Nickel(II) and Iron(II) Complexes with Tetradentate NHC/Amide Hybrid Ligands

2013 ◽  
Vol 68 (5-6) ◽  
pp. 458-466 ◽  
Author(s):  
Iris Klawitter ◽  
Steffen Meyer ◽  
Serhiy Demeshko ◽  
Franc Meyer
Keyword(s):  
Cyclic Voltammetry ◽  
Redox Properties ◽  
Spin States ◽  
Imidazolium Salts ◽  
Tetradentate Ligands ◽  
Square Planar ◽  
Hybrid Ligands

Two methylene-bridged bis(imidazolium) salts [H4L1](PF6)2 and [H4L2](PF6)2 with appended amide groups have been synthesized which, after deprotonation, may serve as potentially tetradentate ligands providing two bis(imidazole-2-ylidene) and two amide donors. Using [H4L1](PF6)2, a square-planar nickel(II) complex [NiL1] and a six-coordinate bis(ligand) iron(II) complex [Fe(HL1)2] have been isolated and structurally characterized. Their low-spin states have been confirmed spectroscopically, and their redox properties have been studied by cyclic voltammetry. Oxidations are metal-centered to give NiIII and FeIII species, respectively

Complexes of hybrid ligands. The synthesis of a thioanisole-substituted fluoro-alcohol and its complexes with Pd2+ and Pt2+; the structure of a palladium(II) complex containing alkoxide, phosphine, thioether, and chloride donors

1987 ◽  
Vol 65 (4) ◽  
pp. 798-803 ◽  
Author(s):  
René T. Boeré ◽  
David E. Esser ◽  
Christopher J. Willis ◽  
Douglas W. Stephan ◽  
Taras W. Obal
Keyword(s):  
Least Squares ◽  
Dihedral Angle ◽  
Chelate Ring ◽  
Monoclinic Space Group ◽  
Structural Determination ◽  
Bond Lengths ◽  
Square Planar ◽  
Planar Molecules ◽  
Hybrid Ligands ◽  
Cis And Trans

The compound 2-thioanisole-1,1,1,3,3,3-hexafluoro-2-propanol, CH3S—C6H4—C(CF3)2OH, HL2, has been prepared, and shown to act (in the ionized form) as a hybrid, chelating, ligand. Neutral bis-complexes M(L2)2 are formed with Pd2+ and Pt2+; the former reacts with PdCl42− to give the Cl-bridged dinuclear complex (L2)Pd(μ-Cl)2Pd(L2), which may in turn be cleaved by PPh3 or PPh2Me to give PdCl(L2)(PR3).A complete structural determination has been made for PdCl(L2)(PPh2Me); C23H20ClF6OPPdS. Crystals are monoclinic, space group P21/n, a = 15.526(5), b = 12.966(9), c = 12.900(8) Å, β = 101.84°, V = 2542(2) Å3, Z = 4. Least-squares refinement on F of 198 variables using 2801 observations converged at R1 = 0.0434, R2 = 0.0559. The complex consists of discrete square-planar molecules with phosphine and alkoxide trans-disposed. Bond lengths are Pd—O, 2.053(3); Pd—P, 2.242(1); Pd—Cl, 2.323(2); Pd—S, 2.252(2) Å. In the six-membered chelate ring, all atoms with the exception of Pd are close to coplanarity; there is a dihedral angle of 127.9° between the O—Pd—S plane and that of the aromatic ring.Multinuclear nmr measurements are used to show that both cis- and trans-forms of complexes PdCl(L2)(PR3) are present in solution, with inversion at coordinated sulfur occurring much more rapidly in the latter.

Integrity and redox properties of homogeneous and heterogeneous DNA films on gold surface probed by cyclic voltammetry

2002 ◽  
Vol 413 (1-2) ◽  
pp. 218-223 ◽  
Author(s):  
Hellas C.M Yau ◽  
Hing Leung Chan ◽  
Sen-fang Sui ◽  
Mengsu Yang
Keyword(s):  
Cyclic Voltammetry ◽  
Gold Surface ◽  
Redox Properties ◽  
Dna Films

Application of a Novel Modified Electrode Based on NaY-Encapsulated Co(PAN) Complex

2008 ◽  
Vol 587-588 ◽  
pp. 109-113
Author(s):  
C. Teixeira ◽  
P. Parpot ◽  
Isabel Neves ◽  
António Maurício C. Fonseca
Keyword(s):  
Cyclic Voltammetry ◽  
Chemical Analysis ◽  
Aqueous Medium ◽  
Surface Analysis ◽  
Modified Electrode ◽  
Modified Electrodes ◽  
Redox Properties ◽  
New Method ◽  
Y Zeolite

CoPAN complex has been entrapped in the supercages of Y zeolite and the redox properties of this zeolite-encapsulated complex were investigated by cyclic voltammetry with a new method for the preparation of carbon toray-zeolite-modified electrode. Formation of the CoPAN complex was ascertained by surface analysis (SEM, XRD), chemical analysis (CA), spectroscopy methods (FTIR and UV/vis) and cyclic voltammetry in aqueous medium with zeolite-modified electrodes. The cyclic voltammetry studies obtained with a zeolite-modified electrode shows evidence for electroactivity restricted to boundary associated CoPAN complex.

Crystal Structure, Spectroscopic and Redox Properties of Copper(II) Bis{2-[(2,6-dimethylphenyl)iminomethyl-3-methoxyphenolate]}

2007 ◽  
Vol 62 (9) ◽  
pp. 1133-1138 ◽  
Author(s):  
Veli T. Kasumov ◽  
Ibrahim Uçar ◽  
Ahmet Bulut ◽  
Fevzi Kösal
Keyword(s):  
Crystal Structure ◽  
Title Complex ◽  
Redox Properties ◽  
Orthorhombic Space Group ◽  
Long Distance ◽  
X Ray ◽  
X Ray Crystallography ◽  
Square Planar ◽  
Planar Molecules ◽  
Exchange Interaction Parameter

The coordination chemistry of N-(2,6-di-methylphenyl)-2-hydroxy-3-methoxybenzaldimine (1) with Cu(II) has been investigated by X-ray crystallography, electronic and EPR spectroscopies, as well as by electro- and magnetochemistry. The title complex 2 crystallizes in the orthorhombic space group P212121 (a = 8.1538, b = 17.7466, c =19.8507 Å). The mononuclear square-planar molecules 2 featuring trans-N2O2 coordination are connected via weak intermolecular C-H· · ·π interactions into infinite chains parallel to the a axis. Although the intermolecular Cu· · ·Cu separations within individual chains and between chains are very long (8.154 and 9.726 Å ), the exchange interaction parameter G = 2.03 < 4, estimated from solid state EPR spectra, suggests the existence of long-distance superexchange pathways between adjacent Cu(II) centers. The electronic and electrochemical features of the compound are also discussed.

Redox Properties of Iron Complexes with Pentadentate Bispidine Ligands

2014 ◽  
Vol 67 (3) ◽  
pp. 398 ◽  
Author(s):  
Peter Comba ◽  
Hubert Wadepohl ◽  
Arkadius Waleska
Keyword(s):  
Aqueous Solution ◽  
Cyclic Voltammetry ◽  
Coordination Chemistry ◽  
Aqueous Solutions ◽  
Iron Complexes ◽  
Redox Properties

The solution coordination chemistry of iron complexes with the pentadentate bispidine ligands L1, L2, and L3 (dimethyl 9-oxo-2,4-di(pyridin-2-yl)-3,7-diazabicyclo[3.3.1]nonane-1,5-dicarboxylate derivatives) was examined. While in acetonitrile, (L1,2)FeII/III species have a preference for Cl– as co-ligand. The corresponding aqua and hydroxido complexes also prevail in the presence of Cl– in aqueous solution. The observed FeII/III potentials in water (cyclic voltammetry) and potentials of (L1–3)FeIV=O (buffered and unbuffered aqueous solutions) are strikingly similar, i.e. the latter are assigned to (L1–3)FeII/III potentials, and published potentials of FeIV=O complexes with other ligands with uncharged amine-pyridine donors, obtained by cyclic voltammetry, have to be considered with caution.

Electrochemistry and spectroelectrochemistry of carboxyphenylethynyl porphyrins

2013 ◽  
Vol 17 (01n02) ◽  
pp. 92-98 ◽  
Author(s):  
Pei-Shang Chao ◽  
Ming-Yu Kuo ◽  
Chen-Fu Lo ◽  
Min-Hsu Hsieh ◽  
Yu-Hsiang Cheng ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Thin Layer ◽  
Reduction Reaction ◽  
Redox Properties ◽  
Electrochemical Measurements ◽  
Porphyrin Ring ◽  
Optically Transparent ◽  
Phenyl Rings ◽  
Spectroelectrochemical Properties

Zinc 5-(4-carboxy-phenylethynyl)-10,20-biphenylporphines bearing various substituents on the 10,20-phenyl rings are studied for their electrochemical and spectroelectrochemical properties. Cyclic voltammetry and optically transparent thin-layer electrochemical measurements suggest that the first reductions of these porphyrins should be the reduction reaction of the carboxylic protons. For the porphyrin ring reactions, our study shows that the redox properties can be significantly affected by the alkoxyl chains on the 10,20-phenyl rings.

The coordination compounds of nickel with glycine and with an N-N ligand

1988 ◽  
Vol 53 (3) ◽  
pp. 563-570 ◽  
Author(s):  
František Březina ◽  
Zdeněk Šindelář ◽  
Jiří Kameníček ◽  
Jan Lasovský
Keyword(s):  
Cyclic Voltammetry ◽  
Coordination Compounds ◽  
Spectral Properties ◽  
Chemical Oxidation ◽  
Redox Properties

The compounds [Ni(Gly)2N-N].nH2O (n = 1, 2; Gly = glycine anion; N-N – ethylenediamine 1,10-phenanthroline, α,α’-bipyridyl) and K[Ni(Gly)3].3H2O were prepared. On the basis of their magnetochemical and spectral properties, the compounds obtained can be characterized as octahedral nickel(II) complexes. Cyclic voltammetry was employed to study the redox properties of selected compounds and possible electrochemical and chemical oxidation were studied. The results obtained permitted comparison with the properties of nickel(II) complexes with dipeptides or tripeptides as ligands.

Untersuchungen an biochemisch wirksamen Ligandensystemen, V

1972 ◽  
Vol 27 (10) ◽  
pp. 1131-1136 ◽  
Author(s):  
P. Barz ◽  
H. P. Fritz
Keyword(s):  
Cyclic Voltammetry ◽  
Radical Cation ◽  
Epr Spectroscopy ◽  
Photoelectron Spectroscopy ◽  
Metal Cations ◽  
Redox Properties ◽  
Neutral Molecule ◽  
Ligand Field ◽  
Ligand Field Spectra

1,2-Dimethylhydrazine co-ordinates to numerous metal cations. The structures of the complexes of Cr, Mn, Co, Ni, Cu, Zn, Cd, Hg and Pt are discussed and the complexing abilities of the 1,2-dimethylhydrazine molecule are determined on the basis of the ligand field spectra of the nickel and the chromium derivative.The results of polarography, cyclic voltammetry and photoelectron spectroscopy yield evidence on the redox properties of the neutral molecule. By means of EPR spectroscopy the nature of the radical products obtained by irradiation of 1,2-dimethylhydrazine, especially of the radical cation, is determined.

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