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1.
Moamen S. Refat Sulekh Chandra Monika Tyagi 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1):22-33
Mn(II), Co(II), Ni(II), and Cu(II) complexes have been synthesized with benzil bis(thiosemicarbazone) (L) and characterized by elemental analyses, molar conductance measurements, magnetic susceptibility measurements, thermogravimetric studies, infrared (IR), electronic, and electron paramagnetic resonance (eEPR) spectral studies. The molar conductance measurements of the complexes in DMF correspond to the non-electrolytic nature of the complexes. Thus these complexes may be formulated as [M(L)X2] (where M = Mn(II), Co(II), Ni(II), Cu(II) and X = Cl? and NO3 ?). On the basis of IR, electronic, and EPR spectral studies, an octahedral geometry has been assigned for Mn(II), Co(II), and Ni(II) complexes, whereas a tetragonal geometry for the Cu(II) complexes is presumed. The free ligand and its metal complexes were tested against the phytopathogenic fungi (i.e., Rhizoctonia baticola, Alternaria alternata) in vitro. 相似文献
2.
Moamen S. Refat Gehad G. Mohamed Mohamed Y. S. Ibrahim Hamada M. A. Killa Hammad Fetooh 《Russian Journal of General Chemistry》2013,83(12):2479-2487
Solid complexes have been prepared and characterized by IR, UV-Vis, elemental analysis, and 1H NMR. Indomethacin forms complexes with Cd(II), Ce(III), and Th(IV) ions in molar ratios (ligand: metal) (2: 1), (3: 1), and (4: 1), respectively. The IR spectra of the complexes suggest that the Indomethacin behaves as a monobasic monodentate ligand coordinated to the metal ions via the deprotonated carboxylate group. Prepared complexes exhibit higher antimicrobial activity against several microorganisms, compared to free ligand. 相似文献
3.
Moamen S. Refat Lamia A. El-Zayat Okan Zafer Yeşilel 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2010,75(2):745-752
Electron donor–acceptor interaction of morpholine (morp) with chloranilic acid (cla) and picric acid (pa) as π-acceptors was investigated spectrophotometrically and found to form stable charge-transfer (CT) complexes (n–π*) of [(Hmorp)2(cla)] and [(Hmorp)(pa)]2. The donor site involved in CT interaction is morpholine nitrogen. These complexes are easily synthesized from the reaction of morp with cla and pa within MeOH and CHCl3 solvents, respectively. 1HNMR, IR, elemental analyses, and UV–vis techniques characterize the two morpholinium charge-transfer complexes. Benesi–Hildebrand and its modification methods were applied to the determination of association constant (K), molar extinction coefficient (?). The X-ray crystal structure was carried out for the interpretation the predict structure of the [(Hmorp)(pa)]2 complex. 相似文献
4.
Moamen?S.?RefatEmail author Foziah?A.?Al-Saif 《Research on Chemical Intermediates》2015,41(3):1421-1445
Mononuclear Mn(II), Co(II), Ni(II), Zn(II), Cd(II), Mg(II), Sr(II), Ba(II), Ca(II), Pt(IV), Au(III), and Pd(II) complexes of the drug amlodipine besylate (HL) have been synthesized and characterized by elemental analysis, spectroscopic technique (IR, UV–Vis, solid reflectance, scanning electron microscopy, X-ray powder diffraction, and 1H-NMR) and magnetic measurements. The elemental analyses of the complexes are confirmed by the stoichiometry of the types [M(HL)(X)2(H2O)]·nH2O [M = Mn(II), Co(II), Zn(II), Ni(II), Mg(II), Sr(II), Ba(II), and Ca(II); X = Cl? or NO3 ?], [Cd(HL)(H2O)]Cl2, [Pd(HL)2]Cl2, [Pt(L)2]Cl2, and [Au(L)2]Cl, respectively. Infrared data revealed that the amlodipine besylate drug ligand chelated as monobasic tridentate through NH2, oxygen (ether), and OH of besylate groups in Mn(II), Co(II), Ni(II), Zn(II), Cd(II), Mg(II), Sr(II), Ba(II), Ca(II), and Au(III) complexes, but in Pt(IV) and Pd(II) complexes, the amlodipine besylate coordinates via NH2 and OH (besylate) groups. An octahedral geometry is proposed for all complexes except for the Cd(II), Pt(IV), and Pd(II) complexes. The amlodipine besylate free ligand and the transition and non-transition complexes showed antibacterial activity towards some Gram-positive and Gram-negative bacteria and the fungi (Aspergillus flavus and Candida albicans). 相似文献
5.
Clidinium is a synthetic anticholinergic agent which has been shown in experimental and clinical studies to have an antispasmodic and antisecretory effect on the gastrointestinal tract. Inhibits the muscarinic effects of acetylcholine at neurotransmitter sites after parasympathetic ganglia. It is used to treat peptic ulcer disease and to help relieve stomach or stomach cramps or cramps due to abdominal cramps, diverticulitis, and irritable bowel syndrome. Mononuclear complexes of the manganese(Ⅱ), nickel(Ⅱ) and mercury(Ⅱ) with clidinium bromide drug (C22H26NO3) types [M(C22H25NO3)2(H2O)4] and [Hg(C22H25NO3)2(H2O)2] where M=Mn (Ⅱ) and Ni(Ⅱ), have been synthesized and characterized on the basis of elemental analysis, conductivity measurements, magnetic, electronic, 1H-NMR and infrared spectral studies. The complexes confirm to 1∶2 stoichiometry and are non-electrolytes. The clidinium drug ligand (C22H26NO3) act as a deprotonated monovalent monodentate chelate coordinating through hydroxyl oxygen where IR spectral bands of clidinium bromide shows a band at 3 226 cm-1 assigned to the OH group stretching frequency, this band ν(O-H) stretching vibration motion is disappeared in case of the infrared spectra of the Mn(Ⅱ), Ni(Ⅱ), and Hg(Ⅱ) complexes suggesting the involvement of the oxygen atom of the deprotonated OH group of clidinium ligand in complexation. The band for the ν(C-O) of alcoholic group of clidinium that appears at 1 240 cm-1 has blue shifted after complexity, indicating the participation of the alcoholic group in the coordination . 1H NMR spectrum for clidinium bromide show a singlet peak at 3.65 ppm due to proton of OH group which isn’t observed in the spectrum of mercury(Ⅱ) complex referring to the deprotonation of OH group and participated in the complexation. Based on electronic spectra, IR spectra and magnetic moment measurements; six coordinated octahedral structures have been proposed for the manganese and nickel(Ⅱ) complexes, while mercury(Ⅱ) complex has a four coordinated geometry. Thermogravimetric analyses studies revealed the presence of coordinated water molecules. For instance the X-ray powder diffraction pattern and scanning electronic microscopy for the Hg(Ⅱ) complex deduced that it was isolated in nanostructured with crystallinity form. 相似文献
6.
Refat MS Sadeek SA Khater HM 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2006,64(3):778-788
The rapid interaction between o-tolidine and p-toluidine (pi-donors) with the pi-acceptors, e.g., 3,5-dinitrobenzoic acid (DNB) and 2,6-dichloroquinone-4-chloroimide (DCQ) results in the formation of 1:1 charge-transfer complexes as the final products, [(o-tolidine) (acceptor)] and [(p-toluidine) (acceptor)]. The final products of the reactions have been isolated and characterized using FTIR, 1HNMR spectroscopy and elemental analysis as well as photometric titration. The stoichiometry and apparent formation constants of the complexes formed were determined by applying the conventional spectrophotometric molar ratio method. 相似文献
7.
Refat MS El-Korashy SA Ahmed AS 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2008,70(4):840-849
Mn(II), Au(III) and Zr(III) complexes with N-benzoylglycine (hippuric acid) (abbreviation hipH) were synthesized and characterized by elemental analysis, molar conductivity, magnetic measurements, spectral methods (mid-infrared, (1)H NMR, mass, X-ray powder diffraction and UV/vis spectra) and simultaneous thermal analysis (TG and DTG) techniques. The molar conductance measurements proved that all hippuric acid complexes are non-electrolytes. The electronic spectra and magnetic susceptibility measurements were used to infer the structures. The IR spectra of the ligand and its complexes are used to identify the type of bonding. The kinetic thermodynamic parameters such as: E*, DeltaH*, DeltaS* and DeltaG* are estimated from the DTG curves. The free ligand and its complexes have been studied for their possible biological antifungal activity. 相似文献
8.
Efficient Palladium‐Assisted One‐Pot Deprotection of (Acetamidomethyl)Cysteine Following Native Chemical Ligation and/or Desulfurization To Expedite Chemical Protein Synthesis
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Dr. Suman Kumar Maity Muhammad Jbara Shay Laps Prof. Ashraf Brik 《Angewandte Chemie (International ed. in English)》2016,55(28):8108-8112
The acetamidomethyl (Acm) moiety is a widely used cysteine protecting group for the chemical synthesis and semisynthesis of peptide and proteins. However, its removal is not straightforward and requires harsh reaction conditions and additional purification steps before and after the removal step, which extends the synthetic process and reduces the overall yield. To overcome these shortcomings, a method for rapid and efficient Acm removal using PdII complexes in aqueous medium is reported. We show, for the first time, the assembly of three peptide fragments in a one‐pot fashion by native chemical ligation where the Acm moiety was used to protect the N‐terminal Cys of the middle fragment. Importantly, an efficient synthesis of the ubiquitin‐like protein UBL‐5, which contains two native Cys residues, was accomplished through the one‐pot operation of three key steps, namely ligation, desulfurization, and Acm deprotection, highlighting the great utility of the new approach in protein synthesis. 相似文献
9.
Chemical Synthesis of Phosphorylated Histone H2A at Tyr57 Reveals Insight into the Inhibition Mode of the SAGA Deubiquitinating Module
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10.
Enas Aljuhani Amnah M. A. Alsuhaibani A. M. El-Didamony N. Hassan Sameh Abo Taleb Moamen S. Refat 《光谱学与光谱分析》2019,39(7):2316-2324
A new six intraperitoneal injection insulin-mimetic vanadyl(Ⅱ) compounds [(VD-13)(VO+2)(AA-1n)] (where (n=1~6); AA1=isoleucine, AA2=threonine, AA3=proline, AA4=phenylalanine, AA5=lysine and AA6=glutamine) were synthesized by the chemical reactions between vitamin D3 (VD3), VOSO4 and amino acids (AAn) with equal molar ratio 1∶1∶1 in neutralized media. The structures of these complexes were elucidated by spectroscopic methods like, infrared and solid reflectance spectroscopes. Magnetic moments and electronic spectra reveal square pyramid geometrical structure of the complexes. The infrared spectra assignments of these complexes revealed that the chelation towards vanadyl(Ⅳ) ions existed via deprotonation of the hydroxyl group of VD3 drug ligand and so amino acids act as bidentate ligand via N-amino and O-carboxylate groups. The anti-diabetic efficiency of these complexes were evaluated against streptozotocin induced diabetic male albino rats. 相似文献