Structural Versatility of Alkali Metal Coordination Polymers Driven by Arylhydrazones of β‑Diketones

The self-assembly reaction of arylhydrazones of β-diketones (AHBD), namely 2-[2-(2,4-dioxopentan-3-ylidene)­hydrazinyl]­benzenesulfonic acid (H₂L¹) and 2-[2-(4,4-dimethyl-2,6-dioxocyclohexylidene)­hydrazinyl]­benzenesulfonic acid (H₂L²), with sodium or potassium hydroxides in MeOH/H₂O (1/1, v/v) produces a series of coordination compounds, [Na₃(μ₃-HL¹)₂(μ₄-HL¹)­(μ-H₂O)­(H₂O)₂]_<i>n</i> (<b>1</b>), [Na₂(HL¹)₂(μ-H₂O)₂(H₂O)₄]·4H₂O (<b>2</b>), [Na­(HL²)­(μ-H₂O)­(H₂O)₂]_<i>n</i>·<i>n</i>H₂O (<b>3</b>), [K­(μ₄-HL¹)­(μ₃-H₂O)]_<i>n</i> (<b>4</b>), and [K­(μ₄-HL²)­(H₂O)]_<i>n</i> (<b>5</b>), which include the one-dimensional (<b>3</b>), two-dimensional (2D) (<b>1</b>, <b>4</b>), and three-dimensional (3D) (<b>5</b>) coordination polymers, as well as the zero-dimensional dimer (<b>2</b>). Compounds <b>1</b>–<b>5</b> were isolated as air stable crystalline solids and characterized by IR, ¹H, and ¹³C­{¹H} NMR spectroscopy, elemental, differential thermal, and single-crystal X-ray diffraction analysis. The latter shows that the monodeprotonated HL^1– (L = L¹, L²) anions act as multiple O-donors through the sulfonate and carbonyl groups and are also capable of simultaneously bridging three and/or four metal cations (in <b>1</b>,<b> 4</b>,<b> </b>and 5), thus giving rise to the intricate 2D and 3D coordination networks. Their topological analysis reveals the trinodal 3,4,7-connected (in <b>4</b>) and pentanodal 3,4-connected (in <b>1</b>) underlying 2D nets with novel types of topologies, as well as the uninodal 4-connected 3D framework with the <b>sra</b> (SrAl₂) topology (in <b>5</b>)