Photoluminescence study of tetra-dendron dendrimers derived from ethylenediamine cores and di-dendron dendrimers derived from mono-Boc-protected ethylenediamine cores

Strong UV absorbance spectra and fluorescence spectra from tetra-dendron dendrimers derived from ethylenediamine cores with different terminal groups (-NH2, -COOCH3) or di-dendron dendrimers derived from mono-Boc-protected ethylenediamine cores were studied under different conditions by varying experimental parameters such as pH value and concentration. The result shows a rapid increase of fluorescence intensity at low pH. It was reasonable that the formation of a fluorescence-emitting moiety had a close relationship to protonated tertiary amine groups in tetra-dendron dendrimers derived from ethylenediamine cores or di-dendron dendrimers derived from mono-Boc-protected ethylenediamine cores. Furthermore, it was confirmed that the concentration of two dendrimers plays an important role in fluorescence intensity. The increase in fluorescence intensity was linear with respect to concentration at low concentration regions but the intensity increases slowly at high concentration regions.