A novel fluorescent sensor for Cr3+ based on rhodamine-cored poly (amidoamine) dendrimer

A novel poly (amidoamine) (PAMAM) dendrimer, comprising rhodamine B unit in the core and 1-phenyl-3-methyl-5-pyrazolone unit at the periphery, has been synthesized and characterized. The dendrimer shows dramatic increase in its fluorescence intensity in the presence of proton and metal cations, especially in the presence of Cr3+. The complex formed by dendrimer and Cr3+ in ethanol solution has also been studied, considering the potential application for Cr3+ fluorescent sensor. The influence of the unique chemical structure and resulted photoinduced electron transfer, as well as spirolactam ring-opening on the photophysical properties of the product has been investigated.

Figure optionsDownload as PowerPoint slideHighlights
► Synthesis of a novel PAMAM simultaneously containing rhodamine and pyrazolone.
► Ring-opening and PET processes codetermine photophysical properties of dendrimer.
► Novel dendrimer shows high selectivity and sensitivity towards Cr3+.
► The formation of a dendrimer G3/Cr3+ complex of 1:10 stoichiometry is evidenced.