Cr–ZnO nanostructured thin film coating on borosilicate glass by cost effective sol–gel dip coating method

Cr-doped ZnO (0.6 molarity) nanosized particles are synthesized by sol–gel dip coating method on borosilicate glass tube. The structural and optical characterization of the particles has been investigated by TEM, SEM, UV–Vis and FTIR spectroscopy. TEM reveals that the Cr-doped ZnO occurs in uniform surface growth along with spherical in shape having size ∼3 nm. The SEM image shows the growth of nanostructured cluster (average size 75 nm) with large surface area. The UV–Vis spectrum of nanoparticles suggests the use of such nanostructured coating for better solar energy harvesting. FT-IR results show the structural and optical correlation of nanoparticles. This observation excludes the presence of any other Cr or ZnO concerned impurity. The present investigation, deals with potential applications toward the motivation for using nanostructured materials in solar energy conversion. Keywords: Sol–gel, Nanoparticles, TE

Structure-Activity Relationship of 4(5)-Aryl-2-amino-1H-imidazoles, N1-Substituted 2-Aminoimidazoles and Imidazo[1,2-a]pyrimidinium Salts as Inhibitors of Biofilm Formation by Salmonella Typhimurium and Pseudomonas aeruginosa

A library of 112 4(5)-aryl-2-amino-1H-imidazoles, 4,5-diphenyl-2-amino-1H-imidazoles, and N1-substituted 4(5)-phenyl-2-aminoimidazoles was synthesized and tested for the antagonistic effect against biofilm formation by Salmonella Typhimurium and Pseudomonas aeruginosa. The substitution pattern of the 4(5)phenyl group and the nature of the N1-substituent were found to have a major effect on the biofilm inhibitory activity. The most active compounds of this series were shown to inhibit the biofilm formation at low micromolar concentrations. Furthermore, the influence of 6 imidazo[1,2-a]pyrimidines and 18 imidazo[1,2-a]pyrimidinium salts on the biofilm formation was tested. These compounds are the chemical precursors of the 2-aminoimidazoles in our synthesis pathway. A good correlation was found between the activity of the imidazo[1,2-a]pyrimidinium salts and their corresponding 2-aminoimidazoles, supporting the hypothesis that the imidazo[1,2-a]pyrimidinium salts are possibly cleaved by cellular nucleophiles to form the active 2-aminoimidazoles. However, the imidazo[1,2-a]pyrimidines did not show any biofilm inhibitory activity, indicating that these molecules are not susceptible to in situ degradation to 2-aminoimidazoles. Finally, we demonstrated the lack of biofilm inhibitory activity of an array of 37 2N-substituted 2-aminopyrimidines, which are the chemical precursors of the imidazo[1,2-a]pyrimidinium salts in our synthesis pathway.status: publishe

Structure-activity relationship of 2-hydroxy-2-aryl-2,3-dihydro-imidazo[1,2-a]pyrimidinium salts and 2N-substituted 4(5)-aryl-2-amino-1H-imidazoles as inhibitors of biofilm formation by Salmonella Typhimurium and Pseudomonas aeruginosa

A library of 80 1-substituted 2-hydroxy-2-aryl-2,3-dihydro-imidazo[1,2-a]pyrimidinium salts and 54 2N-substituted 4(5)-aryl-2-amino-1H-imidazoles was synthesized and tested for the antagonistic effect against biofilm formation by Salmonella Typhimurium and Pseudomonas aeruginosa. The nature of the substituent at the 1-position of the salts was found to have a major effect on their biofilm inhibitory activity. Salts with an intermediate length n-alkyl or cyclo-alkyl chain (C7-C10) substituted at the 1-position in general prevented the biofilm formation of both species at low micromolar concentrations, while salts with a shorter n-alkyl or cyclo-alkyl chain (C1-C5) or longer n-alkyl chain (C11-C14) were much less potent. Salts with a long cyclo-alkyl chain however were found to be strong biofilm inhibitors. Furthermore, we demonstrated the biofilm inhibitory potential of salts with certain aromatic substituents at the 1-position, such as piperonyl or 3-methoxyphenetyl. The activity of the 2-aminomidazoles was found to be dependent on the nature of the 2N-substituent. Compounds with a n-butyl, iso-butyl, n-pentyl, cyclopentyl or n-hexyl chain at the 2N-position have an improved activity as compared to their unsubstituted counterparts, whereas compounds with shorter 2N-alkyl chains do have a reduced activity and compounds with longer 2N-alkyl chains do have an effect that is dependent on the nature of the substitution pattern of the 4(5)-phenyl ring. Finally, we demonstrated that introduction of a 3-methoxyphenethyl or piperonyl group at the 2N-position of the imidazoles could also result in an enhanced biofilm inhibition. (C) 2011 Elsevier Ltd. All rights reserved.status: publishe