Search results for "DFT calculations"
showing 5 items of 65 documents
Structure ofD-ribonic acid-dimethyltin(IV) in coordinating solvents: an experimental and DFT119Sn NMR study
2006
We have investigated a newly synthesized complex of D-ribonic acid with dimethyltin(IV). The structure of the complex in solution has been characterized by means of 1 H, 13 C, and 119 Sn NMR and by DFT calculations. The comparison of experimental and computational results allowed the determination of the stable conformation in solution as well as the detection of a dimerization process. Moreover, evidence is given of active coordination of the metal by the solvent.
Reactions of m-Terphenyl-Stabilized Germylene and Stannylene with Water and Methanol: Oxidative Addition versus Arene Elimination and Different React…
2015
Reactions of the divalent germylene Ge(ArMe6)2 (ArMe6 = C6H3-2,6-{C6H2-2,4,6-(CH3)3}2) with water or methanol gave the Ge(IV) insertion product (ArMe6)2Ge(H)OH (1) or (ArMe6)2Ge(H)OMe (2), respectively. In contrast, its stannylene congener Sn(ArMe6)2 reacted with water or methanol to produce the Sn(II) species {ArMe6Sn(μ-OH)}2 (3) or {ArMe6Sn(μ-OMe)}2 (4), respectively, with elimination of ArMe6H. Compounds 1–4 were characterized by IR and NMR spectroscopy as well as by X-ray crystallography. Density functional theory calculations yielded mechanistic insight into the formation of (ArMe6)2Ge(H)OH and {ArMe6Sn(μ-OH)}2. The insertion of an m-terphenyl-stabilized germylene into the O–H bond was…
Synthesis, characterization, and cellular investigations of porphyrin– and chlorin–indomethacin conjugates for photodynamic therapy of cancer
2021
Indomethacin is a potent non-steroidal anti-inflammatory drug (NSAID) with a strong selective inhibitor activity towards cyclooxygenase-2 (COX-2), an enzyme that is highly overexpressed in various tumour cells, being involved in tumourigenesis. Concomitantly, porphyrins have gained much attention as promising photosensitizers (PSs) for the non-invasive photodynamic therapy (PDT) of cancer. Herein, we report the design, and determine the singlet oxygen generation capacity and in vitro cellular toxicity of porphyrin- and chlorin-indomethacin conjugates (P2-Ind and C2-Ind). Both the conjugates were obtained in high yields and were characterized by 1H, 19F and 13C NMR as well as by high resolut…
Experimental and theoretical studies on corals. I. Toward understanding the origin of color in precious red corals from Raman and IR spectroscopies a…
2010
An attempt to explain the origin of the vivid red color in precious pink and red corals was undertaken. Raman and IR spectroscopies were applied to characterize white, pink and red corals. The position of the Raman signal near 1500 cm−1 of some corals and pearls was associated by several authors with the presence of the mixture of all‐trans‐polyenic pigments, containing 6–16 conjugated CC bonds or β‐carotenoids. This hypothesis was examined theoretically by performing extensive B3LYP‐DFT calculations of vibrational spectra of the model polyenic compounds. The B3LYP/6‐311++G** predicted positions of the dominating Raman mode depend on the number of CC units (Cn parameter) and can be accura…
An experimental and theoretical study of a heptacoordinated tungsten(VI) complex of a noninnocent phenylenediamine bis(phenolate) ligand
2018
Abstract [W(N2O2)(HN2O2)] (H4N2O2 = N,N′-bis(3,5-di-tert-butyl-2-hydroxyphenyl)-1,2-phenylenediamine) with a noninnocent ligand was formed by reaction of the alkoxide precursor [W(eg)3] (eg = the 1,2-ethanediolate dianion) with two equivalents of ligand. The phenol groups on one of the ligands are completely deprotonated and the ligand coordinates in a tetradentate fashion, whereas the other ligand is tridentate with one phenol having an intact OH group. The molecular structure, magnetic measurements, EPR spectroscopy, and density functional theory calculations indicate that the complex is a stable radical with the odd electron situated on the tridentate amidophenoxide ligand. The formal ox…