Synthesis of new fluorene compounds for highly selective sensing of picric acid, Fe3+ and l-arginine

Two compounds, 4-(4-(7-bromo-9, 9-dimethyl-fluoren-2-yl) phenyl) pyridine (4) and 2, 7-Bis-(4-tert-butyl-phenyl)-9,9-dimethyl-9H-fluorene (5), were synthesized by bromination, methylation and Suzuki coupling reaction with fluorene as the starting material. The compounds were used as fluorescent sensors to detect some nitro compounds (NACs), metal cations and amino acids. The test results showed that the 4-(4-(7-bromo-9, 9-dimethyl-fluoren-2-yl) phenyl) pyridine (4) as fluorescence sensor 1 detected 2, 4, 6-Trinitrophenol (TNP) at the magnitude of 10 μM, with a sensitivity of Ksv was 4.6 × 105 M−1 and the detection limit was 6.9 × 10−7 M. The sensitivity detection for Fe3+ with Ksv value was 1.4 × 105 M−1, and the detection limit was 3.6 × 10−7 M. At the same time, it was found that 2, 7-Bis-(4-tert-butyl-phenyl)-9,9-dimethyl-9H-fluorene (5) as fluorescence sensor 2 also showed excellent selective recognition ability toward the arginine (L-arg) in biomolecules with Ksv values of 3.9 × 10 4 M−1, and the detection limit was 1.15 × 10−6 M for arginine (L-arg).