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

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(μ-suc)]n·2nH2O (1), 2D [Ag2(μ-PTA)2(μ4-adip)]n·2nH2O (2), and
3D [Ag2(μ4-PTA)­(μ4-mal)]n (3) 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 1–3 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 1 possesses uninodal 3-connected chains with the
SP 1-periodic net (4,4)­(0,2) topology, 2 features a uninodal
4-connected layer with the skl topology, and 3 reveals
a uninodal 4-connected metal–organic framework with the dia
topology. The presence of the crystallization water molecules in polymers 1 and 2 gives rise to the extension of their
metal–organic structures into 3D (1) or 2D (2) H-bonded networks that disclose rather rare topologies.
All of the obtained silver­(I) coordination polymers feature solubility
in water (S25 °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).