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41.
Majid Rezaeivala Musa Ahmadi Burjor Captain Serap Şahin-Bölükbaşı Ahmad Ali Dehghani-Firouzabadi Robert William Gable 《应用有机金属化学》2020,34(2):e5325
A new unsymmetrical five-coordinate Schiff base ligand (HL) with an N4O donor set ( 2 ) has been prepared by condensation of N1-(2-morpholinoethyl)-N1-([pyridine-2-yl]methyl)propane-1,3-diamine with 2-hydroxy-benzaldehyde. Metal complexes [ML]n+ (M = Zn2+, Cd2+, Mn2+, Cu2+, Ni2+, Ag+, Fe3+, and Co2+ ( 3–10 ) were synthesized by the reaction of the ligand and metal salts in ethanol. The resulting products were characterized by elemental analyses, infrared, 1H and 13C nuclear magnetic resonance spectra (in the case of Cd and Zn complexes), UV–Vis, electrospray ionization-mass spectrometric, and conductivity measurements. The structure of the complexes [ZnL](ClO4) ( 3 ), [CdL](ClO4) ( 4 ), and [CuL](ClO4) ( 7 ) has been determined by single-crystal X-ray diffraction analysis. The metal complexes were determined to have a distorted trigonal bipyramidal (Zn and Cd) or a distorted square pyramidal (Cu) geometry. The cytotoxic potential of each compound (1–10) against MCF-7 and MDA-MB-231 (breast cancer cells), PC-3 (prostate cancer cells), and WI-38 human normal lung fibroblast cells was evaluated using the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide) assay. Compounds 1, 2, and 10 did not display any activity toward any cell line tested. None of the compounds except compound 8 was cytotoxic toward PC-3. Compounds 4 and 8 showed the highest cytotoxic activity against the MCF-7 and MDA-MB-231 cell lines. Because compounds 3, 6, and 9 have similar half-maximal inhibitory concentration values against cancer cells and normal cells, these compounds displayed poor selectivity between cancer and normal cells. More importantly, it was observed that compound 5 acts differently toward different types of cell lines. For example, it displays lower cytotoxicity against the WI-38 normal cell line than it does against the MDA-MB-231 cell line. 相似文献
42.
Terminal Hydride Species in [FeFe]‐Hydrogenases Are Vibrationally Coupled to the Active Site Environment 下载免费PDF全文
Dr. Cindy C. Pham Dr. David W. Mulder Dr. Vladimir Pelmenschikov Dr. Paul W. King Dr. Michael W. Ratzloff Dr. Hongxin Wang Nakul Mishra Dr. Esen E. Alp Dr. Jiyong Zhao Dr. Michael Y. Hu Dr. Kenji Tamasaku Dr. Yoshitaka Yoda Prof. Stephen P. Cramer 《Angewandte Chemie (International ed. in English)》2018,57(33):10605-10609
A combination of nuclear resonance vibrational spectroscopy (NRVS), FTIR spectroscopy, and DFT calculations was used to observe and characterize Fe?H/D bending modes in CrHydA1 [FeFe]‐hydrogenase Cys‐to‐Ser variant C169S. Mutagenesis of cysteine to serine at position 169 changes the functional group adjacent to the H‐cluster from a ‐SH to ‐OH, thus altering the proton transfer pathway. The catalytic activity of C169S is significantly reduced compared to that of native CrHydA1, presumably owing to less efficient proton transfer to the H‐cluster. This mutation enabled effective capture of a hydride/deuteride intermediate and facilitated direct detection of the Fe?H/D normal modes. We observed a significant shift to higher frequency in an Fe?H bending mode of the C169S variant, as compared to previous findings with reconstituted native and oxadithiolate (ODT)‐substituted CrHydA1. On the basis of DFT calculations, we propose that this shift is caused by the stronger interaction of the ‐OH group of C169S with the bridgehead ‐NH‐ moiety of the active site, as compared to that of the ‐SH group of C169 in the native enzyme. 相似文献
43.
Tuğba Alp Arici 《中国化学会会志》2023,70(7):1537-1547
The study focused on determining the effect of acidic and basic cold activation on hydrochar (HC) for the removal of methyl orange (MO). HC was prepared by hawthorn seeds (HS) under hydrothermal carbonization. HC was cold-activated with HCl and NaOH, respectively, and they were grafted with aminopropyltriethoxysilane (APTES) and protonated to obtain AHC-N+ (acid-activated and modified HC) and BHC-N+ (base-activated and modified HC) to determine the effect of acidic and basic activation. They were characterized by elemental analysis, IR, thermal analysis, zeta potential, N2 adsorption–desorption measurements, and SEM–EDX analysis. The prepared adsorbents displayed MO adsorption due to abundant protonated amine groups. BHC-N+ showed higher MO adsorption than AHC-N+. The result showed that more protonated APTES groups grafted on the surface of HC via NaOH activation. The obtained data had a good fitting with the Langmuir isotherm and pseudo-second-order kinetic. The maximum adsorption capacity of BHC-N+ was 250.38 mg g−1. The adsorption mechanism could be attributed to the electrostatic interactions between MO and protonated amine groups of APTES and hydrogen bonding. 相似文献
44.
Nitrosylation of Nitric‐Oxide‐Sensing Regulatory Proteins Containing [4Fe‐4S] Clusters Gives Rise to Multiple Iron–Nitrosyl Complexes 下载免费PDF全文
Pauline N. Serrano Dr. Hongxin Wang Dr. Jason C. Crack Christopher Prior Prof. Matthew I. Hutchings Prof. Andrew J. Thomson Dr. Saeed Kamali Dr. Yoshitaka Yoda Dr. Jiyong Zhao Dr. Michael Y. Hu Dr. Ercan E. Alp Dr. Vasily S. Oganesyan Prof. Nick E. Le Brun Prof. Stephen P. Cramer 《Angewandte Chemie (International ed. in English)》2016,55(47):14575-14579
The reaction of protein‐bound iron–sulfur (Fe‐S) clusters with nitric oxide (NO) plays key roles in NO‐mediated toxicity and signaling. Elucidation of the mechanism of the reaction of NO with DNA regulatory proteins that contain Fe‐S clusters has been hampered by a lack of information about the nature of the iron‐nitrosyl products formed. Herein, we report nuclear resonance vibrational spectroscopy (NRVS) and density functional theory (DFT) calculations that identify NO reaction products in WhiD and NsrR, regulatory proteins that use a [4Fe‐4S] cluster to sense NO. This work reveals that nitrosylation yields multiple products structurally related to Roussin's Red Ester (RRE, [Fe2(NO)4(Cys)2]) and Roussin's Black Salt (RBS, [Fe4(NO)7S3]. In the latter case, the absence of 32S/34S shifts in the Fe?S region of the NRVS spectra suggest that a new species, Roussin's Black Ester (RBE), may be formed, in which one or more of the sulfide ligands is replaced by Cys thiolates. 相似文献
45.
T. Ruckert W. Keune W. Sturhahn M.Y. Hu J.P. Sutter T.S. Toellner E.E. Alp 《Hyperfine Interactions》2000,126(1-4):363-366
Incoherent nuclear resonant absorption of synchrotron radiation at the 14.413 keV nuclear resonance of 57Fe was employed to measure directly the Fe-projected (partial) phonon density of states (DOS) in epitaxial FeCr(0 0 1) superlattices
and in an 57Fe0.03Cr0.97(0 0 1) alloy film MBE-grown on MgO(0 0 1). The measurements were performed at 300 K with 2.3 meV energy resolution around
14.413 keV. At the interfaces, longitudinal vibrations of Fe atoms are suppressed, and a strong resonance phonon mode appears
near 23 meV.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
46.
Platinum (Pt) loaded activated carbons (ACs) were synthesized by the thermal decomposition of platinum (II) acetylacetonate (Pt(acac)2) over chemically activated glucose-based biochar. The effect of Pt loading on surface area, pore characteristics, surface chemistry, chemical structure, and surface morphology were determined by various techniques. XPS studies proved the presence of metallic Pt0 on the AC surface. The graphitization degree of Pt loaded ACs were increased with the loaded Pt0 amount. The electrochemical performance of the Pt-loaded ACs (Pt@AC) was determined not only by the conventional three-electrode system but also by packaged supercapacitors in CR2032 casings. The capacitive performance of Pt@AC electrodes was investigated via cyclic voltammetry (CV), galvanostatic charge-discharge curves (GCD), and impedance spectroscopy (EIS). It was found that the Pt loading increased the specific capacitance from 51 F/g to 100 F/g. The ESR drop of the packaged cell decreased with the Pt loading due to the fast flow of charge through the conductive pathways. The results showed that the surface chemistry is more dominant than the surface area for determining the capacitive performance of Pt loaded AC-based packaged supercapacitors. 相似文献
47.
Lili Gao Bin Chen Michael Lerche Esen E. Alp Wolfgang Sturhahn Jiyong Zhao Hasan Yava? Jie Li 《Journal of synchrotron radiation》2009,16(6):714-722
The applications of nuclear resonant scattering in laser‐heated diamond anvil cells have provided an important probe for the magnetic and vibrational properties of 57Fe‐bearing materials under high pressure and high temperature. Synchrotron X‐ray diffraction is one of the most powerful tools for studying phase stability and equation of state over a wide range of pressure and temperature conditions. Recently an experimental capability has been developed for simultaneous nuclear resonant scattering and X‐ray diffraction measurements using synchrotron radiation. Here the application of this method to determine the sound velocities of compressed Fe3C is shown. The X‐ray diffraction measurements allow detection of microscale impurities, phase transitions and chemical reactions upon compression or heating. They also provide information on sample pressure, grain size distribution and unit cell volume. By combining the Debye velocity extracted from the nuclear resonant inelastic X‐ray scattering measurements and the structure, density and elasticity data from the X‐ray diffraction measurements simultaneously obtained, more accurate sound velocity data can be derived. Our results on few‐crystal and powder samples indicate strong anisotropy in the sound velocities of Fe3C under ambient conditions. 相似文献
48.
Serap Bulut 《Applied mathematics and computation》2009,215(4):1448-1455
In this paper, firstly we define the generalization of the generalized Al-Oboudi differential operator. Then we also define new classes of analytic and p-valently starlike and convex functions with complex order by means of this new general differential operator. Our main purpose is to determine coefficient bounds for functions in certain subclasses of this classes, which are introduced here by means of a family of nonhomogeneous Cauchy-Euler differential equations. Relevant connections of some of the results obtained with those in earlier works are also provided. 相似文献
49.
Xiao Y Fisher K Smith MC Newton WE Case DA George SJ Wang H Sturhahn W Alp EE Zhao J Yoda Y Cramer SP 《Journal of the American Chemical Society》2006,128(23):7608-7612
Nitrogenase catalyzes a reaction critical for life, the reduction of N(2) to 2NH(3), yet we still know relatively little about its catalytic mechanism. We have used the synchrotron technique of (57)Fe nuclear resonance vibrational spectroscopy (NRVS) to study the dynamics of the Fe-S clusters in this enzyme. The catalytic site FeMo-cofactor exhibits a strong signal near 190 cm(-)(1), where conventional Fe-S clusters have weak NRVS. This intensity is ascribed to cluster breathing modes whose frequency is raised by an interstitial atom. A variety of Fe-S stretching modes are also observed between 250 and 400 cm(-)(1). This work is the first spectroscopic information about the vibrational modes of the intact nitrogenase FeMo-cofactor and P-cluster. 相似文献
50.
Serap Seyhan Bozkurt Deniz Erdogan Mine Antep Nalan Tuzmen Melek Merdivan 《液相色谱法及相关技术杂志》2016,39(1):21-29
The possibility of using ionic liquid based chitosan sorbent for the separation and preconcentration of fluoroquinolone antibiotics (marbofloxacin, enoxacin, ofloxacin, ciprofloxacin, and enrofloxacin) has been studied. For this reason, different ionic liquids were prepared and coated on the chitosan sorbent. The conditions of the preconcentration of fluoroquinolones on a microcolumn have been optimized and the extraction efficiencies of the prepared sorbents have been compared. The compounds were eluted with 5 mL of 20% NH3 (v/v, MeOH) solution and determined by HPLC with diode array and fluorescence detector. The limits of detection were found as 4.23 µ g L?1 for marbofloxacin, and 1.09 µg L?1 for enoxacin; 3.23 × 10?3 µg L?1 for ofloxacin; 8.39 × 10?3 µg L?1 for ciprofloxacin; and 19.50 × 10?3 µg L?1 for enrofloxacin. The developed method was applied for the analysis of fluoroquinolone in milk, egg, fish, bovine, and chicken samples and the recoveries were obtained in the range 70–100%. 相似文献