Syntheses And Properties Of Bisthienylethene Complexes Containing Ir(?)or Co(?) Ion/Unit

Bisthienylethe compounds could show different?-electron conjugation structure and molecular configuration before and after the photochromism reaction,thus showing different physical and chemical properties,such as absorption spectra,luminescence spectra,redox potential,optical activity,dielectric constant,etc.The coordination assembly of bisthienylethe and metal ion could result in some multifunctional complex with bisthienylethe-centered photochromism and the other metal-based properties,for example luminescence,nonlinear optical properties,redox properties,magnetic behavior,etc.In some cases,photochromic switching of the bisthienylethene unit could be used as a way of switching these physical and chemical properties provided by the metal units.Therefore,considerable attention has been focused on metal bisthienylethene compounds.In this thesis,we synthesize five bisthienylethene organic ligands and their six complex containing Ir(?)or Co(?)ion/unit,and study their crystal structures,photochromism,luminescence and magnetic properties.Chapter one:The study situation of bisthienylethene compounds,and our study aims and results.Chapter two:Bisthienylethenes L1H and L2H,and their complexes[Ir(dfppy)2(L1)]·2CH3OH(1)and[Ir(dfppy)2(L2)](2)have been synthesized.The crystal structures of 1 shows that neighboring molecules are linked into supramolecular right-and left-handed 21 helical chains through hydrogen bonds.In contrast,neighboring molecules in L2H and 2 interact only through Van der Waals interactions.At room temperature,compounds 1 and 2 in CH2Cl2 reveal broad emission bands at 508 nm and 494 nm,respectively,with a mixing of 3MLCT and 3LC characters.At room temperature,the photochromism ability of L2H in CH2Cl2 is clearly weaker than that of L1H.Moreover,no photochromism has been observed in 1 and 2.Chapter three:The bisthienylethene L3H and its complex[Ir(dfppy)2(L3)]·2CH3OH(3)and[Ir(ppy)2(L3)]·CH3OH(4)have been synthesized.Compound 3 shows aggregation-induced emission(AIE)behavior due to the intermolecular ?…? stacking interactions.In contrast,compound 4 almost has no emission in solution and in solid state.Moreover,L3H does not exhibit photochromism in solution.This could be due to the relatively larger ?-electron conjugation system in L3H which accepts the excitation energy,resulting in fluorescence instead of photochromism.Since L3H is non-photoactive,neither 3 nor 4 shows photochromism.Chapter four:We synthesized two new bisthienylethenes BrLH and PLH,and their mononuclear complexes Co(BrL)2·3CH3OH(5)and Co(PL)2·2CH3OH(6)where the Co(II)ions adopt distorted tetrahedral coordination geometry.The crystal structure of 5 shows that,two neighboring molecules are linked through both aromatic stacking interactions and hydrogen bonds into a supramolecular dimer.Compared with 5,neighboring molecules in 6 are connected only through hydrogen bonds,forming a chain structure.Both 5 and 6 show field-induced slow magnetic relaxation with differetn parameteres(Ueff and ?0).Photochromic behaviors were also observed in 5 and 6,as well as BrLH and PLH in CH2Cl2-CH3CN solution.