Metal Coordination Architectures of 1,4-Bis(imidazol-1-ylmethyl)naphthalene: Syntheses, Crystal Structures, and Theoretical Investigations on the Coordination Properties of the Ligand

Eight new metal complexes of an imidazole-based ligand 1,4-bis(imidazol-1-ylmethyl)naphthalene (L), {[Ag(L)](ClO4)}∞ (1), {[Cd(L)2(H2O)2](NO3)2}∞ (2), {[Mn(L)2(H2O)2](Cl)2}∞ (3), {[Zn(L)2(H2O)2](NO3)2}∞ (4), {[Co(L)2(H2O)2](NO3)2}∞
(5), {[Co(L)2(H2O)(SO4)](H2O)2}∞ (6), {[Mn(L)2(SCN)2]}∞ (7), and {[Zn(L)(L)](H2O)1.5}∞ (8, H2L1 = fumaric acid), were
synthesized and structurally characterized by elemental analyses, IR spectroscopy, and single-crystal X-ray diffraction analyses. 1
has a square-wave-like one-dimensional (1-D) chain structure, which further assembled into a two-dimensional (2-D) layer through
an interchain π···π interaction. 2−7 possess similar (4,4) 2-D sheet structures containing one type of quadrangle grid, and the
adjacent sheets are further interlinked by intersheet π···π stacking interaction to form a three-dimensional (3-D) supramolecular
network. 8 also displays a (4,4) 2-D network structure but with two kinds of different quadrangle grids, being different from that
of 2−7. The structural differences of the eight complexes mainly depend on the geometrical requirement of the different metal ions
and the influence of anions, as well as the presence of auxiliary ligand (in 8). Our research also demonstrates that intra- and/or
intermolecular π···π stacking play important roles in the formation of these coordination networks, especially in the aspect of
linking the low-dimensional entities into high-dimensional supramolecular frameworks. Moreover, a brief analysis of the coordination
properties of L has been carried out by density functional theory, combining experimental results.