Two organic-inorganic hybrid dicyclohexyl-18-crown-6 nickel(II) bis(dithiolate) complexes, [K(DC18C6-B)]2[Ni(mnt)2] (1) and [K(DC18C6-A)]2[Ni(i-mnt)2] (2) (DC18C6-A = cis-syn-cis-dicyclohexyl-18-crown-6; DC18C6-B = cis-anti-cis-dicyclohexyl- 18-crown-6; mnt = maleonitriledithiolate; i-mnt = isomaleonitriledithiolate), have been synthesized by the reactions of dicyclohexyl-18-crown-6with NiCl2 andK2(mnt) or K2(i-mnt) respectively, and characterized by elemental analysis, FT-IR,UV-Vis spectroscopy and X-ray single crystal diffraction. They both crystallize triclinic, space group P1. Complex 1 shows a neutral molecule composed of two [K(DC18C6-B)]+ complex cations and one [Ni(mnt)2]2– complex anion via two K–N coordination bonds. In complex 2, the [K(DC18C6-A)]+ complex cation and [Ni(i-mnt)2]2– complex anion afford a 1D chain- like structure by N–K–N interactions.
The formation constants, K-s for 1:1 complexes of the cis-syn-cis and cis-anti-cis isomers of dicyclohexyl-18-crown-6 with sodium and potassium cations have been electrochemically determined in 10 nonaqueous (protic and aprotic) media. Linear correlations were obtained for log K-s with standard Gibbs transfer energies of the cation from water to a given solvent. The cis-anti-cis isomer was found to be a weaker complexer than the cis-syn-cis one and this was elucidated in terms of the ligand solvation. Energy-minimized structures of the ligands and complexes suuuounded by methanol and acetonitrile molecules were established by molecular dynamics computations.
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