Dansyl moiety attached to the core of Newkome-type dendrimers shows a bathochromic shift of the fluorescence emission spectrum with increase in dendrimer generation. However the ET(30) plots in different solvents show a decrease in slope with increasing generation. This has been explained in terms of modification of transition energies and progressive shielding of the fluorophore with increasing generation. © 2006 Elsevier Ltd. All rights reserved.

Sundarababu Baskaran

Department Of Chemistry

Ashok Kumar Mishra

Subhendu K. Mohanty

Emission spectroscopy

Fluorescence

Shielding

Solvents

Spectrum Analysis

Bathochromic shift

Fluorophores

NEWKOME-TYPE DENDRIMERS

TRANSITION ENERGIES

Dendrimers

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

European Polymer Journal

Photophysical studies of four generations of polyglycerol dendrons with isopropylidene end groups and dansyl moiety as a fluorophore attached at the focal point were carried out. All the four generations showed similar behaviour in their absorption transitions but the emission maximum for all generations of dendrons showed strong dependence on the solvent polarity. The solvatochromic shift of emission maximum showed linearity in the Lippert-Mataga plot, indicating the dominant importance of general solvent effect in all generations of dendrons. Photophysical parameters such as fluorescence quantum yield, fluorescence lifetime and radiative decay rate constant showed solvent polarity dependence. The detailed photophysical study reveals that due to the increased influence of the repeating dendron units of the higher order dendrons on the dansyl microenvironment, it becomes less and less influenced by the solvent. © 2010 Elsevier B.V. All right reserved.

Journal of Photochemistry and Photobiology A: Chemistry

Photophysical investigation of microenvironment in glycerol based dansylated polyether dendrons

Protected Newkome-type second-generation dendrimers (based on Lin's amine) were synthesized with a pyrene moiety attached to the core. The photophysical property in aqueous solution of the protected dendrimers shows self-association behavior in water. Pyrene excimer emission at 475 nm is observed in water even at very low concentrations of protected dendrimer (ca. 5 × 10-8 M). This emission band is absent in other solvents even up to a concentration of 10-5 M. The corresponding unprotected dendrimer does not show the pyrene excimer fluorescence. The amide of pyrene butyric acid with tert-butylamine shows the formation of excimer, albeit with very low intensity. Quenching studies on the dendrimer with hydrophilic quencher iodide anion (I-) reveal that there is significant quenching of fluorescence intensity in the case of N-tert-butyl-4-pyren-1-ylbutyramide as compared to that of the pyrene-attached second-generation protected dendrimer. This shows that the pyrene moiety in the case of the protected dendrimer is significantly shielded from the surrounding.

Macromolecules

Self-association of protected Newkome-type second-generation dendrimers at nanomolar level concentrations in aqueous solution

Journal of the American Chemical Society

Fluorescence and Aggregation Behavior of Poly(amidoamine) Dendrimers Peripherally Modified with Aromatic Chromophores: the Effect of Dendritic Architectures

Chem. Commun.

Generation and pH dependent superquenching of poly(amido) carboxylate dendrons hosting a single “focal point” pyrene

Comptes Rendus Chimie

Towards dendrimers as biomimetic macromolecules

Helvetica Chimica Acta

Spatially Resolved Derivatization of Solid-Phase-Synthesis Beads with Fluorescent Dendrimers: Creation of Localized Microdomains

Bathochromic shift of the fluorescence spectral maximum with increasing generation of dansyl labeled Newkome type dendrimers

Journal	European Polymer Journal
ISSN	00143057
Open Access	No