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C Allen Chang, Hwa-Yu Lee, Syue-Liang Lin, Ching-Ning Meng, Tsung-Ta Wu
Potentiometric speciation studies, mass spectrometry, and DFT calculations helped to predict the various structural possibilities of the dinuclear trivalent lanthanide ion (LnIII , Ln=La, Eu, Tb, Yb, Y) complexes of a novel macrocyclic ligand, m-ODO2A-dimer (H4 L), to correlate with their luminescence properties and the promoted BNPP and HPNP phosphodiester bond hydrolysis reaction rates. The stability constants of the dinuclear Ln2 (m-ODO2A-dimer) complexes and various hydrolytic species confirmed by mass spectrometry were determined...
April 25, 2018: Chemistry: a European Journal
Davood Zare, Yan Suffren, Homayoun Nozary, Andreas Hauser, Claude Piguet
The kinetic lability of hexadentate gallium-based tripods is sufficient to ensure thermodynamic self-assembly of luminescent heterodimetallic [GaLn(L3)3 ](6+) helicates on the hour time scale, where Ln is a trivalent 4f-block cation. The inertness is, however, large enough for preserving the triple-helical structure when [GaLn(L3)3 ](6+) is exposed to lanthanide exchange. The connection of a second gallium-based tripod further slows down the exchange processes to such an extent that spectroscopically active [CrErCr(L4)3 ](9+) can be diluted into closed-shell [GaYGa(L4)3 ](9+) matrices without metal scrambling...
September 28, 2017: Angewandte Chemie
Christoph Kaub, Sergei Lebedkin, Sebastian Bestgen, Ralf Köppe, Manfred M Kappes, Peter W Roesky
To force metal ions in heterometallic coinage metal complexes into preset compartments, we have synthesized a ligand with two N-heterocyclic carbenes (NHCs) separated by a methylene bridge and two bipyridine moieties tethered to each NHC moiety. By using this ligand, tetranuclear heterodimetallic gold/copper and gold/silver complexes were obtained. These complexes show an unprecedented V-shape or linear MAu2 M (M = Cu, Ag) configuration in the solid state. The photophysical properties of the new compounds are significantly affected by the complexed metal ions...
August 24, 2017: Chemical Communications: Chem Comm
Joan Gónzalez-Fabra, Nuno A G Bandeira, Verónica Velasco, Leoní A Barrios, David Aguilà, Simon J Teat, Olivier Roubeau, Carles Bo, Guillem Aromí
The solid-state and solution configurations of the heterodimetallic complexes (Hpy)[LaEr(HL)3 (NO3 )(py)(H2 O)] (1), (Hpy)[CeEr(HL)3 (NO3 )(py)(H2 O)] (2), (Hpy)[CeGd(HL)3 (NO3 )(py)(H2 O)] (3), (Hpy)[PrSm(HL)3 (NO3 )(py)(H2 O)] (4), and (Hpy)2 [LaYb(HL)3 (NO3 )(H2 O)](NO3 ) (5), in which H3 L is 6-(3-oxo-3-(2-hydroxyphenyl)propionyl)pyridine-2-carboxylic acid and py is pyridine, were analyzed experimentally and by using DFT calculations. Complexes 3, 4, and 5 are described here for the first time, and were analyzed by using single-crystal X-ray diffraction and mass spectrometry...
April 11, 2017: Chemistry: a European Journal
Lucile Chatelain, Floriana Tuna, Jacques Pécaut, Marinella Mazzanti
Trinuclear versus dinuclear heterodimetallic UV O2 + Co2+ complexes were selectively assembled via a cation-cation interaction by tuning the ligand. The trimeric complex 2, with a linear [Co-O[double bond, length as m-dash]U[double bond, length as m-dash]O-Co] core, exhibits magnetic exchange and slow relaxation with a reversal barrier of 30.5 ± 0.9 K providing the first example of a U-Co exchange-coupled SMM.
May 2, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Ying Wang, Wei Jia, Ran Chen, Xiao-Jun Zhao, Zhong-Liang Wang
The first K/Cd heterodimetallic complex {[Cd1.5(TTPE)1.5Cl3K(H2O)3]·3H2O}n (1b) based on triazole has been generated from {[Cd(TTPE)(HCOO)](NO3)·3DMAC·H2O}n (1) during the ion- and solvent-exchange experiment in an irreversible SC-SC transformation. Based on its luminescence properties, we have, for the first time, demonstrated that 1b is a heterodimetallic sensor for detection of high-explosives and cyano molecules.
January 3, 2017: Chemical Communications: Chem Comm
Hui-Min Wen, Jin-Yun Wang, Li-Yi Zhang, Lin-Xi Shi, Zhong-Ning Chen
Heterodimetallic Ru-Fe complexes [(tppz)(PPh3)2RuL](ClO4) (L = C[triple bond, length as m-dash]CFc, [](ClO4); C[triple bond, length as m-dash]C-C6H4-C[triple bond, length as m-dash]CFc), [](ClO4); C[triple bond, length as m-dash]C-C6H4-C6H4-C[triple bond, length as m-dash]CFc, [](ClO4)) were synthesized by the reactions of [(tppz)(PPh3)2RuCl](ClO4) (tppz = 2,3,5,6-tetrakis(2-pyridyl)pyrazine) with ferrocence-acetylide ligands and characterized by ESI-MS, and (1)H and (31)P NMR spectroscopies. The structure of [](PF6) was determined by X-ray crystallography...
June 28, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
Joan Serrano-Plana, Isaac Garcia-Bosch, Anna Company, Miquel Costas
Dioxygen is widely used in nature as oxidant. Nature itself has served as inspiration to use O2 in chemical synthesis. However, the use of dioxygen as an oxidant is not straightforward. Its triplet ground-state electronic structure makes it unreactive toward most organic substrates. In natural systems, metalloenzymes activate O2 by reducing it to more reactive peroxide (O2(2-)) or superoxide (O2(-)) forms. Over the years, the development of model systems containing transition metals has become a convenient tool for unravelling O2-activation mechanistic aspects and reproducing the oxidative activity of enzymes...
August 18, 2015: Accounts of Chemical Research
Javier Ruiz, Lucía García, Marilín Vivanco, Ángela Berros, Juan Francisco Van der Maelen
By means of a combined experimental and theoretical approach, the electronic features and chemical behavior of metalla-N-heterocyclic carbenes (MNHCs, N-heterocyclic carbenes containing a metal atom within the heterocyclic skeleton) have been established and compared with those of classical NHCs. MNHCs are strongly basic (proton affinity and pK(a) values around 290 kcal mol(-1) and 36, respectively) with a narrow singlet-triplet gap (around 23 kcal mol(-1)). MNHCs can be generated from the corresponding metalla-imidazolium salts and trapped by addition of transition-metal complexes affording the corresponding heterodimetallic dicarbene derivatives, which can serve as carbene transfer agents...
March 27, 2015: Angewandte Chemie
Joan Serrano-Plana, Miquel Costas, Anna Company
A novel unsymmetric dinucleating ligand (L(N3N4)) combining a tridentate and a tetradentate binding sites linked through a m-xylyl spacer was synthesized as ligand scaffold for preparing homo- and dimetallic complexes, where the two metal ions are bound in two different coordination environments. Site-selective binding of different metal ions is demonstrated. L(N3N4) is able to discriminate between Cu(I) and a complementary metal (M' = Cu(I), Zn(II), Fe(II), Cu(II), or Ga(III)) so that pure heterodimetallic complexes with a general formula [Cu(I)M'(L(N3N4))](n+) are synthesized...
December 15, 2014: Inorganic Chemistry
Lucile Chatelain, James P S Walsh, Jacques Pécaut, Floriana Tuna, Marinella Mazzanti
Mixed-metal uranium compounds are very attractive candidates in the design of single-molecule magnets (SMMs), but only one 3d-5f hetero-polymetallic SMM containing a uranium center is known. Herein, we report two trimeric heterodimetallic 3d-5f complexes self-assembled by cation-cation interactions between a uranyl(V) complex and a TPA-capped M(II)  complex (M=Mn (1), Cd (2); TPA=tris(2-pyridylmethyl)amine). The metal centers were strategically chosen to promote the formation of discrete molecules rather than extended chains...
December 1, 2014: Angewandte Chemie
David L Tierney, Gerhard Schenk
In this mini-review, we briefly discuss the physical origin of x-ray absorption spectroscopy (XAS) before illustrating its application using dinuclear metallohydrolases as exemplary systems. The systems we have selected for illustrative purposes present a challenging problem for XAS, one that is ideal to demonstrate the potential of this methodology for structure/function studies of metalloenzymes in general. When the metal ion is redox active, XAS provides a sensitive measure of oxidation-state-dependent differences...
September 16, 2014: Biophysical Journal
David Aguilà, Leoní A Barrios, Verónica Velasco, Olivier Roubeau, Ana Repollés, Pablo J Alonso, Javier Sesé, Simon J Teat, Fernando Luis, Guillem Aromí
A major challenge for realizing quantum computation is finding suitable systems to embody quantum bits (qubits) and quantum gates (qugates) in a robust and scalable architecture. An emerging bottom-up approach uses the electronic spins of lanthanides. Universal qugates may then be engineered by arranging in a molecule two interacting and different lanthanide ions. Preparing heterometallic lanthanide species is, however, extremely challenging. We have discovered a method to obtain [LnLn'] complexes with the appropriate requirements...
October 8, 2014: Journal of the American Chemical Society
M Hunger, C Limberg, P Kircher
Fluorinated alkoxide ligands RO(-) (R=CH(CF3 )2 ) are the key to the isolation of compounds of the type [Cp2 Mo(OR)2 ]. When electron-donating groups R are employed, the Mo(OR)2 moiety can, and necessarily has to, serve as a ligand for Lewis acidic fragments, allowing the isolation and structural characterization of the first heterodimetallic alkoxide containing a Bi and a Mo center (1).
1999: Angewandte Chemie
Hao Yang, Mahesh Aitha, Amy R Marts, Alyssa Hetrick, Brian Bennett, Michael W Crowder, David L Tierney
In an effort to characterize the roles of each metal ion in metallo-β-lactamase NDM-1, heterodimetallic analogues (CoCo-, ZnCo-, and CoCd-) of the enzyme were generated and characterized. UV-vis, (1)H NMR, EPR, and EXAFS spectroscopies were used to confirm the fidelity of the metal substitutions, including the presence of a homogeneous, heterodimetallic cluster, with a single-atom bridge. This marks the first preparation of a metallo-β-lactamase selectively substituted with a paramagnetic metal ion, Co(II), either in the Zn1 (CoCd-NDM-1) or in the Zn2 site (ZnCo-NDM-1), as well as both (CoCo-NDM-1)...
May 21, 2014: Journal of the American Chemical Society
Sara Sabater, Jose A Mata, Eduardo Peris
Catalytic hydrodefluorination of organic molecules is a major organometallic challenge, owing to the strength of C-F sigma bonds, and it is a process with multiple industrial applications. Here we report a new heterodimetallic ruthenium-palladium complex based on a triazolyl-di-ylidene ligand. The complex is remarkably active in the hydrodefluorination of aromatic and aliphatic carbon-fluorine bonds under mild reaction conditions. We observe that both metals are required to promote the reaction process. The overall process implies that the palladium fragment facilitates the C-F activation, whereas the ruthenium centre allows the reduction of the substrate via transfer hydrogenation from isopropanol/sodium t-butoxide...
2013: Nature Communications
Si-Hai Wu, Jiang-Yang Shao, Hong-Wei Kang, Jiannian Yao, Yu-Wu Zhong
Four heterodimetallic complexes [Ru(Fcdpb)(L)](PF6) (Fcdpb=2-deprotonated form of 1,3-di(2-pyridyl)-5-ferrocenylbenzene; L=2,6-bis-(N-methylbenzimidazolyl)-pyridine (Mebip), 2,2':6',2''-terpyridine (tpy), 4-nitro-2,2':6',2''-terpyridine (NO2tpy), and trimethyl-4,4',4''-tricarboxylate-2,2':6',2''-terpyridine (Me3tctpy)) have been prepared. The electrochemical and spectroelectrochemical properties of these complexes have been examined in CH2Cl2, CH3NO2, CH3CN, and acetone. These complexes display two consecutive redox couples owing to the stepwise oxidation of the ferrocene (Fc) and ruthenium units, respectively...
November 2013: Chemistry, An Asian Journal
Sara Sabater, Jose A Mata, Eduardo Peris
A triazolyl-di-ylidene ligand has been used for the preparation of a homodimetallic complex of gold, and a heterodimetallic compound of gold and iridium. Both complexes have been fully characterized and their molecular structures have been determined by means of X-ray diffraction. The catalytic properties of these two complexes have been evaluated in the reduction of nitroarenes by transfer hydrogenation using primary alcohols. The two complexes afford different reaction products; whereas the Au(I)-Au(I) catalyst yields a hydroxylamine, the Ir(III)-Au(I) complex facilitates the formation of an imine...
May 14, 2012: Chemistry: a European Journal
Loi H Do, Stephen J Lippard
A dinucleating macrocycle, H(2)PIM, containing phenoxylimine metal-binding units has been prepared. Reaction of H(2)PIM with [Fe(2)(Mes)(4)] (Mes = 2,4,6-trimethylphenyl) and sterically hindered carboxylic acids, Ph(3)CCO(2)H or Ar(Tol)CO(2)H (2,6-bis(p-tolyl)benzoic acid), afforded complexes [Fe(2)(PIM)(Ph(3)CCO(2))(2)] (1) and [Fe(2)(PIM)(Ar(Tol)CO(2))(2)] (2), respectively. X-ray diffraction studies revealed that these diiron(II) complexes closely mimic the active site structures of the hydroxylase components of bacterial multicomponent monooxygenases (BMMs), particularly the syn disposition of the nitrogen donor atoms and the bridging μ-η(1)η(2) and μ-η(1)η(1) modes of the carboxylate ligands at the diiron(II) centers...
July 13, 2011: Journal of the American Chemical Society
Si-Hai Wu, Stephen E Burkhardt, Jiannian Yao, Yu-Wu Zhong, Héctor D Abruña
The reaction of 2,3-di(2-pyridyl)-5,6-diphenylpyrazine (dpdpz) with K(2)PtCl(4) in a mixture of acetonitrile and water afforded mono-Pt complex (dpdpz)PtCl(2)4 in good yield, with two lateral pyridine nitrogen atoms binding to the metal center. Two types of Ru(II)-Pt(II) heterodimetallic complexes bridged by dpdpz, namely, [(bpy)(2)Ru(dpdpz)Pt(C≡CC(6)H(4)R)](2+) (7-9, R = H, NMe(2), or Cl, respectively) and [(tpy)Ru(dpdpz)Pt(C≡CPh)] (+) (12), were then designed and prepared, where bpy = 2,2'-bipyridine and tpy = 2,2';6',2''-terpyridine...
May 2, 2011: Inorganic Chemistry
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