Solvent-modulated zincII networks with different stacking arrangements

Abstract

Two ZnII complexes, [Zn2(L)2(DMF)(H2O)2]·DMF (1) and [Zn(L)(DEF)]·DEF (2), were synthesized by solvothermal reactions using 4,4′-(2,3,5,6-tetramethylbenzene1,4-diyl)dibenzoic acid (H2L) and Zn(NO3)2·6H2O in different solvents of DMF, ethanol, and water for 1 and N,N-diethylformamide (DEF) for 2. The L2− with different coordination modes connect [Zn2(COO)2] secondary building units (SBUs) to generate a wavy 2-D (4,4) network of 1 while in 2 there are paddlewheel [Zn2(COO)4] SBUs which are connected by L2− to form a planar 2-D (4,4) network. The 2-D layered structures show different stacking arrangements and are further linked by hydrogen bonding or C–H⋯π interactions to give 3-D architectures. The different structures and stacking arrangements of 1 and 2 result from different reaction solvents. Photoluminescence properties of the complexes were investigated.