Photoinduced triplet-state electron transfer of platinum porphyrin: a one-step direct method for sensing iodide with an unprecedented detection limit

Abstract

Herein, we report for the first time the photoinduced triplet-state electron transfer of Pt(ii)TMPyP as an easy, rapid, environmentally friendly, ultra-sensitive and economical method for the determination of iodide in the aqueous phase.

Optical Detection of Bromide Ions Using Pt(II)-5,10,15,20-Tetra-(4-methoxy-phenyl)-porphyrin

“…The basicity of the bromide ion is higher than the basicity of the iodide ion, so this is the main factor enabling the recognition of bromide. During the performed experiments, the shape of the UV-vis spectra did not change the position of the bands, confirming that the interaction with bromide ions occurs with Pt at the porphyrin macrocycle center ( Figure 6) [32]. In the previous reported studies concerning the use of the same Pt-metalloporphyrin for iodide/bromide [20] or triiodide ion detection [23], the mechanism of detection was different, because in the first case the Pt-metalloporphyrin was incorporated into a PVC membrane and used as a potentiometric sensor, and in the second case it was part of a hybrid material with AuNPs.…”

“…The basicity of the bromide ion is higher than the basicity of the iodide ion, so this is the main factor enabling the recognition of bromide. During the performed experiments, the shape of the UV-vis spectra did not change the position of the bands, confirming that the interaction with bromide ions occurs with Pt at the porphyrin macrocycle center ( Figure 6) [32].…”

Fluorescence quenching of 8-methyl quinolinium: An efficient halide indicator mechanism

“…Apparently, the excited state charge transfer complex that is formed during the quenching of quinolinium indicators by anions is probably de-excited to the ground state by a non-radiative pathway since no exciplex emission is observed in the presence of the quenchers. It can be noted that quenching of fluorescence through photoinduced electron transfer (PET) transfer process has been suggested for similar systems [12][13][14]27,40,41].…”

“…The determination/ recognition of halides in the environment is important both for monitoring excessive halide levels as well as halide deficiencies in natural resources [19][20][21]. Fluorescence quenching processes allow quantitative determination of halides [15,[22][23][24][25][26][27]. The determination of halide using fluorescence quenching is a popular technique because of the high sensitivity that it can offer and the simplicity of quenching mechanism.…”

Recent Advances in Luminescent Recognition and Chemosensing of Iodide in Water

“…These two sensing approaches include 1) Cation displacement assays where transition-metal-complexes of Hg 2 + , Ag + and Cu + 2 , with a modest emission, irreversibly react with I À ions to form its corresponding salts (MI n ) along with release a luminescent ligand. This displacement reaction is an indirect measure of binding and generates a fluorescence "Turn-on" response ( Figure 1 Among these strategies two approaches that are specifically good for I À include (a) the use of luminescent complexes of Hg 2 + and Pt 2 + due to the strong affinity of the anion for these metals [46][47][48]59] and (b) chemosensors based on organic receptors containing ionic H-bond donors [66][67][68][69][70] of the kind (CÀ H) + or halogen donors (CÀ I) [80][81][83][84] in combination with hydrophobic moieties because these fragments can generate a binding site with a low degree of hydration which favors the formation of the supramolecular complex. The lower hydration enthalpy of I À can also make it easier the binding with the organic receptor compared to oxoanions and lighter halides which are better hydrogen bond acceptors but with higher hydration energies ( Table 1).…”