Polyamido amine dendrimers functionalized with poly(phenylenevinylene) dendrons at their periphery

Abstract

A series of polyamido amine (PAMAM) dendrimers (Generations 2, 3, 4, and 6) fully functionalized at their periphery with first‐ and second‐generation poly (phenylenevinylene) (PPV) dendrons have been efficiently prepared. MALDI‐TOF mass spectrometry proved to be particularly useful for the characterization of the new hybrid dendrimers as well as for the estimation of the average number of PPV dendrons attached to the surface. The optical absorption and emission properties of these systems were studied. The materials display extremely high molar extinction coefficients and emit blue light with only slightly lower fluorescence quantum yields than the corresponding free dendrons. Self‐quenching interactions between PPV units were not observed in THF. However, the luminescence properties underwent a dramatic change when toluene was used as the solvent. The lower polarity of toluene caused shrinkage of the PAMAM structure and brought the PPV chromophores closer together, leading to self‐quenching interactions and excimer formation. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6409–6419, 2009

Functionalized CdSe/ZnS Quantum Dots for Intracellular pH Measurements by Fluorescence Lifetime Imaging Microscopy

“…In addition, the peripheral branches seem to adopt a more extended (or open) configuration when they are fully negatively charged. This so-called “open configuration” could also contribute to the fluorescence enhancement observed at high pH by providing a more hydrophobic microenvironment around the QD and protection against quenching by solvent molecules, ions, dissolved gases, or other impurities. , …”

“…This so-called "open configuration" could also contribute to the fluorescence enhancement observed at high pH by providing a more hydrophobic microenvironment around the QD and protection against quenching by solvent molecules, ions, dissolved gases, or other impurities. 26,61 Calibration of pH-Sensitive Probes in an Intracellular-Mimicking Medium. In addition to pH, the fluorescence of a QD can be affected by different physiological factors such as the ionic strength, the presence of biological macromolecules, and the viscosity of the medium, among others.…”

PAMAM dendrimers functionalized with ruthenium nitrosyl as nitric oxide carriers

“…According to the discussed above, using the e values for k = 232 and 275 nm for trans-[Ru(NO)(NH 3 ) 4 (ina)](BF 4 ) 3 , would be possible to estimate the number of the PAMAM amines functionalized with the ruthenium nitrosyl complex [30,56]. Thus, assuming that the e values for the G0 functionalized with four trans-[Ru(NO)(NH 3 ) 4 (-ina)](BF 4 ) 3 , would be in principle approximately four times of that observed for the free complex [30], the number of functionalized amines was estimated and these results are shown in Table 6S (Supplementary material).…”

Aggregation-Induced Emission Properties in Fully π-Conjugated Polymers, Dendrimers, and Oligomers

“…In addition, this globular structure creates holes or interstices that can also be used as hosts to encapsulate molecules or metallic nanoparticles [ 83 ]. The development and study of dendrimers with fluorescent properties began almost from the first time that these types of structures were discovered [ 84 , 85 , 86 , 87 ], and it is possible to find examples in which dendrimers have been used to increase the fluorescent properties of chromophores [ 88 , 89 ]. However, a few fully conjugated dendrimeric structures have been studied with the aim of evaluating whether they show effects of increased solid-state fluorescence or aggregation by themselves, and basically consists in the incorporation of luminogens in the dendritic backbone during the synthetic procedure.…”