Determined by spectroscopic methods

Ebook "Challenges in molecular structure determination" provide a practice-oriented and systematic introduction to both organic and inorganic structure determination by spectroscopic methods. This includes mass spectrometry, vibrational spectroscopies, UV/VIS spectroscopy and NMR as well as applying combinations of these methods. The authors show how to elucidate chemical structures with a minimal number of spectroscopic techniques. Readers can train their skills by more than 400 problems with varying degree of sophistication.

500p coduathanh1122 27-03-2024 7 1   Download

Results of this investigation have been correlated with the films structural and optical properties. Among the structural properties, surface roughness and morphology, and crystalline quality of the films have been obtained by using the XRD and AFM methods. Additionally, optical properties such as band gap tune-ability and dielectric constant have been determined by spectroscopic ellipsometer.

7p viberbers 09-08-2023 4 3   Download

The new complexes (1–3) were characterized by elemental analysis and spectroscopic methods and the molecular structure of 1a was determined by X-ray diffraction studies. These complexes were applied in the Suzuki–Miyaura cross-coupling reaction of phenylboronic acid with aryl halides in neat water. The activities of catalysts were monitored by gas chromatography–flame ionization detector and nuclear magnetic resonance.

10p langthannam 29-12-2021 12 0   Download

Novel benzimidazolium bromides salts having (4-methoxyphenyl)ethyl, (phthalimide-2-yl)methyl, 4-nitrobenzyl, 2-phenylethyl, penthyl, or allyl groups were synthesized and their characterizations were conducted by 1 H and 13 C NMR and IR spectroscopic methods, and microanalysis. In vitro antitumor activities of the novel benzimidazole compounds (1–7) were determined by using ovarian (A2780) and prostate (PC-3) cancer cell lines. Antitumor properties of all compounds were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay.

22p langthannam 29-12-2021 3 0   Download

In the current study, four new phenolic oxime ligands (HL1ox–HL4ox) containing diazo groups (-N=N-) were synthesized and used for liquid-liquid extraction of heavy metal ions [Cu(II), Ni(II), and Zn(II)]. The new compounds were characterized by analytical and spectroscopic methods. Solid-state structures of HL1ox–HL3ox were determined by single-crystal X-ray diffraction studies. Hirshfeld surface analysis of the compounds was performed to determine the contribution of different intermolecular contacts to the stability of the structures.

16p tudichquannguyet 29-11-2021 2 1   Download

The complexes of peripherally tetra-substituted metal-free (8), lead(II) (9), and zinc(II) (10) phthalocyanine derivatives were synthesized for the first time in this work. The structures of these new complex compounds have been elucidated using many spectral methods such as electronic absorption, FT-IR, 1H NMR, 13C NMR, elemental analysis, and mass spectra. The thermogravimetric behavior of compounds 8–10 was determined by thermogravimetric analysis method in addition to these spectral methods.

10p tudichquannguyet 29-11-2021 6 0   Download

Thes tructures of the crystalline compounds were characterized via their spectral analyses. General information about the structures of the newly obtained Hofmann-type clathrates was obtained from their vibration spectra by considering significant changes in the vibration peaks of the cyanide group, water ligand molecule, and guest molecules (water and 1,4-dioxane). The thermal behavior of the Hofmann-type clathrates was investigated in the range of 25–500°C.

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The binding constant and possible stoichiometric ratio (1:1) values were determined by Benesi-Hildebrand and Job’s plot systems, respectively. The mechanism of the probe MCPC with Cu2+ was further confirmed by ESI-MS and FT-IR analyses, as well as supported by theoretical calculations. Furthermore, the probe MCPC was successfully employed for the practical applications to sense Cu2+ in different herbal and black tea samples. The proposed sensing method was also verified by ICP-OES method.

25p tudichquannguyet 29-11-2021 7 1   Download

The 4-(2-[3,4-dimethoxyphenoxy] phenoxy) phthalonitrile was synthesized as the starting material of new syntheses. Zinc, copper, and cobalt phthalocyanines were achieved by reaction of starting compound with Zn(CH3 COO)2 , CuCl2 , and CoCl2 metal salts. Basic spectroscopic methods such as nuclear magnetic resonance electronic absorption, mass and infrared spectrometry were used in the structural characterization of the compounds. Absorption, excitation, and emission measurements of the fluorescence zinc phthalocyanine compound were also investigated in THF.

23p tudichquannguyet 29-11-2021 13 1   Download

A pentaammineazidocobalt(III) complex, [Co(NH3)5N3](MnO4)2XH2O has been synthesized by an one-pot synthesis method. It was characterized by studies such as infrared (IR) and UV-visible spectroscopy. The single crystal X-ray structure analysis revealed that the title complex crystallizes in space group Cc. The cobalt center is six coordinated with slightly octahedral geometry. The supramolecular architecture is also formed by intermolecular N-H…O (anion and H2O) and Mn-O…O-H hydrogen bonds.

14p tudichquannguyet 29-11-2021 7 1   Download

From the roots of Eurycoma longifolia, seven compounds including β-carboline-2N-oxide-1-propionic acid (1), 9,10-dimethoxycanthin-6-one (2), β-carboline-1-propionic acid (3), infractine (4), eurylene (5), eurycomanone (6), 14,15-β-hydroxyklaineanol (7) were isolated. Their structures were determined by means of spectroscopic methods (UV, IR, HR-ESIMS, 1D and 2D NMR). Compound (1) has been isolated for the first time from nature and compound (4) has been isolated for the first time from Eurycoma longifolia.

6p cothumenhmong11 06-05-2021 6 1   Download

Study on the chemical constituents of methanol extract from leaves of Moringa oleifera Lam. (Moringaceae) has resulted in the isolation of four compounds: Vitexin, isoquercitrin, tricosanol and tetradecanoic acid. Their structures were determined by spectroscopic methods.

5p tamynhan9 02-12-2020 24 2   Download

Investigation on the chemical constituents of ethyl acetate extract from leaves of Taxus wallichiana Zucc. (Taxaceae), collected in Ha Giang province, has resulted in the isolation of three metabolites for the first time: sciadopitysin (1), β-sitosterol (2), and isoquercitrin (3). Their structures were determined by spectroscopic methods.

6p koxih_kothogmih5 04-09-2020 24 1   Download

Investigation on the chemical constituents of methanol extract from roots of Morinda officinalis How. (Rubiaceae) has resulted in the isolation of three anthraquinones: anthragallol 2-methyl ether (1), physcion (2), and emodin (3). Their structures were determined by spectroscopic methods. All three compounds were isolated from Vietnamese Morinda officinalis for the first time.

6p nguathienthan6 06-07-2020 14 0   Download

In this study, phytochemical investigation of the n-hexane and ethyl acetate extract of leaves and twigs of Urena lobata L. led to the isolation of β-sitosterol (1), β-sitosterol3-O-β-D-glucopyranoside (2), 2-acetylamino-3-phenylpropyl 2-benzoylamino-3-phenylpropanoate (3), quercetin (4), and trans-tiliroside (5). Their chemical structures were determined by spectroscopic methods, including MS, 1D-, 2D- NMR, and by comparing their spectral data with those reported in previous papers. Compounds 3 and 5 were isolated for the first time from Urena lobata L.

8p abcxyz123_02 03-03-2020 14 2   Download

Bridelia micrantha commonly known as coastal golden leaf is a member of the family Phyllanthaceae. In preliminary studies, nine fractions, named F1- F9, were obtained by fractionating the crude methanol extract of the stem bark of Bridelia micrantha using column chromatographic techniques. The F6 fraction was found to be the most active when tested for the antibacterial activity. This study is thus aimed at investigating the effect of fractionation on antibacterial activity of F6 fraction.

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Ratio subtraction and isosbestic point methods are two innovative spectrophotometric methods for determining the concentrations of metronidazole (I) and diloxanide furoate (II) in a mixture. Metronidazole was determined by direct spectrophotometric method at kmax 314.0 nm in the presence of diloxanide furoate in the range of 4–24 lg ml1 with a mean recovery percentage of 99.83 ± 1.41. Two spectrophotometric methods were developed for the spectral resolution of diloxanide furoate when present in mixture with metronidazole without preliminary separation.

7p kethamoi1 20-11-2019 25 2   Download

Taraxeryl acetate (1), physcion (2), 1-nonacosanol (3), β-sitosterol (4), quercetin (5), βsitosterol 3-O-β-D-glucopyranoside (6), and quercitrin (7) were isolated from the leaves of Alnus nepalensis D. Don. (Betulaceae). Their structures were determined by spectroscopic methods.

6p chikychiky 11-11-2018 27 0   Download

The reactions between benzimidazole, imidazole, or 1,2,4-triazole with either benzyl chloride or isopropyl bromide yielded 6 azolium salts, namely 1,3-dibenzylimidazolium chloride (M1), 1,3-dibenzylbenzimidazolium chloride (M2), 1,3-dibenzyl-1,2,4-triazolium chloride (M3), 1,3-diisopropylimidazolium bromide (M4), 1,3- diisopropylbenzimidazolium bromide (M5), and 1,3-diisopropyl-1,2,4-triazolium bromide (M6). These salts can be further used as the starting compounds for the synthesis of complexes based on N-heterocyclic carbenes for various applications.

6p giesumanh 10-11-2018 31 0   Download

Two biflavones, podocarpusflavone A (1) and amentoflavone (2) and two megastigmane glycosides, byzantionoside B (3) and (6S,9R)-roseoside (4) were isolated from the methanol extract of the leaves of Antidesma bunius. Their structures were determined by spectroscopic methods and in comparison with the published data.

5p lamtan3547 04-11-2018 35 0   Download