Self-assembled bamboo-like carbon nanotubes based on chiral H8BINOL sensors to recognize cinchonidine efficiently by diastereoisomer complexes

Abstract

Fluorescence recognition for the antimalarial cinchonidine could be achieved efficiently and rapidly through bamboo-like carbon nanotubes based on chiral conjugated H₈BINOL derivatives. Herein, it was proved that the chiral fluorescence probe H₈BINOL exhibited excellent fluorescence identification ability for cinchonidine. The structure and size of the S-1 (S-(3,3′-phenyl)-5,5′6,6′,7′,8,8′-octahydro-[1,1′-dinaphthalene]-2,2′-diol) and R-1 (R-(3,3′-phenyl)-5,5′6,6′,7′,8,8′-octahydro-[1,1′-dinaphthalene]-2,2′-diol) were studied by using the DLS, TEM, and SEM spectra, which exhibited a self-assembled bamboo-like carbon nanotube structure. In the CD (circular dichroism) test, cinchonidine was added to a pair of enantiomers of H₈BINOL derivatives. The different configurations of H₈BINOL derivatives showed significantly different Cotton effects for cinchonidine, indicating that cinchonidine formed diastereoisomer π–π complexes with different configurations of H₈BINOL derivatives. From the AFM tests, it was revealed that cinchonidine could effectively quench the fluorescent spot of the probes quickly. The fluorescence titration tests demonstrated that 6.4 × 10⁻⁷ mol of cinchonidine could completely quench the fluorescence sensor of S-1 (2 × 10⁻⁵ M, 2 mL) through the formation of a 1 : 1 complex. The limit of detection (LOD) of S-1 was calculated to be 6.08 × 10⁻¹⁰, which indicates that S-1 has a high sensitivity and can be applied effectively to the practice of identifying cinchonidine. Meanwhile, the fluorescence sensor R-1 also exhibited the same sensibility with a low limit of detection (7.60 × 10⁻¹⁰).