One- or two-dimensional 2,3-naphtho crown ether complexes [Na(N15C5)]2[M(SCN)4] and [K(N18C6)]2[M(SCN)4] (M = Pd, Pt) constructed by π-π stacking interactions

Four novel 2,3-naphtho-15-crown-5 (N15C5) and 2,3-naphtho-18-crown-6 (N18C6) complexes [Na(N15C5)](2)[Pd(SCN)(4)] (1), [Na(N15C5)](2)[Pt(SCN)(4)] (2), [K(N18C6)](2)[Pd(SCN)(4)] (3) and [K(N18C6)](2)[Pt(SCN)(4)] (4) were synthesized and characterized by elemental analysis, FT-IR spectra and single-crystal X-ray diffraction. The structure analyses reveal that both 1 and 2 are assembled into zigzag chains by the strong intermolecular pi-pi stacking interactions between adjacent 2,3-naphthylene groups of N15C5. The molecules of complexes 3 and 4 are linked into 1D chains by the bridging K-O(ether) interactions between the adjacent [K(N18C6)](+) units and the resulting chains are constructed into a novel 2D network by inter-chain pi-pi stacking interactions between the neighboring 2,3-naphthylene moieties of N18C6. According to the supramolecular self-assemblies of complexes 1-4, two types of stacking model of naphthylene groups are given and discussed.