1D and 2D Silver-Based Coordination Polymers with Thiomorpholine-4-carbonitrile and Aromatic Polyoxoacids as Coligands: Structure, Photocatalysis, Photoluminescence, and TD-DFT Study

• Published in: Crystal growth & design Vol. 20; no. 7; pp. 4461 - 4478
• Main Authors: Ristić, Predrag, Todorović, Tamara R, Blagojević, Vladimir, Klisurić, Olivera R, Marjanović, Ivana, Holló, Berta Barta, Vulić, Predrag, Gulea, Mihaela, Donnard, Morgan, Monge, Miguel, Rodríguez-Castillo, María, López-de-Luzuriaga, José M, Filipović, Nenad R
• Format: Journal Article
• Language: English
• Published: American Chemical Society 01.07.2020
• ISSN: 1528-7483; 1528-7505
• DOI: 10.1021/acs.cgd.0c00287

Four silver-based coordination polymers, {[Ag­(L)2]­(BF4)}∞ (1), {[Ag­(H2BTC)­(L)]·(H3BTC)}∞ (2), {[Ag2(H2BTEC)­(L)2]·3.33H2O}∞ (3), and [Ag­(H25SSA)­(L)]∞ (4), were synthesized using thiomorpholine-4-carbonitrile (L) as the primary ligand and three aromatic polyoxoacids as coligands: trimesic (H3BTC), pyromellitic (H4BTEC), and 5-sulfosalicylic acid (H35SSA). Compounds 1 and 3 are two-dimensional, while 2 and 4 are one-dimensional. L acts as a bis-monodentate ligand, while the Ag­(I) ion is three-coordinated in 2 and four-coordinated in all of the other compounds. The tetrahedral coordination of Ag­(I) in 3 leads to an almost complete absence of intermolecular interactions with the metal center. All compounds show reasonable photocatalytic activity for photocatalytic degradation of mordant blue 9 dye, with reaction rates in the 0.036–0.056 min–1 range. Changes in the reaction rates can be correlated with the type and coordination of the coligand. Complex 3 exhibits photoluminescence at 77 K, while 4 exhibits photoluminescence at both room temperature and 77 K. Luminescence lifetimes indicate electronic transitions of singlet parentage, where transitions are allowed. A TD-DFT study determined the contributions of individual singlet–singlet electronic excitations to the fluorescence, indicating that metal– intraligand transitions are responsible for luminescence in both complexes.