Magnetic Studies on the Dissociation Equilibria of Dinuclear Nickel(II) Alkanoates in Non-Aqueous Solutions

Dinuclear nickel(II) alkanoates, [Ni2(RCOO)4(quin)2] (R = C2H5CH(CH3)–, C2H5C(CH3)2–, and (C3H7)2CH–; quin = quinoline), were prepared, and then characterized by means of magnetic-susceptibility and IR spectroscopy. The equilibria between the mono- and dinuclear species in mixed acetone–benzene, mixed ethanol–benzene, and mixed tetrahydrofuran–benzene solution are discussed in terms of the donor number of acetone, ethanol, and tetrahydrofuran and in terms of the Ni–O bond strength. By comparing the Ni–O and Cu–O bond strengths, the exchange-coupling strength through the carboxylate bridges between the nickel(II) ions was estimated from that between copper(II) ions.