Controllable assembly of copper(i)-iodide coordination polymers by tecton design of benzotriazol-1-yl-based pyridyl ligands: from 2D layer to 3D self-penetrating or homochiral networks

Abstract

To systematically explore the influence of the pyridyl N-donor spatial positions of benzotriazol-1-yl-based pyridyl tectons on structural assemblies of coordination polymers, three closely related ligands, 1-(2-pyridylmethyl)-1H-benzotriazole (2-pbt), 1-(4-pyridylmethyl)-1H-benzotriazole (4-pbt), and 1-(3-pyridylmethyl)-1H-benzotriazole (3-pbt), were designed and prepared. Their reactions with CuI under hydrothermal conditions afforded three new copper(I)-iodide coordination polymers, namely, [CuI(2-pbt)]_∞ (1), [Cu₂I₂(4-pbt)]_∞ (2), and [Cu₃I₃(3-pbt)]_∞ (3). Single-crystal X-ray diffraction analysis shows that 1 has a two-dimensional (2D) (4,4) sheet structure containing rhomboid [Cu₂I₂] dimeric units, which are further extended to form a three-dimensional (3D) framework by interlayer C–H⋯π supramolecular interactions. Complexes 2 and 3, with one-dimensional (1D) looped-chain [Cu₂I₂]_n and 1D staircase double-chain [Cu₃I₃]_n copper(I)-iodide arrays, show an unusual 3D six-connected self-penetrating rob net with the Schläfli symbol of (4⁸.6⁶.8) and a 3D four-connected homochiral diamond net, respectively. The results reveal that the different spatial positions of pyridyl N-donors in this series of ligands play an important role in constructing coordination polymers 1–3. Moreover, the photoluminescent properties and thermal stability of 1–3 in the solid state have also been investigated.