Chemical reactions in homogenous systems are generally associated with positive-order kinetics;that is,the reaction rate increases with the increased concentration of reactants.In this work,we report a coordination re...Chemical reactions in homogenous systems are generally associated with positive-order kinetics;that is,the reaction rate increases with the increased concentration of reactants.In this work,we report a coordination reaction of Cu^(2+)ions,cyanuric acid(CA),and pyridine in aqueous solution which shows negative-order kinetics with respect to the concentration of pyridine.As the pyridine concentration increases,the complexation of CA with pyridine overwhelms its dissociation in water,resulting in the redistribution of CA;that is,CA is sealed in the pyridine phase by forming an unreactive hydrogenbonded complex.As a result,the number of accessible anionic CA for crystallization in water decreases,and thus the crystallization slows down and almost terminates.Further,the crystallization yields two types of crystals with similar structures but disparate colors(red and blue),and the origin is investigated by the ligand field analysis.展开更多
基金the financial support by the Australian Research Council(grant no.DP190101607).
文摘Chemical reactions in homogenous systems are generally associated with positive-order kinetics;that is,the reaction rate increases with the increased concentration of reactants.In this work,we report a coordination reaction of Cu^(2+)ions,cyanuric acid(CA),and pyridine in aqueous solution which shows negative-order kinetics with respect to the concentration of pyridine.As the pyridine concentration increases,the complexation of CA with pyridine overwhelms its dissociation in water,resulting in the redistribution of CA;that is,CA is sealed in the pyridine phase by forming an unreactive hydrogenbonded complex.As a result,the number of accessible anionic CA for crystallization in water decreases,and thus the crystallization slows down and almost terminates.Further,the crystallization yields two types of crystals with similar structures but disparate colors(red and blue),and the origin is investigated by the ligand field analysis.
