Synthesis And Application Of A Fluorescent[2]Rotaxane And Chemsensors Based On A Rhodamine B Unite

Rhodamine B and its derivatives are often used as dye tracers within water to determine the rate and direction of flow and transport. Due to their excellent spectroscopic properties, Rhodamine B dyes are used extensively to derivatize biomolecules and as fluorescent chemosensors for metal ions.Rotaxanes are a class of supermolecular compounds that have many promising applications. Previous researchers have demonstrated that a specific class of host [2]rotaxane can bind fluoresceinated peptides with high association constants and deliver them into cells, while the location of rotaxanes in cells have never been determined. Here in the first chapter of this dissertation, we discussed the design and synthesis of a novel class of host [2]rotaxane, which consists of a DB24C8as a wheel, a Rhodamine B unit and a2,2-diphenylethanamine as the two bulky terminal stoppers, and a sec-ammonium salt as the axle that links two stoppers.The designed [2]rotaxane was synthesized by a total eight syntheticsteps. As a fluorescent rhodamine B unite was introduced, we considered that Rhodamine B [2]rotaxane could also deliver materials into cells, and its cellular location and metabolization may be monitored via a fluorescent microscopy.The second chapter of this dissertation is about the design and synthesis of a novel fluorescent chemsensorfor Cr3+based on a Rhodamine B-azacrown ether conjugate and its applications in cells. The experimental results clearly indicated that sensor1was a highly sensitive and selective chemosensor for Cr3+in a methanol/H2O (3:2, v/v, pH7.2) solution, and can been used to detect Cr3+in the same solution.. The binding constant of sensor with Cr3+was1.03×104M-1,and the detection limit of sensor1for Cr3+was calculated to be7.5ppb (0.144μM). Comparison between sensor1and sensor2indicated that the macrocyclic structure of1played a key role in its excellent chemosensing property, which provides a new avenue for designing cation chemsensors. In addition, cell imaging studies of human L-02hepatocytes show that sensor1was further demonstrated to be a potential probe for detecting Cr3+in living cells.The last part of this dissertation is about the design and synthesis of some potential u opioid receptor (MOR) agonists based on a4-phenylpiperidine unit from reported MOR agonists. By exploring optimized synthetic methods, the designed compounds were synthezed in ahigh yieldwith convenient procedures and mild reaction conditions. It could pave the way for potential applications in the future biological studies.