115 documents found, page 1 of 12

4-hydroxyquinolin-2(1H)-one isolated in cryogenic argon and xenon matrices: tau...

4-Hydroxyquinolin-2(1H)-one (4HQ2O) was synthesized, isolated in cryogenic matrices (argon and xenon), and studied by infrared spectroscopy. Quantum chemical calculations carried out at the DFT(B3LYP)/6-311++G (3df,3pd) level of theory were used to determine the conformational and tautomeric properties of the molecule. Two tautomeric forms were identified in the as-deposited matrices with the help of the theore...

Exploring saccharinate-tetrazoles as selective Cu(II) ligands: structure, magne...

The role of copper in the proliferation of cancer cells is under investigation and has been explored in the context of cancer chemotherapy. The evidence that proliferation of cancer cells requires a higher abundance of Cu(II) than their normal counterparts has prompted the development of new copper chelators that can avidly bind copper ions, forming redox active metal complexes that ultimately lead to harmful r...

Photochemistry of 1-and 2-Methyl-5-aminotetrazoles: structural effects on react...

The influence of the position of the methyl substituent in 1- and 2-methyl-substituted 5-aminotetrazoles on the photochemistry of these molecules is evaluated. The two compounds were isolated in an argon matrix (15 K) and the matrix was subjected to in situ narrowband UV excitation at different wavelengths, which induce selectively photochemical transformations of different species (reactants and initially form...

Genesis of rare molecules using light-induced reactions of Matrix-Isolated Tetr...

Tetrazoles exhibit a very rich photochemistry, strongly influenced by the nature of substituents in the tetrazolic ring. Photolysis of representative tetrazoles trapped in a rigid environment of solidified noble gases at cryogenic temperatures (usually argon at 10–15 K) results in photofragmentation of the monomeric species with a wide range of exit channels. Since the obtained fragments are generally confined ...

Effect of cholesterol-poly(N,N-dimethylaminoethyl methacrylate) on the properti...

The development of new polymer-liposome complexes (PLCs) as delivery systems is the key issue of this work. Three main areas are dealt with: polymer synthesis/characterization, liposome formulation/characterization and evaluation of the PLCs uptake by eukaryotic cells. Poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA) with low molecular weight and narrow polydispersity was synthesized by Atom Transfer Radical...

The thermal sigmatropic isomerization of pseudosaccharyl crotyl ether

The thermal sigmatropic isomerization of pseudosaccharyl crotyl ether

The thermally induced sigmatropic isomerization of the pseudosaccharyl crotyl ether, 3-(E)-but-2-enoxy)-1,2-benzisothiazole 1,1-dioxide (CBID), has been investigated by using temperature dependent infrared spectroscopy, differential scanning calorimetry (DSC), and polarized light thermomicroscopy. The reaction can take place in both melted and crystalline phases, affording the product resulting from the [3,30] ...

Amino-Imino Tautomerization upon in Vacuo Sublimation of 2-Methyltetrazole-Sacc...

The amino−imino tautomerization of the nitrogen-linked conjugate 2-methyltetrazole-saccharinate (2MTS) was observed upon sublimation of the compound in vacuo. As shown previously by X-ray diffraction [Ismael, A.; Paixão, J. A.; Fausto, R.; Cristiano, M. L. S. J. Mol. Struct., 2011, 1023, 128−142], in the crystalline phase the compound exists in an amino-bridged tautomeric form. Infrared spectroscopic investiga...

Photoisomerization of saccharin

Most known applications of saccharin and saccharyl derivatives and their potential for new uses rely on the thermal and photochemical stability of the saccharyl system. Here, we show that saccharin undergoes structural rearrangement when subjected to a narrow-band ultraviolet irradiation. Monomeric saccharin was isolated in low-temperature argon matrices and its photochemistry was characterized by means of infr...

Molecular structure of nitrogen-linked methyltetrazole-saccharinates

The molecular structures of nitrogen-linked 1- and 2-methyltetrazole-saccharinates, were investigated in the crystalline phase using X-ray crystallography and infrared and Raman spectroscopies, complemented by quantum chemical calculations performed at the DFT(B3LYP)/6-31++G(d,p) level of theory for the isolated molecules. In the neat crystalline solid (space group P 1, a = 6.9763 Å, b = 8.3097 Å, c = 10.0737 Å...