| Supramolecular chemistry is a rising subject in the last three decades, In a variety of receptor molecules, cyclodextrins having an interior hydrophobic cavity and an exterior hydrophilic environment, can accommodate many organic, inorganic and biological molecules in their toroidal cavity to form stable host-guest inclusion complexes. Therefore, they have been paid much attention by the researchers of supramolecular chemistry. The recognition selectivity of natural cyclodextrins to the guest molecule is poor, for this reason, the molecular imprinting technique(MIT) is introduced to the study of cyclodextrins supramolecular system, and the molecular imprinted polymer (MIP) prepared by using the technique has stable physical and chemical properties and good repeatability. This technique enhances the recognition ability and selectivity of cyclodextrins for guest molecules and hence it has become a hotspot of research in the field of supramolecular field.In recent years, MIP based on cyclodextrins and their derivatives has been widely applied to design and construct chemical sensors, however, there are several shortcoming:(1)The preparation process of MIP is complicated, time-consuming and laborious, because the polymerization reaction was implemented by the crosslinking agent; (2) There are few literatures on chemical sensors that MIP are actually immobilized on the electrode; (3) The sensitivity of the imprinted sensor directly modified on the electrode needs to be improved; (4) MIP based on cyclodextrins was barely reported in the application of ECL sensor. Based on the existing defects of MIP, by introducing bipyridine ruthenium to the side arm of cyclodextrins, we synthesize a series of bipyridine(terpyridine) ruthenium cyclodextrins polymers. Based on the strong adsorption on the electrode of these polymer, we prepare molecular imprinted membrane through the process of molecular self-assembly-adsorption-elution. Due to the unique ECL characteristics of bipyridine(terpyridine) ruthenium, we construct ECL sensors based on bipyridine(terpyridine) ruthenium cyclodextrins polymers and molecular imprinting technique, furthermore, we investigate the molecular recognition efficiency and selectivity of the MIP-ECL sensor. This thesis mainly includes the following chapters:(1) With ?-cyclodextrin as a starting material, we synthesize a new monosubstituted cyclodextrin derivative by attaching 4-tolyl-2,2':6',2"-terpyridine (p-TTP) to the C6-position of cyclodextrin, and the functionalized cyclodextrin derivative react with ruthenium trichloride to produce cyclodextrin metal complex; Besides, p-TTP is modified by introducing carboxyl group and amino group to the C4-position and C4'-position respectively. Dp-TTP ruthenium complex cyclodextrins derivatives are obtained by coordination reaction with the above synthesized complexes. Lastly, the self-condensation of Dp-TTP ruthenium complex cyclodextrins derivative produce multimer T6. In order to investigate the influence of hydroxy groups on molecular recognition, permethylated cyclodextrin derivative multimer T3 is synthesised with a similar method. To investigate the influence of the degree of polymerization on the polymer properties, monomeric complex T4, dimeric complex T5 and Ru (p-TTP) 2Cl2 complex are synthesized successfully, permethylated cyclodextrins analogue T1 and T2 are prepared.1H and 13C NMR together with MALDI-TOF MS analysis are employed to confirm the constructure of these compounds.(2) With (3-cyclodextrin as a starting material, the hydroxy groups of C6-position and C4-position are protected with t-butyldimethylsilyl (TBS) and acetyl respectively, then TBS is deproteced, and a disubstituted cyclodextrin derivatives is obtained by Mitsunobu reaction by attaching p-aniline to the C6-position of cyclodextrin. Bipyridine functionalized cyclodextrin has been prepared from the disubstituted cyclodextrin and 2,2'-bipyridine by acylation and the resulting compound reacts with Ru (bpy)2Cl2 to give monomer complex D1. Finally, by self-condensation between carboxyl and amine group from the beginning and end of D1 produce multimer D2.1H and 13C NMR and MALDI-TOF MS analysis are employed to confirm the constructure of these compounds.(3) we study the UV absorbance, fluorescence, ECL and adsorption properties. The research results demonstrated that tris-(2,2'-bipyridyl)ruthenium cyclodextrins supramolecular exhibits most highly strong fluorescence and ECL intensity among all the compounds, besides that, Dp-TTP, with weaker fluorescence and ECL itself, however, these luminescence property has been enhanced after modified with the ligand. During the research of adsorption stability of these supramoleculars on glassy carbon electrode, we found that polymer T3, T6 and D2 demonstrated stronger adsorption ability and stability than mononuclear and dimer complex. Furthermore, from AFM result of these compounds we found that they show a staggered mesh structure, and MALDI-TOF MS confirmed that their polymerization degree are all more than 6, thus both the results are the reason mat they have a good adsorption stability. These research will provide theoretical and experiment basis for the construction of ECL sensor based on molecular imprinting.(4)In this chapter, we investigate the molecular recognition characteristic of bipyridine-ruthenium cyclodextrins on guest molecule Dab on ECL, and research results show polymer T6 exhibit greater quenching in the presence of Dab, but polymer T3 show weakest quenching, herein, this kind of phenomenon can be deduced that the molecular recognition ability on guest molecule of polymer as ECL sensor becomes weaker with the increase of hydroxyl from cyclodextrins. Based on the adsorption stability on glassy carbon electrode of these complexes, we select polymer T3, T6 and D2 as the host molecules and BH as template molecule to prepare the glassy carbon electrode with molecularly imprinted membrane and construct MIP-ECL sensor in three steps molecular self-assembly, adsorption and elution. We investigate the molecular recognition of MIP_ECL sensor on BH and EST, and the result show the sensor based. |
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