Diverse Structures and Luminescence Properties of Nine Novel Zn/Cd(II)-Organic Architectures Assembled by Two Different Rigid Ligands

Nine new compounds, namely, {[Zn(2-pybim)(ip)](2)center dot H2O}(n) (1), [Zn(2-pybim)(2)(Hip)(2)](n) (2), {[Zn(2-pybim)(2)(H(2)tm)](H(3)tm)}(n) (3), {[Cd(2-pybim)(ip)-(H2O)](2)center dot H2O}(n) (4), [Cd(2-pybini)(2)(bz)(2)](n) (5), {[Zn(3-pybim)(2)(Htm)(H2O)]center dot H2O}(n) (6), [Zn(4-pybim)(2)(PP)(1.5)](n) (7), [Zn-2(4-pybim)(2)(iP)(2)](n) (8), and [Zn(4-pybim)(Htm)-(H2O)](n) (9) (H(2)ip = iso-phthalic acid, H(2)pp = p-phthalic acid, H(3)tm = trimesic acid, Hbz = benzoic acid, n-pybim = 2-(n-pyridyl)benzimidazle [n = 2, 3 4]), were successfully synthesized. Compounds 1, 4, 6, 7, and 9 exhibit one-dimensional chains. Compounds 2, 3, and 5 are zero-dimensional. Stacking interactions extend them into high-dimensional frameworks. Compound 8 can be simplified as a {4.8(2)}{4.8(3).10(2)}{4(2).6.8(2).10}{4(2).6} topology. The luminescence properties of solid compounds 1-9 were also investigated at 298 K. Remarkably, compound 9 shows excellent luminescence properties with 29.16% quantum yield (QY) and 23.85 (ns) luminescent decay lifetime, which are much higher than the QY and luminescent decay lifetime of the 4-pybim ligand (tau(4-pybim), = 1.02 ns, QY(4-pybim)( )= 2.42%) and the other compounds (1-8). On the basis of the results of the comparison of the crystal structures and luminescence properties of compounds 1-9, our conclusions indicate that a crystal structure with parallel-dispaced molecular packing (J-aggregation) interactions of strong pi-electron conjugate systems can achieve a high luminescence efficiency.