Syntheses, structures, and biological activities of two supramolecules consisting of resorcinolcalix[4]arene and amino-pyridine moieties

Self-assembly of C-iso-butyl-resorcinolcalix[4]arene (CBCR) with 4-aminopyridine (4-AP) or 3-dimethylaminopyridine (3-DMAP) in ethanol afforded two host-guest complexes CBCR⋅4-AP (1) and CBCR⋅2(3-DMAP) (2), respectively. Supramolecules 1 and 2 were characterized by FT-IR, ¹H NMR, ¹³C NMR spectroscopies and single crystal X-ray diffraction analysis. The antioxidant and antibacterial experiments were conducted on complexes 1, 2 and the starting materials. The 2,2-diphenyl-1-(2,4,6-trinitrophenyl)hydrazyl and 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) free radical scavenging rate could reach 91.73% and 98.55% when the concentration of complex 2 was 500 and 31.25 mg/mL, respectively. The antibacterial test of complex 1 showed that the antibacterial circle diameter against Escherichia coli was 10.25 mm, with a MIC value of 12.5 mg/mL, and the antibacterial circle diameter against Staphylococcus aureus was 14.33 mm with a MIC value of 3.12 mg/mL.