Study On The Synthesis,Structures And Properties Of Novel Arylmethyl Radical Crystals

This thesis reviewed the research progress of arylmethyl radical functional materials and the application of the protonation effect in organic molecules.In the previous research work in our laboratory,we synthesized a series of organic radical materials based on obip and obip-CHO,and on this basis,the novel radical materials are further researched.Firstly,we report herein a novel type of solid-state stable diarylmethyl monoradicals 5,which were synthesized via facile "one-pot" approach.The monoradicals 5 can be easily converted to solid-state stable diarylmethyl triradicals 7 promoted by unusual and symmetric proton-shared hydrogen bond.Diarylmethyl triradicals 7 reveal higher ambient phosphorescent quantum yield and enhanced near-infrared absorption.More-over,switchable phosphorescent and magnetic transformation between triradicals 7 and monoradicals 5 controlled by proton-shared hydrogen bond avails to develop switch materials.After the transformation of triradicals to monoradicals with ammonia vapor,the EPR signal with seven singularities was switched "off",accompanied by appearance of the isotropic monoradical EPR signal;while the EPR signal with seven singularities can be again switch "on",promoted by the proton-shared hydrogen bond,after re-protonation with HClO4 aqueous solution.Unprecedentedly,the proton-shared hydrogen bond serves as a phosphorescent and magnetic switch.The present work provides a new access to synthesize stable diarylmethyl radicals and develop new switchable materials.Secondly,on the basis of the above content,a crystal of HCl hydrate 1·(HCl)2(H2O)3 was obtained by solvent evaporation method in HCl solution.Generally speaking,because hydrochloric acid is volatile,hydrochloric acid hydrate crystals are obtained at low temperatures.However,we obtain a stable hydrochloric acid hydrate crystal at room temperatur and unconventional cis-linear conformation of the water dimer at ambient condition were found in the novel organic crystal.Finally,we recently reported three novel triarylmethyl carbocation radicals.It is found that these three triarylmethyl carbocation radical salts are positional isomers and exhibit different magnetic susceptibility values at 300 K.Herein,we report a new triarylmethyl carbocation radical which was easily synthesized via "one-pot"approach.Interestingly,this "cis" triarylmethyl carbocation radical converted to the"trans" one by protonation.Such an obviously conformational change is triggered by the intermolecular hydrogen bond interaction involving one exocyclic "keto" oxygen atom and the protonated pyridinium nitrogen atom.Two triarylmethyl carbocation radical crystals were characterized by the elemental analysis and single crystal X-ray diffraction.The change in conformation,also gives rise to change in crystal structure,phosphorescence and magnetic susceptibility properties.