Syntheses And Applications Of Functionalized Rhodamine Derivatives

Rhodamine dyes and their derivatives enjoy widespread use as tracer agents and biological probes for their good photophysical properties. As a important parameter, pH in living cells affects many functions of metabolism. Therefore, the detection of pH value in living cells is meaningful. To the best of our knowledge, the widely used rhodamine pH detectors are all based on rhodamine B and rhodamine6G. Several substantial problems are inevitable for these probes, for example, poor water solubility. And, also, there is barely any report about rhodamine probes on detection of certain object in organelles. Beside, regioisomer is a troublesome problem for rhodamine derivatives with carboxyl group, and will limit its application in biology.1. In this thesis,5pH probes A2-A6based on rhodamine were designed and synthesized. The photophysical properties of them were studies and fluorescence quantum yield change against pH was also conducted. These5pH probes all showed clear response to pH, and their maximum quantum yields were0.32(A2),0.88(A3),0.87(A4),0.67(A5),0.64(A6). pKa values of these probe were8.80(A2),7.94(A3),5.40(A4),5.91(A5),5.76(A6). A2-A6showed different cells penetrating ability by conducting confocal imaging experiment. All of them can penetrate living cells within different incubating time. A5and A6afford better ability, and cost only5min to stain lysosomes in living cells. Fluorescence lifetime change against pH experiments proved that fluorescence lifetime of A5and A6afford sensitive response to pH and won’t be affected by protein in living cells.2.5-and6-carboxyl substituted regioisomers were synthesized and designed to be separated by chemical method. The method was pdtimized to follow the route as bilow. First, synthesize and separating of4-and5-carboxyl substituted intermidate with two bromides on the conjugate plain by recrystallization. Then, two of the regioisomers were synthesized by Pd-catalyzed cross-coupling reaction of the intermidates with interesting N-alkyls, respectively.