目前，刺激响应发光材料因在存储、防伪、传感和生物成像等领域的应用潜力而受到广泛研究。与被广泛报道的单刺激响应发光材料相比，具有多色转换和可逆响应行为的多刺激响应发光材料功能更加丰富，应用前景更加广阔。因此，开发具有多刺激响应性质的金属配合物，并且深入研究其响应机理意义重大。基于此，本文选择含有丰富羧基配位点的紫精衍生物H₂bcbpy·2Cl和含有丰富N、O配位点的吡啶酰腙化合物（H₂L¹和H₂L²）两类含氮杂环配体，设计合成其配合物，并且探究其多刺激响应性质及机理。主要研究内容如下：

1、以紫精衍生物H₂bcbpy·2Cl为主要配体，以间苯二甲酸（IPA）和对苯二甲酸（PTA）为辅助配体，与Zn(II)和Cd(II)设计合成了过渡金属配合物{[Zn(bcbpy)_0.5(IPA)]⋅CH₃CN}_n (1)和{[Cd(bcbpy)_0.5(PTA)(H₂O)]⋅0.5(C₂H₇N)}_n (2)，配合物1和2表现出对紫外线和X射线双重光致变色的性质，光照后晶体均由无色变为蓝色。实验表明，光致变色的机理是由于光诱导电子转移形成自由基。将1在230 ℃的空气中加热30分钟得到{[Zn(bcbpy)_0.5(IPA)]}_n (1T)。由于电子转移路径C–H···O氢键的距离变长，1T的光致变色灵敏度不如1。配合物1和2表现出光控荧光和温度依赖磷光的性质。随着紫外光照射时间的持续增加，1和2的发光强度逐渐减弱。从液氮中移除后，在365 nm的紫外灯照射后，1和2分别会发出7 s和6 s的青色余辉。当温度由77 K到297 K逐渐升高，磷光寿命逐渐降低，1的磷光发射由青色变为黄色。鉴于配合物1和2具有快速的光响应特性和高稳定性，可将其开发成为无墨可擦除打印材料。该工作为基于紫精配体的多功能材料的开发提供新的思路。

2、基于吡啶酰腙化合物H₂L¹和H₂L²，与Eu(III)离子分别设计合成了铕-酰腙配合物[Eu₂L¹₂(phen)₂(NO₃)₂] (Eu-1)和[Eu₂L²₂(CH₃OH)₂(NO₃)₂] (Eu-2)，Eu-1和Eu-2是很少被报道的具有力致发光变色（MCL）性质的镧系配合物材料。Eu-1和Eu-2表现出高对比度的MCL，这归因于研磨导致的晶态向非晶态的相转变。添加抗生素环丙沙星（CIP）或诺氟沙星（NOR）后，Eu-1和Eu-2的溶液表现出显著的荧光增强现象，发射表现为Eu³⁺离子特征发射的红色。检出限结果表明，Eu-1和Eu-2对人体尿液中的CIP和NOR具有良好的传感性能。这种感应机制是由于CIP或NOR加入后，原有的配合物结构被破坏，CIP和NOR分别与Eu³⁺形成了新的配合物，从而发光产生变化。两例探针的高灵敏度和强抗干扰能力使它们在检测人体尿液中CIP和NOR方面有很大的应用前景。在此基础上，Eu-1和Eu-2已成功研制为用于检测CIP和NOR的荧光试纸。该工作为Eu(III)基多刺激响应材料的构建和开发提供了新的策略。

At present, stimulus-responsive luminescent materials are extensively studied for their promising applications in storage, anti-counterfeiting, sensing and bio-imaging. Compared with the widely reported single-stimulus-responsive luminescent materials, multi-stimuli-responsive luminescent materials with multi-color transition and reversible response behaviors are more functional and have broader application prospects. Consequently, it is of great significance to develop metal complexes with multi-stimuli responsive properties and to study their response mechanisms in depth. In this paper, two types of nitrogen-containing heterocyclic ligands, namely, H₂bcbpy·2Cl, a viologen derivative containing abundant carboxyl coordination sites, and pyridinylhydrazone compounds (H₂L¹ and H₂L²) containing abundant N and O coordination sites, were designed and synthesized to investigate their multi-stimuli responsive properties and mechanisms. The main research contents are as follows:

1. Transition metal complexes {[Zn(bcbpy)_0.5(IPA)]⋅CH₃CN}_n (1) and {[Cd(bcbpy)_0.5(PTA)(H₂O)]⋅0.5(C₂H₇N)}_n (2) were designed and synthesized from Zn(II) and Cd(II) using the viologen derivative H₂bcbpy·2Cl as the primary ligand and isophthalic acid (IPA) and terephthalic acid (PTA) as the secondary ligands. Complexes 1 and 2 exhibit dual photochromic properties when exposed to UV and X-rays. The crystals both changed from colorless to blue after illumination. It was shown that the mechanism of photochromism is due to the formation of free radicals by photo-induced electron transfer. Heating 1 in air at 230 °C for 30 min gave {[Zn(bcbpy)_0.5(IPA)]}_n (1T). The photochromic sensitivity of 1T is not so good as that of 1 due to the longer distance of the electron transfer pathway C–H···O. Complexes 1 and 2 exhibit photocontrolled fluorescence and temperature-dependent phosphorescence. The luminescence intensity of 1 and 2 gradually decreased with the continuous increase of light exposure time. After removal from liquid nitrogen, 1 and 2 emit a cyan afterglow for 7 s and 6 s, respectively, upon irradiation with a 365 nm UV lamp. When the temperature gradually increases from 77 K to 297 K, the phosphorescence lifetime gradually decreases and the emission color of 1 changes from cyan to yellow. In view of the fast photoresponsive properties and high stability of the complexes 1 and 2, they can be developed as inkless erasable printing materials. This work provides a novel idea for the development of multifunctional materials based on viologen ligands.

2. Europium-acylhydrazone complexes [Eu₂L¹₂(phen)₂(NO₃)₂] (Eu-1) and [Eu₂L²₂(CH₃OH)₂(NO₃)₂] (Eu-2) were designed and synthesized based on the pyridine acylhydrazone compounds, H₂L¹ and H₂L², and Eu(III) ions respectively. Eu-1 and Eu-2 are seldomly reported lanthanide-containing materials with mechanochromic luminescence (MCL) properties. Eu-1 and Eu-2 exhibit MCL with high contrast, which is attributed to the phase transition from crystalline to amorphous state due to grinding. Upon addition of the antibiotics ciprofloxacin (CIP) or norfloxacin (NOR), solutions of Eu-1 and Eu-2 exhibited significant fluorescence enhancement with the characteristic red emission of Eu³⁺. The detection limit results indicated that Eu-1 and Eu-2 have good sensing performance for CIP and NOR in human urine. This sensing mechanism is due to the disruption of the original complex structure upon the addition of CIP or NOR, and the formation of new complexes of Eu³⁺ with CIP or NOR, respectively, resulting in changes of luminescence. The high sensitivity and strong anti-interference ability of the two examples of probes make them promising for the detection of CIP and NOR in human urine. On this basis, Eu-1 and Eu-2 have been successfully developed as fluorescent test strips for the detection of CIP and NOR. This work provides a new strategy for the construction and development of Eu(III)-based multi-stimuli responsive materials.