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https://www.readbyqxmd.com/read/28211689/a-stable-porphyrin-based-porous-mog-metal-organic-framework-as-an-efficient-solvent-free-catalyst-for-c-c-bond-formation
#1
Wei Jiang, Jin Yang, Ying-Ying Liu, Shu-Yan Song, Jian-Fang Ma
We herein report the porous 4-fold interpenetrated mog (moganite) metal-organic framework (MOF) [Cd3(tipp)(bpdc)2]·DMA·9H2O (1·Cd; H2tipp = 5,10,15,20-tetrakis(4-(imidazol-1-yl)phenyl)porphyrin, H2bpdc = biphenyl-4,4'-dicarboxylic acid, DMA = N,N'-dimethylacetamide). The incorporation of Cd and carboxylate oxygen affords 1·Cd rich Lewis acid and basic sites. This MOF 1·Cd was then applied as an efficient heterogeneous catalyst for the important cyanosilylation of aldehydes and Knoevenagel condensation reactions...
February 17, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28198811/%C3%AE-thalassemia-patients-revealed-a-significant-change-of-untargeted-metabolites-in-comparison-to-healthy-individuals
#2
Syed Ghulam Musharraf, Ayesha Iqbal, Saqib Hussain Ansari, Sadia Parveen, Ishtiaq Ahmad Khan, Amna Jabbar Siddiqui
β-Thalassemia is one of the most prevalent forms of congenital blood disorders characterized by reduced hemoglobin levels with severe complications, affecting all dimensions of life. The mechanisms underlying the phenotypic heterogeneity of β-thalassemia are still poorly understood. We aimed to work over metabolite biomarkers to improve mechanistic understanding of phenotypic heterogeneity and hence better management of disorder at different levels. Untargeted serum metabolites were analyzed after protein precipitation and SPE (solid phase extraction) from 100 β-thalassemia patients and 61 healthy controls using GC-MS...
February 13, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28196402/pimelic-acid-the-first-precursor-of-the-bacillus-subtilis-biotin-synthesis-pathway-exists-as-the-free-acid-and-is-assembled-by-fatty-acid-synthesis
#3
Miglena Manandhar, John E Cronan
Biotin synthetic pathways are readily separated into two stages, synthesis of the seven carbon α, ω-dicarboxylic acid pimelate moiety and assembly of the fused heterocyclic rings. The biotin pathway genes responsible for pimelate moiety synthesis vary widely among bacteria whereas the ring synthesis genes are highly conserved. Bacillus subtilis seems to have redundant genes, bioI and bioW, for generation of the pimelate intermediate. Largely consistent with previous genetic studies we found that deletion of bioW caused a biotin auxotrophic phenotype whereas deletion of bioI did not...
February 14, 2017: Molecular Microbiology
https://www.readbyqxmd.com/read/28193054/conductometric-gradient-ion-exclusion-chromatography-for-volatile-fatty-acids
#4
C Phillip Shelor, Purnendu K Dasgupta, Hongzhu Liao
We describe a fatty acid vapor extractor (FAVE) as a postcolumn device for sensitive detection following ion exclusion chromatographic (ICE) separation of weak acids. The device consists of a single length of a permselective membrane tube surrounded by a jacket that consists of two isolated sections. The separation column effluent flows through the lumen. A suitable strong acid is put in the upstream, short section of the jacket and permeates in, rendering the lumenal flow strongly acidic (pH ≤ 2) that suppresses eluite weak acid dissociation...
December 20, 2016: Analytical Chemistry
https://www.readbyqxmd.com/read/28182181/photocatalytic-esterification-under-mitsunobu-reaction-conditions-mediated-by-flavin-and-visible-light
#5
M März, J Chudoba, M Kohout, R Cibulka
The usefulness of flavin-based aerial photooxidation in esterification under Mitsunobu reaction conditions was demonstrated, providing aerial dialkyl azodicarboxylate recycling/generation from the corresponding dialkyl hydrazine dicarboxylate. Simultaneously, activation of triphenylphosphine (Ph3P) by photoinduced electron transfer from flavin allows azo-reagent-free esterification. An optimized system with 3-methylriboflavin tetraacetate (10%), oxygen (terminal oxidant), visible light (450 nm), Ph3P, and dialkyl hydrazine dicarboxylate (10%) has been shown to provide efficient and stereoselective coupling of various alcohols and acids to esters with retention of configuration...
February 9, 2017: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/28161252/synthesis-and-biological-evaluation-of-cyclic-imides-incorporating-benzenesulfonamide-moieties-as-carbonic-anhydrase-i-ii-iv-and-ix-inhibitors
#6
Alaa A-M Abdel-Aziz, Andrea Angeli, Adel S El-Azab, Mohamed A Abu El-Enin, Claudiu T Supuran
A group of cyclic imides was synthesized by reaction of amino-substituted benzenesulfonamides with a series of acid anhydrides such as succinic, maleic, tetrahydrophthalic, pyrazine-2,3-dicarboxylic acid anhydride, and substituted phthalic anhydrides. The synthesized sulfonamides were evaluated as carbonic anhydrase (CA, EC 4.2.1.1) inhibitors against the human (h) isoforms hCA I, II, IV and IX, involved in a variety of diseases among which glaucoma, retinitis pigmentosa, etc. Some of these sulfonamides showed effective inhibitory action (in the nanomolar range) against the cytosolic isoform hCA II and the transmembrane, tumor-associated one hCA IX, making them interesting candidates for preclinical evaluation in glaucoma or various tumors in which the two enzymes are involved...
January 24, 2017: Bioorganic & Medicinal Chemistry
https://www.readbyqxmd.com/read/28145706/ligand-promoted-photoreductive-dissolution-of-goethite-by-atmospheric-low-molecular-dicarboxylates
#7
Zhenzhen Wang, Hongbo Fu, Liwu Zhang, Weihua Song, Jianmin Chen
Recent evidences suggested that organic ligands in atmosphere water play an important role in the mobilization of iron from mineral aerosol. In this study, the dissolution of goethite (α-FeOOH) was investigated in the presence of three low-molecular dicarboxylates enriched in the atmosphere, as well as a reference organic acid of methanesulfonate (MSA), which is especially abundant in marine atmospheric boundary layer. Iron mobilized from α-FeOOH was promoted under the irradiation and the deaerated condition, and the soluble Fe(II) concentration was enhanced greatly in the ligand-containing suspensions exposed to light...
February 1, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28133667/tris-bipyridine-based-dinuclear-ruthenium-ii-osmium-iii-complex-dyads-grafted-onto-tio2-nanoparticles-for-mimicking-the-artificial-photosynthetic-z-scheme
#8
Ludovic Favereau, Abhinandan Makhal, David Provost, Yann Pellegrin, Errol Blart, Erik Göransson, Leif Hammarström, Fabrice Odobel
The Z-Scheme function within molecular systems has been rarely reported for solar energy conversion although it offers the possibility to achieve higher efficiency than single photon absorber photosystems due to the use of a wider range of visible light. In this study, we synthesized and investigated the electrochemical and spectroscopic properties of two new dyads based on ruthenium and osmium tris-bipyridine complexes covalently linked via a butane bridge to explore their ability to realize the Z-scheme function once immobilized on TiO2...
January 30, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28133655/kinetics-mechanisms-and-ionic-liquids-in-the-uptake-of-n-butylamine-onto-low-molecular-weight-dicarboxylic-acids
#9
Michelle C Fairhurst, Michael J Ezell, Carla Kidd, Pascale S J Lakey, Manabu Shiraiwa, Barbara J Finlayson-Pitts
Atmospheric particles adversely affect visibility, health, and climate, yet the kinetics and mechanisms of particle formation and growth are poorly understood. Multiphase reactions between amines and dicarboxylic acids (diacids) have been suggested to contribute. In this study, the reactions of n-butylamine (BA) with solid C3-C8 diacids were studied at 296 ± 1 K using a Knudsen cell interfaced to a quadrupole mass spectrometer. Uptake coefficients for amines on the diacids with known geometric surface areas were measured at initial amine concentrations from (3-50) × 10(11) cm(-3)...
January 30, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28124823/synthesis-of-fdca-esters-without-concomitant-levulinic-acid-formation-starting-from-non-food-feedstocks
#10
Frits van der Klis, Jacco van Haveren, Daan S van Es, Harry Bitter
5-(Hydroxymethyl)-furfural (HMF) is a versatile intermediate in biomass conversion pathways, however the notoriously unstable nature of HMF imposes challenges to design selective routes to chemicals like furan-2,5-dicarboxylic acid (FDCA). Here we present a new strategy for obtaining furans, bypassing the formation of the unstable HMF. Instead of starting with glucose/fructose and thus forming HMF as an intermediate, the new route starts from uronic acids, which are abundantly present in many agro residues like e...
January 26, 2017: ChemSusChem
https://www.readbyqxmd.com/read/28117828/green-and-low-cost-production-of-thermally-stable-and-carboxylated-cellulose-nanocrystals-and-nanofibrils-using-highly-recyclable-dicarboxylic-acids
#11
Huiyang Bian, Liheng Chen, Ruibin Wang, Junyong Zhu
Here we demonstrate potentially low cost and green productions of high thermally stable and carboxylated cellulose nanocrystals (CNCs) and nanofibrils (CNF) from bleached eucalyptus pulp (BEP) and unbleached mixed hardwood kraft pulp (UMHP) fibers using highly recyclable dicarboxylic solid acids. Typical operating conditions were acid concentrations of 50 - 70 wt% at 100 °C for 60 min and 120 °C (no boiling at atmospheric pressure) for 120 min, for BEP and UMHP, respectively. The resultant CNCs have a higher thermal degradation temperature than their corresponding feed fibers and carboxylic acid group content from 0...
January 9, 2017: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/28112300/design-of-a-flexible-organometallic-tecton-host-guest-chemistry-with-picric-acid-and-self-assembly-of-platinum-macrocycles
#12
Achintya Jana, Sourav Bhowmick, Supreet Kaur, Hemant K Kashyap, Neeladri Das
The synthesis and characterization of a new pyrazine-based "flexible" and ditopic platinum(ii) organometallic molecule (3) is being reported. Flexibility in this molecule is due to the presence of ether functional groups that bridge the rigid core and periphery. Due to the presence of square planar Pt(ii) centers at the two ends, the molecule's potential to act as an acceptor building block in the construction of metallamacrocycles was tested. Upon reaction of 3 with various dicarboxylates in a 1 : 1 stoichiometric ratio, [2 + 2] self-assembled neutral metallacycles (M1-M3) were obtained in high yields...
January 23, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28105809/two-3d-cd-ii-metal-organic-frameworks-linked-by-benzothiadiazole-dicarboxylates-fantastic-s-cd6-cage-benzothiadiazole-antidimmer-and-dual-emission
#13
Qing Cheng, Xiao Han, Yue Tong, Chao Huang, Jie Ding, Hongwei Hou
On the basis of the same benzothiadiazole (BTD) ligand 2,1,3-benzothiadiazole-4,7-dicarboxylic acid (H2L), two new isomers of three-dimensional (3D) BTD-derived Cd(II) metal-organic frameworks 1-2 {[S@Cd6L6]·xH2O}n were obtained by the different solvothermal reactions, which were structurally similar. Surprisingly, structural analyses reveal that in 1 or 2, one free sulfur atom was fixed in a Cd(II) cluster cage by strong intermolecular interaction to form the secondary building unit (SBU) S@Cd6. Each SBU S@Cd6 is connected by six L(2-) ligands and further extended into the 3D porous framework...
January 20, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28105696/a-cryptand-metal-organic-framework-as-a-platform-for-the-selective-uptake-and-detection-of-group-i-metal-cations
#14
Sergey A Sapchenko, Pavel A Demakov, Denis G Samsonenko, Danil N Dybtsev, Martin Schröder, Vladimir P Fedin
The metal-organic framework (MOF) complex (H3 O)2 [Zn4 (ur)(Hfdc)2 (fdc)4 ] (1, ur=urotropine, H2 fdc=furan-2,5-dicarboxylic acid) incorporates cryptand-like cavities, which can be used to separate and detect Rb(+) and Cs(+) optically. This is the first example of the effective employment of a MOF material for optical detection of these cations.
January 20, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28105254/disease-monitoring-of-hepatocellular-carcinoma-through-metabolomics
#15
REVIEW
Asem I Fitian, Roniel Cabrera
We elucidate major pathways of hepatocarcinogenesis and accurate diagnostic metabolomic biomarkers of hepatocellular carcinoma (HCC) identified by contemporary HCC metabolomics studies, and delineate a model HCC metabolomics study design. A literature search was carried out on Pubmed for HCC metabolomics articles published in English. All relevant articles were accessed in full text. Major search terms included "HCC", "metabolomics", "metabolomics", "metabonomic" and "biomarkers". We extracted clinical and demographic data on all patients and consolidated the lead candidate biomarkers, pathways, and diagnostic performance of metabolomic expression patterns reported by all studies in tables...
January 8, 2017: World Journal of Hepatology
https://www.readbyqxmd.com/read/28103019/highly-water-stable-novel-lanthanide-wheel-cluster-organic-frameworks-featuring-coexistence-of-hydrophilic-cagelike-chambers-and-hydrophobic-nanosized-channels
#16
Yuan-Yuan Zhou, Yang Shi, Bing Geng, Qi-Bing Bo
In attempts to investigate the potential luminescent sensing materials for sensitive detection of environmental pollutants, a new family of lanthanide wheel cluster organic frameworks (Ln-WCOFs) UJN-Ln4 has been constructed by employing one of the cycloalkane dicarboxylic acid derivatives. Adopting different conformations, the ligand links Ln4 second building units (SBUs) and Ln24 tertiary building units (TBUs) to form a unique wheel cluster layer-pillared 3D framework featuring the coexistence of hydrophobic nanosized channels and trigonal antiprism arrays with hydrophilic cagelike chambers...
February 1, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28101682/synthesis-spectral-and-extended-spectrum-beta-lactamase-studies-of-transition-metal-tetraaza-macrocyclic-complexes
#17
Dinesh Kumar, Nutan Sharma, Manjula Nair
Urinary tract infections commonly occur in humans due to microbial pathogens invading the urinary tract, which can bring about a range of clinical symptoms and potentially fatal sequelae. The present study is aimed at addressing the development of a new antimicrobial agent against extended spectrum beta lactamase (ESBL) producing E. coli bacteria. We have synthesised some biologically potent (NNNN) donor macrocycles (L 1  = dibenzo[f,n]dipyrido[3,4-b:4',3'-j][1,4,9,12]tetraazacyclohexadecine-6,11,18,23(5H,12H, 7H, 24H)-tetraone, and L 2  = 6,12,19,25-tetraoxo-4,6,11,12,16,18,23,24-octahydrotetrabenzo [b,g,k,p][1,5,10,14]tetra azacyclooctadecine-2,13-dicarboxylic acid) and their Ti and Zr metal complexes in alcoholic media using microwave protocol...
January 18, 2017: Journal of Biological Inorganic Chemistry: JBIC
https://www.readbyqxmd.com/read/28098457/surface-forces-and-rheology-of-titanium-dioxide-in-the-presence-of-dicarboxylic-acids-from-molecular-interactions-to-yield-stress
#18
E-Jen Teh, Yee-Kwong Leong, Vincent S J Craig
The surface forces and yield stress of titanium dioxide were measured in the presence of dicarboxylic acids in order to understand the molecular basis for the observed rheological response. The yield stress was measured using the static vane technique, and the surface forces were characterized using an atomic force microscope. The trans and cis isomers of butenedioic acid (fumaric and maleic acids, respectively) were chosen as the relative orientation of the carboxylic groups differs substantially. This enables us to test the hypothesis that an increase in adhesion leads to an increase in yield stress as a consequence of the dicarboxylic acids participating in highly directed bridging...
January 31, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28095321/cellulose-to-depolymerize%C3%A2-or-not-to
#19
REVIEW
Sergiu Coseri
Oxidation of the primary OH groups in cellulose is a pivotal reaction both at lab and industrial scale, leading to the value-added products, i.e. oxidized cellulose which have tremendous applications in medicine, pharmacy and hi-tech industry. Moreover, the introduction of carboxyl moieties creates prerequisites for further cellulose functionalization through covalent attachment or electrostatic interactions, being an essential achievement designed to boost the area of cellulose-based nanomaterials fabrication...
January 15, 2017: Biotechnology Advances
https://www.readbyqxmd.com/read/28094932/series-d-f-heteronuclear-metal-organic-frameworks-color-tunability-and-luminescent-probe-with-switchable-properties
#20
Xun Feng, Yuquan Feng, Nan Guo, Yiling Sun, Tian Zhang, Lufang Ma, Liya Wang
A series of five unique d-f heteronuclear luminescent metal-organic frameworks (MOFs) in an entangled polyrotaxane array and the light-harvesting block homonuclear zinc compound have been isolated successfully and characterized. The series of isostructural polymers feature 3,4-connected (4.8(2))(4.8(3).9(2))(6.8.9)2(6.9(2))(8(3)) topology and high stability, exhibiting diverse void spaces. By taking advantage of the isostructural MOFs 2 and 3, the intensities of red and green emissions can be modulated by adjusting the ratios of Eu(III) and Tb(III) ions correspondingly, and white-light emission can be generated by a combination of different doped Tb(III) and Eu(III) concentrations...
January 17, 2017: Inorganic Chemistry
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