多刺激响应材料在光、热、压力和溶剂等外部刺激下，能发生可逆的裸眼或者发光的颜色变化，由于其在光学开关、传感器、存储、显示器和防伪等方面存在的潜在应用而引起了人们的关注。其中，紫精配合物可以在外界刺激下（如紫外光、X-射线、热、有机胺和电）展现出肉眼可见的颜色变化，是潜在的多功能材料。紫精配合物一般呈现三种可逆的氧化还原状态：二价阳离子状态(MV²⁺)、自由基阳离子(MV^•+)和中性(MV⁰)。当紫精化合物受到外界刺激时，电子会从适当的供体转移到受体，产生游离基，并伴随着颜色的变化。探究其电子转移过程和开发新型多功能刺激响应材料一直是一个巨大的挑战。基于此，本文的主要研究内容如下：

（1）基于紫精配体Hcbbpy与过渡金属（锌和镉）配合物的合成及多刺激响应性质

选取1-(3-羧基苄基)-4,4'-联吡啶氯化物 (Hcbbpy)为配体，与过渡金属(Cd和Zn)成功构筑了三例配合物。其中配合物1可呈现十种状态和七种颜色，表现出多种热致变色和光致变色行为。根据他们的晶体结构，明确给出了详细的电子供体和电子转移的途径。在外部刺激下的多种颜色的改变可能归功于电子转移的多种途径。配合物2在粉碎后会发生单晶到单晶的转变，变成2G。2和2G均呈现两步光致变色的行为，详细研究了2和2G两步变色的原因及其电子转移的途径。配合物3对紫外光和X-射线都表现出快速的光致变色行为，并且可以沉积在滤纸上，在无墨印刷材料方面具有潜在的应用价值。

（2）基于紫精配体和辅助配体及Zn(II)/Cd(II)配合物的合成及多刺激响应性质

以 Hcbbpy和Hcbbpd作为主要配体，以均苯三甲酸、邻苯二甲酸、间苯二甲酸和对苯二甲酸为辅助配体，和金属Zn(II)/Cd(II)合成了一系列配合物。配合物4和5对X-射线和紫外光显示为双光致变色行为。并且配合物4表现出热致变色性质。此外，配合物4和5在固体状态下显示出荧光和室温磷光现象。同时基于配合物4和5的光致变色、荧光和室温磷光现象，成功设计了多重加密和防伪功能。配合物6在各种外部刺激下，如紫外线(365 nm)、X-射线、热、电和乙胺，都表现出变色行为。配合物6的晶体也显示出荧光和室温磷光双重发射。此外，通过对配位聚合物6进行后合成修饰，首次制备了Eu(III)功能化的杂化体，即Eu³⁺@Zn-MOF。Eu³⁺@Zn-MOF的样品继承了配合物6的光致变色特性，并给出了铕离子的特征荧光。基于6和Eu³⁺@Zn-MOF的多色切换，成功开发了它们在无墨可擦除打印、电致变色信息标签、信息加密和防伪等领域潜在的应用。配合物7和8在紫外线和X-射线下都显示出高对比度的可逆光致变色特性。其中，7表现出对紫外光的超快响应，响应时间只有0.5 s，有趣的是，首次发现用盐酸蒸汽可以快速脱色，而且用NH₃蒸汽熏蒸后可以实现可逆循环。配合物9的晶体具有室温磷光，发出0.5 s的绿色余辉，在低温(77K)下呈现出8秒的动态余辉。配合物10的荧光具有激发波长依赖性，此外，在室温(297K)有0.5s的黄色余辉，在低温(77K)下呈现出8秒的青色余辉。而配合物11在低温(77K)下显示出7s的绿色余辉。研究了配合物10在无墨打印和信息传输、防伪方面潜在的应用。此外利用配合物9-11特殊的磷光性能，成功研制了动态防伪图案，为日后的防伪提供了新的策略。

 （3）基于紫精配体H₂bybpy配合物的合成及其刺激响应性质

首次发现了配体N,N'-双(2-羧基乙基)-4,4′-吡啶二氯化物(H₂bybpy)在77K下具有光致变色和动态余辉现象。并与氯化镉、硝酸铕和硝酸铽成功设计合成了三个配合物。配合物12同时具有光致变色、室温磷光和电致变色性能。有趣的是，配合物12在阴离子溶液中可以发生单晶到单晶的转变，在10分钟内，配位的Cl^-可以和I^-和SCN^-离子发生交换，颜色分别由无色变为深黄色(12-I^-)和黄色(12-SCN^-)。配合物12具有光致变色现象，而12-I^-和12-SCN^-却没有。此外，配合物12被成功地制成试纸，用于快速检测I^-和SCN^-，它也显示出作为无墨打印、多重加密和防伪材料的潜在应用。配合物13和14在紫外光下表现出可逆的光致变色性质。此外，配合物13在不同的pH溶液中表现出良好的稳定性，并且能够可视化检测诺氟沙星（NORF）和环丙沙星（CIP），检测限分别为7.90×10^-7和9.48×10^-7 M。此外，配合物13由于其良好的光学性质和出色的荧光特性被进一步开发为可擦除无墨打印和检测NORF和CIP的双重功能试纸材料。

Multi-stimulus responsive materials, which can undergo reversible color changes in response to external stimuli such as light, heat, pressure and solvents, have attracted attention due to their potential applications in optical switching, sensors and storage, displays, anti-counterfeiting, etc. Among them, viologen complexes can exhibit color changes visible to the naked eye in response to external stimuli (e.g., UV light, X-ray, heat, organic amines, and electricity) and are potentially versatile materials. Viologen complexes generally exhibit three reversible redox states: divalent cation state (MV²⁺)、free radical cation(MV^•+) and neutral (MV⁰). When viologen complexes are subjected to external stimuli, electrons are transferred from the appropriate donor to the acceptor, accompanied by color changes during electron transfer. It has been a great challenge to reasonably investigate its electron transfer process and develop new multifunctional stimulating materials. Based on this, the main research of this paper is as follows.

(1) Syntheses and multi-stimulus response properties of complexes based on the viologen-ligand Hcbbpy with transition metals (Zn(II) and Cd(II))

Three complexes were successfully constructed using 1-(3-carboxy)-4,4'-bipyridinium chloride (Hcbbpy) ligand with transition metals (Cd(II) and Zn(II)). Complex 1 exhibits seven colors and ten states, exhibiting a variety of thermochromic and photochromic behaviors. According to their crystal structures, detailed electron donors and electron transfer pathways are clearly given. The multiple color changes in response to external stimuli may be attributed to multiple pathways of electron transfer. Complex 2 undergoes a single- crystal- to- single- crystal transition to 2G after crushing. 2 and 2G present a two-step photochromic phenomenon. The reasons for the two-step color change of 2 and 2G and their electron transfer pathways are investigated in detail. Complex 3 exhibits dual photochromic behavior upon UV light and X-ray, which is due to the formation of free radicals. It can be deposited on filter paper to show potential applications as inkless printing materials.

 (2) Syntheses and multi-stimuli response properties of Zn (II)/Cd (II) complexes based on viologen ligand Hcbbpy and auxiliary ligands

A series of Zn (II)/Cd (II) complexes were synthesized with 1-( 3-carboxy ) -4,4 ' -bipyridine chloride ligand and(4-carboxy) -4,4′ -bipyridine chloride ligand, trimesic acid, phthalic acid and terephthalic acid ligands. Complexes 4 and 5 show dual photochromic behavior for X-ray and UV light. Complex 4 also exhibits thermochromic properties. In addition, Complexes 4 and 5 exhibit fluorescence and room temperature phosphorescence (RTP) in solid state. Based on the photochromism, fluorescence and RTP of complexes 4 and 5, a variety of encryption and anti-counterfeiting functions have been successfully designed. Complex 6 exhibits discoloration behavior under various external stimuli, such as UV 365 nm, X-ray, heat, electricity and amine induced discoloration. The crystal of complex 6 also shows fluorescence and RTP. In addition, Eu (III) -functionalized hybrids, namely Eu³⁺@ Zn-MOF, were synthesized and modified for the first time based on coordination polymerization. The sample of Eu³⁺@ Zn-MOF inherits the photochromic properties of complex 6 and gives the unique fluorescence of europium ions. Based on the multi-color switching of 6 and Eu³⁺@Zn-MOF, their potential applications in the fields of inkless, erasable printing, electrochromic information labeling, information encryption and anti-counterfeiting have been successfully developed. Complexes 7 and 8 show reversible photochromic properties with high contrast under UV and X-ray. 7 exhibits an ultrafast reaction to UV light and the light reaction time is only 0.5 s. Importantly, the colored product is quickly decolorized with hydrochloric acid vapor for the first time and the cycle can be achieved after fumigation with NH₃ vapor. Complexes 9-11 are sensitive to UV light and exhibit reversible photochromic properties. The crystal of complex 9 exhibits RTP at room temperature, emitting green afterglow of 0.5 s and dynamic afterglow of 8 s at low temperature (77K). The fluorescence of complex 10 is excitation wavelength dependent. In addition, complex 10 has a yellow afterglow of 0.5s at room temperature (297K) and a cyan afterglow of 8s at low temperature (77K), while complex 11 shows a green afterglow of 7 s at low temperature (77K). The potential applications of complex 10 in inkless printing, information transmission and anti-counterfeiting were studied. In addition, the application of dynamic anti-counterfeiting was successfully developed by using the special phosphorescence properties of complexes 9-11 which provided a new strategy for future anti-counterfeiting.

 (3) Syntheses and stimuli-response properties of complexes based on viologen ligand H₂bybpy

The photochromic and dynamic afterglow properties of the ligand N, N ' -bis (2-carboxyl )-4,4'-pyridine dichloride at 77 K were found for the first time. Three complexes were successfully designed and synthesized with cadmium chloride, europium nitrate and terbium nitrate. Complex 12 exhibits photochromic, RTP and electrochromic properties. Interestingly, Complex 12 can undergo a single crystal to single crystal transition in an anionic solution. The coordinated Cl^- can be converted to I^- and SCN^- ions within 10 minutes, and the color changes from colorless to dark yellow (12-I^-) and yellow (12-SCN^-), respectively. Complex 12 exhibits photochromism, while 12-I^- and 12-SCN^- did not. The difference in photochromic behavior between the two complexes is mainly due to the different electron transfer pathways between the carboxyl group and the viologen. In addition, complex 12 was successfully made into test strips for rapid detection of I^- and SCN^-, which also showed potential applications as inkless printing, multiple encryption and anti-counterfeiting materials. Complexes 13 and 14 exhibit reversible photochromism under UV light. In addition, complex 13 shows good stability in different pH solutions, and it can visually detect NORF and CIP with detection limits of 7.90×10^-7 and 9.48×10^-7 M, respectively. In addition, complex 13 was further developed as a dual-functional test paper material for erasable inkless printing and detection of NORF and CIP due to its good optical properties and excellent fluorescence properties.