Design of Silver(I)−PTA Coordination Polymers through Controlled N,P-Coordination of 1,3,5-Triaza-7-phosphaadamantane (PTA) with Arylcarboxylates

Self-assembly reactions of silver(I) nitrate with 1,3,5-triaza-7-phosphaadamantane (PTA) as a main ligand and linker, and various benzenecarboxylic acids [benzoic (Hba), 4-cyanobenzoic (Hcba), 2-aminobenzoic (Haba), or terephthalic (H2tpa) acid] as ancillary ligand sources, provide the first general synthetic entry toward the controlled N,P-coordination mode of PTA, giving rise to the new series of coordination polymers [Ag(ba)(μ-PTA)]n (1), [Ag(μ-cba)(μ-PTA)]n·5nH2O (2), [Ag(μ-aba)(μ-PTA)]n·3nH2O (3), and [Ag2(μ4-tpa)(μ-PTA)2]n·2nH2O (4). They have been isolated as air- and light-stable crystalline solids, characterized by IR and NMR spectroscopies, and elemental and single crystal X-ray diffraction analyses, which feature the generation of infinite PTA-driven 1D or 2D metal−organic networks composed of various Ag-benzenecarboxylate nodes and PTA linkers. A crucial synthetic and architectural defining role is played by the ancillary benzenecarboxylate ligand, a slight modification of which allows design of topologically distinct coordination networks that vary from 1D zigzag (in 1), ladder-like (in 2), and tubular-like (in 3) chains to 2D gridlike undulating nets (in 4). Weak agostic interactions are observed between the CH groups of the ancillary ligands (in 1) or the methylene groups of PTA (in 2 and 4) and the silver(I) center. The metal−organic chains of 2 and 3 also act as host matrices for intercalated guest water molecules, which are associated by multiple H-bonds into infinite 2D {(H2O)11}n wavelike layers (in 2) or discrete (H2O)3 clusters (in 3), resulting also in further extension of silver−organic hosts to 3D supramolecular frameworks. Compounds 1−4 widen the very limited family of PTA-driven coordination polymers, representing also the first heteroligand coordination compounds that simultaneously bear PTA and carboxylate ligands.