Synthesis and supramolecular structure of Zn, Cd, Hg complexes constructed by 2,3-naphtho-15-crown-5

Three novel crown ether complexes containing d10 metals and 2,3-naphtho-15-crown-5 (N15C5): [Na(N15C5)H2O]2[Zn(NCS)4] (1), [Na(N15C5)]2Cd2(SCN)6] (2) and {Na[Na(N15C5)]}[Hg(SCN)4] (3) have been prepared and characterized by elemental analysis, FT-IR spectra, UV-vis spectra and single-crystal X-ray diffraction. All the complexes are composed of complex cations of crown and anions of corresponding d10 metals bridged by SCN− groups in different modes. Cooperative interactions of both coordinative bonds and weak interactions connect these ions to result into interesting supramolecular structures and these structures become more and more complicated with the central metals from Zn, Cd to Hg. In complex 1, neighboring complex cations and complex anions interact with each other through O-H⋯S weak interactions, leading to three-dimensional supramolecular structures. In complex 2, the μ2 and μ3-bridging SCN− groups bridge Cd atoms into one-dimensional chains with crown cations attached above and below the chains, respectively. In complex 3, tetrahedral [Hg(SCN)4]2− hold both kinds of cations (crown cations and discrete alkali metal ions) together into a novel one-dimensional double-chain with large thickness of 10.32 Å, the section consisting of Na atoms are arranged with the sequence of Na1Na2Na2Na1 and interesting alternatively arranged sixteen- or eight-membered rings.