A three-dimensional supramolecular network structure through hydrogen bonding and π–π interaction: synthesis, structure, and the fluorescence detection of balsalazide disodium

Abstract

Three co-crystal compounds 1–3 (NDI-A·fluorene) (1), (H₃TIBTC·4,4′-bipy) (2), (H₃DIBTC·4,4′-bipy) (3) (NDI-A = N,N′-di(4-pyridylacylamino)-1,4,5,8-naphthalenediimide, H₃TIBTC = 2,4,6-triiodo-1,3,5-benzene tricarboxylic acid, H₃DIBTC = 2,4-diiodo-1,3,5-benzenetricarboxylic acid, 4,4′-bipy = 4,4′-bipyridine) were firstly synthesized by hydrothermal methods. The structural analysis shows that the co-crystal compounds 1–3 have 3D, 2D, and 1D supramolecular structures through hydrogen bonds and π–π interactions. Structural analysis shows that co-crystals 1–3 are constructed into a hydrogen bond ring and chain with graph set notations R³₃(28), R²₂(26), C (8), and R⁶₆(38), through hydrogen bonds, respectively. Co-crystal 1 has obvious fluorescence properties due to its large conjugate plane. Through the study of the fluorescence emission spectra of NDI-A, fluorene and the co-crystal 1 with their solid lifetimes, the mechanism of luminescence of co-crystal 1 was explored. Based on the good fluorescence properties of co-crystal 1, the detection effect of balsalazide disodium was systematically studied. It was found that co-crystal 1 can qualitatively and quantitatively detect balsalazide disodium under the condition of simulating the ion environment in plasma (K_sv = 8 × 10² M⁻¹; detection limit: 7.25 × 10⁻⁵ mol L⁻¹).