Polynorbornene-based Fluorescence Chemosensors For Recognition O F Metal Ions

Fluorescent chemical sensor with high sensitivity, selectivity, and easy on-site analysis, portable and multi-functional characteristics, has been widely used in chemical, environmental, food, life sciences, medical and military fields. Compared to small molecules polymer fluorescent chemical sensor due to the fluorescence sensor amplification effect, good water solubility, detection performance can be regulated and easy multifunctional advantages in recent years has aroused widespread concern. In this paper, us the norbornene synthesized a series of functional norbornene derivatives, and through the ring-opening metathesis polymerization of its homopolymer. Fluorescence emission spectra, ultraviolet absorption, 1HNMR characterization test methods which monomers and polymers for ion selective recognition.1. A quinoline-functionlized norbornene(2-1) and its homopolymer(PN1) for metal ions recognition have been synthesized and characterized. In CH3 CN solution,2-1 exhibited fluorescence enhancement response toward Hg2+, Zn2+ and Cu2+, with Hg2+ resulting in a green emission at 465 nm, and Zn2+/Cu2+ increasing 2-1’s original emission at 416 nm. NMR titrations and DFT calculations results indicated that 2-1bound Hg2+ in an imidic acid tautomeric form of the amide quinoline receptor, while Zn2+ and Cu2+ were bound to 2-1 in an amide tautomeric form. In addition, owing to the strong imidic acid tautomeric binding mode of 2-1-Hg2+complex, 2-1 can recognized Hg2+ from Zn2+/Cu2+ and other competitive metal ions. In contrast, the homopolymer PN1, which was obtained by ring opening metathesis polymerization(ROMP) method, exhibited only fluorescence enhancement sensing to Hg2+and Cu2+in an amide tautomeric binding mode with increasing emission at 416 nm.2. A hydroxyquinoline functionlized polynobern(PN2) was designed and synthesized. In 100% water solution, PN2 shows a “turn–on” fluorescence response of Zn2+ and Cd2+ with a 50 nm blue shift. Further, both the PN2-Zn2+ and PN2-Cd2+complexes were found to respond pyrophosphate(PPi) over other important biological anions via fluorescence quenching. PN2 was also capable of monitoringthe intracellular Zn2+and PPi in real time.3. A new quinoline-functionlized norbornene with piperazine linker 4-1 and its homopolymer PN3 were designed and synthesized. In acetonitrile and acetonitrilewater(1:1, v/v) solution, both 4-1 and PN3 show a ratio of fluorescence response to Zn2+ with a 95 nm red shift. In addition, polymer-base chemosensor PN3 shows more sensitive sensing of Zn2+ than that of 4-1. Their cations binding mechanism were also discussed by1 H NMR titrations.