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Mannepalli LK, Gadipelly C, Deshmukh G, Likhar P, Pottabathula S. Advances in C-C Coupling Reactions Catalyzed by Homogeneous Phosphine Free Palladium Catalysts. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2020. [DOI: 10.1246/bcsj.20190307] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
| | - Chandrakanth Gadipelly
- The Wolfson Faculty of Chemical Engineering, Technion-Israel Institute of Technology, Haifa – 3200003, Israel
| | - Gunjan Deshmukh
- Department of Chemical Engineering, Institute of Chemical Technology, Mumbai – 400019, India
| | - Pravin Likhar
- I & PC Division, CSIR – Indian Institute of Chemical Technology, Hyderabad – 500607, India
| | - Srinivas Pottabathula
- R&D, Vadodara Manufacturing Division, Reliance Industries Limited, Vadodara 391346, India
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Ramachandran R, Viswanathamurthi P. Ruthenium(II) carbonyl complexes containing pyridine carboxamide ligands and PPh₃/AsPh₃/Py coligands: synthesis, spectral characterization, catalytic and antioxidant studies. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2013; 103:53-61. [PMID: 23257330 DOI: 10.1016/j.saa.2012.10.072] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 10/25/2012] [Accepted: 10/30/2012] [Indexed: 06/01/2023]
Abstract
New ruthenium(II) carbonyl complexes bearing pyridine carboxamide and triphenylphosphine/triphenylarsine/pyridine have been prepared by direct reaction of ruthenium(II) precursors with some pyridine carboxamide ligands, N,N-bis(2-pyridinecarboxamide)-1,2-ethane (H(2)L(1)), N,N-bis(2-pyridinecarboxamide)-1,2-benzene (H(2)L(2)) and N,N-bis(2-pyridinecarboxamide)-trans-1,2-cyclohexane (H(2)L(3)). The organic ligands offering two N(amide) and two N(pyridine) donor sites to the metal centre. They have been characterized by elemental analyses, FT-IR, UV-Visible, NMR ((1)H, (13)C and (31)P) and ESI-MS techniques. Based on the above data, an octahedral structure has been assigned for all the complexes. The catalytic efficiency of the complexes in transfer hydrogenation of ketones in the presence of iPrOH/KOH and N-alkylation of amine in the presence of tBuOK was examined. Furthermore, the antioxidant activity of the ligands and its ruthenium(II) complexes were determined by DPPH radical, nitric oxide radical, hydroxyl radical and hydrogen peroxide scavenging methods, which indicates that the ruthenium(II) complexes exhibit more effective antioxidant activity than the ligands alone.
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3
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Rajput A, Mukherjee R. Coordination chemistry with pyridine/pyrazine amide ligands. Some noteworthy results. Coord Chem Rev 2013. [DOI: 10.1016/j.ccr.2012.03.024] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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4
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Sanna D, Pecoraro VL, Micera G, Garribba E. Application of DFT methods to the study of the coordination environment of the VO2+ ion in V proteins. J Biol Inorg Chem 2012; 17:773-90. [PMID: 22526563 DOI: 10.1007/s00775-012-0895-y] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Accepted: 03/18/2012] [Indexed: 11/24/2022]
Abstract
Density functional theory (DFT) methods were used to simulate the environment of vanadium in several V proteins, such as vanadyl-substituted carboxypeptidase (sites A and B), vanadyl-substituted chloroplast F(1)-ATPase (CF(1); site 3), the reduced inactive form of vanadium bromoperoxidase (VBrPO; low- and high-pH sites), and vanadyl-substituted imidazole glycerol phosphate dehydratase (IGPD; sites α, β, and γ). Structural, electron paramagnetic resonance, and electron spin echo envelope modulation parameters were calculated and compared with the experimental values. All the simulations were performed in water within the framework of the polarizable continuum model. The angular dependence of [Formula: see text] and [Formula: see text] on the dihedral angle θ between the V=O and N-C bonds and on the angle φ between the V=O and V-N bonds, where N is the coordinated aromatic nitrogen atom, was also found. From the results it emerges that it is possible to model the active site of a vanadium protein through DFT methods and determine its structure through the comparison between the calculated and experimental spectroscopic parameters. The calculations confirm that the donor sets of sites B and A of vanadyl-substituted carboxypeptidase are [[Formula: see text], H(2)O, H(2)O, H(2)O] and [N(His)(||), N(His)(⊥), [Formula: see text], H(2)O], and that the donor set of site 3 of CF(1)-ATPase is [[Formula: see text], OH(Thr), H(2)O, H(2)O, [Formula: see text]]. For VBrPO, the coordination modes [N(His)(||), N(His)(∠), OH(Ser), H(2)O, H(2)O(ax)] for the low-pH site and [N(His)(||), N(His)(∠), OH(Ser), OH(-), H(2)O(ax)] or [N(His)(||), N(His)(∠), [Formula: see text], H(2)O] for the high-pH site, with an imidazole ring of histidine strongly displaced from the equatorial plane, can be proposed. Finally, for sites α, β, and γ of IGPD, the subsequent deprotonation of one, two, and three imidazole rings of histidine and the participation of a carboxylate group of a glutamate residue ([N(His)(||), [Formula: see text], H(2)O, H(2)O], [N(His)(||), N(His)(||), [Formula: see text], H(2)O], and [N(His)(||), N(His)(||), [Formula: see text], OH(-), [Formula: see text]], respectively) seems to be the most plausible hypothesis.
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Affiliation(s)
- Daniele Sanna
- Istituto CNR di Chimica Biomolecolare, Trav. La Crucca 3, 07040, Sassari, Italy
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5
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Epoxidation of cyclooctene using soluble or MCM-41-supported molybdenum tetracarbonyl–pyridylimine complexes as catalyst precursors. J Organomet Chem 2011. [DOI: 10.1016/j.jorganchem.2011.07.040] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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6
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Swanson RA, Haywood RS, Gibbons JB, Cordova KE, Patrick BO, Moore C, Rheingold AL, Daley CJ. Diamidato-bis(diphenylphosphino) platinum(II) complexes: Synthesis, characterization, and reactivity in the presence of acid. Inorganica Chim Acta 2011. [DOI: 10.1016/j.ica.2010.12.056] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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7
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Steric effect on construction of extended architectures of Ni(II) complexes directed by intermolecular C-H...F and C-H...O interactions. J STRUCT CHEM+ 2010. [DOI: 10.1007/s10947-010-0140-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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8
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Micera G, Garribba E. Application of DFT Methods in the Study of VIVO2+-Peptide Interactions. Eur J Inorg Chem 2010. [DOI: 10.1002/ejic.201000382] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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9
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Song YJ, Lee JH, Koo HG, Lee TG, Myoung SH, Kim C, Kim SJ, Kim Y. Two isomers containing a [Cu(Me2bpzb)] unit: Molecule (0-D) and 1-D. INORG CHEM COMMUN 2010. [DOI: 10.1016/j.inoche.2010.03.039] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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10
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Pisano L, Kiss D, Várnagy K, Sanna D, Micera G, Garribba E. Potentiometric, Spectroscopic and DFT Study of the V
IV
O Complexes Formed by Di(pyridin‐2‐yl) Ligands. Eur J Inorg Chem 2009. [DOI: 10.1002/ejic.200900045] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Luisa Pisano
- Department of Chemistry, University of Sassari, Via Vienna 2, 07100 Sassari, Italy, Fax: +39‐79‐212069
| | - Dóra Kiss
- Department of Inorganic and Analytical Chemistry, University of Debrecen, 4010 Debrecen, Hungary
| | - Katalin Várnagy
- Department of Inorganic and Analytical Chemistry, University of Debrecen, 4010 Debrecen, Hungary
| | - Daniele Sanna
- Istituto C.N.R. di Chimica Biomolecolare Trav. La Crucca 3, 07040 Li Punti, Sassari, Italy
| | - Giovanni Micera
- Department of Chemistry, University of Sassari, Via Vienna 2, 07100 Sassari, Italy, Fax: +39‐79‐212069
| | - Eugenio Garribba
- Department of Chemistry, University of Sassari, Via Vienna 2, 07100 Sassari, Italy, Fax: +39‐79‐212069
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Lee DN, Ryu JY, Kwak H, Lee YM, Lee SH, Poong JI, Lee J, Shin W, Kim C, Kim SJ, Kim Y. Steric effect on construction of Cu(II) complexes with pyridine carboxamide ligands. J Mol Struct 2008. [DOI: 10.1016/j.molstruc.2007.10.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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12
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Várnagy K, Csorba T, Kiss D, Garribba E, Micera G, Sanna D. VIVO Complexes of Bis(imidazol-2-yl) Derivatives: A Potentiometric, Spectroscopic and DFT Study. Eur J Inorg Chem 2007. [DOI: 10.1002/ejic.200700502] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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13
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Lee AV, Schafer LL. Modular
N
,
O
‐Chelating Ligands: Group‐4 Amidate Complexes for Catalytic Hydroamination. Eur J Inorg Chem 2007. [DOI: 10.1002/ejic.200700036] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Alison V. Lee
- Department of Chemistry, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Laurel L. Schafer
- Department of Chemistry, The University of British Columbia, Vancouver, British Columbia, Canada
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Swanson RA, Patrick BO, Ferguson MJ, Daley CJ. Tetracoordinate diamidato-bis(phosphanyl) metal systems: Synthesis, characterization, and electrochemical analysis of palladium(II) complexes. Inorganica Chim Acta 2007. [DOI: 10.1016/j.ica.2006.12.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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15
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Jacob W, Mukherjee R. Synthesis, structure, and properties of monomeric Fe(II), Co(II), and Ni(II) complexes of neutral N-(aryl)-2-pyridinecarboxamides. Inorganica Chim Acta 2006. [DOI: 10.1016/j.ica.2006.07.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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16
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Christofis P, Katsarou M, Papakyriakou A, Sanakis Y, Katsaros N, Psomas G. Mononuclear metal complexes with Piroxicam: Synthesis, structure and biological activity. J Inorg Biochem 2005; 99:2197-210. [PMID: 16176832 DOI: 10.1016/j.jinorgbio.2005.07.020] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2005] [Revised: 07/28/2005] [Accepted: 07/30/2005] [Indexed: 12/21/2022]
Abstract
Piroxicam (=Hpir) is a non-steroidal anti-inflammatory and an anti-arthritic drug. VO(2+), Mn(2+), Fe(3+), MoO(2)(2+) and UO(2)(2+) complexes with deprotonated piroxicam have been prepared and characterized with the use of infrared, UV-Vis, nuclear magnetic resonance and electron paramagnetic resonance spectroscopies. The experimental data suggest that piroxicam acts as a deprotonated bidentate ligand in all complexes and is coordinated to the metal ion through the pyridine nitrogen and the amide oxygen. Molecular mechanics calculations in the gas state have been performed in order to propose a model for the Fe(3+), VO(2+) and MoO(2)(2+) complexes. Potential anticancer cytostatic and cytotoxic effects of piroxicam complexes with VO(2+), Mn(2+) and MoO(2)(2+) on human promyelocytic leukemia HL-60 cells have been investigated. Among all complexes, only VO(pir)(2)(H(2)O) clearly induces apoptosis after 24-h incubation, whereas piroxicam induces apoptosis after 57-h incubation.
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Affiliation(s)
- Petros Christofis
- Institute of Physical Chemistry, NCSR Demokritos, 15310 Aghia Paraskevi Attikis, GR15310 Athens, Greece
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Zhong C, Zhao M, Stern C, Barrett AGM, Hoffman BM. Novel Metal-Linked Face-to-Face Porphyrazine Dimer. Inorg Chem 2005; 44:8272-6. [PMID: 16270965 DOI: 10.1021/ic050788s] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report the synthesis and physical studies of a novel porphyrazine (pz) dimer [1[Ni,Cu]]2, which has Ni(II) ions incorporated into the pz cores and is linked by two Cu(II) ions coordinated to bis(picolinamide) chelates attached to the pz periphery. [1[Ni,Cu]]2 was prepared from precursor pz 2 with a selenodiazole ring fused to the pz core. This ring was deprotected to form the diamino-pz 3, which reacted with 2 mol of picolinoyl chloride hydrochloride to form pz 1[2H,2H], with peripheral bis(picolinamide) chelates; this was metalated to form [1[Ni,Cu]]2. The crystal structures of 1[2H,2H] and [1[Ni,Cu]]2 are presented. The latter is a dimer in which parallel, face-to-face pz's with an average separation of 3.30 angstroms are linked through the peripheral picolinamide ligands by a pair of peripheral Cu(II) ions. Each Cu(II) is coordinated with distorted square-planar geometry by a picolinamide from each pz. In this report, we focus on the interaction of these two peripheral Cu(II) ions. We discuss the preparation and magnetic properties of the pz dimer complex [1[Ni,Cu]]2 with two Cu(II) ions in the peripheral chelate but a diamagnetic metal ion Ni(II) in the pz core. Although [1[Ni,Cu]]2 contains two Cu(II) ions (S = 1/2), we could detect no electron paramagnetic resonance signal, which suggests very strong antiferromagnetic exchange between those two Cu(II) ions. Temperature-dependent magnetic susceptibility measurement gives an exchange splitting between the S = 0 ground state and the excited triplet state of delta = 660 cm(-1).
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Affiliation(s)
- Chang Zhong
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113, USA
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Kandasamy K, Singh HB, Butcher RJ, Jasinski JP. Synthesis, structure, and catalytic properties of V(IV), Mn(III), Mo(VI), and U(VI) complexes containing bidentate (N, O) oxazine and oxazoline ligands. Inorg Chem 2005; 43:5704-13. [PMID: 15332823 DOI: 10.1021/ic0352093] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Synthesis of seven complexes containing oxazoline ([(L(1))(2)V=O] (4), [(L(1))(2)MoO(2)] (5), [(L(1))(2)UO(2)] (6); HL(1) (1) [HL(1) = 2-(4',4'-dimethyl-3'-4'-dihydroxazol-2'-yl)phenol]), chiral oxazoline ([(L(2))(2)UO(2)] (7); HL(2) (2) [HL(2) = (4'R)-2-(4'-ethyl-3'4'-dihyroxazol-2'-yl)phenol]), and oxazine ([(L(3))(2)V=O] (8), [(L(3))(2)Mn(CH(3)COO(-))] (9), [(L(3))(2)Co] (10); HL(3) (3) [HL(3) = 2-(5,6-dihydro-4H-1,3-oxazolinyl)phenol]) and their characterization by various techniques such as UV-vis, IR, and EPR spectroscopy, mass spectrometry, cyclic voltammetry, and elemental analysis are reported. The novel oxazine (3) and complexes 4, 5, 8 and 9 were also characterized by X-ray crystallography. Oxazine 3 crystallizes in the monoclinic system with the P2(1)/n space group, complexes 4 and 9 crystallize in the monoclinic system with the P2(1)/c space group, and complexes 5 and 8 crystallize in the orthorhombic system with the C222(1) space group and the P2(1)2(1)2(1) chiral space group, respectively. The representative synthetic procedure involves the reaction of metal acetate or acetylacetonate derivatives with corresponding ligand in ethanol. Addition of Mn(OAc)(2).4H(2)O to an ethanol solution of 3 gave the unexpected complex Mn(L(3))(2).(CH(3)COO(-)) (9) where the acetate group is coordinated with the metal center in a bidentate fashion. The catalytic activity of complexes 4-9 for oxidation of styrene with tert-butyl hydroperoxide was tested. In all cases, benzaldehyde formed exclusively as the oxidation product.
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Affiliation(s)
- Karuppasamy Kandasamy
- Departments of Chemistry, Indian Institute of Technology, Bombay, Powai, Mumbai 400 076, India
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Garg BS, Kumar DN, Sarbhai M. Copper(II) complexes of new biomimetic polydentate amide ligands: a spectroscopic study. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2005; 61:141-147. [PMID: 15556432 DOI: 10.1016/j.saa.2004.04.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2003] [Revised: 04/02/2004] [Accepted: 04/06/2004] [Indexed: 05/24/2023]
Abstract
Complexes of Cu(II) with N,N'-bis(3-carboxy-1-oxopropanyl)-1,2-ethylenediamine(C(10)H(16)N(2)O(6),L(1)), N,N'-bis(3-carboxy-1-oxopropanyl)-1,2-phenylenediamine(C(14)H(16)N(2)O(6),L(2)), N,N'-bis(2-carboxy-1-oxophenelenyl)-1,2-phenylenediamine(C(22)H(16)N(2)O(6),L(3)) and N,N'-bis(3-carboxy-1-oxoprop-2-enyl)-1,2-phenylenediamine(C(14)H(12)N(2)O(6),L(4)) have been prepared and characterised by elemental analyses, vibrational spectra, magnetic susceptibility measurements, ligand field spectra, EPR spectra, thermal studies and X-ray diffraction spectra. Vibrational spectra indicate coordination of amide and carboxylate oxygens of the ligands giving a MO(4) square planar chromophore. Ligand field and EPR spectra support square planar geometry around Cu(II). [Cu(L(1))] complex has the maximum activation energy and [Cu(L(3))] complex has the minimum activation energy.
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Affiliation(s)
- Bhagwan S Garg
- Department of Chemistry, University of Delhi, Delhi 110 007, India
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Kumar Singh A, Mukherjee R. Structure and properties of bivalent nickel and copper complexes with pyrazine-amide-thioether coordination: stabilization of trivalent nickel. Dalton Trans 2005:2886-91. [PMID: 16094477 DOI: 10.1039/b504893a] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Acyclic pyrazine-2-carboxamide and thioether containing hexadentate ligand 1,4-bis[o-(pyrazine-2-carboxamidophenyl)]-1,4-dithiobutane (H(2)bpzctb), in its deprotonated form, has afforded light brown [Ni(II)(bpzctb)](1)(S=1) and green [Cu(II)(bpzctb)](2)(S=1/2) complexes. The crystal structures of 1.CH(3)OH and 2.CH(2)Cl(2) revealed that in these complexes the ligand coordinates in a hexadentate mode, affording examples of distorted octahedral M(II)N(2)(pyrazine)N'(2)(amide)S(2)(thioether) coordination. Each complex exhibits in CH(2)Cl(2) a reversible to quasireversible cyclic voltammetric response, corresponding to the Ni(III)/Ni(II)(1) and Cu(II)/Cu(I)(2) redox process. The E(1/2) values reveal that the complexes of bpzctb(2-) are uniformly more anodic by approximately 0.2 V than those of the corresponding complexes with the analogous pyridine ligand, 1,4-bis[o-(pyridine-2-carboxamidophenyl)]-1,4-dithiobutane (H(2)bpctb), attesting that compared to pyridine, pyrazine is a better stabilizer of the Ni(ii) or Cu(i) state. Coulometric oxidation of the previously reported complex [Ni(II)(bpctb)] and 1 generates [Ni(III)(bpctb)](+) and [Ni(III)(bpzctb)](+) species, which exhibit a LMCT transition in the 470--480 nm region and axial EPR spectra corresponding to a tetragonally elongated octahedral geometry. Complex 2 exhibits EPR spectra characteristic of the d(z(2)) ground state.
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Affiliation(s)
- Akhilesh Kumar Singh
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208 016, India
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Smith KI, Borer LL, Olmstead MM. Vanadium(IV) and vanadium(V) complexes of salicyladimine ligands. Inorg Chem 2004; 42:7410-5. [PMID: 14606836 DOI: 10.1021/ic034640p] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The synthesis and characterization of a V(IV) and a V(V) complex of the salicyladimine ligand system are described. The reaction of salicylaldehyde and 1,3-diaminohydroxypropane with vanadyl sulfate produced a monomer (VOL1) which, upon heating in methanol, crystallized as a V(V) complex (VO(2)L1). The reaction of 3-methoxysalicylaldehyde, 1,3-diaminohydroxypropane, and vanadyl sulfate resulted in a binuclear complex held together by hydrogen bonding (VOL2). VOL1 was determined to catalyze the epoxidation of cyclohexene better than VOL2. The synthesis and characterization of VOL1, VOL2, and VO(2)L1 are described. The role of each complex as a catalyst for the epoxidation of cyclohexene is investigated. Results indicate that the V(V) complex performs better than either of the V(IV) complexes.
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Affiliation(s)
- Kathryn I Smith
- Department of Chemistry, California State University Sacramento, 6000 J Street, Sacramento, California 95819, USA
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Garg BS, Nandan Kumar D, Sarbhai M, Reddy MJ. Spectral studies of dimeric copper(II) complexes of acid amide derivatives as models for type III copper enzymes. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2003; 59:2775-2783. [PMID: 14499838 DOI: 10.1016/s1386-1425(03)00060-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Dimeric (hydrated and anhydrated) complexes of Cu(II) with N,N'-bis(3-carboxy-1-oxo-2-prop-2-enyl)ethylenediamine(BCOPENH(2), A) and N,N'-bis(2-carboxy-1-oxo-phenylenyl)ethylenediamine(BCOPHENH(2), B) have been prepared and characterised by elemental analysis, magnetic susceptibility measurements, EPR, thermal and spectral (IR, UV/Vis) studies. EPR parameters and magnetic behaviour indicates that the complexes are antiferromagnetic in nature and most likely adopt the typical carboxylate cage structure. Interesting amide bonding patterns have been observed and various EPR parameters have been evaluated on the basis of these studies, tentative probable structures of the complexes have been proposed.
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Affiliation(s)
- Bhagwan S Garg
- Department of Chemistry, University of Delhi, Delhi 110007, India
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Elias H, Schwartze-Eidam S, Wannowius KJ. Kinetics and mechanism of ligand substitution in bis(N-alkylsalicylaldiminato)oxovanadium(IV) complexes. Inorg Chem 2003; 42:2878-85. [PMID: 12716179 DOI: 10.1021/ic020682m] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Conventional and stopped-flow spectrophotometry was used to to study the kinetics of ligand substitution in a number of bis(N-alkylsalicylaldiminato)oxovanadium(IV) complexes (=VO(R-X-sal)(2)) by 1,1,1- trifluoropentane-2,4-dione (=Htfpd) in acetone, according to the following reaction: VO(R-X-sal)(2) + 2Htfpd --> VO(tfpd)(2) + 2R-X-salH. The acronym R-X-salH refers to N-alkylsalicylaldimines with substituents X = H, Cl, Br, CH(3), and NO(2) in the 5-position of the salicylaldehyde ring and N-alkyl groups R = n-propyl, isopropyl, phenyl, and neopentyl. Under excess conditions ([Htfpd](0) >> [VO(R-X-sal)(2)](0)), substitution by Htfpd occurs in two observable steps, as characterized by pseudo-first-order rate constants k(obsd(1)) and k(obsd(2)). Both rate constants increase linearly with [Htfpd](0) according to k(obsd(1)) = k(s(1)) + k(1)[Htfpd](0) and k(obsd(2)) = k(s(2)) + k(2)[Htfpd](0), with k(s(1)) and k(s(2)) describing small contributions of solvent-initiated pathways. Depending on the nature of R and X, second-order rate constants k(1) and k(2) lie in the range 0.098-0.87 M(-1) s(-1) (k(1)) and 0.022-0.41 M(-1) s(-1) (k(2)) at 298 K. For ligand substitution in the system VO(n-propyl-sal)(2)/Htfpd, the activation parameters DeltaH++ = 35.8 +/- 2.8 kJ mol(-1) and DeltaS++ = -146 +/- 23 J K(-1) mol(-1) (k(1)) and DeltaH++ = 40.2 +/- 1.3 kJ mol(-1) and DeltaS++ = -142 +/- 11 J K(-1) mol(-1) (k(2)) were obtained. The Lewis acidity of the complexes VO(n-propyl-X-sal)(2) with X = H, Cl, Br, CH(3), and NO(2) was quantified spectrophotometrically by determination of equilibrium constant K(py), describing the formation of the adduct VO(n-propyl-X-sal)(2).pyridine. The adduct VO(tfpd)(2).n-propyl-salH, formed as product in the system VO(n-propyl-sal)(2)/Htfpd, was characterized by its dissociation constant, K(D) = (3.30 +/- 0.10) x 10(-3) M. The mechanism suggested for the two-step substitution process is based on initial formation of the adducts VO(R-X-sal)(2).Htfpd (step 1) and VO(R-X-sal)(tfpd).Htfpd (step 2).
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Affiliation(s)
- Horst Elias
- Eduard Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Petersenstrasse 18, D-64287 Darmstadt, Germany.
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Samanta S, Ghosh D, Mukhopadhyay S, Endo A, Weakley TJR, Chaudhury M. Oxovanadium(IV) and -(V) complexes of dithiocarbazate-based tridentate Schiff base ligands: syntheses, structure, and photochemical reactivity of compounds involving imidazole derivatives as coligands. Inorg Chem 2003; 42:1508-17. [PMID: 12611517 DOI: 10.1021/ic020438v] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The tridentate dithiocarbazate-based Schiff base ligands H(2)L (S-methyl-3-((5-R-2-hydroxyphenyl)methyl)dithiocarbazate, R = NO(2), L = L(2); R = Br, L = L(3)) react with [VO(acac)(2)] in the presence of imidazole derivatives as coligands to form oxovanadium(IV) and cis-dioxovanadium(V) complexes. With benzimidazole and N-methylimidazole, the products are oxovanadium(IV) complexes, viz. [VOL(3)(BzIm)].0.5CH(3)CN (1a) and [VOL(N-MeIm)(2)] (L = L(3), 1b; L = L(2), 1c), respectively. In both 1a,b, the O and S donor atoms of the tridentate ligand are cis to the terminal oxo group (in the "equatorial" plane) and mutually trans, but the N donor atom is respectively cis and trans to the oxo atom, as revealed from X-ray crystallography. When imidazole or 4-methylimidazole is used as the ancillary ligand, the products obtained are water-soluble cis-dioxovanadium(V) complexes [VO(2)L(R'-ImH)] (L = L(3) and L(2), R' = H and Me, 2a-d). These compounds have zigzag chain structures in the solid state as confirmed by X-ray crystallographic investigations of 2a,d, involving an alternating array of LVO(2)(-) species and the imidazolium counterions held together by Coulombic interactions and strong hydrogen bonding. Complexes 2a-d are stable in water or methanol. In aprotic solvents, viz. CH(3)CN, DMF, or DMSO, however, they undergo photochemical transformation when exposed to visible light. The putative product is a mixed-oxidation divanadium(IV/V) species obtained by photoinduced reduction as established by EPR, electronic spectroscopy, and dynamic (1)H NMR experiments.
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Affiliation(s)
- Satyabrata Samanta
- Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, Kolkata 700 032, India
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Huang BH, Yu TL, Huang YL, Ko BT, Lin CC. Reactions of amides with organoaluminum compounds: factors affecting the coordination mode of aluminum amidates. Inorg Chem 2002; 41:2987-94. [PMID: 12033910 DOI: 10.1021/ic011072+] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Factors affecting the coordination mode of an amidato group on aluminum will be presented. The reaction of N-tert-butylalkylacetamide ((t)BuNHCR([double bond]O)) with 1.1 molar equiv of Me(3)Al in refluxing hexane affords a pentacoordinated, dimeric compound [Me(2)Al[eta(2)-(t)BuNC(R)(mu(2)-O)]](2) (3, R = p-(t)Bu-C(6)H(4); 4, R = 2,6-F,F-C(6)H(3); 5, R = Me; 6, R = CF(3); 7, R = p-F(3)C-C(6)H(4)). However, in the presence of 2.2 molar equiv of Me(3)Al, N-tert-butyl-4-tert-butylbenzamide ((t)BuNHC(p-(t)Bu-C(6)H(4))([double bond]O in refluxing hexane gives [Me(2)Al[eta(2)-(t)BuNC(p-(t)Bu-C(6)H(4))(mu(2)-O)]AlMe(3)], 8. In contrast, the reaction of R'NHCR' '([double bond]O) with 1 molar equiv of R(3)Al at room temperature produces tetracoordinated, dimeric, eight-membered ring aluminum compounds [R(2)Al[mu,eta(2)-R'NC(R' ')O]](2) (9, R = Me, R' = 2,6-(i)Pr, (i)()Pr-C(6)H(3), R' ' = Ph; 10, R = Me, R' = (i)Bu, R' ' = Ph; 11, R = Et, R' = Bn, R' ' = Ph; 12, R = Me, R' = Ph, R' ' = CF(3); 13, R = Me, R' = Bn, R' ' = CF(3)). On the other hand, 4'-chlorobenzanilide ((p-Cl-C(6)H(4))NHCPh([double bond]O)) reacts with R(3)Al to produce trimeric, twelve-membered ring aluminum compounds [R(2)Al[mu, eta(2)-(p-Cl-C(6)H(4))NC(Ph)O]](3) (14, R = Me; 15, R = Et). Furthermore, the reaction of 2'-methoxybenzanilide with 1 molar equiv of Me(3)Al in hexane yields a dinuclear aluminum complex [Me(2)Al(o-OMe-Ph)NC(Ph)(O)AlMe(3)], 16.
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Affiliation(s)
- Bor-Hunn Huang
- Department of Chemistry, National Chung-Hsing University, Taichung 402, Taiwan, Republic of China
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Bhattacharyya S, Mukhopadhyay S, Samanta S, Weakley TJR, Chaudhury M. Synthesis, characterization, and reactivity of mononuclear O,N-chelated vanadium(IV) and -(III) complexes of methyl 2-Aminocyclopent-1-ene-1-dithiocarboxylate based ligand: reporting an example of conformational isomerism in the solid state. Inorg Chem 2002; 41:2433-40. [PMID: 11978110 DOI: 10.1021/ic0108639] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Vanadium(IV) and -(III) complexes of a tetradentate N(2)OS Schiff base ligand H(2)L [derived from methyl 2-((beta-aminoethyl)amino)cyclopent-1-ene-1-dithiocarboxylate and salicylaldehyde] are reported. In all the complexes, the ligand acts in a bidentate (N,O) fashion leaving a part containing the N,S donor set uncoordinated. The oxovanadium(IV) complex [VO(HL)(2)] (1) is obtained by the reaction between [VO(acac)(2)] and H(2)L. In the solid state, compound 1 has two conformational isomers 1a and 1b; both have been characterized by X-ray crystallography. Compound 1a has the syn conformation that enforces the donor atoms around the metal center to adopt a distorted tbp structure (tau = 0.55). Isomer 1b on the other hand has an anti conformation with almost a regular square pyramidal geometry (tau = 0.06) around vanadium. In solution, however, 1 prefers to be in the square pyramidal form. A second variety of vanadyl complex [VO(L(cyclic))(2)](I(3))(2) (2) with a new bidentate O,N donor ligand involving isothiazolium moiety has been obtained by a ligand-based oxidation of the precursor complex 1 with iodine. Preliminary X-ray and FAB mass spectroscopic data of 2 have supported the formation of a heterocyclic moiety by a ring closure reaction involving a N-S bond. Vanadium(III) complex [V(acac)(HL)(2)] (3) has been obtained through partial ligand displacement of [V(acac)(3)] with H(2)L. Compound 3 has almost a regular octahedral structure completed by two bidentate HL ligands along with an acetylacetonate molecule. Electronic spectra, magnetism, EPR, and redox properties of these compounds are reported.
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Affiliation(s)
- Sudeep Bhattacharyya
- Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, Kolkata 700 032, India
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