生物小分子的电分析化学研究——Ⅳ.维生素K_3的电化学性质和光谱电化学表征

Study on Electroanalytical Chemistry of Small Biological Molecules Ⅳ. Electrochemical Behaviors and Spectroelectrochemical Characterization of Vitamin K_3

研究了维生素K_3在热解石墨电极上的电化学行为、分子定向和分子间的相互作用,用紫外吸收光谱电化学验证了它的电化学还原机理.实验结果表明维生素K_3在热解石墨电极上的反应是受吸附作用控制的2e、2H^+准可逆过程,维生素K_3分子是以C(6,7)位上的H按垂直方向吸附于热解石墨电极表面的,且吸附分子间存在着相斥的相互作用,其吸附平衡常数约为1.11×10~5,吸附能约为28.8KJ.mol^(-1).吸收光谱电化学实验结果表明维生素K_3电化学还原产物为2-甲基1,4-萘酚.

The electrochemical behaviors,molecular orientation and surface interaction of vitamin K3(VK3) have been studied on pyrolytic graphite electrode (PGE). The electroreduc-tive mechanism of VK3 has been verified by adsorption spectroelectrochemistry. The experimental data indicate that the electrode reaction is controlled by adsorption with 2H+ and 2e quasi-reverisible process on PGE. The VK3 is adsorbed toward the surface of PGE in a perpendicular orientation with the H groups at C(6) and C(7) position. Adsorbed molecules have a repulsive interaction at either surface. The equilibrium constant is 1.11×105 and the energy of adsorption is 28. 8 kJ/mol. The experimental results of adsorption spectroelectrochemistry indicate that the electrochemical reductive product of VK3 is 2-methyl -1,4-naphthylenediol.