL represents 2,6-bis[bis(2-pyridylmethyl)aminomethyl]-4-methylphenol(Hbpmp), 2,6-bis[N-(2-pyridylmethyl)-2-(2-pyridyl)ethylaminomethyl]-4-methylphenol(Hbpmep), 2,6-bis[bis[2-(2-pyridyl)ethyl]aminomethyl]-4-methylphenol(Hbpmep), and 2,6-bis[bis(2-benzirnidazolylmethyl)aminometnyl]-4-metnylphenol(Hbbimp), and X is N3−, NCS−, Cl−, Br−, H2O, or py(pyridine). The electronic spectra and magnetic moments of the complexes revealed that [Co2L(CH3COO)2]ClO4 (L=bpmp, bpmep, or bpep) are high-spin octahedral, whereas the other complexes have five-coordinate structure of high-spin configuration. Some of the bpmp and the bpmep complexes reacted reversibly with molecular oxygen more or less. The P1⁄2 of some complexes were determined spectrometrically. The oxygen affinities of the complexes are highly dependent on the natures of the dinucleating ligands and additional bridging or unidentate ligands.