Synthesis and magnetism of tetrachlorophthalato-bridged manganese(II) binuclear complexes

Summary Four novel manganese(II) binuclear complexes have been prepared and characterized, namely Mn₂(TCPHTA)(L)₄]-(ClO₄)₂ where L is 2,2-bipyridyl (bipy), 1,10-phenanthroline (phen), 4,4-dimethyl-2,2-bipyridyl (Me₂bipy) or 5-nitro-1,10-phenanthroline (NO₂-phen) and TCPHTA is the tetrachlorophthalate dianion]. Based on i.r. spectra, elemental analyses, conductivity measurements, extended tetrachlorophthalato-bridged structures consisting of two manganese(II) ions in which each manganese(II) ion has a distorted octahedral environment are proposed for these structures. The temperature dependence of the magnetic susceptibility for Mn₂(TCPHTA)(phen)₄]-(ClO₄)₂·H₂O was measured over the 4–300 K range and the observed data were successfully simulated by an equation based on the spin Hamiltonian operator ( = –2J ₁· ₂), giving the exchange integralJ = –1.05 cm^–1. This result is indication of a weak antiferromagnetic spin exchange interaction between the metal ions.