| Viologen-based chromic materials have been widely studied due to their chromic propertiesof multi-stimulusresponse.However,these materials still have certain disadvantages,such as poor optical contrast,low response rate,free radical stability and reversible cycle stability.In contrast,extended viologen derivatives can be utilized asexcellent electron acceptors to construct novel chromic materials withthe rigid structure,the large conjugation,the high stability and reversibility and so on.The design and synthesis novel materials with properties of multi-stimulusresponse based onextended viologen derivatives are still at the primary stage.In this paper,thirteen functional materials with novel structurehave been synthesized which contain donor–acceptor(D–A)system.The properties of photochromism,hydrochromicand the ability to detect amineshave been further explored.This paper is mainly divided into the following sections:1.The research background,chromic mechanisms and research progress of chromic materials have been mainly introduces in this paper.2.Two functional ligands have been obtained by alkylating of4'-(3-pyridine)-4,2':6',4"-terpyridine with4-methylbenzoic and 3-methylbenzoic.Eight hybridcomplexes have been obtained with novel structures and excellent performance.Isostructuralcomplexes Zn2Cl4(4-pbatripy)2·(DMF)·(H2O)4(1)and Zn2Br4(4-pbatripy)2·(DMF)·(H2O)4(2)possesses 1D zigzag chainformed by Zn2+and4-pbatripy.Intriguingly,1 and 2 havedifferent performance onphotosensitivity and photochromism.The sensitively response to UV light of 1 have been proved.Isostructural Cd Cl2(4-pbatripy)·(H2O)2(3)and Cd Br2(4-pbatripy)·(H2O)2(4)contain similardimers,constructed by four Cd2+ions,two ligands and four terminal coordinated X-anion(Cl-for 3,Br-for 4),which are furtherassembled into3D supramolecular frameworks through hydrogen-bond weak interactions.Although the structures of two complexes are similar,3 exhibits more excellent photosensitivity,which may due to the shorter distance between Cl-and N+.Complex Tb3(COO)4(4-pbatripy)3·(H2O)4(5)contains a[Tb3O22C8]second building unit(SBU),which constructs a 3D network structure with 4-pbatripy ligands.Moreover,the adjacent aromatic carboxylaterings in one layer are close to to each other along the a direction,and the nearest centroid to centroid distance is 21.7899(2)?.Cd3Cl6(4-mbatripy)2(6)form a1D zigzag chainthat constructed by Cd2+and4-mbatripy;Cd2Br4(4-mbatripy)2(7)Contains two coordinated Cd2+,which bridged by a?2–Br andthen the organic moiety 4-mbatripyligands prop upthe neighboring structural units,giving rise to the 2D framework.Different from the above complexes Mn Cl3(4-mbatripy)·(DMF)(8)Constructs a 2D network structure through O-H…Cl hydrogen bonding and has no color-changing behavior simultaneously.3.Two functional ligands have been obtained by alkylating of4'-(4-pyridine)-4,2':6',4"-terpyridine with3-methylbenzoic.Three nolve complexes have beensynthesized by reacting with transition metal.Interestingly,the complex Zn3Cl6(4-mtpptbpy)2·(H2O)6(9)exhibits a 7-foldpseudo interpenetrated structure,and can be reallyresponsive to visible light,such as violet,blue,and green.Attractively,complex 9 can be selectivelysensitiveto soft X-rays(Cu-K?).For the complex Zn3Br2Cl4(4-mtpptbpy)·8H2O(10),it only responds to UV light.The structure ofcomplex Mn3Cl6(4-mtpptbpy)2·(H2O)2(11)contains a trinuclear[Mn3(CO2)6Cl4]structural unit.Six bidentate carboxyl groups as well as four chlorides connect adjacent Mn(II)ions to form a trinuclear[Mn3(CO2)6Cl4]secondary building unit,and each 4-mtpptbpy ligand connects with three trinuclear[Mn3(CO2)6Cl4]units.As a result,the overall structure can be regarded as 2Dframework.The adjacent layers are assembled into a 3D supramolecular network through C–H···Cl hydrogen bonds.Complex 11 exhibits rarehydrochromicwhich can specificity respond to soft X-rays(Al-K?)and selectively respond to amine vapors.4.Twoisostructuralcompounds that based on 4'-(4-pyridine)-2,2':6',2"-terpyridine have been synthesized.Both of them possesses1D zigzag chainformed by adjacent structural unit through hydrogen bonds.Moreover,they have high sensitivity to detect solvents and metal ionsespeciallytrace metal ions in different solvents.In particular,they can selectively sense Zn Cl2in solid phase with high sensitivity,goodrecyclability,and environment friendly5.Summarize my work and look forward to the research prospects of this topic. |
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