Tuning Different Kinds of Entangled Networks Formed by Isomers of Bis(1,2,4-triazol-1-ylmethyl)benzene and a Flexible Tetracarboxylate Ligand

In order to tune the Zn­(II) coordination
polymer architectures,
three position isomers, 1,4- (pbtmb), 1,3- (mbtmb), and 1,2-bis­(1,2,4-triazol-1-ylmethyl)­benzene
(obtmb), and flexible tetracarboxylate ligand, 5,5′-(1,4-phenylenebis­(methylene))­bis­(oxy)­diisophthalic
acid (H4L1), were used to assemble compounds with different kinds
of entangled networks, namely, {[Zn2(L1)­(pbtmb)2]·4H2O}n (1), {[Zn2(L1)­(mbtmb)2]·4H2O}n (2), and [Zn2(L1)­(obtmb)2]n (3). Flexible bis­(triazole) ligands present diverse
conformations in these compounds. Compound 1 shows a
4-fold interpenetrating three-dimensional architecture with 4-connected
mog (moganite) topology. Compound 2 displays a 2D + 2D
→ 3D polycatenation network simplified as new 4-connected topology
with the Schlafli notation of {4,64;8}2{42,64}. Compound 3 is a 2D polythreading
structure, in which two layed networks interpenetrate in a (2D/2D)
parallel fashion. The powder X-ray diffraction, thermal stabilities,
and the photoluminescence of 1–3 have
also been investigated.