Synthesis,Supramolecular Structures And Research Of Mimicking Catalytic Bromination Kinetics Of Vanadium Complexes

As possessing excellent bioactivity,vanadium plays an important role in our life.Vanadium is widely used in the field of manufacturing new material,biology and medicine;besides,vanadium shows its outstanding performances in different kinds of catalytic reactions as active catalysts,in which the vanadium dependent catalytic bromination oxidation is studied mostly.As we known,it brings anti-cancer and anti-bacterial properties when the aromatic compounds were introduced of halogen group.Traditional ways for bromine oxidation of aromatic compound is electrophilic substitution,but the method is of low availability of bromide,and produces a lot of industrial waste which pollutes seriously.Therefore,to search and synthesize substantial catalysts with high activity in safe and non-toxic process will be one of the key topics.Under the mild condition,natural vanadium haloperoxidases(V-HPOs)can be applied,while in virtue of the instability of their structure,investigators are devoting themselves to find proper substitution for natural V-HPOs.The center vanadium of natural V-HPOs is coordinated with N,O atoms from amino acid to form the active catalytic center,and which is also linked with amass of hydrogen bonds between V-HPOs and residues or water molecules;therefore,the structure of V-HPOs is highly stablilized.Thus,it's important to choose proper organic ligands in mimicking synthesis.In our work,pyridine/pyrazole and their derivatives containing N,O atoms are chosen as primary ligands,and some rigid/flexible carboxylic acids as auxiliary ligands to prepare 8vanadium functional model complexes.The prototype in our design is the natural vanadium haloperoxidase,and we have changed diverse methods to achieve target products.The complexes are determined by the X-ray single crystal diffraction,and characterized by IR,UV-vis spectra,SEM and electrochemical determination.Besides,series vanadium complexes are applied in bromination oxidation based on phenol red as catalysts,comparing the diversities of complexes with different valence state of center metal or coordinated with different ligands,the better structure of catalysts is obtained.It's worthy to be noted that,we have proposed the catalytic bromination mechnism for vanadium(III)complexes.