Synthesis, spectral characteristics and sensor ability of new polyamidoamine dendrimers, modified with curcumin

To prepare a novel highly photo-stable fluorescent chemosensor, curcumin was successfully immobilized to polyamidoamine dendrimer of zero (S1), first (S2) and second (S3) generations conjugated-UV absorber moieties. Chemical structure of synthesized chemosensors were well-analysed by FTIR, ¹H-NMR, ¹³CNMR, elemental analysis, DSC and UV-vis techniques. Photo-physical characteristics and solvatochromism effect of three novel chemosensors in organic solvents with different dielectric constants ranged 2.21-37.78 were studied. The pH determination ability of S1, S2 and S3 in the range of 2-12 were also examined. Newly synthesized materials were employed for detection of different metal cations including Ag⁺, Ba²⁺, Cu²⁺, Ca²⁺, Cd²⁺, Fe³⁺, Hg²⁺, Ni²⁺, Pb²⁺ and Zn²⁺ and their possibility to apply as a cation chemosensor were evaluated. The results showed significant changes in their fluorescence intensity upon the different pHs and cations indicating their possibility to apply as a pH and metal cation chemosensor. Among the new chemosensors under study, S1 represented high sensitivity to pH in the range of 4-8 and high selectivity for Cu²⁺ over the other cations.