Transition metal quinone–thiosemicarbazone complexes 1: Evaluation of EPR covalency parameters and redox properties of pseudo-square-planar copper(II)–naphthoquinone thiosemicarbazones

Polyhedron ◽  
2005 ◽  
Vol 24 (8) ◽  
pp. 889-899 ◽  
Author(s):  
Rajeev C. Chikate ◽  
Avadhoot R. Belapure ◽  
Subhash B. Padhye ◽  
Douglas X. West
Keyword(s):  
Transition Metal ◽  
Redox Properties ◽  
Square Planar ◽  
Thiosemicarbazone Complexes ◽  
Covalency Parameters

Novel Inorganic Hydrogels Based on The Polymerization of Cyanometalate Transition Metal Complexes With [PdCl4]2-: A New Approach To Ceramic And Alloy Precursors

1994 ◽  
Vol 346 ◽  
Author(s):  
Andrew B. Bocarsly ◽  
Gireesh Kumar ◽  
Marija Heibel
Keyword(s):  
Transition Metal ◽  
Metal Ion ◽  
Sol Gel ◽  
Metallic Matrix ◽  
Linear Polymers ◽  
New Approach ◽  
Square Planar ◽  
Delafossite Structure ◽  
Cyanide Ligand ◽  
Sol Gel Transition

ABSTRACTThe reaction of a wide variety of cyanometalate complexes of the general form [M(CN)x]n- (where M= a transition metal ion) with square planar [PdCl4]2- in aqueous solution leads to the formation of linear polymers. Polymerization occurs via substitution of chloride ligands on the Pd(II) centers, by the nitrogen end of the cyanide ligand to generate extended bridging cyanide structures. Upon generation at room temperature polymer solutions of this type under go a sol-gel transition to generate robust hydrogels having water content in excess of 95%. In the case of the cyanocobaltate/tetrachloropalladate gel, pyrolysis at 900°C produces ferromagnetic Pd/Co metallic alloys having novel morphological character. Materials formed with a hydrogel having a 2:1 Pd to Co stoichiometry are found to be “sponge-like”. When placed in water, the metallic matrix swells becoming pliable and holding up to seven equivalents of water per metal site. The conductivity and magnetic properties of this material are maintained in the swollen state. Sintering of the Pd/Co hydrogel in air generates the layered oxide, PbCoO2 having a delafossite structure.

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

CO2 reduction catalysis by tunable square-planar transition-metal complexes: a theoretical investigation using nitrogen-substituted carbon nanotube models

2017 ◽  
Vol 19 (43) ◽  
pp. 29068-29076 ◽  
Author(s):  
Yu-Te Chan ◽  
Ming-Kang Tsai
Keyword(s):  
Density Functional Theory ◽  
Carbon Nanotube ◽  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Density Functional ◽  
Co2 Reduction ◽  
Functional Theory ◽  
Square Planar ◽  
Planar Transition

The CO2 reduction capabilities of transition-metal-chelated nitrogen-substituted carbon nanotube models (TM-4N2v-CNT, TM = Fe, Ru, Os, Co, Rh, Ir, Ni, Pt or Cu) are characterized by density functional theory.

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.

Übergangsmetallkomplexe mit Schwefelliganden, LXXVI Redox- und Additionsreaktionen von Nickelkomplexen mehrzähniger Thioether-Thiolat-Liganden. Röntgenstrukturanalysen von (NMe4)2[Ni(′S2′)2] und [Ni(′S4 – C3′)(PMe3)] / Transition Metal Complexes with Sulfur Ligands, LXXVI Redox and Addition Reactions of Nickel Complexes with Multidentate Thioether-Thiolato Ligands. X-Ray Structure Determinations of (NMe4)2[Ni(′S2′)2] and [Ni(′S4–C3′)(PMe3)]

1991 ◽  
Vol 46 (12) ◽  
pp. 1601-1608 ◽  
Author(s):  
Dieter Sellmann ◽  
Stefan Fünfgelder ◽  
Falk Knoch ◽  
Matthias Moll
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Structure Analysis ◽  
Transition Metal Complexes ◽  
Nickel Complexes ◽  
Addition Reactions ◽  
Coordination Geometry ◽  
X Ray ◽  
Square Planar ◽  
Structure Determinations

In order to elucidate specific properties of nickel sulfur complexes, redox and addition-elimination reactions of [Ni(′OS4')]2, [Ni(′NHS4')]2, [Ni(′S5')], [Ni('S4—C5')], and [Ni('S4—C3')] were investigated ('OS4′ 2' = 2,2'-bis(2-mercaptophenylthio)diethylether(2—), 'NHS4'2- = 2,2'-bis(2-mercaptophenylthio)diethylamine(2—), 'S5'2- = 2,2'-bis(2-mercaptophenylthio)diethylsulfide(2—), 'S4-C5'2- = 1,5-bis(2-mercaptophenylthio)pentane(2—), 'S4—C3'2- = 1,3-bis(2-mercaptophenylthio)propane(2—)).Cyclovoltammetry proves the complexes to be redox inactive between —1.4 and +0.8 V vs. NHE. Above +0.8 V the complexes are irreversibly oxidized, below —1,4 V desalkylation takes place and [Ni(′S,′)2]2- is formed. An X-ray structure analysis was carried out of (NMe4)2[Ni(′S2')2], which shows a planar anion with the Ni center in a nearly perfect square planar coordination. Distances and angles are practically identical to those in the [Ni(′S2')2-] monoanion.The complexes coordinate only phosphines as coligands, but thioether donors simultaneously decoordinate and, dependant of reaction temperature, mono- or trisphosphine complexes are formed. [Ni(′S4—C3')(PMe3)] was characterized by X-ray structure analysis and exhibits a square pyramidal coordination geometry.

scholarly journals Crystallographic and structural characterization of heterometallic platinum compounds. Part II. Heterobinuclear Pt compounds with Pt⋯M (M = transition or lantanide metal) > 3.0 Å

2012 ◽  
Vol 10 (6) ◽  
pp. 1709-1759 ◽  
Author(s):  
Milan Melnik ◽  
Ondrej Sprusansky ◽  
Clive Holloway
Keyword(s):  
Transition Metal ◽  
Chlorine Atom ◽  
Structural Characterization ◽  
Platinum Compounds ◽  
Factors Affecting ◽  
Bond Lengths ◽  
Trigonal Bipyramidal ◽  
Square Planar ◽  
Independent Molecules

AbstractThis review covers almost two hundred and twenty heterobinuclear platinum compounds in which Pt⋯M separation is over 3.0 Å. The M is a transition metal (Cu, Ag, Au, Ti, V, Cr, Mo, W, Mn, Re, Fe, Ru, Os, Co, Rh, Ir, Ni and Pd). There is an example of a lanthanide, Yb and a actinide, U. The Pt atom has oxidation numbers 0, +2 and +4. The Pt coordination geometries include trigonal planar Pt(0); square planar Pt(II); trigonal bipyramidal, and pseudo octahedral Pt(IV), with the most frequent being square planar. The most common ligands for Pt are P and C donor atoms, as well as a chlorine atom. The Pt — Ag distance of 3.002(1) Å is the shortest found in this series. There are examples which contain two crystallographically independent molecules, which differ mostly by degree of distortion and even one unique example, which contains eight such molecules. These are examples of distortion isomerism. Factors affecting bond lengths and angles are discussed and some ambiguities in coordination polyhedral are outlined.

scholarly journals Transition metal complexes of 5-bromosalicylidene-4-amino-3-mercapto-1,2,4-triazine-5-one: Synthesis, characterization, catalytic and antibacterial studies

2011 ◽  
Vol 76 (1) ◽  
pp. 75-83 ◽  
Author(s):  
A.S. Ramasubramanian ◽  
Ramachandra Bhat ◽  
Ramakrishna Dileep ◽  
Sandya Rani
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Pathogenic Bacteria ◽  
Magnetic Moments ◽  
Spectroscopic Techniques ◽  
Antibacterial Studies ◽  
Metal Precursors ◽  
Square Planar ◽  
Bactericidal Properties

Transition metal complexes of 5-bromosalicylidene-4-amino-3- mercapto-1,2,4-triazine-5-one with metal precursors, such as Cu(II), Ni(II), Co(II) and Pd(II), were synthesized and characterized by physicochemical and spectroscopic techniques. All the complexes are of the ML type. Based on analytical, spectral data and magnetic moments, the Co(II) and Ni(II) complexes were assigned octahedral geometries, while the Cu (II) and Pd(II) complexes square planar. A study on the catalytic oxidation of benzyl alcohol, cyclohexanol, cinnamyl alcohol, 2-propanol and 2- methyl-1-propanol was performed with N-methylmorpholine-N-oxide (NMO) and molecular oxygen as co-oxidants. All the complexes and their parent organic moiety were screened for their biological activity on several pathogenic bacteria and were found to possess appreciable bactericidal properties.

scholarly journals Transition metal complexes with thiosemicarbazide-based ligands. Part 60. Reactions of copper(II) bromide with pyridoxal S-methylisothiosemicarbazone (PLITSC). Crystal structure of [Cu(PLITSC−H)H2O]Br•H2O

2014 ◽  
Vol 79 (3) ◽  
pp. 291-302 ◽  
Author(s):  
Vukadin Leovac ◽  
Ljiljana Vojinovic-Jesic ◽  
Sonja Ivkovic ◽  
Marko Rodic ◽  
Ljiljana Jovanovic ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Thermal Analysis ◽  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Elemental Analysis ◽  
Structural Characterization ◽  
Electronic Spectra ◽  
Square Planar

The synthesis and structural characterization of a square-planar copper(II) complex with pyridoxal S-methylisothiosemicarbazone (PLITSC) of the formula [Cu(PLITSC?H)H2O]Br?H2O (1) as the first Cu(II) complex with monoanionic form of this ligand were described. Complex 1 together with two previously synthesized complexes [Cu(PLITSC)Br2] (2) and [Cu(PLITSC)Br(MeOH)]Br (3) were characterized by elemental analysis, IR and electronic spectra and also by the methods of thermal analysis, conductometry and magnetochemistry.

Kinetic trans effect in square planar transition metal complexes

1974 ◽  
Vol 96 (13) ◽  
pp. 4121-4125 ◽  
Author(s):  
L. G. Vanquickenborne ◽  
J. Vranckx ◽  
C. Goeller-Walrand
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Trans Effect ◽  
Square Planar ◽  
Planar Transition
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