• Journal of the Korean Chemical Society
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• v.31 no.2
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• pp.168-177
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• 1987

The equilibria of chemical reaction between $\alpha$-Ni(rac-[14]-decane)$^{2+}$ and polar solvents(L; ANT, MFA, DMSO, DMF, and DMA) have been investigated by the spectrophotometric method at $25^{\circ}C$. (The equilibrium constants($K_1$) of) the first step in ANT, MFA, DMSO, DMF, and DMA were 31.0, 27.5, 21.3 15.9, and 6.4, respectively. The smallness of equilibrium constants ($K_2$) of the second step compared with $K_1$, was observed. $\alpha$-Ni(rac-[14]-dacane)$^{2+}$ + L $\leftrightharpoons$ [$\alpha$-Ni(rac-[14]-decane){\cdot}L]$^{2+}$ : $K_1$.[$\alpha$-Ni(rac-[14]-decane){\cdot}L)$^{2+}$+ L $\leftrightharpoons$ [$\alpha$-Ni(rac-[14]-decane){\cdot}$L_2$)$^{2+}$ :$K_2$. The relationship between d-d absorption energy and half-wave potential of complex ions at ACT was considered. Macrocyclic ligands increasing d-d transition energy caused half-wave potentials of Ni(II)-macrocycle to be shifted more positively. The half-wave potentials for Ni(rac-1[14]7-diene)$^{2+}$, Ni(meso-1[14]7-diene)$^{2+}$, Ni(1[14]4-diene)$^{2+}$, $\alpha$-Ni(rac-[14]-decane)$^{2+}$, ${\beta}-Ni(rac-[14]-decane)$^{2+}$, and Ni(meso-[14]-decane)$^{2+}$ reductions were -1.419, -1.431, -1.450, -1.473, and -1.480 (V vs. SCE), respectively. The d-d transition energies ($\nu_{max},\;cm^{-1}$) of the Ni(meso-[14]-decane)$^{2+}$ isomer were discussed with the dielectric constant (${\varepsilon}/{\varepsilon}_0$) of the various solvents, $\nu_{max}(cm^{-1})$ increased with increasing ${\varepsilon}/{\varepsilon}_0$.