A Series of Coordination Polymers Constructed by Flexible 4‑Substituted Bis(1,2,4-triazole) Ligands and Polycarboxylate Anions: Syntheses, Structures, and Photoluminescent Properties

Eleven
Zn/Cd-containing coordination polymers (CPs) incorporating
both flexible 4-substituted bis­(1,2,4-triazole) ligands and polycarboxylate
anions, namely, [Zn­(L1)­(o-BDC)]·1.5H2O (1), [Zn­(L1)­(m-BDC)] (2), [Cd2(L1)­(BTEC)]·H2O (3), [Zn­(L2)­(m-BDC)]·1.25H2O (4), [Zn­(L2)­(p-BDC)]·4H2O
(5), [Cd­(L2)­(p-BDC)]·H2O (6), [Zn2(L2)­(BTEC)] (7),
[Zn­(L3)­(m-BDC)]·3.5H2O (8), [Zn2(L3)­(p-BDC)2]·2H2O (9), [Zn2(L3)2(BTEC)]·2H2O (10), and [Cd2(L3)2(BTEC)]
(11) {L1 = 1,2-bis­[2-(4H-1,2,4-triazol-4-yl)­phenoxy]­ethane,
L2 = 1,2-bis­[3-(4H-1,2,4-triazol-4-yl)­phenoxy]­ethane, L3 = 1,2-bis­[4-(4H-1,2,4-triazol-4-yl)­phenoxy]­ethane, o-H2BDC = phthalic acid, m-H2BDC = isophthalic acid, p-H2BDC
= terephthalic acid, and H4BTEC = pyromellitic acid} have
been prepared and identified by physical measurements. Compound 1 possesses a layered structure. Compound 2 shows
one-dimensional chains. Weak π–π intermolecular
stackings further join these chains into a two-dimensional (2D) supramolecular
layered structure. Compound 3 displays a three-dimensional
(3D) (4,8)-connected (32·42·52)­(34·48·512·64) net. Compound 4 consists of two interlocked
single-wall metal–organic nanotubes (SWMONTs) with both polyrotaxane
and polycatenane characters. Compound 5 exhibits a 3D
5-fold interpenetrating diamond motif. Compound 6 furnishes
a 3D α-Po net. Compound 7 reveals a 3D (4,6)-connected
net with (43·63)­(46·66·83) topology. Compound 8 features
a 2D 4-connected network with (65·8) topology. Compound 9 shows a 3D 3-fold interpenetrating α-Po net. Compounds 10 and 11 display 3D (4,4)-connected nets with
the same (64·7·8)­(62·84) topology. The effects of the bis­(triazole) ligands, aromatic polycarboxylate
anions, and metals ions on the framework assemblies have been discussed.
Solid-state luminescent of compounds 1–11 are reported as well. Moreover, fluorescent properties of compounds 4–7 in various solvent suspensions were
investigated at room temperature.