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A potent anesthetic drug salt: experimental and computational studies. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2022.133049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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2
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Synthesis, structure, magnetic properties and DFT study of a dinuclear copper(II) macrocyclic complex containing acetate groups. Inorganica Chim Acta 2021. [DOI: 10.1016/j.ica.2021.120310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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3
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Electrochemical behavior, structural, morphological, Calf Thymus-DNA interaction and in-vitro antimicrobial studies of synthesized Schiff base transition metal complexes. Heliyon 2019; 5:e02039. [PMID: 31334376 PMCID: PMC6614710 DOI: 10.1016/j.heliyon.2019.e02039] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 06/10/2019] [Accepted: 07/01/2019] [Indexed: 11/30/2022] Open
Abstract
New tetradentate Schiff base transition metal complexes have been derived from salicylidene-4-imino-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one and histidine were characterized by CHN analysis, magnetic susceptibility measurements, molar conductance, FAB-MS, IR, 1H-NMR, UV, CV, EPR, Fluorescence emission, AFM and Powder XRD techniques. AFM images and Powder XRD data endure that the complexes are nano-size grains with polycrystalline structure. The spectral evidences showed that all the metal chelates are square planar geometry except [VOL] complex which exist square-pyramidal geometry. Electrochemical data (CV) for [CuL] and [VOL] complexes in acetonitrile solution indicates that the redox potential of metal ions is affected by the coordinated ligand. Electron Spin Resonance (ESR) spectra of [CuL] and [VOL] complexes were well coinciding with proposed geometries and other reported complexes. CT-DNA interaction studies of [CuL] complex reveals that an intercalation binding mode occurs between complex and DNA base pairs. The in vitro antimicrobial activity of complexes has been tested against the growth of some fungal and bacterial species persist that chelates have better control than ligand.
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Dinuclear CuI
and AgI
Pyrazolates Supported with Tertiary Phosphines: Synthesis, Structures, and Photophysical Properties. Eur J Inorg Chem 2019. [DOI: 10.1002/ejic.201801318] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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5
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Synthesis, characterization, crystal structure and DFT study of a dinuclear zinc(II) macrocyclic complex. Polyhedron 2016. [DOI: 10.1016/j.poly.2016.08.036] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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6
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γ-Irradiation and characterization of synthesized methoxybenzylpyrimidine formimidate Schiff-base and some metal-complex derivatives. ARAB J CHEM 2016. [DOI: 10.1016/j.arabjc.2011.09.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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8
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Dicopper(II) pyrazolenophanes: Ligand effects on their structures and magnetic properties. Coord Chem Rev 2016. [DOI: 10.1016/j.ccr.2016.02.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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9
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Synthesis, characterization and crystal structure of dinuclear cobalt(II) macrocyclic complexes, containing thiocyanate and azide groups. Polyhedron 2016. [DOI: 10.1016/j.poly.2016.01.042] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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10
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A double decker type complex: copper(i) iodide complexation with mixed donor macrocycles via [1 : 1] and [2 : 2] cyclisations. Dalton Trans 2016; 45:4528-33. [PMID: 26674476 DOI: 10.1039/c5dt03751d] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
19-membered and a 38-membered macrocycles obtained as a mixture via respective [1 : 1] and [2 : 2] cyclisations were separated and their coordination behaviours with copper(i) iodide were investigated. One of the notable products isolated is a tetranuclear bis(macrocycle) complex with the larger macrocycle adopting a double decker type structure. Furthermore, removal of the lattice solvent molecules in the above complex in air motivates the displacement of the double decker units along the a-axis by sliding in a single-crystal-to-single-crystal manner.
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Ruthenium(III) Complexes of Heterocyclic Tridentate (ONN) Schiff Base: Synthesis, Characterization and its Biological Properties as an Antiradical and Antiproliferative Agent. Int J Mol Sci 2016; 17:ijms17010060. [PMID: 26742030 PMCID: PMC4730305 DOI: 10.3390/ijms17010060] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2015] [Revised: 11/11/2015] [Accepted: 11/13/2015] [Indexed: 02/04/2023] Open
Abstract
The current work reports the synthesis, spectroscopic studies, antiradical and antiproliferative properties of four ruthenium(III) complexes of heterocyclic tridentate Schiff base bearing a simple 2′,4′-dihydroxyacetophenone functionality and ethylenediamine as the bridging ligand with RCHO moiety. The reaction of the tridentate ligands with RuCl3·3H2O lead to the formation of neutral complexes of the type [Ru(L)Cl2(H2O)] (where L = tridentate NNO ligands). The compounds were characterized by elemental analysis, UV-vis, conductivity measurements, FTIR spectroscopy and confirmed the proposed octahedral geometry around the Ru ion. The Ru(III) compounds showed antiradical potentials against 2,2-Diphenyl-1-Picrylhydrazyl (DPPH) and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals, with DPPH scavenging capability in the order: [(PAEBOD)RuCl2] > [(BZEBOD)RuCl2] > [(MOABOD)RuCl2] > [Vit. C] > [rutin] > [(METBOD)RuCl2], and ABTS radical in the order: [(PAEBOD)RuCl2] < [(MOABOD)RuCl2] < [(BZEBOD)RuCl2] < [(METBOD)RuCl2]. Furthermore, in vitro anti-proliferative activity was investigated against three human cancer cell lines: renal cancer cell (TK-10), melanoma cancer cell (UACC-62) and breast cancer cell (MCF-7) by SRB assay.
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Ruthenium(II) 8-quinolinolates: Synthesis, characterization, crystal structure and catalysis in the synthesis of 2-oxazolines. J Organomet Chem 2015. [DOI: 10.1016/j.jorganchem.2015.06.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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13
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Lyotropic liquid crystallinity in mixed-tautomer Schiff-base macrocycles. Chem Commun (Camb) 2015; 51:16205-8. [DOI: 10.1039/c5cc06253e] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
New Schiff-base macrocycles that combine keto-enamine and enol-imine tautomers are reported. As well as forming host–guest complexes with organic cations, these macrocycles form a lyotropic liquid crystal in organic solvents.
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Ligand effects on the structure and magnetic properties of alternating copper(II) chains with 2,2'-bipyrimidine- and polymethyl-substituted pyrazolates as bridging ligands. Inorg Chem 2014; 53:5759-71. [PMID: 24828822 DOI: 10.1021/ic500544n] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A novel series of heteroleptic copper(II) compounds of formulas {[Cu2(μ-H2O)(μ-pz)2(μ-bpm)(ClO4)(H2O)]ClO4·2H2O}n (1), {[Cu2(μ-H2O)(μ-3-Mepz)2(μ-bpm)](ClO4)2·2H2O}n (2), and {[Cu2(μ-OH)(μ-3,5-Me2pz)(μ-bpm)(H-3,5-Me2pz)2](ClO4)2}n (3) [bpm = 2,2'-bipyrimidine, Hpz = pyrazole, H-3-Mepz = 3-methylpyrazole, and H-3,5-Me2pz = 3,5-dimethylpyrazole] have been synthesized and structurally characterized by X-ray diffraction methods. The crystal structures of 1 and 2 consist of copper(II) chains with regular alternating bpm and bis(pyrazolate)(aqua) bridges, whereas that of 3 is made up of copper(II) chains with regular alternating bpm and (pyrazolate)(hydroxo) bridges. The copper centers are six- (1) or five-coordinate (2) in axially elongated, octahedral (1) or square-pyramidal (2) environments in 1 and 2, whereas they are five-coordinate in distorted trigonal-bipyramidal surroundings in 3. The values of the copper-copper separations across the bpm/pyrazolate bridges are 5.5442(7)/3.3131(6) (1), 5.538(1)/3.235(1) (2), and 5.7673(7)/3.3220(6) Å (3). The magnetic properties of 1-3 have been investigated in the temperature range of 25-300 K. The analysis of their magnetic susceptibility data through the isotropic Hamiltonian for an alternating antiferromagnetic copper(II) chain model [H = -J∑i=1-n/2 (S2i·S2i-1 + αS2i·S2i+1), with α = J'/J and Si = SCu = 1/2] reveals the presence of a strong to moderate antiferromagnetic coupling through the bis(pyrazolate)(aqua) [-J = 217 (1) and 215 cm(-1) (2)] and (pyrazolate)(hydroxo) bridges [-J = 153 cm(-1) (3)], respectively, whereas a strong to weak antiferromagnetic coupling occurs through the bis-bidentate bpm [-J' = 211 (1), 213 (2), and 44 cm(-1) (3)]. A simple orbital analysis of the magnetic exchange interaction within the bpm- and pyrazolate-bridged dicopper(II) fragments of 1-3 visualizes the σ-type pathways involving the (dx(2)-y(2)) (1 and 2) or d(z(2)) (3) magnetic orbitals on each metal ion, which account for the variation of the magnetic properties in these three novel examples of one-dimensional copper(II) compounds with regular alternating intrachain antiferromagnetic interactions.
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15
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New Chiral and Achiral Imines and Bisimines Derived from 2-Phenyl-1 H-imidazole-4-carbaldehyde. Synthesis, Structural Studies and Complexation Stability Constants. J Heterocycl Chem 2014. [DOI: 10.1002/jhet.1692] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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16
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Endo- and Exocyclic Supramolecular Complexes of Mixed-Donor Macrocycles via [1:1] and [2:2] Cyclizations. Inorg Chem 2013; 52:8416-26. [DOI: 10.1021/ic400247q] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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17
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Copper(II) Complexes of 3,4,5-Trisubstituted Pyrazolates: In Situ Formation of Pyrazole Rings from Different Carbon Centers. Chem Asian J 2012; 8:623-9. [DOI: 10.1002/asia.201200858] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Revised: 10/29/2012] [Indexed: 11/09/2022]
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18
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Synthesis and Magnetic Properties of a New Family of Macrocyclic MII3LnIII Complexes: Insights into the Effect of Subtle Chemical Modification on Single-Molecule Magnet Behavior. Inorg Chem 2012; 51:10603-12. [DOI: 10.1021/ic300819u] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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19
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Synthesis, physical and electrochemical characterization of mono- and heterobinuclear m-functionalized iron(III) Schiff base complexes. TRANSIT METAL CHEM 2012. [DOI: 10.1007/s11243-012-9606-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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20
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Facile synthesis of Cu(II) complexes of mono- and bicondensed N donor Schiff base 1H-pyrazolate ligands: Crystal structures, spectroscopic and magnetic properties. Polyhedron 2012. [DOI: 10.1016/j.poly.2012.02.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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21
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3-Acetyl-1-(3-methylphenyl)-5-phenyl-1 H-pyrazole-4-carbonitrile. Acta Crystallogr Sect E Struct Rep Online 2012; 68:o485-6. [PMID: 22347089 PMCID: PMC3275233 DOI: 10.1107/s160053681200181x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Accepted: 01/15/2012] [Indexed: 11/17/2022]
Abstract
In the title compound, C19H15N3O, the central pyrazole ring makes dihedral angles of 35.52 (12) and 62.21 (11)° with the attached phenyl and methyl-substituted phenyl rings, respectively. The corresponding angle between the phenyl and methyl-substituted phenyl rings is 62.90 (11)°. In the crystal, molecules are connected by weak C—H⋯O hydrogen bonds, forming supramolecular chains propagating along the a-axis direction.
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1-{3-[1-(Hydroxyimino)ethyl]-4-methyl-1H-pyrazol-5-yl}ethanone. Acta Crystallogr Sect E Struct Rep Online 2011; 67:o2634-5. [PMID: 22058770 PMCID: PMC3201455 DOI: 10.1107/s1600536811036518] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Accepted: 09/07/2011] [Indexed: 11/10/2022]
Abstract
In the title compound, C(8)H(11)N(3)O(2), the oxime and the acetyl groups adopt a transoid conformation, while the pyrazole H atom is localized in the proximity of the acetyl group and is cis with respect to the acetyl O atom. In the crystal, dimers are formed as the result of hydrogen-bonding inter-actions involving the pyrazole NH group of one mol-ecule and the carbonyl O atom of another. The dimers are associated into sheets via O-H⋯N hydrogen bonds involving the oxime hydroxyl and the unprotonated pyrazole N atom, generating a macrocyclic motif with six mol-ecules.
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Extra Large Macrocycle: 40-Membered Macrocycle via 2:2 Cyclization and Its Dimercury(II) Complex. Inorg Chem 2011; 50:8392-6. [DOI: 10.1021/ic2009607] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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24
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Metal-Free and Dicopper(II) Complexes of Schiff Base [2 + 2] Macrocycles Derived from 2,2′-Iminobisbenzaldehyde: Syntheses, Structures, and Electrochemistry. Inorg Chem 2011; 50:3697-706. [DOI: 10.1021/ic200059n] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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25
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A family of 13 tetranuclear zinc(ii)-lanthanide(iii) complexes of a [3 + 3] Schiff-base macrocycle derived from 1,4-diformyl-2,3-dihydroxybenzene. Dalton Trans 2011; 40:11425-32. [DOI: 10.1039/c1dt11038a] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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27
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Synthesis of 3- and 5-formyl-4-phenyl-1H-pyrazoles: promising head units for the generation of asymmetric imineligands and mixed metal polynuclear complexes. NEW J CHEM 2011. [DOI: 10.1039/c0nj00774a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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28
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Campestarenes: novel shape-persistent Schiff basemacrocycles with 5-fold symmetry. Chem Commun (Camb) 2011; 47:1169-71. [DOI: 10.1039/c0cc04493h] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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29
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30
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Synthesis and Characterization of Dinuclear Metal Complexes Stabilized by Tetradentate Schiff Base Ligands. ACTA ACUST UNITED AC 2010. [DOI: 10.3844/ajassp.2010.628.633] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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31
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Doubly Pyrazolate-Bridged Dinuclear Complexes of a Highly Constrained Bis-terdentate Ligand: Observation of a [High Spin-Low Spin] State for [FeII2(PMAP)2][SbF6]2·2.25(C3H8O) (PMAP = 3,5-bis{[N-(2-pyridylmethyl)amino]-methyl}-1H-pyrazolate). Inorg Chem 2010; 49:4560-9. [DOI: 10.1021/ic1001013] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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32
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Polynuclear transition metal complexes of metal⋯metal-bridging compartmental pyrazolate ligands. Coord Chem Rev 2009. [DOI: 10.1016/j.ccr.2009.03.026] [Citation(s) in RCA: 195] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Solvent induced reactivity of 3,5-dimethylpyrazole towards zinc (II) carboxylates. Dalton Trans 2009:7428-36. [PMID: 19727464 DOI: 10.1039/b905534g] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reactions of 3,5-dimethylpyrazole with zinc(II)acetate dihydrate and varieties of aromatic carboxylic acids led to formation of mono-nuclear zinc complexes of composition [Zn(HDMP)2(RCO2)2] (R = C6H5, p-CH3-C6H4, p-NO2-C6H4 etc. HDMP = 3,5-dimethylpyrazole) in methanol, whereas the same reactants in dimethylformamide (DMF) gave binuclear 3,5-dimethylpyrazolato bridged zinc carboxylate complexes containing monodentate 3,5-dimethylpyraozole ligands with composition [Zn2(mu-DMP)2(HDMP)2(RCO2)2]. The mononuclear complexes can be converted to the corresponding binuclear complexes by simply dissolving in DMF. The reaction of zinc(II)acetate dihydrate with p-nitrobenzoic acid and 3,5-dimethylpyrazole in different solvents gave solvated mononuclear complexes of the corresponding solvent. All these solvated complexes having the core [Zn(HDMP)2(p-NO2-C6H4CO2)2] contain two structurally independent molecules in the asymmetric unit (Z' = 2).
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Synthesis, structures, spectral and electrochemical properties of copper(II) complexes of sterically hindered Schiff base ligands. Inorganica Chim Acta 2009. [DOI: 10.1016/j.ica.2008.03.083] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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36
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(1,3,4-Oxadiazole)copper(II) Compounds: Dimensionality, Magnetism and Nuclease Activity. Eur J Inorg Chem 2009. [DOI: 10.1002/ejic.200800812] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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37
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Bulky Pyrazolate‐Based Compartmental Ligand Scaffolds: Encapsulation of an Edge‐Sharing Cu
6
O
2
Bitetrahedral Core. Eur J Inorg Chem 2008. [DOI: 10.1002/ejic.200800655] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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38
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39
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Bi- and Trinuclear Copper(II) Complexes with a Bridging Pyrazole/Oxime Ligand: Structures and Magnetic Properties. Z Anorg Allg Chem 2008. [DOI: 10.1002/zaac.200800293] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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40
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Supramolecular Self-Assembled Polynuclear Complexes from Tritopic, Tetratopic, and Pentatopic Ligands: Structural, Magnetic and Surface Studies. Inorg Chem 2007; 46:7767-81. [PMID: 17696336 DOI: 10.1021/ic070336a] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Polymetallic, highly organized molecular architectures can be created by "bottom-up" self-assembly methods using ligands with appropriately programmed coordination information. Ligands based on 2,6-picolyldihydrazone (tritopic and pentatopic) and 3,6-pyridazinedihydrazone (tetratopic) cores, with tridentate coordination pockets, are highly specific and lead to the efficient self-assembly of square [3 x 3] Mn9, [4 x 4] Mn16, and [5 x 5] Mn25 nanoscale grids. Subtle changes in the tritopic ligand composition to include bulky end groups can lead to a rectangular 3 x [1 x 3] Mn9 grid, while changing the central pyridazine to a more sterically demanding pyrazole leads to simple dinuclear copper complexes, despite the potential for binding four metal ions. The creation of all bidentate sites in a tetratopic pyridazine ligand leads to a dramatically different spiral Mn4 strand. Single-crystal X-ray structural data show metallic connectivity through both mu-O and mu-NN bridges, which leads to dominant intramolecular antiferromagnetic spin exchange in all cases. Surface depositions of the Mn9, Mn16, and Mn25 square grid molecules on graphite (HOPG) have been examined using STM/CITS imagery (scanning tunneling microscopy/current imaging tunneling spectroscopy), where tunneling through the metal d-orbital-based HOMO levels reveals the metal ion positions. CITS imagery of the grids clearly shows the presence of 9, 16, and 25 manganese ions in the expected square grid arrangements, highlighting the importance and power of this technique in establishing the molecular nature of the surface adsorbed species. Nanoscale, electronically functional, polymetallic assemblies of this sort, created by such a bottom-up synthetic approach, constitute important components for advanced molecule-based materials.
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Tricopper(ii) complexes of unsymmetrical macrocycles incorporating phenol and pyridine moieties: the development of two stepwise routes. Dalton Trans 2007:4000-7. [PMID: 17828360 DOI: 10.1039/b707905b] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two stepwise approaches to preparing large unsymmetrical macrocycles incorporating diethylenetriamine lateral units are described: the first utilises protecting group chemistry, whereas the second exploits irreversible amide bond formation in the presence of an excess of the amine. In the first approach condensation of two equivalents of N-acetyldiethylenetriamine 1 with 2,6-diformyl-4-methylphenol, followed by a sodium borohydride reduction of the newly formed imine bonds and acidic removal of the protecting groups, yields a phenol-containing "two-armed" precursor as an HCl salt 2. Using the second approach the new pyridine-containing "two-armed" precursor , is prepared from 2,6-dimethylpyridinedicarboxylate and an excess of diethylenetriamine. These two "two-armed" di-primary amine precursors, 2 (after reaction with KOH) and 3, can be condensed with the dicarbonyl head units of choice. The lead templated condensation of 2 with 2,6-diacetylpyridine results in the formation of the macrocyclic dilead(II) complex {[Pb(II)(2)(L1)(Cl)](ClO(4))(2)}(infinity) 4. Transmetallation of 4 with three equivalents of copper(II) perchlorate produces Cu(II)(3)(L1)(OH)(ClO(4))(4) 5. Condensation of 3 with 2,6-diacetylpyridine or 2,6-diformylpyridine in the presence of barium(ii) ions results in the macrocyclic complexes [Ba(II)(H(2)L2)](ClO(4))(2) 6 and [Ba(II)(H(2)L3)](ClO(4))(2) 7, respectively. Copper(II) acetate templates the formation of the crystallographically characterised unsymmetrical macrocyclic complex [Cu(II)(3)(L4)(OH)(NCS)(2)].EtOH, 8.EtOH, from 3, 2,6-diformyl-4-methylphenol and NaNCS.
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