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)­(<i>o</i>-BDC)]·1.5H₂O (<b>1</b>), [Zn­(L1)­(<i>m</i>-BDC)] (<b>2</b>), [Cd₂(L1)­(BTEC)]·H₂O (<b>3</b>), [Zn­(L2)­(<i>m</i>-BDC)]·1.25H₂O (<b>4</b>), [Zn­(L2)­(<i>p</i>-BDC)]·4H₂O (<b>5</b>), [Cd­(L2)­(<i>p</i>-BDC)]·H₂O (<b>6</b>), [Zn₂(L2)­(BTEC)] (<b>7</b>), [Zn­(L3)­(<i>m</i>-BDC)]·3.5H₂O (<b>8</b>), [Zn₂(L3)­(<i>p</i>-BDC)₂]·2H₂O (<b>9</b>), [Zn₂(L3)₂(BTEC)]·2H₂O (<b>10</b>), and [Cd₂(L3)₂(BTEC)] (<b>11</b>) {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, <i>o</i>-H₂BDC = phthalic acid, <i>m</i>-H₂BDC = isophthalic acid, <i>p</i>-H₂BDC = terephthalic acid, and H₄BTEC = pyromellitic acid} have been prepared and identified by physical measurements. Compound <b>1</b> possesses a layered structure. Compound <b>2</b> shows one-dimensional chains. Weak π–π intermolecular stackings further join these chains into a two-dimensional (2D) supramolecular layered structure. Compound <b>3</b> displays a three-dimensional (3D) (4,8)-connected (3²·4²·5²)­(3⁴·4⁸·5¹²·6⁴) net. Compound <b>4</b> consists of two interlocked single-wall metal–organic nanotubes (SWMONTs) with both polyrotaxane and polycatenane characters. Compound <b>5</b> exhibits a 3D 5-fold interpenetrating diamond motif. Compound <b>6</b> furnishes a 3D α-Po net. Compound <b>7</b> reveals a 3D (4,6)-connected net with (4³·6³)­(4⁶·6⁶·8³) topology. Compound <b>8</b> features a 2D 4-connected network with (6⁵·8) topology. Compound <b>9</b> shows a 3D 3-fold interpenetrating α-Po net. Compounds <b>10</b> and <b>11</b> 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 <b>1</b>–<b>11</b> are reported as well. Moreover, fluorescent properties of compounds <b>4</b>–<b>7</b> in various solvent suspensions were investigated at room temperature