Synthesis Of Viologen Derivatives And Photochromic Oxygen Sensor

The detection of oxygen content is very important in many fields such as medieine, industrial production, food storing and environmental monitoring. Due to the optical oxygen sensor have many advantages such as easy operation and high sensitivity, good repeatability, low cost, safey, anti-disturbance of electromagnetism, and it can be used for long-distance, successive and on-line monitoring of oxygen in dangerous environxnent. Therefore, the researehes of optical oxygen sensors have gotten attention of people in recent years.A series of N,N’-bis(alkylcarbamoylmethyl)-4,4’-bipyridinium dichloride(CnBpyeaCl2) has been synthesized. The structure of the products was characterized by FT-IR, 1H NMR, 13 C NMR and MS. The synthesis of C8BpyeaCl2 optimum technology conditions by microwave irradiation.First, the equilibrium surface tension of C8BpyeaCl2 aquous solution was measured that explaind the compound have surface-active. The interactions between cyclodextrin(β-CD) and C8BpyeaCl2 in aqueous solutions have been studied with isothermal titration calorimetry and 1H NMR. We found the stoichiometry of the β-CD and C8BpyeaCl2 system is 2:1. The thermostability of C8BpyeaCl2 and C8BpyeaCl2@2β-CD was measured by XRD, the results show that complexes have been formed. Furthermore, their preliminary photochromic properties have also been investigated by UV-visible diffuse reflectance spectroscopy and cyclic voltammetry.Finally, the reversible of C8BpyeaCl2 and C8BpyeaCl2@2β-CD were studied, and the fade speed changes with the oxygen concentration after irradiation. The results show that C8BpyeaCl2 and C8BpyeaCl2@2β-CD were exhibited excellent reversible photochromic properties. C8BpyeaCl2 can be turned dark purple from white by the UV lamp irradiation in a 20 seconds, and quickly returns to its initial color in air within 20 minutes, the fade speed changed with irradiation time in air. Moreover, the fade speed depended on the oxygen concentration after irradiation at the same time, the lower oxygen concentration, the more slowly fade speed; and it is irreversible in the absence of oxygen conditions after irradiation. Compared with C8BpyeaCl2, C8BpyeaCl2@2β-CD can be turned blue from white by the UV lamp irradiation besides a faster fade speed.