Synthesis And Properties Of N-Heterocyclic Carbene Iron Complex

Hypoxic microenvironment has been proved to be involved in tumor metastasis,growth and tumor angiogenesis.Therefore,improving tumor microenvironment plays an important role in the treatment of tumor diseases.At present,a variety of strategies which supply oxygen to tumor have been designed,such as hyperbaric oxygen injection,oxygen carrying microbubbles,in situ production of oxygen by reaction of H₂O₂with metal or catalase,and transportation of dissolved oxygen in perfluorocarbons or hemoglobin to regulate tumor hypoxic microenvironment,so as to strengthen radiotherapy.The catalytic decomposition of water by metal complexes to molecular oxygen will also provide a new solution for improving the tumor hypoxic microenvironment.On the other hand,metal complexes,such as cisplatin,oxaliplatin and so on,are widely used in clinical anti-tumor therapy,which opens a new space for the study of metal complexes in tumor therapy.Water oxidation process requires a higher energy barrier in thermodynamics,involves a complex process of multi-proton/multi-electron transfer,and has a slow kinetic reaction,which is the bottleneck of water decomposition research.Therefore,it is very important to develop efficient and stable water oxidation catalyst to accelerate the water oxidation process.In this paper,a metal iron（II）complex[（L1）₂Fe]·（PF6）₂[（1）,L1=2,6-bis（3-methylimidazolium-1-yl）pyridine],metal iron（II）complex[（L2）₂Fe]·（PF6）₂[（2）,L2=（2,6-bis（3-methy Limidazolium-1-yl）pyridine-4-carboxylic acid）]and metal iron（III）complex[（L3）₂Fe]·PF₆[（3）,L3=(Tris（3-methylimidazolium-1-yl）（phenyl）borate bis（hexafluorophosphate）]were synthesized using a N-heterocyclic carbene ligand.Their structure were characterized by high resolution mass spectrometer,nuclear magnetic resonance spectrometer and XRD single crystal diffraction.And the photophysical and electrochemistry properties were characterized by the ultraviolet-visible absorption spectrum,fluorescence spectrum and cyclic voltammetry.The results showed that the metal iron（III）complex（3）has a oxygen-producing activity through electrochemistry tests,with an overpotential of only 250 m V at p H 2.The inhibition effect of three complexes on the activity of some tumor cells was preliminarily verified by cell proliferation inhibition.The results showed that complex（3）had obvious inhibitory effect on the activity of tumor cells.