Solvent Effect on the Supramolecular Patterns and Luminescent Properties of Organic Salts Comprising Naphthalene-1,5-disulfonic Acid and Triphenylmethylamine

Abstract

The solvent reaction of naphthalene-1,5-disulfonic acid and triphenylmethylamine gives rise to nine organic salts, namely, 2(HTPMA)+·(NDS)2–·2(MeOH) (1), 2(HTPMA)+·(NDS)2–·6(EtOH) (2), 2(HTPMA)+·(NDS)2–·4(n-PrOH) (3), 2(HTPMA)+·(NDS)2–·4(n-BuOH) (4), 2(HTPMA)+·(NDS)2–·2(n-PeOH) (5), 2(HTPMA)+·(NDS)2–·3(DO)·2(H2O) (6), 2(HTPMA)+·(NDS)2–·4(DMF) (7), 2(HTPMA)+·(NDS)2–·4(DMSO) (8), and 2(HTPMA)+·(NDS)2–·4(H2O) (9) (H2NDS = naphthalene-1,5-disulfonic acid, TPMA = triphenylmethylamine, DO = 1,4-dioxane), which have been characterized by elemental analysis, infrared spectroscopy, thermogravimetric analysis, photoluminescence (PL), and powder and single-crystal X-ray diffraction (XRD). Structural analyses indicate that the nature of the solvent molecules can effectively influence the hydrogen bonding modes of the −SO3– and −NH3+ groups, which then result in diverse architectures. The HTPMA+ cations and NDS2– anions in salts 1, 3, and 4 are alternately arranged to form column motifs, which then pack with each other to form lamellar structures with a wide interlayer space. The NDS2– anions in salts 2 and 5 adopt standing and recumbent positions and act as pillars to extend adjacent double layers formed by HTPMA+ cations into pillared layered supramolecular networks. In comparison, pairs of HTPMA+ cations in salt 6 act as pillars and extend the layers formed by two kinds of NDS2– anions to generate pillared layered frameworks. Salts 7 and 8 exhibit a similar packing diagram, in which adjacent monolayers of HTPMA+ cations are pillared by the NDS2– anions in a recumbent position. Salt 9 is a porous hydrogen-bonding organic framework assembled from the alternate arrangement of HTPMA+ cations and NDS2– anions, and its products at 50 and 120 °C exhibit different structures after being immersed in aqueous solution with the composition of 2(HTPMA)+·(NDS)2–·4(H2O) (10) and 2(HTPMA)+·2(TPMA)·(NDS)2– (11). Luminescent investigation reveals that the emission maximum of salts 1–9 varies from 382 to 393 nm. Moreover, the detailed chemical behaviors for salt 9, such as thermal stability, temperature-dependent infrared spectroscopy, powder XRD, PL, are carefully studied.