A two-dimensional coordination polymer with a brick wall structure: Synthesis, crystal structure, and properties of a nickel(II) hexaazamacrocyclic complex with azido ligand

A 2D hexaazamacrocyclic complex trans-[Ni(hto)(N3)2] (2) (hto = 1,3,6,9,11,14-hexaazatricyclo[12.2.1.16,9]octadecane) was synthesized from the mononuclear fragment [Ni(hto)]Cl2·2H2O (1) and sodium azido in methanol solution. The crystal structure of complex 2 is centrosymmetric and the nickel(II) atom has an axially elongated octahedral geometry with four nitrogen atoms from the hexaazamacrocycle and two nitrogen atoms from the azido ligands. Each trans-[Ni(hto)(N3)2] unit extends its structure to form a 2D brick wall network based on hydrogen bonding interactions between the nitrogen atoms of azido ligands and the secondary amine of the macrocycle in neighboring four units. Complex 2 exhibits blue fluorescent emission in the solid state at room temperature.