Static and Dynamic Bimolecular Fluorescence Quenching of Porphyrin Dendrimers in Solution

Abstract

The fluorescence quenching kinetics of two porphyrin dendrimer series (GnTPPH(2) and GnPZn) by different type of quenchers is reported. The microenvironment surrounding the core in GnPZn was probing by core-quencher interactions using benzimidazole. The dependence of quencher binding constant (K ( a )) on generation indicates the presence of a weak interaction between branches and the core of the porphyrin dendrimer. The similar free volume in dendrimers of third and fourth generation suggests that structural collapse in high generations occurs by packing of the dendrimer peripheral layer. Dynamic fluorescence quenching of the porphyrin core by 1,3-dicyanomethylene-2-methyl-2-pentyl-indan (PDCMI) in GnTPPH(2) is a distance dependent electron transfer process with an exponential attenuation factor beta = 0.33 A(-1). The quenching by 1,2-dibromobenzene occurs by diffusion process of the quencher toward to the porphyrin core, and its rate constant is practically independent of dendrimer generation.

Effect of N‐Butyl‐N‐Methyl‐Morpholinium Bromide Ionic Liquid on the Conformation Stability of Human Serum Albumin

“…Fluorescence quenching mechanism was investigated to check the possible interactions of [Mor1,4][Br] with HSA to form a complex. The decrease in the fluorescence intensity of fluorophore occurs due to a variety of molecular interactions apart from the ground state complex formation and collisional quenching which are excited state reactions, energy transfer and rearrangement of molecules . The fluorescence quenching is classified as static and dynamic quenching.…”

“…The decrease in the fluorescence intensity of fluorophore occurs due to a variety of molecular interactions apart from the ground state complex formation and collisional quenching which are excited state reactions, energy transfer and rearrangement of molecules. [52][53][54][55] The fluorescence quenching is classified as static and dynamic quenching. The later one is strongly due to the collision between the fluorophore and the quencher, while the former one results from ground state complex formation between fluorophore and quencher.…”

Interaction of a green ester-bonded gemini surfactant with xanthine oxidase: Biophysical perspective

“…It is to note over here, that shoulder peak is not intense due to devoid of exact excitation wavelength (280 nm) encompassing mainly tyrosine residues. Moreover, quenching effect observed over here may also be assigned to the variety of molecular interactions viz., excited state reactions, energy transfer, molecular rearrangements, ground state complex formation or collision quenching [55,56]. Furthermore, the process of quenching was confirmed by employing the following Stern-Volmer equation:…”

Synthetic Aspects of Porphyrin Dendrimers

“…For this purpose, three generations of dendronswere alternatively attached to the A 4 ‐porphyrin core 7a [5,10,15,20‐tetrakis(4‐hydroxyphenyl)porphyrin, Figure 1]. 10a The fluorescence quenching kinetics of this dendrimer series with different types of quenchers were studied more recently 10b…”