4721-22-6Relevant academic research and scientific papers
Dynamics within a single molecular layer. Aggregation, relaxation, and the absence of motion
Horne,Blanchard
, p. 12788 - 12795 (1996)
We report on the transient and steady-state optical responses of the chromophore 2,2′-bithiophene-5,5′-diylbis(phosphonic acid) (BDP) incorporated within a single zirconium-phosphonate layer as a function of chromophore density. While the dilute solution optical response of BDP reveals no anomalous behavior, its characteristics are substantially different when confined within a monolayer. We vary the concentrations of layer constituents to determine the extent of interaction between BDP moieties within a single monolayer. We observe limited initial aggregation of BDP, the extent of which is determined largely by the conditions under which the monolayer is formed. Over time, the fractional contribution of BDP aggregates to the total optical response decreases to a limiting value, implicating surface adsorption site density as the dominant factor in determining the morphology of the organobis(phosphonate) layer. Motional relaxation measurements of BDP within the layer show that the chromophores are immobile on the hundreds-of-picoseconds time scale of our experiments.
The role of substrate identity in determining monolayer motional relaxation dynamics
Horne,Blanchard
, p. 6336 - 6344 (1998)
We report on the lifetime and motional dynamics of Zirconium Phosphonate (ZP) monolayers containing oligothiophene chromophores in a range of concentrations. Monolayers were formed on fused silica substrates and on a 15 ? oxide layer formed on crystalline Si(100) substrates. For both interfaces, the fluorescence lifetime behavior of the chromophores is identical and does not depend on chromophore concentration within the monolayer. Transient anisotropy measurements reveal that, for both substrates, the chromophores are oriented at ~35°with respect to the surface normal. For monolayers formed on silica, there is no evidence for chromophore motion, while motion is seen for monolayers formed on silicon. Despite the substantial similarity between the two families of monolayers, the surface roughness of the primed silicon substrate allows for greater motional freedom of the chromophores in the monolayers. We discuss these findings in the context of the differences in substrate surface roughness and domain sizes as measured by atomic force microscopy (AFM).
Rapid one-pot synthesis of alkane-α ω, diylbisphosphonic acids from dihalogenoalkanes under microwave irradiation
Villemin, Didier,Moreau, Bernard,Kaid, M'Hamed,Didi, Mohamed Amine
experimental part, p. 1583 - 1586 (2010/10/01)
A one-pot, two-step synthesis of alkylenebisphosphonic acids from dihalogenoalkanes was performed under microwave irradiation. The reaction is very rapid and convenient for the synthesis of small samples of alkylenebisphosphonic acids. Copyright Taylor & Francis Group, LLC.
Microwave michaelis-becker synthesis of diethyl phosphonates, tetraethyl diphosphonates, and their total or partial dealkylation
Meziane, Dalila,Hardouin, Julie,Elias, Abdelhamid,Guenin, Erwann,Lecouvey, Marc
experimental part, p. 369 - 377 (2010/07/16)
Diethyl phosphonates and tetraethyl alkyldiphosphonates were efficiently and rapidly prepared via the Michaelis-Becker reaction, under microwave irradiation. These compounds were then hydrolyzed to phosphonic and diphosphonic acids or selectively monodealkylated to give monoesters of phosphonic acids and symmetrical diethyl esters of diphosphonic acids. These reactions were also achieved rapidly in satisfactory yields with microwave methodology. This methodology was applied with success to the functionalization of a polymer resin.
Highly potent bisphosphonate ligands for phosphoglycerate kinase
Jakeman, David L.,Ivory, Andrew J.,Williamson, Michael P.,Blackburn, G. Michael
, p. 4439 - 4452 (2007/10/03)
We have synthesized a series of novel analogs of 1,3-bisphospho-D- glyceric acid, 1,3-BPG, and evaluated their binding to phosphoglycerate kinase, PGK (EC 2.7.2.3). Nonscissile methanephosphonic acids replace the two phosphate monoesters of 1,3-BPG and lead to several stable, tight-binding mimics of this intermediate species in glycolysis. Multiple fluorine substitution for hydrogen in the α-methylene groups of the phosphonic acid 1,3-BPG analogs markedly improves their binding to PGK as determined by NMR analysis. The best ligands bind some 50-100 times more strongly than does the substrate 3-phospho-D-glyceric acid and show a requirement for pK(a)3 to be generally below 6.0, while the presence of a β-carbonyl group seems to be of secondary importance.
