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https://www.readbyqxmd.com/read/28813053/copper-ii-benzimidazole-complexes-as-efficient-fluorescent-probes-for-l-cysteine-in-water
#1
Duraiyarasu Maheshwaran, Selvarasu Priyanga, Ramasamy Mayilmurugan
Copper(ii) complexes [Cu(L1)(H2O)2](SO3CF3)21 and [Cu(L2)(H2O)2](SO3CF3)22 based on 2,6-bis(benzimidazolyl)pyridine were synthesized and are reported herein as highly selective "turn-on" optical probes for l-cysteine. The Cu(ii)/Cu(i) redox potential of probe 1 (0.14 V vs. NHE) was lower than that of 2 (0.233 V vs. NHE) in water. The molecular structure of 2 adopted a square pyramidal geometry (τ = 0.2545), with the Cu-Npy bond (1.958 Å) of its middle pyridine unit being shorter than the other two Cu-Nbenzim bonds (Cu-N, 1...
August 16, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28813049/unprecedented-solvent-induced-inter-conversion-between-monomeric-and-dimeric-silylene-zinc-iodide-adducts
#2
Sandeep Yadav, Ekta Sangtani, Diksha Dhawan, Rajesh G Gonnade, Debashree Ghosh, Sakya S Sen
Usually, when a silylene reacts with a transition metal Lewis acid, it forms an adduct which could be either monomeric or dimeric. However, we present here that a silylene, [PhC(NtBu)2SiN(SiMe3)2] can form both monomeric [PhC(NtBu)2Si{N(SiMe3)2} → ZnI2]·THF (1) and dimeric [{PhC(NtBu)2}(N(SiMe3)2)SiZnI,(μ-I)]2 (2) adducts upon reaction with ZnI2. The formation of 1 and 2 relies upon the solvent used for the reaction or crystallization. When the crystallization is carried out in THF complex 1 is formed, however, when the reaction and crystallization are performed in acetonitrile complex 2 is obtained...
August 16, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28813043/folic-acid-supramolecular-ionogels
#3
Rahul Ranjan, Kamla Rawat, H B Bohidar
Herein, we report on folic acid (FA, a low molecular weight gelator) thermoreversible supramolecular organo (in 1 : 1 (v/v) water-DMSO binary solvent), and ionogels made in 1-ethyl-3-methyl imidazolium chloride, [C2mim][Cl], and 1-octyl-3-methyl imidazolium chloride, [C8mim][Cl], solutions with 0.1 ≤ [IL] ≤ 5% (w/v). The self-assembled fibrils of folic acid were largely formed due to secondary forces, such as π-π stacking, H-bonding, and hydrophobic interactions above a gelator concentration of 0...
August 16, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28813020/nine-new-triterpene-glycosides-magnumosides-a%C3%A2-a%C3%A2-b%C3%A2-b%C3%A2-c%C3%A2-c%C3%A2-and-c%C3%A2-from-the-vietnamese-sea-cucumber-neothyonidium-massinium-magnum-structures-and-activities-against-tumor-cells-independently-and-in-synergy-with-radioactive-irradiation
#4
Alexandra S Silchenko, Anatoly I Kalinovsky, Sergey A Avilov, Vladimir I Kalinin, Pelageya V Andrijaschenko, Pavel S Dmitrenok, Ekaterina A Chingizova, Svetlana P Ermakova, Olesya S Malyarenko, Tatyana N Dautova
Nine new sulfated triterpene glycosides, magnumosides A₁ (1), A₂ (2), A₃ (3), A₄ (4), B₁ (5), B₂ (6), C₁ (7), C₂ (8) and C₄ (9) as well as a known colochiroside B₂ (10) have been isolated from the tropical Indo-West Pacific sea cucumber Neothynidium (=Massinium) magnum (Phyllophoridae, Dendrochirotida) collected in the Vietnamese shallow waters. The structures of new glycosides were elucidated by 2D NMR spectroscopy and mass-spectrometry. All the isolated new glycosides were characterized by the non-holostane type lanostane aglycones having 18(16)-lactone and 7(8)-double bond and differed from each other by the side chains and carbohydrate moieties structures...
August 16, 2017: Marine Drugs
https://www.readbyqxmd.com/read/28812944/binding-forces-between-a-novel-schiff-base-palladium-ii-complex-and-two-carrier-proteins-human-serum-albumi-and%C3%AE-lactoglobulin
#5
Somaye Shahraki, Ali Heydari
Ligand binding studies on carrier proteins are crucial in determining the pharmacological properties of drug candidates. Here, a new palladium(II) complex was synthesized and characterized. The in vitro binding studies of this complexwith two carrier proteins, human serum albumin (HSA) and β-lactoglobulin (βLG) was investigated by employing biophysical techniques as well as computational modeling. The experimental results showed thatthe Pd(II) complex interacted with two carrier proteins with moderate binding affinity (Kb ~̴ 0...
August 16, 2017: Journal of Biomolecular Structure & Dynamics
https://www.readbyqxmd.com/read/28812893/%C3%AE-sulfinyl-benzoates-as-precursors-to-li-and-mg-carbenoids-for-the-stereoselective-iterative-homologation-of-boronic-esters
#6
Giorgia Casoni, Murat Kucukdisli, James M Fordham, Matthew Burns, Eddie L Myers, Varinder K Aggarwal
The stereoselective reagent-controlled homologation of boronic esters is one of a small number of iteratable synthetic transformations that if automated could form the basis of a veritable molecule-making machine. Recently, α-stannyl triisopropylbenzoates and α-sulfinyl chlorides have emerged as useful building blocks for the iterative homologation of boronic esters. However, α-stannyl benzoates need to be prepared using stoichiometric amounts of the (+)- or (-)-enantiomer of the scarcely available and expensive diamine sparteine; also, these building blocks, together with the byproducts that are generated during homologation, are perceived as being toxic...
August 16, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28812889/influence-of-small-fluorophilic-and-lipophilic-organic-molecules-on-dppc-bilayers
#7
Martin Brehm, Ghulam Saddiq, Tobias Watermann, Daniel Sebastiani
In this study, we investigate the effect of a series of additive molecules with different types of philicities on the structure and dynamics of DPPC bilayers. To this aim, we performed extensive force field molecular dynamics simulations of the systems, using our recently developed perfluoroalkane force field. We found that addition of perfluoro-n-decane and fluorotelomer alcohol at 323 K leads to a phase transition of the membrane from liquid crystalline to gel phase, whereas the addition of n-decane and partially fluorinated n-decane leaves the liquid crystalline phase intact...
August 16, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28812888/triply-bonded-gallium%C3%A2-phosphorus-molecules-theoretical-designs-and-characterization
#8
Jia-Syun Lu, Ming-Chung Yang, Ming-Der Su
The effect of substitution on the potential energy surfaces of triple-bonded RGa≡PR (R = F, OH, H, CH3, SiH3, SiMe(SitBu3)2, SiiPrDis2, Tbt (C6H2-2,4,6-{CH(SiMe3)2}3), and Ar* (C6H3-2,6-(C6H2-2,4,6-i-Pr3)2)) compounds was theoretically examined by using the density functional theory (i.e., M06-2X/Def2-TZVP, B3PW91/Def2-TZVP and B3LYP/LANL2DZ+dp). The theoretical evidences strongly suggest all of the triple-bonded RGa≡PR species prefer to select a bent form with an angle (∠Ga-P-R) of about 90°. Moreover, the theoretical observations indicate only the bulkier substituents, in particular for the strong donating groups (e...
August 16, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28812886/room-temperature-ring-opening-of-quinoline-isoquinoline-and-pyridine-with-low-valent-titanium
#9
Seung-Yeol Baek, Takashi Kurogi, Dahye Kang, Masahiro Kamitani, Seongyeon Kwon, Douglas Solowey, Chun-Hsing Chen, Maren Pink, Patrick J Carroll, Daniel J Mindiola, Mu-Hyun Baik
The complex (PNP)Ti=CHtBu(CH2tBu) (PNP = N[2-PiPr2-4-methylphenyl]2-) dehydrogenates cyclohexane to cyclohexene by forming a transient low-valent titanium-alkyl species, [(PNP)Ti(CH2tBu)], which reacts with two equivalents of quinoline (Q) at room temperature to form H3CtBu and a Ti(IV) species where the less hindered C2=N1 bond of Q is ruptured and coupled to another equivalent of Q. The product isolated from this reaction is an imide with a tethered cycloamide group, (PNP)Ti=N[C18H13N] (1). Under photolytic conditions, intramolecular C-H bond activation across the imide-moiety in 1 occurs to form 2, and thermolysis reverses this process...
August 16, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28812879/germanium-and-tin-monoxides-trapped-by-oxophilic-germylene-and-stannylene-ligands
#10
Yunxia Gao, Ying Yang, Wenjun Zheng, Yuanyuan Su, Xiang Zhang, Herbert W Roesky
Germanium and tin monoxides (MO, M = Ge, Sn) were trapped by the 1,2,4-diazaphospholide-based germylene and stannylene M[3,5-tBu2dp]2 (M = Ge (2), Sn (3)), resulting in the Lewis acid-base adduct of composition M(μ-O)[M{η(1)(N)-(3,5-tBu2dp)}2]2 (M = Ge (4), Sn (5)). Compounds 4 and 5 were characterized by single-crystal X-ray structural analysis. The bonding features of 4 and 5 were supported by DFT calculations.
August 16, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28812774/self-adaptive-hydrogels-to-mineralization
#11
Tooba Shoaib, Ariel Carmichael, R E Corman, Yun Shen, Thanh H Nguyen, Randy H Ewoldt, Rosa M Espinosa-Marzal
Mineralized biological tissues, whose behavior can range from rigid to compliant, are an essential component of vertebrates and invertebrates. Little is known about how the behavior of mineralized yet compliant tissues can be tuned by the degree of mineralization. In this work, a synthesis route to tune the structure and mechanical response of agarose gels via ionic crosslinking and mineralization has been developed. A combination of experimental techniques demonstrates that crosslinking via cooperative hydrogen bonding in agarose gels is disturbed by calcium ions, but they promote ionic crosslinking that modifies the agarose network...
August 16, 2017: Soft Matter
https://www.readbyqxmd.com/read/28812751/hydrogen-bonded-rosettes-comprising-%C3%AF-conjugated-systems-as-building-blocks-for-functional-one-dimensional-assemblies
#12
Bimalendu Adhikari, Xu Lin, Mitsuaki Yamauchi, Hayato Ouchi, Keisuke Aratsu, Shiki Yagai
Hydrogen-bonded supermacrocycles (rosettes) are attractive disk-shaped noncovalent synthons for extended functional columnar nanoassemblies. They can serve not only as noncovalent monomer units for supramolecular polymers and discrete oligomers in a dilute solution but also as constituent entities for soft matters such as gels and lyotropic/thermotropic liquid crystals. However, what are the merits of using supramolecular rosettes instead of using expanded π-conjugated covalent molecules? This review covers the self-assembly of photochemically and electrochemically active π-conjugated molecules through the formation of supramolecular rosettes via directional complementary multiple hydrogen-bonding interactions...
August 16, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28812745/hysteresis-and-bonding-reconstruction-in-the-pressure-induced-b3-b1-phase-transition-of-3c-sic
#13
Miguel A Salvadó, R Franco, Pilar Pertierra, T Ouahrani, J M Recio
The determination of kinetic factors affecting phase metastability is crucial for the design of materials out of the ambient conditions. At a given temperature, the kinetic barrier associated with the reconstruction of the bonding network of a pressure-induced phase transition can be only overcome at pressures where the available vibrational energy of the system is equal or higher than the corresponding activation energy. Our work demonstrates that these pressures provide boundaries to hysteresis cycles that can be evaluated following a three-step computational strategy: (i) total energy electronic structure calculations, (ii) determination of vibrational contributions by means of a simple Debye model, and (iii) description of the energetic profile along the transition path in the framework of the martensitic approximation...
August 16, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28812629/confronting-the-risks-of-large-scale-invasive-species-control
#14
R Keller Kopf, Dale G Nimmo, Paul Humphries, Lee J Baumgartner, Michael Bode, Nick R Bond, Andrea E Byrom, Julien Cucherousset, Reuben P Keller, Alison J King, Heather M McGinness, Peter B Moyle, Julian D Olden
No abstract text is available yet for this article.
May 23, 2017: Nature ecology & evolution
https://www.readbyqxmd.com/read/28812535/associating-mutations-causing-cystinuria-with-disease-severity-with-the-aim-of-providing-precision-medicine
#15
Henry J Martell, Kathie A Wong, Juan F Martin, Ziyan Kassam, Kay Thomas, Mark N Wass
BACKGROUND: Cystinuria is an inherited disease that results in the formation of cystine stones in the kidney, which can have serious health complications. Two genes (SLC7A9 and SLC3A1) that form an amino acid transporter are known to be responsible for the disease. Variants that cause the disease disrupt amino acid transport across the cell membrane, leading to the build-up of relatively insoluble cystine, resulting in formation of stones. Assessing the effects of each mutation is critical in order to provide tailored treatment options for patients...
August 11, 2017: BMC Genomics
https://www.readbyqxmd.com/read/28812364/catalytic-asymmetric-desymmetrization-of-cyclopentendiones-via-diels-alder-reaction-of-3-hydroxy-2-pyrones-construction-of-multifunctional-bridged-tricyclic-lactones
#16
Li-Min Shi, Wu-Wei Dong, Hai-Yan Tao, Xiu-Qin Dong, Chun-Jiang Wang
An unprecedented asymmetric Diels-Alder reaction of 3-hydroxy-2-pyrones with prochiral cyclopentene-1,3-diones via desymmetrization was efficiently realized with high stereoselective control with the aid of fine-tunable cinchona alkaloid derived bifunctional amine-thiourea catalysts bearing multiple hydrogen-bonding donors. This protocol provides an expedient access to the multifunctional-bridged tricyclic lactones featuring four contiguous stereogenic centers and one remote quaternary stereogenic center with a broad substrate scope...
August 16, 2017: Organic Letters
https://www.readbyqxmd.com/read/28812355/adaptively-recognizing-parallel-stranded-duplex-structure-for-fluorescent-dna-polarity-analysis
#17
Mei-Yun Ye, Rui-Tao Zhu, Xiang Li, Xiao-Shun Zhou, Zheng-Zhi Yin, Qian Li, Yong Shao
Besides the canonical Watson-Crick (WC) linked antiparallel-stranded duplex (aps-DNA), DNA is also able to form bioactive parallel-stranded duplex (ps-DNA) with the two involving strands adopting the equal 5'-3' polarity. Discriminating ps-DNA from aps-DNA with an ideal selectivity is more challenging because of their comparable duplex topologies. Herein, we designed a unique probe of HPIN to fluorescently recognize ps-DNA but to keep an almost nonfluorescent response in binding with aps-DNA. The success of the Hoogsteen hydrogen bonding pattern in lighting up the HPIN fluorescence over the reverse Watson-Crick (rWC) one suggests the critical role of HPIN in structurally adaptive recognition to the strand polarity-determined base-pairing peculiarity...
August 16, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28812347/rational-design-of-polymeric-nanoparticles-with-tailorable-biomedical-functions-for-cancer-therapy
#18
Wenhai Lin, Wei Zhang, Tingting Sun, Shi Liu, Yu Zhu, Zhigang Xie
Polymeric nanoparticles (NPs) play a key role in nanoscale formulations for bioimaging, cancer treatment and theranostics. In this work, we designed and synthesized a series of hydrophobic polymers (P1-6) with different pendent groups via one-step multicomponent Passerini reaction. These polymers possessed similar molecular structures and various biomedical functions. Interestingly, they could self-assemble into stable NPs in aqueous media. All formed NPs were redox-sensitive because of the existence of disulfide bonds in the backbone...
August 16, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28812346/metal-free-synthesis-of-2-aminobenzothiazoles-via-iodine-catalyzed-and-oxygen-promoted-cascade-reactions-of-isothiocyanatobenzenes-with-amines
#19
Yuanshuang Xu, Bin Li, Xinying Zhang, Xuesen Fan
In this paper, a highly efficient and sustainable synthesis of 2-aminobenzothiazoles through the cascade reactions of isothiocyanatobenzenes with primary or secondary amines by using iodine as a catalyst and oxygen as an oxidant is presented. Mechanistically, the formation of the title compounds involves the in situ formation of the required benzothiourea intermediate followed by its intramolecular cross dehydrogenative coupling of a C(sp2)-H bond and a S-H bond. To our knowledge, this should be the first example in which 2-aminobenzothiazoles are efficiently prepared from simple and cheap isothiocyanates and amines under metal free conditions by using iodine as a catalyst and molecular oxygen as an oxidant with water as the byproduct...
August 16, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28812331/a-synthesis-of-crocagin-a
#20
Filip Bihelovic, Desiree Stichnoth, Rolf Müller, Dirk Trauner, Frank Surup
Crocagin A (1) combines an attractive molecular structure with an unusual biosynthesis and bioactivity. Here, we present an efficient synthesis of crocagin A that hinges on an early formation of its heterotricyclic core, an electrophilic amination, and a stereoselective hydrogenation of a tetrasubstituted double bond. Our synthesis confirms the absolute configuration of crocagin A and provides access to the natural product and derivatives thereof for further biological testing.
August 15, 2017: Angewandte Chemie
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