Photophysical behavior of oligoethylene glycols labeled with naphthalene carboxylate and phosphate esters

Abstract

SAM LEE and MITCHELL A. WINNIK. Can. J. Chem. 72, 1587 (1994).The fluorescence spectra of tri-and tetraethylene glycol esterified with 2-(1-naphthy1)ethyl ethyl phosphate and 241-naphthy1)ethyl 2-(ethoxy)ethyl phosphate were studied in dilute solutions of tetrahydrofuran (THF) and diethyl ether. They were con~pared with the fluorescence from tri-and tetraethylene glycol esterified with I-naphthyl acetic acid. These compounds form intramolecular excimers. The extent of excimer formation is not extensive, but the relative amount of excimer emission from these compounds varies with the choice of solvent. Three synthetic intermediates to the phosphates, the 2-(1-naphthy1)ethyl ~,~-diiso~ro~~l~hos~horamidites of tri-and tetraethylene glycol and of 2-ethoxyethanol, were also examined. These compounds fonn intramolecular exciplexes. In THF, the relative amount of exciplex emission from the phosphoramidites follows the same trend as the carboxylate esters. In diethyl ether, the trend is different. Rates of fluorescence decay have been measured for these compounds. The results are discussed in terms of how inforn~ation about the conformational and dynamic behavior of these molecules in solution can be obtained, and how the solvent can influence the relative amounts of excimer or exciplex fluorescence.

Synthesis of Symmetric Fluorescently Labeled Poly(ethylene glycols) Using Phosphoramidites of Pyrenebutanol and Their Characterization by MALDI Mass Spectrometry

“…This is shown in Scheme . The two proposed strategies are equally effective. , However, each reaction affords different impurities from hydrolysis (if the chromophore-containing reactant is moisture-sensitive) and incomplete coupling of the starting materials which may adversely affect the subsequent fluorescence experiments if they are not removed completely. The fluorescent impurities from Scheme A would include the doubly labeled “polymer B” and “polymer B” labeled with the fluorescent probe at both of its ends, with one end chain attached.…”

“…Recently, we reported the synthesis of oligomers of oxyethylene glycol labeled with naphthalene probes in the chain interior. 6 Here, in the first part of this paper, we describe the extension of our strategy to the synthesis of polymers which are functionalized at two specific sites, separated by "y" monomers, and symmetrically positioned within the chain. An important challenge in the synthesis of these compounds was obtaining convincing characterization data.…”

Biosynthesis of 3-Amino-5-hydroxybenzoic Acid, the Precursor of mC7N Units in Ansamycin Antibiotics

“…3-Amino-5-hydroxybenzoic acid (AHBA) was shown to be a specific and proximate precursor of the mC 7 N unit both by feeding experiments with labeled AHBA and by complementation experiments with blocked mutants 12a,− and ansamitocins and into mitomycins (cf. Scheme ) 12b.…”

Luminescent Pyrene-Decorated Organotin Compounds: Observation of Monomer and Excimer Emission

“…Also, at the same time new applications of such compounds are being continuously discovered, − and recently, much attention has also been focused on their luminescent properties. Accordingly, pyrene-appended fluorescent chromophores have attracted considerable interest − because of the fact that the pyrene group possesses a high quantum yield and can form excimers even at relatively low concentrations. − Unlike other excimer-forming fluorophores such as naphthalene, , absorption and fluorescence spectra of pyrene do not overlap and reduce the FRET formation or energy migration. In addition, the applications of the excimeric species have a strong correlation with physical state and environment. , Therefore, triggering new molecules with different chromophoric environments is important. ,, Several examples of pyrene-containing organic dendrimers are reported in the literature, but pyrene units decorated on inorganic platforms have been less explored. ,, …”

“…Accordingly, pyrene-appended fluorescent chromophores have attracted considerable interest 19−24 because of the fact that the pyrene group possesses a high quantum yield and can form excimers even at relatively low concentrations. 25−27 Unlike other excimer-forming fluorophores such as naphthalene, 28,29 absorption and fluorescence spectra of pyrene do not overlap and reduce the FRET formation or energy migration. In addition, the applications of the excimeric species have a strong correlation with physical state and environment.…”