Structural Diversity for a Series of Novel Zn Metal–Organic Frameworks Based on Different Secondary Building Units

The secondary building unit (SBU) has been identified
as a useful tool in the synthesis of metal–organic frameworks
(MOFs). Herein, we synthesized six novel Zn complexes, namely, {[Zn3(tci)2(DMF)2)]·2DMF·2CH3OH}n (1), {[Zn3(tci)2(DMSO)2(H2O)2]·2DMSO·3H2O}n (2), {[ZnNa­(tci)­(H2O)]·2H2O}n (3), {[Zn5(tci)2(OH)4(H2O)2]·2H2O}n (4), {[Zn3(tci)2(phen)2(H2O)2]·4H2O}n (5), and {[Zn3(tci)2(btb)2(H2O)2]·6H2O}n (6) by utilizing different SBUs (tci = tris­(2-carboxyethyl)
isocyanurate, phen = 1,10-phenanthroline, btb = 1,4-bis (1,2,4-triazole-1-ylmethyl)
benzene). Complexes 1–4 were synthesized
only by changing solvents, and complexes 5 and 6 were obtained by adding different auxiliary ligands on the
same conditions. Structural analyses show that complexes 1 and 2 possess two-dimensional (2D) structures based
on linear and triangular trinuclear Zn clusters. Complexes 3 and 4 exhibit 2D and three-dimensional (3D) frameworks
built on rare infinite rod-shaped SBUs, while complex 5 belongs to a 3D framework with two kinds of left- and right-helical
chains built from discrete dinuclear Zn clusters and mononuclear Zn
atoms. Complex 6 exhibits high-connected 3D framework
based on extended linear trinuclear Zn clusters.