Aliphatic Dicarboxylate Directed Assembly of Silver(I) 1,3,5-Triaza-7-phosphaadamantane Coordination Networks: Topological Versatility and Antimicrobial Activity

Abstract

The present work describes the facile synthesis, full characterization, and architectural diversity of three new bioactive silver-organic networks, namely 1D [Ag₂(μ-PTA)₂(<i>μ-</i>suc)]_<i>n</i>·2<i>n</i>H₂O (<b>1</b>), 2D [Ag₂(μ-PTA)₂(μ₄<i>-</i>adip)]_<i>n</i>·2<i>n</i>H₂O (<b>2</b>), and 3D [Ag₂(μ₄-PTA)­(μ₄<i>-</i>mal)]_<i>n</i> (<b>3</b>) coordination polymers, generated via a mixed-ligand strategy using PTA (1,3,5-triaza-7-phosphaadamantane) as a main building block and flexible aliphatic dicarboxylic acids (succinic (H₂suc), adipic (H₂adip), or malonic (H₂mal) acids) as an ancillary ligand source. The compounds <b>1</b>–<b>3</b> were isolated as moderately air and light stable crystalline solids and were fully characterized by IR and ¹H and ³¹P­{¹H} NMR spectroscopy, elemental analysis, ESI(±)-MS spectrometry, and single-crystal X-ray crystallography. The type of aliphatic dicarboxylate plays a key role in defining the dimensionality and structural and topological features of the resulting networks, which are also driven by the PTA blocks that adopt unconventional N,P- or N₃,P-coordination modes. The topological analysis of simplified underlying nets revealed that <b>1</b> possesses uninodal 3-connected chains with the SP 1-periodic net (4,4)­(0,2) topology, <b>2</b> features a uninodal 4-connected layer with the skl topology, and <b>3</b> reveals a uninodal 4-connected metal–organic framework with the dia topology. The presence of the crystallization water molecules in polymers <b>1</b> and <b>2</b> gives rise to the extension of their metal–organic structures into 3D (<b>1</b>) or 2D (<b>2</b>) H-bonded networks that disclose rather rare topologies. All of the obtained silver­(I) coordination polymers feature solubility in water (<i>S</i>_25 °C ≈ 3–5 mg mL^–1) and show significant antibacterial and antifungal activity against the selected strains of Gram-negative (Escherichia coli, Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus) bacteria and yeast (Candida albicans)