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Editorial: From “Cosmic Cooking” to Chemistry of the Future: A Collective Dialogue on Chemistry as a Tribute to Prof. Sourav Pal. Front Chem 2022; 10:908165. [PMID: 35572113 PMCID: PMC9099370 DOI: 10.3389/fchem.2022.908165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 03/31/2022] [Indexed: 11/29/2022] Open
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Edible Insects and Other Chitin-Bearing Foods in Ethnic Peru: Accessibility, Nutritional Acceptance, and Food-Security Implications. J ETHNOBIOL 2018. [DOI: 10.2993/0278-0771-38.3.424] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Structure of Framework Aluminum Lewis Sites and Perturbed Aluminum Atoms in Zeolites as Determined by27Al{1H} REDOR (3Q) MAS NMR Spectroscopy and DFT/Molecular Mechanics. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201409635] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Structure of framework aluminum Lewis sites and perturbed aluminum atoms in zeolites as determined by 27Al{1H} REDOR (3Q) MAS NMR spectroscopy and DFT/molecular mechanics. Angew Chem Int Ed Engl 2014; 54:541-5. [PMID: 25393612 DOI: 10.1002/anie.201409635] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Indexed: 11/07/2022]
Abstract
Zeolites are highly important heterogeneous catalysts. Besides Brønsted SiOHAl acid sites, also framework AlFR Lewis acid sites are often found in their H-forms. The formation of AlFR Lewis sites in zeolites is a key issue regarding their selectivity in acid-catalyzed reactions. The local structures of AlFR Lewis sites in dehydrated zeolites and their precursors--"perturbed" AlFR atoms in hydrated zeolites--were studied by high-resolution MAS NMR and FTIR spectroscopy and DFT/MM calculations. Perturbed framework Al atoms correspond to (SiO)3AlOH groups and are characterized by a broad (27)Al NMR resonance (δi = 59-62 ppm, CQ = 5 MHz, and η = 0.3-0.4) with a shoulder at 40 ppm in the (27)Al MAS NMR spectrum. Dehydroxylation of (SiO)3AlOH occurs at mild temperatures and leads to the formation of AlFR Lewis sites tricoordinated to the zeolite framework. Al atoms of these (SiO)3Al Lewis sites exhibit an extremely broad (27)Al NMR resonance (δi ≈ 67 ppm, CQ ≈ 20 MHz, and η ≈ 0.1).
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Bismuth A3-Corroles: Useful Precursors for the Development of meso-Substituted Free-Base Corroles. SYNTHESIS-STUTTGART 2014. [DOI: 10.1055/s-0034-1379012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Chain-end-functionalized polyphosphazenes via a one-pot phosphine-mediated living polymerization. Macromol Rapid Commun 2014; 35:1135-41. [PMID: 24700544 PMCID: PMC4115175 DOI: 10.1002/marc.201400114] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 03/17/2014] [Indexed: 11/09/2022]
Abstract
A simple polymerization of trichlorophosphoranimine (Cl3 P = N-SiMe3 ) mediated by functionalized triphenylphosphines is presented. In situ initiator formation and the subsequent polymerization progress are investigated by (31) P NMR spectroscopy, demonstrating a living cationic polymerization mechanism. The polymer chain lengths and molecular weights of the resulting substituted poly(organo)phosphazenes are further studied by (1) H NMR spectroscopy and size exclusion chromatography. This strategy facilitates the preparation of polyphosphazenes with controlled molecular weights and specific functional groups at the α-chain end. Such well-defined, mono-end-functionalized polymers have great potential use in bioconjugation, surface modification, and as building blocks for complex macromolecular constructs.
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Millipedes as food for humans: their nutritional and possible antimalarial value-a first report. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE : ECAM 2014; 2014:651768. [PMID: 24688592 PMCID: PMC3945075 DOI: 10.1155/2014/651768] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Revised: 10/22/2013] [Accepted: 10/23/2013] [Indexed: 11/18/2022]
Abstract
The first record of millipedes (Diplopoda) being regularly used for food by humans (the Bobo people of Burkina Faso) is given, including information on how the millipedes are prepared. The species in question are Tymbodesmus falcatus (Karsch, 1881) and Sphenodesmus sheribongensis (Schiøtz, 1966) (Gomphodesmidae) and an unidentified species of Spirostreptidae. New information on the nutritional value of millipedes is provided; unsaturated fatty acids, calcium, and iron contents are particularly high. The millipedes' defensive secretions, hydrogen cyanide and benzoquinones, present a severe challenge for the spread of millipedes as an everyday food source. On the other hand, the possibility that benzoquinones may act as insect-repellents, as known from studies on nonhuman primates, and that sublethal cyanide ingestion may enhance human innate resistance to malaria, suggests promising ethnomedical perspectives to our findings.
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Water-Soluble, Biocompatible Polyphosphazenes with Controllable and pH-Promoted Degradation Behavior. JOURNAL OF POLYMER SCIENCE. PART A, POLYMER CHEMISTRY 2014; 52:287-294. [PMID: 24729657 PMCID: PMC3980369 DOI: 10.1002/pola.27002] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Accepted: 10/30/2013] [Indexed: 11/15/2022]
Abstract
The synthesis of a series of novel, water-soluble poly(organophosphazenes) prepared via living cationic polymerization is presented. The degradation profiles of the polyphosphazenes prepared are analyzed by GPC, 31P NMR spectroscopy, and UV-Vis spectroscopy in aqueous media and show tunable degradation rates ranging from days to months, adjusted by subtle changes to the chemical structure of the polyphosphazene. Furthermore, it is observed that these polymers demonstrate a pH-promoted hydrolytic degradation behavior, with a remarkably faster rate of degradation at lower pH values. These degradable, water soluble polymers with controlled molecular weights and structures could be of significant interest for use in aqueous biomedical applications, such as polymer therapeutics, in which biological clearance is a requirement and in this context cell viability tests are described which show the non-toxic nature of the polymers as well as their degradation intermediates and products.
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The Role of 2,6-Diaminopyridine Ligands in the Isolation of an Unprecedented, Low-Valent Tin Complex. Chemistry 2013; 19:15504-17. [DOI: 10.1002/chem.201301340] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Indexed: 11/10/2022]
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A water soluble tri-cationic porphyrin-EDTA conjugate induces apoptosis in human neuroendocrine tumor cell lines. Bioorg Chem 2011; 40:108-113. [PMID: 22024042 PMCID: PMC3268353 DOI: 10.1016/j.bioorg.2011.09.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Revised: 09/27/2011] [Accepted: 09/28/2011] [Indexed: 11/05/2022]
Abstract
In this study, a completely water soluble tri-cationic porphyrin–EDTA conjugate was synthesized. We present data demonstrating the tumoristatic effects of the novel fully water soluble cationic porphyrin TMPy3PhenEDTA-P-Cl4 in the dark, in the medullary thyroid carcinoma cell lines MTC-SK and SHER-I and weaker effects in the small intestinal neuroendocrine tumor cell line KRJ-I. In addition, cytotoxic effects were also studied in normal human fibroblasts that represent normal tissue and the results are compared to the tumor cell lines.
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Backbone assignment and secondary structure of the PsbQ protein from photosystem II. BIOMOLECULAR NMR ASSIGNMENTS 2011; 5:169-175. [PMID: 21259076 DOI: 10.1007/s12104-011-9293-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Accepted: 01/07/2011] [Indexed: 05/30/2023]
Abstract
PsbQ is one of the extrinsic proteins situated on the lumenal surface of photosystem II (PSII) in the higher plants and green algae. Its three-dimensional structure was determined by X-ray crystallography with exception of the residues 14-33. To obtain further details about its structure and potentially its dynamics, we approached the problem by NMR. In this paper we report (1)H, (15)N, and (13)C NMR assignments for the PsbQ protein. The very challenging oligo-proline stretches could be assigned using (13)C-detected NMR experiments that enabled the assignments of twelve out of the thirteen proline residues of PsbQ. The identification of PsbQ secondary structure elements on the basis of our NMR data was accomplished with the programs TALOS+, web server CS23D and CS-Rosetta. To obtain additional secondary structure information, three-bond H(N)-H(α) J-coupling constants and deviation of experimental (13)C(α) and (13)C(β) chemical shifts from random coil values were determined. The resulting "consensus" secondary structure of PsbQ compares very well with the resolved regions of the published X-ray crystallographic structure and gives a first estimate of the structure of the "missing link" (i.e. residues 14-33), which will serve as the basis for the further investigation of the structure, dynamics and interactions.
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Suzuki-Miyaura cross-coupling reaction on copper-trans-A(2)B corroles with excellent functional group tolerance. Tetrahedron 2011; 67:4243-4252. [PMID: 21760646 PMCID: PMC3134141 DOI: 10.1016/j.tet.2011.04.024] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Revised: 03/29/2011] [Accepted: 04/07/2011] [Indexed: 12/01/2022]
Abstract
The palladium-catalyzed Suzuki-Miyaura cross-coupling reaction has been investigated on meso-substituted trans-A(2)B-corrole using tailored Pd-catalyst systems.We present the first examples of Suzuki-Miyaura cross-coupling reactions on meso-substituted trans-A(2)B-corrole derivatives with neutral, sterically hindered, inactivated and heteroaromatic boronic acids and esters, alkenylboronic acids, as well as quickly deboronating aryl boronic acids and benzo-condensated five membered heterocyclic boronic acids. In addition, we established a high-yield procedure for the Suzuki-Miyaura cross-coupling reaction of corroles with neutral boronic acids.Due to the lability of the free-base corrole macrocycles, functionalization of the corrole periphery was performed with the corresponding Cu-metallated species. meso-Substituted trans-A(2)B-corrole can hence be regarded as highly versatile platform towards more sophisticated corrole systems.X-ray structure analysis of a functionalized meso-substituted trans-A(2)B copper corrole exhibited the typical features of such a Cu-complex: short N-Cu distances and a saddled corrole configuration.Moreover, we observed a sensitivity of the formal oxidation state of the coordinated copper ions towards Suzuki-Miyaura cross-coupling reaction conditions, where the central copper(III) ion approaches the characteristic features of a copper(II) species. This redox behaviour was examined by UV/vis absorption spectra, nuclear magnetic resonance (NMR) experiments and time-dependent density functional theoretical calculations.
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Determination of (3)J((1)H3'-(31)P) couplings in a DNA oligomer with enhanced sensitivity employing a constant-time TOCSY difference experiment. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2011; 49:125-128. [PMID: 21308770 DOI: 10.1002/mrc.2729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2010] [Revised: 11/23/2010] [Accepted: 12/22/2010] [Indexed: 05/30/2023]
Abstract
A constant-time TOCSY difference experiment for the determination of (3)J((1)H3'-(31)P) coupling constants in non-isotope-labelled DNA oligonucleotides is presented. The method is tested on a DNA octamer and compared with the established constant-time NOESY difference method. Each (3)J((1)H3'-(31)P) coupling constant is determined from amplitude changes caused by phosphorous decoupling, which are observable on multiple cross-peaks, thus leading to a high accuracy of the value of the (3)J((1)H3'-(31)P) coupling constant. The new experiment delivers up to three times the sensitivity compared with previously reported methods.
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Syntheses, crystal structures, reactivity, and photochemistry of gold(iii) bromides bearing N-heterocyclic carbenes. Dalton Trans 2011; 40:9899-910. [PMID: 21879094 DOI: 10.1039/c1dt11175b] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Proisocrinins A-F, brominated anthraquinone pigments from the stalked crinoid Proisocrinus ruberrimus. JOURNAL OF NATURAL PRODUCTS 2009; 72:2036-2039. [PMID: 19943623 DOI: 10.1021/np900171h] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
New brominated anthraquinone pigments, proisocrinins A-F (1-6), were isolated from the strikingly scarlet-colored stalked crinoid Proisocrinus ruberrimus, which had been collected in the deep sea of the Okinawa Trough, Japan. The structures of the compounds were elucidated by spectroscopic analysis including HRMS, 1D 1H and 13C NMR, and 2D NMR. CD spectroscopy revealed that all compounds are present as optically active enantiomers. This is the first report of tribromo and tetrabromo anthraquinones from a natural source.
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DNA interactions and photocatalytic strand cleavage by artificial nucleases based on water-soluble gold(III) porphyrins. J Biol Inorg Chem 2009; 14:1037-52. [PMID: 19471974 DOI: 10.1007/s00775-009-0547-z] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2009] [Accepted: 05/04/2009] [Indexed: 11/28/2022]
Abstract
The novel gold porphyrin complex (5,10,15-tris(N-methylpyridinium-4-yl)-20-(1-pyrenyl)-porphyrinato)gold(III) chloride, [Au(III)(TMPy3Pyr1P)]Cl4, was prepared and characterized by optical spectroscopy, high-resolution nuclear magnetic resonance (NMR), and electrospray mass spectrometry. This cationic multichromophore compound exhibits excellent water solubility and does not form aggregates under physiological conditions. Binding interactions of this complex and related model compounds with nucleic acid substrates have been studied and characterized by NMR and circular dichroism spectroscopy. The photoreactivity of [Au(III)(TMPy3Pyr1P)]Cl4 was investigated under anaerobic and aerobic conditions in the presence of an excess of purine nucleoside, guanosine, and plasmid DNA. Photocatalytic oxidative degradation of guanosine and the change from supercoiled to circular plasmid DNA upon monochromatic irradiation and polychromatic blue-light exposure with a maximum at 420 nm was explored. The potential of the novel water-soluble cationic metallointercalator complex [Au(III)(TMPy3Pyr1P)]Cl4 to serve as a catalytic photonuclease for the cleavage of DNA has been demonstrated.
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Characterization of the sodium binding sites in microcrystalline ATP by 23Na-solid-state NMR and ab initio calculations. Inorganica Chim Acta 2009. [DOI: 10.1016/j.ica.2008.05.030] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Homonuclear long-range correlation spectra from HMBC experiments by covariance processing. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2007; 45:583-9. [PMID: 17534873 DOI: 10.1002/mrc.2013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
We present a new application of covariance nuclear magnetic resonance processing based on 1H--13C-HMBC experiments which provides an effective way for establishing indirect 1H--1H and 13C--13C nuclear spin connectivity at natural isotope abundance. The method, which identifies correlated spin networks in terms of covariance between one-dimensional traces from a single decoupled HMBC experiment, derives 13C--13C as well as 1H--1H spin connectivity maps from the two-dimensional frequency domain heteronuclear long-range correlation data matrix. The potential and limitations of this novel covariance NMR application are demonstrated on two compounds: eugenyl-beta-D-glucopyranoside and an emodin-derivative.
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Separated quadrupolar field experiment. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2005; 172:209-213. [PMID: 15649747 DOI: 10.1016/j.jmr.2004.09.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2004] [Revised: 09/16/2004] [Indexed: 05/24/2023]
Abstract
We describe an NMR experiment that produces spectra correlating the first-order quadrupolar spectrum and the central transition spectrum of half-integer quadrupolar spins, allowing one to separate the quadrupolar parameters in overlapping spectra under both static and magic-angle-spinning conditions. Promising fields of applications include situations where the sample cannot easily be rotated, or where it cannot be rotated at the magic angle.
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Benchmarking of ruthenium initiators for the ROMP of a norbornenedicarboxylic acid ester. ACTA ACUST UNITED AC 2003. [DOI: 10.1016/s1381-1169(03)00048-7] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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