Synthesis and characterization of fluorescent poly(aromatic amide) dendrimers

Aulenta, F., Drew, M.G.B., Foster, A., Hayes, W. ORCID: https://orcid.org/0000-0003-0047-2991, Rannard, S., Thornthwaite, D.W., Worrall, D.R. and Youngs, T.G.A. (2005) Synthesis and characterization of fluorescent poly(aromatic amide) dendrimers. Journal of Organic Chemistry, 70 (1). pp. 63-78. ISSN 0022-3263 doi: 10.1021/jo048799a

Abstract/Summary

The synthesis of a series of poly(aromatic amide) dendrimers up to the second generation is described herein. The AB, building block used throughout the synthesis of the dendrimers was the allyl ester of 3,5-diaminocinnamic acid, which has been synthesized from 3,5-dinitrobenzoic acid in good yield with use of a four-step procedure. Dendron synthesis was achieved via a convergent approach with use of a sequence of deprotection/coupling steps. Two commercially available alcohols, L-menthol and citronellol, were coupled to the AB(2) monomer by using an alkyl diacid spacer and two core units; 1,7-diaminoheptane and tris(2-aminoethyl)amine have been used to produce the final dendrimers. Characterization was carried out by NMR and IR spectroscopies, MALDI-TOF mass spectrometry, GPC, and DSC. The novel monomer and dendritic derivatives exhibited a strong fluorescence emission in the visible region (lambda approximate to 500 nm) of the spectrum and a weak emission in the near-infrared (lambda approximate to 850 nm) upon excitation in the near-UV region. The fluorescence emission characteristics were found to be solvent and dendrimer generation dependent.