71850-73-2Relevant academic research and scientific papers
Alkali ion exchanged nafion as a confining medium for photochemical reactions
Arumugam, Selvanathan,Kaanumalle, Lakshmi S.,Ramamurthy
, p. 139 - 145 (2008/02/04)
Methanol-swollen Nafion beads were used as microreactors to control the photochemical reaction pathways. Product selectivity in three unimolecular reactions, namely, the photo-Fries rearrangement of naphthyl esters, Norrish Type I reaction of 1-phenyl-3-p-tolyl-propan-2-one and Norrish Type I and Type II reactions of benzoin alkyl ethers were examined. The influence of cations over the photodimerization of acenaphthylene and cross-photodimerization between acenaphthylene and N-benzyl maleimide included within Nafion were also examined. The photochemical behaviors of the above substrates were significantly altered within Nafion compared with their solution photochemistry. Of particular interest, the product distributions were found to depend on the counter cations of Nafion.
Dendrimers as photochemical reaction media. Photochemical behavior of unimolecular and bimolecular reactions in water-soluble dendrimers
Kaanumalle, Lakshmi S.,Ramesh,Maddipatla, V. S. N. Murthy,Nithyanandhan, Jayaraj,Jayaraman, Narayanaswamy,Ramamurthy
, p. 5062 - 5069 (2007/10/03)
Synthesis and studies of poly(alkyl aryl ether) dendrimers, possessing carboxylic acid functionalities at their peripheries, are reported. 5-Bromopentyloxy methylisophthalate was utilized as the monomer to 0-alkylate the phenolic hydroxyl groups of poly(alkyl aryl ether) dendrimers. Dendrimers of first, second, and third generations, possessing 6, 12, and 24 carboxylic acids, respectively, were thus prepared. These dendrimers were soluble in alkaline aqueous solutions, and the ensuing microenvironmental properties of the aqueous solutions were assessed by pyrene solubilization studies. Upon establishing the presence of nonpolar microenvironments within the dendritic structures, solubilizations of few organic substrates were conducted and their photochemical behaviors were assessed. Specifically, the photolysis of 1-phenyl-3-p-tolyl-propan-2-one and benzoin ethyl ether and photodimerization of acenaphthylene were conducted. These studies revealed that the product distribution and the "cage effect" were more distinct and efficient for the third generation dendrimer, than for the first and second generation dendrimers. The photochemical studies of carboxylic acid functionalized dendrimers were compared to that of hydroxyl group terminated poly(alkyl aryl ether) dendrimers.
Amphiphilic homopolymer as a reaction medium in water: Product selectivity within polymeric nanopockets
Arumugam, Selvanathan,Vutukuri, Dharma Rao,Thayumanavan,Ramamurthy
, p. 13200 - 13206 (2007/10/03)
A styrene-based water-soluble polymer has been explored for its use as a host for lipophilic substrates in aqueous medium. Unimolecular reactions, namely, photo-Fries rearrangement of naphthyl esters, α-cleavage reaction of 1-phenyl-3-p-tolyl-propan-2-one, and Norrish type I and type II reactions of benzoin alkyl ethers were examined. We find that the hydrophobic domains generated by the polymer not only restrict the mobility of the radicals but also modestly incarcerate the substrate, intermediates, and products during the time scale of the reactions. Comparative studies of the same photoreactions in micelles formed from small molecule surfactants and an amphiphilic diblock copolymer demonstrate that the styrene-based water-soluble polymer aggregates in aqueous medium offer better selectivity.
Norrish Type I and Type II Reactions of Ketones as Photochemical Probes of the Interior of Zeolites
Ramamurthy, V.,Corbin, D. R.,Eaton, D. F.
, p. 5269 - 5278 (2007/10/02)
The Norrish type I and type II reactions of alkylbenzoin ethers, alkyldeoxybenzoins and α-alkyldibenzyl ketones included within the microporous structures of zeolites X and Y have been investigated.Product distributions varied significantly from that observed in benzene.In addition, it differed between various alkali-metal cation-exchanged samples.These variations are interpreted to result from the restriction offered by the zeolite micropores on the motions of the adsorbed organic molecule.Although this study is restricted to ketones, the knowledge gained is expected to be of general value.
