Crystal Structure Diversities Based on 4,4′-(2,3,6,7-Tetramethoxyanthracene-9,10-diyl)dibenzoic Acid: From 2D Layer to 3D Net Framework

Five metal–organic coordination complexes with
the formulas
of {Mn­(L)­(H2O)2}n (1), {[Cd1.5L1.5(DEF)2]·2DEF}n (2), [Co1.5(L)1.5(H2O)]n (3), {[Co­(L)­(H2O)2]·4H2O}n (4), and {[Ni­(L)­(H2O)2]·4H2O}n (5), (H2LOMe = 4,4′-(2,3,6,7-tetramethoxyanthracene-9,10-diyl)­dibenzoic
acid) based on a new rigid dicarboxylate ligand were synthesized and
structurally characterized. Structural analysis reveals that H2LOMe acts as multibidentate bridging
linker to connect metal ions and possesses similar coordination modes
with terephthalic acid. Complex 1 is a (44)-sql layer incorporating bidentate-bridging H2LOMe and infinite Mn­(CO2)2 SBUs.
Complexes 2 and 3 have similar 2D (36)-hxl layer topology structure based on bidentate-chelating/bridging
H2LOMe ligand and trinuclear hourglass
SBUs. Complexes 4 and 5 are isostructural
and possess 3D open frameworks based on infinite M-(μ2-H2O) chain. From the viewpoint of crystal structure diversity
and comparison, our results further demonstrate that the coordination
mode of metal ions and ligand are the vital elements in determining
the final crystal structure. Moreover, thermal stabilities of 1–5 and temperature-dependent photoluminescence
behaviors of 1 and 2 are discussed.