Structural Modification Photochromism Of Pyridinum Iodoargentate Hybrids

Based on the organic-inorganic hybrid materials of electron donor-acceptor D-A type,not only have composition,structure,functional diversity as well as significant synergistic effect,but also produce colored free radicals under the stimulation of temperature/light/electricity/magnetism/solvent,furthermore it shows the photochromic performance of multi-factor response.Among them,photochromic inorganic-organic hybrid materials have potential applications in decoration,display,sensing,data storage,protection,memory,catalysis and so on.Numerous photochromic hybrid materials are mainly formulated as strongly Lewis basic chlorometallates,metal cyanides,metallophosphates,carboxylates and zeolites,which are mainly matched with strong?-acidity electron acceptors such as viologens and 1,4,5,8-naphthalenediimides?NDIs?.Saha put forward:strongly Lewis basic anions?OH^-and F^-?undergo thermal ET with most NDIs,generating NDI^·-radical anions,weaker Lewis bases?AcO-,H₂PO₄-,Cl-,etc.?often require the photoexcitation of moderately?-acidic NDIs to generate the corresponding NDI^·-radical anions via photoinduced ET?PET?.Poorly Lewis basic I^-does not participate in thermal ET or PET with most NDIs but forms anion/NDI CT or anion-?complexes.Taking into account the fact that the practical application of photochromic materials bring convenience to life,so it is necessary to enrich the photochromic materials in components,structures and improve the performance of the photochromic materials.Based on this,it is proposed that introduce the the differentp-acidityelectron acceptors to mach with different Lewis base and study the related photochromic properties.Recently,matchedwithmethylnicotinohydrazide,carbomethoxypyridinium,benzotriazolium and pyrazinium,several photochromic iodometallates have been recently reported by our group,which exhibit simultaneous intermolecular CT and unique photo-induced intermolecular ET and show unique photochromism.It largely attributed to the introduction of moderately electron-deficient acceptors.On this basics,introducing the moderate electron-deficient organic moieties which mached with semiconductive iodoargentates possessing intrinsically structural diversity,tunable energy gaps and unique photosensitivity can modulate the electron behavior of iodoargentates from photolysis of iodoargentates to photoactive ET and consequent photochromic behavior.In this thesis,selecting pyridine and its derivatives as electron-deficient organic moieties,which mached with Poorly Lewis basic iodoargentates can successfully synthesize six iodoargentate hybrids by changing the organic components,AgI,HI,solvent,temperature and then exhibit unique photochromism and photochromic mechanism.The study found that:1?Herein,matched with medium pyridine and its derivatives,six iodoargentates hybrids[MPy][AgI₂]?1?,[MPy][Ag₂I₃]?2?,[o-MCMP][Ag₄I₅]?3?,[m-MCMP][Ag₇I₉]?4?,[m-HCMP][AgI₂]·H₂O?5?,[p-HCMP][AgI₂]·H₂O?6?,?MPy⁺=N-methylpyridinium,o-MCMP⁺=N-methyl-2-?carbomethoxy?pyridinium?,p-MCMP⁺=N-methyl-3-?carbomethoxy?pyridinium),p-HCMP⁺=N-protonated-3-?carbomethoxy?pyridinium),m-HCMP⁺=N-protonated-4-?carbomethoxy?pyridinium))exhibit different light response behavior and photochromic mechanisms.2?When pyridine is the structure directing agent to synthesize iodoargentate hybrids,photolysis of iodoargentates induced the generation of Ag particles,and then the secondary electron transfer from Ag⁰to methylpyridine cations occurred.The aggregation density of inorganic moieties are important factors for photochromism caused by photolysis.3?When pyridinederivatives are the structure directing agent to synthesize iodoargentate hybrids,photoinduced electron transfer from iodoargentates to organic cations.The electron-donating abilities of anions are main factor for ET photochromism.When the anions are the same,the charge transfer caused by strong electron-accepting abilities of aeceptors may block the photoinduced electron transfer.