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1.
Yasuhiro Inada AhmedM. Mohammed HannesH. Loeffler Shigenobu Funahashi 《Helvetica chimica acta》2005,88(3):461-469
Umbrella‐sampling molecular‐dynamics simulations were performed to investigate the water‐exchange reactions of zinc(II), cadmium(II), and mercury(II) ions in aqueous solution. The dissociation of a coordinating water molecule to the M? O distance at 3.34, 3.16, and 3.26 Å for ZnII, CdII, and HgII, respectively, leads the system to a transition state. For ZnII, the first hydration shell is occupied by five spectator water molecules in the transition state, indicating that the water‐exchange reaction proceeds via a dissociative mode of activation. In contrast, the number of spectator water molecules of 5.85 and 5.95 for CdII and HgII, respectively, suggests an associative exchange for these larger metal ions. The average M? O distance of the spectator molecules is shortened by 0.06 Å for the dissociative exchange of ZnII, while it is elongated by 0.04 and 0.03 Å for CdII and HgII, respectively. The water‐exchange rate constants of 4.1×108, 6.8×108, and 1.8×109 s?1 are estimated for ZnII, CdII, and HgII, respectively, at 298 K in terms of the transition‐state theory based on the assumption of a transmission coefficient of unity. 相似文献
2.
Dr. Jakub Šebera Prof. Jaroslav Burda Dr. Michal Straka Prof. Akira Ono Prof. Chojiro Kojima Prof. Yoshiyuki Tanaka Dr. Vladimír Sychrovský 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(30):9884-9894
A reaction mechanism that describes the substitution of two imino protons in a thymine:thymine (T:T) mismatched DNA base pair with a HgII ion, which results in the formation of a (T)N3‐HgII‐N3(T) metal‐mediated base pair was proposed and calculated. The mechanism assumes two key steps: The formation of the first HgII? N3(T) bond is triggered by deprotonation of the imino N3 atom in thymine with a hydroxo ligand on the HgII ion. The formation of the second HgII? N3(T) bond proceeds through water‐assisted tautomerization of the remaining, metal‐nonbonded thymine base or through thymine deprotonation with a hydroxo ligand of the HgII ion already coordinated to the thymine base. The thermodynamic parameters ΔGR=?9.5 kcal mol?1, ΔHR=?4.7 kcal mol?1, and ΔSR=16.0 cal mol?1 K?1 calculated with the ONIOM (B3LYP:BP86) method for the reaction agreed well with the isothermal titration calorimetric (ITC) measurements by Torigoe et al. [H. Torigoe, A. Ono, T. Kozasa, Chem. Eur. J. 2010 , 16, 13218–13225]. The peculiar positive reaction entropy measured previously was due to both dehydration of the metal and the change in chemical bonding. The mercury reactant in the theoretical model contained one hydroxo ligand in accord with the experimental pKa value of 3.6 known for an aqua ligand of a HgII center. The chemical modification of T:T mismatched to the T‐HgII‐T metal‐mediated base pair was modeled for the middle base pair within a trinucleotide B‐DNA duplex, which ensured complete dehydration of the HgII ion during the reaction. 相似文献
3.
Antonio Francs‐Monerris Javier Carmona‐García A. Ulises Acua Juan Z. Dvalos Carlos A. Cuevas Douglas E. Kinnison Joseph S. Francisco Alfonso Saiz‐Lopez Daniel Roca‐Sanjun 《Angewandte Chemie (International ed. in English)》2020,59(19):7605-7610
Mercury is a contaminant of global concern that is transported throughout the atmosphere as elemental mercury Hg0 and its oxidized forms HgI and HgII. The efficient gas‐phase photolysis of HgII and HgI has recently been reported. However, whether the photolysis of HgII leads to other stable HgII species, to HgI, or to Hg0 and its competition with thermal reactivity remain unknown. Herein, we show that all oxidized forms of mercury rapidly revert directly and indirectly to Hg0 by photolysis. Results are based on non‐adiabatic dynamics simulations, in which the photoproduct ratios were determined with maximum errors of 3%. We construct for the first time a complete quantitative mechanism of the photochemical and thermal conversion between atmospheric HgII, HgI, and Hg0 compounds. These results reveal new fundamental chemistry that has broad implications for the global atmospheric Hg cycle. Thus, photoreduction clearly competes with thermal oxidation, with Hg0 being the main photoproduct of HgII photolysis in the atmosphere, which significantly increases the lifetime of this metal in the environment. 相似文献
4.
Akira Ono Hiroki Kanazawa Hikari Ito Misato Goto Koudai Nakamura Hisao Saneyoshi Jiro Kondo 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(47):16991-16994
Numerous applications of metal‐mediated base pairs (metallo‐base‐pairs) to nucleic acid based nanodevices and genetic code expansion have been extensively studied. Many of these metallo‐base‐pairs are formed in DNA and RNA duplexes containing Watson–Crick base pairs. Recently, a crystal structure of a metal–DNA nanowire with an uninterrupted one‐dimensional silver array was reported. We now report the crystal structure of a novel DNA helical wire containing HgII‐mediated T:T and T:G base pairs and water‐mediated C:C base pairs. The Hg‐DNA wire does not contain any Watson–Crick base pairs. Crystals of the Hg‐DNA wire, which is the first DNA wire structure driven by HgII ions, were obtained by mixing the short oligonucleotide d(TTTGC) and HgII ions. This study demonstrates the potential of metallo‐DNA to form various structural components that can be used for functional nanodevices. 相似文献
5.
Crystal Structure of Metallo DNA Duplex Containing Consecutive Watson–Crick‐like T–HgII–T Base Pairs
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Dr. Jiro Kondo Tom Yamada Chika Hirose Dr. Itaru Okamoto Dr. Yoshiyuki Tanaka Prof. Akira Ono 《Angewandte Chemie (International ed. in English)》2014,53(9):2385-2388
The metallo DNA duplex containing mercury‐mediated T–T base pairs is an attractive biomacromolecular nanomaterial which can be applied to nanodevices such as ion sensors. Reported herein is the first crystal structure of a B‐form DNA duplex containing two consecutive T–HgII–T base pairs. The HgII ion occupies the center between two T residues. The N3‐HgII bond distance is 2.0 Å. The relatively short HgII‐HgII distance (3.3 Å) observed in consecutive T–HgII–T base pairs suggests that the metallophilic attraction could exist between them and may stabilize the B‐form double helix. To support this, the DNA duplex is largely distorted and adopts an unusual nonhelical conformation in the absence of HgII. The structure of the metallo DNA duplex itself and the HgII‐induced structural switching from the nonhelical form to the B‐form provide the basis for structure‐based design of metal‐conjugated nucleic acid nanomaterials. 相似文献
6.
Manfredo Hrner Gelson Manzoni de Oliveira Mariana Boneberger Behm Herton Fenner 《无机化学与普通化学杂志》2006,632(4):615-618
A solution of deprotonated 1,3‐bis(4‐bromophenyl)triazene reacts with Hg(CH3COO)2 in methanol / tetrahydrofurane to give yellow crystalline needles of {HgII[NNN(PhBr)2]2}n, a triazenide complex polymer of HgII with metal‐η2,η2‐arene π‐interactions, performed by coordinated single triazenide chains. The crystal structure of the new polymeric complex of HgII belongs to the monoclinic space group P21/n. The lattice of [HgII(BrPhNNNPhBr)2]n can be viewed as a one‐dimensional assembling of planar tectons [HgII(BrPhNNNPhBr)2] linked through metalocene alike HgII‐η2,η2‐arene π‐interactions along the crystallographic b axis. 相似文献
7.
8.
Dr. Marek Łuczkowski Dr. Michał Padjasek Józef Ba Tran Prof. Lars Hemmingsen Olga Kerber Dr. Jelena Habjanič Prof. Dr. Eva Freisinger Prof. Dr. Artur Krężel 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(66):e202202738
In nature, thiolate-based systems are the primary targets of divalent mercury (HgII) toxicity. The formation of Hg(Cys)x cores in catalytic and structural protein centers mediates mercury's toxic effects and ultimately leads to cellular damage. Multiple studies have revealed distinct HgII-thiolate coordination preferences, among which linear HgII complexes are the most commonly observed in solution at physiological pH. Trigonal or tetrahedral geometries are formed at basic pH or in tight intraprotein Cys-rich metal sites. So far, no interprotein tetrahedral HgII complex formed at neutral pH has been reported. Rad50 protein is a part of the multiprotein MRN complex, a major player in DNA damage-repair processes. Its central region consists of a conserved CXXC motif that enables dimerization of two Rad50 molecules by coordinating ZnII. Dimerized motifs form a unique interprotein zinc hook domain (Hk) that is critical for the biological activity of the MRN. Using a series of length-differentiated peptide models of the Pyrococcus furiosus zinc hook domain, we investigated its interaction with HgII. Using UV-Vis, CD, PAC, and 199Hg NMR spectroscopies as well as anisotropy decay, we discovered that all Rad50 fragments preferentially form homodimeric Hg(Hk)2 species with a distorted tetrahedral HgS4 coordination environment at physiological pH; this is the first example of an interprotein mercury site displaying tetrahedral geometry in solution. At higher HgII content, monomeric HgHk complexes with linear geometry are formed. The Hg(Cys)4 core of Rad50 is extremely stable and does not compete with cyanides, NAC, or DTT. Applying ITC, we found that the stability constant of the Rad50 Hg(Hk)2 complex is approximately three orders of magnitude higher than those of the strongest HgII complexes known to date. 相似文献
9.
A. I. Vedernikov L. G. Kuz’mina Yu. A. Strelenko J. A. K. Howard S. P. Gromov 《Russian Chemical Bulletin》2010,59(5):927-940
Novel 15-hydroxybenzomonothia-15-crown-5 containing the sulfur atom linked with the benzene ring and its S-oxide were synthesized. The stability constants for the complexes of the obtained benzocrown ethers and a reference 15-hydroxybenzo-15-crown-5
with Na, Ca, AgI, Cd, HgII, and PbII perchlorates were determined by 1H NMR titration. In MeCN-d3, the benzothiacrown ether demonstrates a high selectivity towards the thio- and oxothiophilic Hg2+ (logK
1 = 7.1) and Pb2+ ions (logK
1 = 7.4). In MeCN-d3-D2O mixtures, the stabilities of the most of complexes decrease sharply due to competitive hydration of the metal cations except
for the “soft” Ag+ and Hg2+ ions having low affinity for the “hard” oxygen atoms and, on the contrary, very high affinity for the “soft” SII atoms. This results in the change in selectivity of complexation: at the water content in solution of 20%, the benzothiacrown
ether binds preferably the Hg2+ (logK
1 = 5.0) and Ag+ ions (logK
1 = 2.7). In MeCN-d3, the benzothiacrown-derived sulfoxide is a weak and non-selective complexing agent towards all the metal cations under study;
the reference 15-hydroxybenzo-15-crown-5 forms more stable complexes with the oxophilic sodium, calcium, and lead(ii) cations. The conformational features of the benzocrown ethers and their metal complexes established by NMR spectroscopy
and X-ray diffraction are discussed. The found characteristics of the complexing ability of benzomonothia-15-crown-5 where
the sulfur atom is in conjugation with the benzene ring reveal that the macrocyclic ligands with such a structure are promising
as high-selective and efficient complexing agents for the “soft” mercury(ii) and silver(i) cations in acetonitrile-water mixtures. 相似文献
10.
11.
Ismail Ercan Filiz Ercan Cengiz Arc Orhan Atakol 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(2):m137-m138
A new tetranuclear CuII–HgII–HgII–CuII complex, [Cu2Hg2Cl4(C18H18N2O2)2], has been prepared by means of a copper complex found in the literature. The molecular structure of this complex was determined by X‐ray diffraction and the Cu–Hg–Hg–Cu chain was seen to be non‐linear. The change in magnetic susceptibility with temperature was recorded for this complex and observed to abide by the Curie–Weiss law. The coordination around the HgII ions is square pyramidal. The Cu?Hg bridging distance is 3.5269 (7) Å. 相似文献
12.
Lau YH Price JR Todd MH Rutledge PJ 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(10):2850-2858
A cyclam‐based fluorescent sensor featuring a novel triazole pendant arm has been synthesised using click chemistry. The sensor is highly responsive to both CuII and HgII in neutral aqueous solution and displays excellent selectivity in the presence of various competing metal ions in 50‐fold excess. The addition of specific anions such as I? and S2O32? causes a complete revival of fluorescence only in the case of HgII, providing a simple and effective method for distinguishing solutions containing CuII, HgII or a mixture of both ions, even in doped seawater samples. X‐ray crystal structures of both the HgII sensor complex and a model CuII complex show that pendant triazole coordination occurs through the central nitrogen atom (N2), providing to the best of our knowledge the first reported examples of this unusual coordination mode in macrocycles. Fluorescence, mass spectrometry and 1H NMR experiments reveal that the mechanism of anion‐induced fluorescence revival involves either displacement of pendant coordination or complete removal of the HgII from the macrocycle, depending on the anion. 相似文献
13.
A new fluorescein-based chemodosimeter (II) for Hg2+ ion was designed and synthesized, and it displayed excellent selective and sensitive toward Hg2+ ion over other commonly metal ions in aqueous media. II was a colorless, non-fluorescent compound. Upon addition of Hg2+ to the solution of II, the thiosemicarbazide moiety of II would undergo an irreversible desulfurization reaction to form its corresponding oxadiazole (IV), a colorful and fluorescent product. During this process, the spirocyclic ring of II was opened, causing instantaneous development of visible color and strong fluorescence emission in the range of 500-600 nm. Based on the above mechanism, a fluorogenic Hg2+-selective chemodosimeter was developed. The fluorescence increase is linearly with Hg2+ concentration up to 1.0 μmol L−1 with a detection limit of 8.5 × 10−10 mol L−1 (3σ). Compared with the rhodamine-type chemodosimeter, II is more stable in aqueous media and exhibits higher sensitivity toward Hg2+. The findings suggest that II will serve as a practical chemodosimeter for rapid detection of Hg2+ concentrations in realistic media. 相似文献
14.
《Arabian Journal of Chemistry》2022,15(9):104080
In the present study, a dual recognition strategy for ultrasensitive detection of Hg2+ was successfully developed for the first time based on aptamer functionalized sulfur quantum dots (Apt-SQDs). The developed Apt-SQDs not only retained the good fluorescence properties of quantum dots but also overcame the problem of poor selectivity of SQDs for heavy metal ions. This system used the dual recognition strategy, including the combination of Sx2? and Hg2+ and T-Hg2+-T structures to excellently identify and capture Hg2+, and an ultrahigh sensitivity fluorescent aptasensor was fabricated. The fluorescent aptasensor had a good response to Hg2+ at concentrations ranging of 10?15 to 10?7 M with an ultralow limit of detection of 0.3 fM, and the response to other metal ions was far less than that to Hg2+. It was successfully applied to detect Hg2+ in nearby environmental water samples (tap water, lake water and river water) with a good recovery rate. Moreover, portable test papers that would be useful for Hg2+ monitoring in environmental water were designed. The dual recognition strategy not only achieves ultrasensitive fluorescent detection of Hg2+ but also provides a new insight into the further expansion of the application of SQDs. 相似文献
15.
Dr. Alain Manceau Dr. Paco Bustamante Dr. Ahmed Haouz Prof. Dr. Jean Paul Bourdineaud Maria Gonzalez-Rey Dr. Cyprien Lemouchi Prof. Dr. Isabelle Gautier-Luneau Valérie Geertsen Elodie Barruet Dr. Mauro Rovezzi Dr. Pieter Glatzel Dr. Serge Pin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(4):997-1009
Of all divalent metals, mercury (HgII) has the highest affinity for metallothioneins. HgII is considered to be enclosed in the α and β domains as tetrahedral α-type Hg4Cys11-12 and β-type Hg3Cys9 clusters similar to CdII and ZnII. However, neither the four-fold coordination of Hg nor the existence of Hg–Hg atomic pairs have ever been demonstrated, and the HgII partitioning among the two protein domains is unknown. Using high energy-resolution XANES spectroscopy, MP2 geometry optimization, and biochemical analysis, evidence for the coexistence of two-coordinate Hg-thiolate complex and four-coordinate Hg-thiolate cluster with a metacinnabar-type (β-HgS) structure in the α domain of separate metallothionein molecules from blue mussel under in vivo exposure is provided. The findings suggest that the CXXC claw setting of thiolate donors, which only exists in the α domain, acts as a nucleation center for the polynuclear complex and that the five CXC motifs from this domain serve as the cluster-forming motifs. Oligomerization is driven by metallophilic Hg⋅⋅⋅Hg interactions. Our results provide clues as to why Hg has higher affinity for the α than the β domain. More generally, this work provides a foundation for understanding how metallothioneins mediate mercury detoxification in the cell under in vivo conditions. 相似文献
16.
《Acta Crystallographica. Section C, Structural Chemistry》2017,73(9):724-730
3‐(Pyridin‐4‐yl)acetylacetone (HacacPy) acts as a pyridine‐type ligand towards CdII and HgII halides. With CdBr2, the one‐dimensional polymer [Cd(μ‐Br)2(HacacPy)Cd(μ‐Br)2(HacacPy)2]∞ is obtained in which five‐ and six‐coordinated CdII cations alternate in the chain direction. Reaction of HacacPy with HgBr2 results in [Hg(μ‐Br)Br(HacacPy)]∞, a polymer in which each HgII centre is tetracoordinated. In both compounds, each metal(II) cation is N‐coordinated by at least one HacacPy ligand. Equimolar reaction between these CdII and HgII derivatives, either conducted in ethanol as solvent or via grinding in the solid state, leads to ligand redistribution and the formation of the well‐ordered bimetallic polymer catena‐poly[[bromidomercury(II)]‐μ‐bromido‐[aquabis[4‐hydroxy‐3‐(pyridin‐4‐yl)pent‐3‐en‐2‐one]cadmium(II)]‐di‐μ‐bromido], [CdHgBr4(C10H11NO2)2(H2O)]n or [{HgBr}(μ‐Br){(HacacPy)2Cd(H2O)}(μ‐Br)2]∞. HgII and CdII cations alternate in the [100] direction. The HacacPy ligands do not bind to the HgII cations, which are tetracoordinated by three bridging and one terminal bromide ligand. The CdII centres adopt an only slightly distorted octahedral coordination. Three bromide ligands link them in a (2 + 1) pattern to neighbouring HgII atoms; two HacacPy ligands in a cis configuration, acting as N‐atom donors, and a terminal aqua ligand complete the coordination sphere. Classical O—H…Br hydrogen bonds stabilize the polymeric chain. O—H…O hydrogen bonds between aqua H atoms and the uncoordinated carbonyl group of an HacacPy ligand in a neighbouring strand in the c direction link the chains into layers in the (010) plane. 相似文献
17.
Mohamed M. Shoukry Kamal Aziz Eman M. Shoukry Samia Hamdallah 《Transition Metal Chemistry》1989,14(2):115-118
Summary The formation constants of 1-phenyl-3-thiazole-2-ylthiourea complexes with some bivalent metal ions (CuII, NiII, ZnII and MnII) have been determined in 75% EtOH–H2O. Complexes of CuII, NiII, ZnII, HgII and PdII have been isolated and characterized by conductance, i.r., electronic spectra and magnetic measurements. The ligand forms ML complexes with CuII and HgII and ML2 with NiII, ZnII and PdII, where L is the uninegatively charged bidentate ligand and binds through the ring nitrogen and thiocarbonyl sulphur atoms. 相似文献
18.
Matthias Weil 《无机化学与普通化学杂志》2005,631(8):1346-1348
Light‐yellow single crystals of the mixed‐valent mercury‐rich basic nitrate Hg8O4(OH)(NO3)5 were obtained as a by‐product at 85 °C from a melt consisting of stoichiometric amounts of (HgI2)(NO3)2·2H2O and HgII(OH)(NO3). The title compound, represented by the more detailed formula HgI2(NO3)2·HgII(OH)(NO3)·HgII(NO3)2·4HgIIO, exhibits a new structure type (monoclinic, C2/c, Z = 4, a = 6.7708(7), b = 11.6692(11), c = 24.492(2) Å, β = 96.851(2)°, 2920 structure factors, 178 parameters, R1[F2 > 2σ(F2)] = 0.0316) and is made up of almost linear [O‐HgII‐O] and [O‐HgI‐HgI‐O] building blocks with typical HgII‐O distances around 2.06Å and a HgI‐O distance of 2.13Å. The Hg22+ dumbbell exhibits a characteristic Hg‐Hg distance of 2.5079(7) Å. The different types of mercury‐oxygen units form a complex three‐dimensional network exhibiting large cavities which are occupied by the nitrate groups. The NO3? anions show only weak interactions between the nitrate oxygen atoms and the mercury atoms which are at distances > 2.6Å from one another. One of the three crystallographically independent nitrate groups is disordered. 相似文献
19.
Dr. Marek Łuczkowski Dr. Brian A. Zeider Alia V. H. Hinz Dr. Monika Stachura Dr. Saumen Chakraborty Prof. Lars Hemmingsen Dr. David L. Huffman Prof. Vincent L. Pecoraro 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(27):9042-9049
Although metal ion homeostasis in cells is often mediated through metallochaperones, there are opportunities for toxic metals to be sequestered through the existing transport apparatus. Proper trafficking of CuI in human cells is partially achieved through complexation by HAH1, the human metallochaperone responsible for copper delivery to the Wilson and Menkes ATPase located in the trans‐Golgi apparatus. In addition to binding copper, HAH1 strongly complexes HgII, with the X‐ray structure of this complex previously described. It is important to clarify the solution behavior of these systems and, therefore, the binding of HgII to HAH1 was probed over the pH range 7.5 to 9.4 using 199Hg NMR, 199mHg PAC and UV–visible spectroscopies. The metal‐dependent protein association over this pH range was examined using analytical gel‐filtration. It can be concluded that at pH 7.5, HgII is bound to a monomeric HAH1 as a two coordinate, linear complex (HgS2), like the HgII–Atx1 X‐ray structure (PDB ID: 1CC8). At pH 9.4, HgII promotes HAH1 association, leading to formation of HgS3 and HgS4 complexes, which are in exchange on the μs–ns time scale. Thus, structures that may represent central intermediates in the process of metal ion transfer, as well as their exchange kinetics have been characterized. 相似文献
20.
Synthesis and properties of 7-formyl-8-hydroxyquinoline and its transition metal complexes 总被引:4,自引:0,他引:4
Ahmed A. El-Asmy Adel Z. El-Sonbati Abdulla A. Ba-Issa Mohamed Mounir 《Transition Metal Chemistry》1990,15(3):222-225
Summary CoII, NiII, CuII, CdII and HgII complexes of 7-formyl-8-hydroxyquinoline (HFHQ) have been prepared, and characterized by elemental analysis, molar conductivities, electronic and i.r. spectra, and magnetic measurements. It was found that the ligand acts as a neutral monodentate or a monobasic bidentate donor. The CoII, NiII and CuII complexes possess, respectively, tetrahedral, octahedral and square-planar structures based on their magnetic and electronic spectral data. The electrical conductivities of HFHQ and its metal complexes were measured at different temperatures and their activation energies were calculated. The values obtained for the CoII, NiII, CdII and HgII complexes agree fairly well with those reported for semiconductors. The ligand was tested as a corrosion inhibitor for aluminium; the limiting concentration of HFHQ to give maximum efficiency (99.2%) is 10–3 mole dm–3 at 22°C. The metal-ligand ratios and apparent formation constants for the species generated in ethanol solution were determined spectrophotometrically. 相似文献