Counter-complementarity control of the weak exchange interaction in a bent {Ni(II)3} complex with a μ-phenoxide-μ-carboxylate double bridge

We have prepared and structurally characterized a novel {Ni3} bent complex bearing a double μ-phenoxide-μ-carboxylate bridge. Both terminal Ni(II) sites are symmetry related, offering a simplified exchange interaction scheme. DC magnetic data is consistent with a weak antiferromagnetic interaction between the central and terminal Ni(II) ions. As expected for a Ni(II) system, local zero-field splitting is observed, which can be experimentally established. Broken symmetry quantum chemical calculations, as well as ab initio CASSCF-SA-SOC computations that support the magnetic experimental data, were also performed. From the analysis of other reported closely related Ni(II) systems, a counter-complementarity effect exerted by the carboxylate bridge is proposed, which might explain the weaker exchange interactions compared to those observed in double μ-phenoxide bridged Ni(II) compounds.