Synthesis And Spectroscopic Properties Of Acylhydrazone Compounds Based On Azoflore Structure

The pH value not only has an apparent effect on the properties of chemical compounds, but also has the very important significance in biology. Studies have shown that the changes of intracellular pH values could cause cardiopulmonary and neurological diseases such as Alzheimer’s syndrome. Cytoplasmic pH anomalies have the close association with some cell dysfunction. As a result, the design and synthesis of new pH fluorescent probes which are used to detect the pH changes in biological and chemical environments have received an increasing attention in the field of applied chemistry and environment science. The most direct and widely used pH measurement method is colorimetric indicator and glass electrode. Despite the convenience and effectiveness, the colorimetric detection method has an obvious defect that it cannot be used in vivo for live cell imaging. Although some physiological changes reach into extreme pH ranges, for example, gastric juice, to the best of our knowledge, the study of these pH fluorescent probes within the interval of pH less than5or greater than9is still rare. On the other hand, hydrazone fluorescent probes study has focused on the recognition of transition metal ions and negative ions such as fluoride, acetate ions.Therefore, developing the hydrazone fluorescent probes which can be used in extreme pH ranges has the vital significance.In this paper, we designed and systhesized three series of hydrazone indolizine derivatives, besides we studied fluorescence and UV-Vis properties of these compounds, and still investigated their applications in metal ions recognition.The experimental results:1. The compounds of D-1-D-3,5-methylindolizine as fluorophore, all have the ability of H+recognition. The fluorescenct emission intensity of three compounds is low.Replacing withdrawing group into donating group, the emission intensity has great enhancement.The maximum wavelength emisson of three compounds undergoes a hypsochromic shift from the neutral solutions to the extreme pH solutions. In spite of that, hydrazones can bind many metal cations in solution,the metal titration experiments show that the oxygen atom of carbonyl group and nitrogen atom can not bind with those chosen metal ions effectively.2.The compounds of Q-l-Q-3, pyrrolo[1,2-a]quinoline as fluorophore, all have the ability of H+recognition.Replacement of withdrawing group into donating group, the emission intensity has great enhancement.The wavelength emisson of three compounds undergoes a hypsochromic shift from the neutral solutions to the extreme pH solutions. These three compounds win out in responding highly sensitively to a minor pH change and possessing a pKa of1.94,2.06and12.84.3.The compounds of T-1～T-2, pyrrolo[2,1,5-cd]indolizine as fluorophore, all have the ability of H+recognition.The two probes are highly sensitive within the pH range of0.83±and1.67±1, respectively.The metal titration experiments show that T-1and T-2can not bind with those chosen metal ions effectively.The experiment results indicate that T-1and T-2show excellent selective response to H+.