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Metal Complexes

Qingchun Zhang, Bo Jin, Xiaofang Wang, Shan Lei, Zhaotao Shi, Jia Zhao, Qiangqiang Liu, Rufang Peng
There is a growing interest in the development of new iron chelators as novel promising therapeutic strategies for neurodegenerative disorders. In this article, a series of mono(catecholamine) derivatives, 2,3-bis(hydroxy)- N -(hydroxyacyl)benzamide, containing a pendant hydroxy, have been synthesized and fully characterized by nuclear magnetic resonance, Fourier transform infrared spectroscopy and mass spectrum. The thermodynamic stability of the chelators with FeIII , MgII and ZnII ions was then investigated...
June 2018: Royal Society Open Science
Alessandro Pratesi, Damiano Cirri, Lorenzo Ciofi, Luigi Messori
The reactions of auranofin and three pseudohalide derivatives with bovine serum albumin were explored by ESI-Q-TOF mass spectrometry; a detailed molecular description of the resulting adducts is achieved revealing even subtle differences in reactivity within this series of gold(I) complexes. Our study shows that this kind of investigative approach, formerly applied to the interactions of metal-based drugs with small model proteins of MW 10-15 kDa, e.g., cytochrome c and lysozyme, may now be extended with success to far larger proteins such as serum albumin (MW 66 kDa)...
August 15, 2018: Inorganic Chemistry
Isaac J S De Vlugt, Michael J Lecours, Patrick J J Carr, Ahdia Anwar, Rick A Marta, Eric Fillion, Vincent Steinmetz, W Scott Hopkins
Density functional theory (DFT) calculations and infrared multiple photon dissociation (IRMPD) spectroscopy are employed to probe [TM•(B12 H12 )]- and [TM•(B12 H12 )2 ]2- clusters [TM = Ag(I), Cu(I), Co(II), Ni(II), Zn(II), Cd(II)]. A comparison is made between the charge-transfer properties of the clusters containing the hydrogenated dodecaborate dianions, B12 H12 2- , and the fluorinated analogues, B12 F12 2- , for clusters containing Cd(II), Co(II), Ni(II), and Zn(II). IRMPD of the [TM•(B12 H12 )]- and [TM•(B12 H12 )2 ]2- species yields B12 H11 - via hydride abstraction and B12 H12 - in all cases...
August 15, 2018: Journal of Physical Chemistry. A
Vanessa Moura, Iris Ribeiro, Priscilla Moriggi, Artur Capão, Carolina Salles, Suleima Bitati, Luciano Procópio
To explore how a succession of bacteria grown on steel coupons in a marine environment can influence their corrosion process, we designed a microcosm in laboratory to evaluate corrosion kinetics and microbial diversity over 30 days. The results described a clear influence of corrosion by a succession of different bacterial groups. During the initial period, 2-7 days, a sharp increase in the rate of corrosion was detected accompanied by the presence of Alteromonadaceae, Vibrionaceae, Oceanospirillaceae, Rhodobacteraceae, Rhodospirillaceae and Flavobacteriaceae bacteria families...
August 14, 2018: Archives of Microbiology
Alagesan Muthukumar, Subramani Sangeetha, Govindasamy Sekar
α-Keto amides are a key frame in biology, medicinal chemistry and synthetic chemistry as drug molecules and key intermediates. Based on the structural aspect, an acyclic α-keto amide has multiple reactive centres which have electrophilic and nucleophilic characters. In this review, we focus on the recent developments of both asymmetric and achiral reactions involving acyclic α-keto amides as the reactants for the synthesis of cyclic and acyclic molecules through the formation of C-C, C-O, C-N and C-H bonds...
August 15, 2018: Organic & Biomolecular Chemistry
Bernabé L Rivas, Bruno F Urbano, Julio Sánchez
The polymeric materials have presented a great development in adsorption processes for the treatment of polluted waters. The aim of the current review is to present the recent developments in this field of study by examining research of systems like functional water-soluble polymers and water-soluble polymer-metal complexes coupled to ultrafiltration membranes for decontamination processes in liquid-liquid phase. Noticing that a water-soluble polymer can be turned into insoluble compounds by setting a crosslinking point, connecting the polymer chains leading to polymer resins suitable for solid-liquid extraction processes...
2018: Frontiers in Chemistry
Aiyuan Ma, Xuemei Zheng, Song Li, Yihong Wang, Shan Zhu
Metallurgical slag and dust (MSD) from lead and zinc smelting, steel dust and galvanized steel scrap are important secondary sources of zinc and other valuable metals. This paper describes the production feasibility and rationality of a cleaner zinc recovery process using MSD and a hydrometallurgical method. It was found that the addition of CH3 COONH4 to a NH3 -H2 O system promotes zinc extraction, and 83.76% of zinc could be dissolved and recovered from the MSD under the following conditions: total ammonia concentration of 5 mol l-1 , stirring speed of 300 r...
July 2018: Royal Society Open Science
Saied M Soliman, Jörg H Albering, Assem Barakat
Isatin oxamohydrazide ( L ) reacted with the aqueous solution of silver nitrate at room temperature afforded the polymeric silver(I) nitrato complex, [Ag2 L'(NO3 )2 ] n , (1) of the azine ligand ( L' ). Similarly, the reaction of L with silver(I) perchlorate gave the [Ag2 L'2 (ClO4 )2 ] n , (2) coordination polymer. Careful inspection of the crystals from the nitrato complex preparation showed the presence of another crystalline product which is found to be [Ag(Isatin-3-hydrazone)NO3 ], (3) suggesting that the reaction between silver(I) nitrate and L proceeds first by the hydrolysis of L to the isatin hydrazone which attacks another molecule of L to afford L' ...
July 2018: Royal Society Open Science
Artem R Khabibullin, Aleksandra Karolak, Mikalai M Budzevich, Mark L McLaughlin, David L Morse, Lilia M Woods
The successful delivery of toxic cargo directly to tumor cells is of primary importance in targeted (α) particle therapy. Complexes of radioactive atoms with the 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) chelating agent are considered as effective materials for such delivery processes. The DOTA chelator displays high affinity to radioactive metal isotopes and retains this capability after conjugation to tumor targeting moieties. Although the α-decay chains are well defined for many isotopes, the stability of chelations during the decay process and the impact of released energy on their structures remain unknown...
July 1, 2018: MedChemComm
Jelena M Mašković, Antonios Hatzidimitriou, Ana Damjanović, Tatjana P Stanojković, Srećko R Trifunović, Athina A Geronikaki, Dionysia Papagiannopoulou
A new thiazole-containing multidentate ligand 2-((2-phenylthiazol-4-yl)methylthio)ethanamine, L, was synthesized and used to prepare new complexes of the formula PdII LCl2 (Pd-L), CuII L2 Cl2 (Cu-L) and fac -[Re/99m TcI (CO)3 (L)]+ (Re/99m Tc-L). The ligand L and the metal complexes were characterized spectroscopically. Furthermore, the structures of Re-L and Cu-L were elucidated by X-ray crystallography. Ligand L acts as a bidentate (Nth , S) chelator in Pd-L, as a bidentate (N, S) chelator in Cu-L and as a tridentate (Nth , S, N) chelator in Re-L...
May 1, 2018: MedChemComm
Manzoor Ahmad Malik, Ovas Ahmad Dar, Parveez Gull, Mohmmad Younus Wani, Athar Adil Hashmi
In recent years, the number of people suffering from cancer and multidrug-resistant infections has sharply increased, leaving humanity without any choice but to search for new treatment options and strategies. Although cancer is considered the leading cause of death worldwide, it also paves the way many microbial infections and thus increases this burden manifold. Development of small molecules as anticancer and anti-microbial agents has great potential and a plethora of drugs are already available to combat these diseases...
March 1, 2018: MedChemComm
Yu-Ting Wang, Yan Fang, Meng Zhao, Ming-Xue Li, Yu-Mei Ji, Qiu-Xia Han
In this paper, synthesis and characterization of metal complexes [Cu2 (L)3 ]ClO4 ( 1 ), [Ga(L)2 ]NO3 ·2H2 O ( 2 ) and [In(L)2 ]NO3 ·H2 O ( 3 ) (HL = 2-acetylpyridine N (4)-phenylthiosemicarbazone) was carried out, including elemental analysis, spectral analysis (IR, UV-vis, NMR), and X-ray crystallography. Complex 1 contains one S-bridged binuclear [Cu2 (L)3 ]+ unit, where two Cu atoms display diverse coordination geometries: one being square planar geometry and the other octahedral geometry. Both 2 and 3 are mononuclear complexes, and the metal centers in 2 and 3 are chelated by two NNS tridentate ligands possessing a distorted octahedral geometry...
November 1, 2017: MedChemComm
Michael J Mills, John Nguyen, Susan Jarosz, Mehran Salari, Patrick Hurley
Arteriovenous shunting associated with angiomyolipoma is an unusual entity, which carries important implications to embolization approach. We present a distinctive case involving a 41-year-old woman who presented with retroperitoneal hemorrhage relating to renal angiomyolipoma. During angiography for urgent embolization, a complex vascular supply with arteriovenous shunting was encountered. Superselective embolization using alcohol or small particles is the standard approach to definitive treatment of symptomatic angiomyolipoma; however; their use is precluded in the setting of arteriovenous shunt hemodynamics...
October 2018: Radiology Case Reports
Anne E Robinson, Jessica E Lowe, Eun-Ik Koh, Jeffrey P Henderson
Invasive gram-negative bacteria often express multiple virulence-associated metal ion chelators to combat host-mediated metal deficiencies. Escherichia coli , Klebsiella , and Yersinia pestis isolates encoding the Yersinia High Pathogenicity Island (HPI) secrete yersiniabactin (Ybt), a metallophore originally shown to chelate iron ions during infection. However, our recent demonstration that Ybt also scavenges copper ions during infection led us to question whether it might be capable of retrieving other metals as well...
August 14, 2018: Journal of Biological Chemistry
Waleed M Hussein, Daniel Feder, Gerhard Schenk, Luke W Guddat, Ross P McGeary
Purple acid phosphatases (PAPs) are metalloenzymes that catalyse the hydrolysis of phosphate esters under acidic conditions. Their active site contains a Fe(III)Fe(II) metal centre in mammals and a Fe(III)Zn(II) or Fe(III)Mn(II) metal centre in plants. In humans, elevated PAP levels in serum strongly correlate with the progression of osteoporosis and metabolic bone malignancies, which make PAP a target suitable for the development of chemotherapeutics to combat bone ailments. Due to difficulties in obtaining the human enzyme, the corresponding enzymes from red kidney bean and pig have been used previously to develop specific PAP inhibitors...
August 3, 2018: European Journal of Medicinal Chemistry
Amy L Speelman, Corey J White, Bo Zhang, E Ercan Alp, Jiyong Zhao, Michael Hu, Carsten Krebs, James Penner-Hahn, Nicolai Lehnert
Heme and non-heme iron-nitrosyl complexes are important intermediates in biology. While there are numerous examples of low-spin heme iron-nitrosyl complexes in different oxidation states, much less is known about high-spin (hs) non-heme iron-nitrosyls in oxidation states other than the formally ferrous NO adducts ({FeNO}7 in the Enemark-Feltham notation). In this study, we present a complete series of hs-{Fe-NO}6-8 complexes using the TMG3tren coligand. Redox transformations from the hs-{FeNO}7 complex [Fe(TMG3tren)(NO)]2+ to its {FeNO}6 and {FeNO}8 analogs do not alter the coordination environment of the iron center, allowing for detailed comparisons between these species...
August 14, 2018: Journal of the American Chemical Society
Qilong Gao, Naike Shi, Qiang Sun, Andrea Sanson, Ruggero Milazzo, Alberto Carnera, He Zhu, Saul H Lapidus, Yang Ren, Qingzhen Huang, Jun Chen, Xianran Xing
The understanding of the negative thermal expansion (NTE) mechanism is vital not only for the development of new NTE compounds but also for effectively controlling thermal expansion. Here, we report an interesting isotropic NTE property in cubic GaFe(CN)6 Prussian blue analogues (α l = -3.95 × 10-6 K-1 , 100-475 K), which is a new example to understand the complex NTE mechanism. A combined study of synchrotron X-ray diffraction, X-ray total scattering, X-ray absorption fine structure, neutron powder diffraction, and density functional theory calculations shows that the NTE of GaFe(CN)6 originates from the low-frequency phonons (< ∼100 cm-1 ), which are directly related to the transverse vibrations of the atomic -Ga-N≡C-Fe- chains...
August 14, 2018: Inorganic Chemistry
Cristiano Matricardi, Christoph Hanske, Juan Luis Garcia-Pomar, Judith Langer, Agustin Mihi, Luis M Liz-Marzán
Metal colloids are of great interest in the field of nanophotonics, mainly due to their morphology-dependent optical properties, but also because they are high quality building blocks for complex plasmonic architectures. Close-packed colloidal supercrystals not only serve for investigating the rich plasmonic resonances arising in strongly coupled arrangements, but also enables tailoring the optical response, on both the nano- and the macroscale. Bridging these vastly different length scales at reasonable fabrication costs has remained fundamentally challenging, but is essential for applications in sensing, photovoltaics or optoelectronics, among other fields...
August 14, 2018: ACS Nano
Vera Schroeder, Timothy M Swager
Activating molecules or functional groups with high chemoselectivity in complex environments is the central goal of transition-metal-based catalysis. Promoting strong interactions between a selected substrate and a catalytic system can also be used to create highly selective and customizable sensors, and these concepts are widely recognized for enzymatic processes. We demonstrate the successful translation of organometallic reactions to sensing capability. Specifically, we have developed single-walled carbon nanotube (SWCNT) chemiresistive sensors for the highly selective detection of acrylates using conditions for the aerobic oxidative Heck reaction...
August 14, 2018: Journal of the American Chemical Society
Shuang-Quan Zang, Si Li, Zhao-Yang Wang, Guang-Gang Gao, Bing Li, Peng Luo, Yu-Jin Kong, Hong Liu
Using thiol group modified polyhedral oligomeric silsesquioxane (POSS) as protected ligand, novel atom-precise multi-heteorocluster-based dendrimers Ag₁₂@POSS₆ (1a and 1b) have been assembled for the first time. Through the reactive -SH groups, six POSS shell ligands stabilize the central 12-core silver(I) cluster by diverse Ag-S interactions. When such Ag₁₂@POSS₆ complex was stimulated by different solvents (acetone or tetrahydrofuran), the core Ag₁₂ silver(I) cluster underwent reversible structural transformation between flattened cubo-octahedral (in 1a) and normal cubo-octahedral (in 1b) configuration, concomitant shell POSS clusters rearranging from pseudo-octahedral to quasi-octahedral mode...
August 14, 2018: Angewandte Chemie
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