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Kim S, Kim D, Song Y, Lee HJ, Lee H. Synthesis and Structural Characterisation of Palladium(II) Complexes with N,N′,N-Tridentate N′-Substituted N,N-Di(2-picolyl)amines and their Application to Methyl Methacrylate Polymerisation. Aust J Chem 2014. [DOI: 10.1071/ch13731] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The reaction of [Pd(CH3CN)2Cl2] with N′-substituted N,N-di(2-picolyl)amine-based ancillary ligands, for example N,N-di(2-picolyl)cyclohexylmethylamine (L1), N,N-di(2-picolyl)benzylamine (L2), N,N-di(2-picolyl)aniline (L3), and 1,4-bis[bis(2-pyridylmethyl)aminomethyl]benzene (L4), in the presence of NaClO4 in ethanol yields a new series of [(NN′N)PdCl]X (X = ClO4, Cl) complexes, i.e. mononuclear [LnPdCl]ClO4 (Ln = L1, L2, L3) and binuclear [L4Pd2Cl2]Cl2. X-Ray crystallographic analysis determined that the Pd atom in complexes [(NN′N)PdCl]X showed a slightly distorted square-planar geometry involving three nitrogen atoms and a chlorido ligand. Moreover, the unit cell included a ClO4– or Cl– anion as the counterion. The complex [L1PdCl]ClO4 showed the highest catalytic activity for the polymerisation of methyl methacrylate in the presence of modified methylaluminoxane at 60°C among the mononuclear PdII complexes. Specifically, the activity of binuclear [L4Pd2Cl2]Cl2 was 2-fold higher than the corresponding mononuclear [L2PdCl]ClO4 per active palladium metal centre.
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Lassalle-Kaiser B, Hureau C, Pantazis DA, Pushkar Y, Guillot R, Yachandra VK, Yano J, Neese F, Anxolabéhère-Mallart E. Activation of a water molecule using a mononuclear Mn complex: from Mn-aquo, to Mn-hydroxo, to Mn-oxyl via charge compensation. ENERGY & ENVIRONMENTAL SCIENCE 2010; 3:924-938. [PMID: 24772190 PMCID: PMC3997265 DOI: 10.1039/b926990h] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Activation of a water molecule by the electrochemical oxidation of a Mn-aquo complex accompanied by the loss of protons is reported. The sequential (2 × 1 electron/1 proton) and direct (2 electron/2 proton) proton-coupled electrochemical oxidation of a non-porphyrinic six-coordinated Mn(II)OH2 complex into a mononuclear Mn(O) complex is described. The intermediate Mn(III)OH2 and Mn(III)OH complexes are electrochemically prepared and analysed. Complete deprotonation of the coordinated water molecule in the Mn(O) complex is confirmed by electrochemical data while the analysis of EXAFS data reveals a gradual shortening of an Mn-O bond upon oxidation from Mn(II)OH2 to Mn(III)OH and Mn(O). Reactivity experiments, DFT calculations and XANES pre-edge features provide strong evidence that the bonding in Mn(O) is best characterized by a Mn(III)-oxyl description. Such oxyl species could play a crucial role in natural and artificial water splitting reactions. We provide here a synthetic example for such species, obtained by electrochemical activation of a water ligand.
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Affiliation(s)
- Benedikt Lassalle-Kaiser
- Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), UMR–CNRS 8182, Univ Paris Sud 11, F-91405 Orsay, France
| | - Christelle Hureau
- CNRS, LCC (Laboratoire de Chimie de Coordination), 205 Route de Narbonne, 31077 Toulouse, France, Université de Toulouse, UPS, INPT, LCC, 31077 Toulouse, France. ; Fax: +33(0)5 61 33 30 03; Tel: +33(0)5 61 33 31 20
| | - Dimitrios A. Pantazis
- Institute for Physical and Theoretical Chemistry, University of Bonn, Wegelerstrasse 12, D-53115 Bonn, Germany, Max-Planck Institute for Bioinorganic Chemistry, Stiftstr.32-34, D-45470 Mulheim an der Ruhr, Germany
| | - Yulia Pushkar
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd., Berkeley, CA, 94720, USA
| | - Régis Guillot
- Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), UMR–CNRS 8182, Univ Paris Sud 11, F-91405 Orsay, France. ; Fax: +33 5(0)169 15 47 54; Tel: + 33(0)1 69 15 47 52
| | - Vittal K. Yachandra
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd., Berkeley, CA, 94720, USA
| | - Junko Yano
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd., Berkeley, CA, 94720, USA
| | - Frank Neese
- Institute for Physical and Theoretical Chemistry, University of Bonn, Wegelerstrasse 12, D-53115 Bonn, Germany, Max-Planck Institute for Bioinorganic Chemistry, Stiftstr.32-34, D-45470 Mulheim an der Ruhr, Germany
| | - Elodie Anxolabéhère-Mallart
- Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), UMR–CNRS 8182, Univ Paris Sud 11, F-91405 Orsay, France
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3
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Singla M, Mathur P. Oxidation of alcohols using a manganese (II) complex based on a pentakis benzimidazole amide ligand. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2009; 74:536-543. [PMID: 19660981 DOI: 10.1016/j.saa.2009.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2008] [Revised: 05/13/2009] [Accepted: 07/01/2009] [Indexed: 05/28/2023]
Abstract
A pentakis benzimidazole based penta-amide ligand diethylenetriamine-N,N,N',N',N''-pentakis(2-methyl benzimidazolyl)penta-amide [GBDTPA] has been synthesized and utilized to prepare Mn (II) complexes of general composition [Mn(2)(GBDTPA)X(4)], where X is an exogenous anionic ligand (X = Cl(-), NO(3)(-) and Br(-)). The oxidation of alcohols has been investigated using [Mn(2)(GBDTPA)Cl(4)] as the catalyst and TBHP as an alternate source of oxygen. The respective aldehydic products have been isolated and characterized by (1)H NMR.
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Affiliation(s)
- Manisha Singla
- Department of Chemistry, Delhi University, Delhi 110007, India.
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4
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Groni S, Hureau C, Guillot R, Blondin G, Blain G, Anxolabéhère-Mallart E. Characterizations of chloro and aqua Mn(II) mononuclear complexes with amino-pyridine ligands. Comparison of their electrochemical properties with those of Fe(II) counterparts. Inorg Chem 2009; 47:11783-97. [PMID: 19007154 DOI: 10.1021/ic8015172] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The solution behavior of mononuclear Mn(II) complexes, namely, [(L(5)(2))MnCl](+) (1), [(L(5)(3))MnCl](+) (2), [(L(5)(2))Mn(OH(2))](2+) (3), [(L(5)(3))Mn(OH(2))](2+) (4), and [(L(6)(2))Mn(OH(2))](2+) (6), with L(5)(2/3) and L(6)(2) being penta- and hexadentate amino-pyridine ligands, is investigated in MeCN using EPR, UV-vis spectroscopies, and electrochemistry. The addition of one chloride ion onto species 6 leads to the formation of the complex [(L(6)(2))MnCl](+) (5) that is X-ray characterized. EPR and UV-vis spectra indicate that structure and redox states of complexes 1-6 are maintained in MeCN solution. Chloro complexes 1, 2, and 5 show reversible Mn(II)/Mn(III) process at 0.95, 1.02, and 1.05 V vs SCE, respectively, whereas solvated complexes 3, 4, and 6 show an irreversible anodic peak around 1.5 V vs SCE. Electrochemical oxidations of 1 and 5 leading to the Mn(III) complexes [(L(5)(2))MnCl](2+) (7) and [(L(6)(2))MnCl](2+) (8) are successful. The UV-vis signatures of 7 and 8 show features associated with chloro to Mn(III) LMCT and d-d transitions. The X-ray characterization of the heptacoordinated Mn(III) species 8 is also reported. The analogous electrochemical generation of the corresponding Mn(III) complex was not possible when starting from 2. The new mixed-valence di-mu-oxo [(L(5)(2))Mn(muO)(2)Mn(L(5)(2))](3+) species (9) can be obtained from 3, whereas the sister [(L(5)(3))Mn(muO)(2)Mn(L(5)(3))](3+) species can not be generated from 4. Such different responses upon oxidations are commented on with the help of comparison with related Mn/Fe complexes and are discussed in relation with the size of the metallacycle formed between the diamino bridge and the metal center (5- vs 6-membered). Lastly, a comparison between redox potentials of the studied Mn(II) complexes with those of Fe(II) analogues is drawn and completed with previously reported data on Mn/Fe isostructural systems. This gives us the opportunity to get some indirect insights into the metal specificity encountered in enzymes among which superoxide dismutase is the archetypal model.
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Affiliation(s)
- Sihem Groni
- Equipe de Chimie Inorganique, Institut de Chimie Moléculaire et des Matériaux d'Orsay, Université Paris-Sud 11, UMR 8182 CNRS, Orsay F-91405, France
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5
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Kinetics and mechanism of the formation of (1,8)bis(2-hydroxybenzamido)3,6-diazaoctaneiron(III) and its reactions with thiocyanate, azide, acetate, sulfur(IV) and ascorbic acid in solution, and the synthesis and characterization of a novel oxo bridged diiron(III) complex. The role of phenol–amide–amine coordination. TRANSIT METAL CHEM 2006. [DOI: 10.1007/s11243-006-0079-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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6
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Sabater L, Guillot R, Aukauloo A. Pillared salicylaldehyde derivatives as building blocks for the design of cofacial salen-type ligands. Tetrahedron Lett 2005. [DOI: 10.1016/j.tetlet.2005.02.092] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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