Search results for "Octahedron"
showing 10 items of 405 documents
Limiting nuclearity in formation of polynuclear metal complexes through [2 + 3] cycloaddition: synthesis and magnetic properties of tri- and pentanuc…
2014
A tridentate ligand p-chloro-2-{(2-(dimethylamino)ethylimino)methyl}phenol (HL) was used to generate an octahedral nickel complex [Ni(L)Cl(H2O)2] 1 which was further converted into a square-planar nickel complex [Ni(L)(N3)] 2. The [2 + 3] cycloaddition reaction between metal coordinated azide 2 and different organonitriles under microwave irradiation afforded tri- and pentanuclear nickel(II) complexes 4a-4c. Reaction with benzonitrile and 3-cyano pyridine furnished the trinuclear species [Ni3L2(5-phenyltetrazolato)4(DMF)2] 4a and [Ni3L2{5-(3-pyridyl)-tetrazolato}4(DMF)2]·2H2O 4b, respectively. The nickel centers were found to be linearly disposed to each other and the complex is formed by a…
A new N6 hexadentate ligand and a novel heptacoordinated N6O-type Fe(III) compounds: Synthesis, characterization and structure of [Fe(dimpyen)(OH)](A…
2011
Abstract In this contribution, we report the syntheses of a novel N6 donor set ligand, dimpyen = N1,N2-di[(1-methyl-1H-2-imidazolyl) methyl]-N1,N2-di(2-pyridilmethyl)-1,2-ethanediamine. This type of ligand was designed to modulate the properties of the metal ions bound to it. The reaction with Fe(II) gives off a new heptacoordinated iron(III) complex. We study the spectroscopic (UV–Vis), magnetic and electrochemical behavior and also made the structural determination with X-ray diffraction at 134 K and a heptacoordinated N6O-type derivative of Fe(III) is reported as well. This complex crystallize as perchlorate or hexafluorophosphate and the formula of these derivatives are [Fe(dimpyen)(OH)…
Structural versatility in cobalt(ii) complexes with 1,2,4,5-benzenetetracarboxylic acid (H4bta) and 4,4′-bipyridine-N,N′-dioxide (dpo)
2007
Four new high-spin cobalt(II) complexes of formula [Co(H2O)6](H2bta)·dpo·4H2O (1), [{Co(H2O)4(dpo)}2(bta)]·4H2O·(2), [Co(H2O)2)(dpo)2(H2bta)]n (3) and [Co(H2O)3(dpo)(bta)1/2]n (4) (H4bta = 1,2,4,5-benzenetetracarboxylic acid and dpo = 4,4′-bipyridine-N,N′-dioxide) have been synthesized and their structures solved by single crystal X-ray diffraction methods. Compound 1 is an ionic salt whose structure is made up of [Co(H2O)6]2+ cations, H2bta2− anions, uncoordinated dpo groups and crystallization water molecules, which are linked by extensive hydrogen bonds to afford a three-dimensional network. The structure of 2 consists of bta-bridged dinuclear cobalt(II) complexes where four coordinated …
A two-dimensional oxamate- and oxalate-bridged Cu(II)Mn(II) motif: crystal structure and magnetic properties of (Bu4N)2[Mn2{Cu(opba)}2ox].
2013
A new compound of formula (Bu4N)2[Mn2{Cu(opba)}2ox] (1) [Bu4N(+) = tetra-n-butylammonium cation, H4opba = 1,2-phenylenebis(oxamic acid), and H2ox = oxalic acid] has been synthesized and magneto-structurally investigated. The reaction of manganese(II) acetate, [Cu(opba)](2-), and ox(2-) in dimethyl sulfoxide yielded single crystals of 1. The structure of 1 consists of heterobimetallic oxamato-bridged Cu(II)Mn(II) chains which are connected through bis-bidentate oxalate coordinated to the manganese(II) ions to afford anionic heterobimetallic layers of 6(3)-hcb net topology. The layers are interleaved by n-Bu4N(+) counterions. Each copper(II) ion in 1 is four-coordinate in a square planar envi…
Copper(II) and nickel(II) chelates with dihydrogen Trans-1,2-diaminocyclohexane-N,N,N′,N′-tetraacetate(2−) ion (H2CDTA2−). Synthesis, XRD structure a…
1996
Abstract Stoichiometric reactions of metal hydroxycarbonates with the acid trans -1,2-cyclohexanediaminotetraacetic acid (H 4 CDTA) in water under reduced pressure yielded [Cu(H 2 CDTA)]·H 2 O ( I ) and [Ni(H 2 CDTA) (H 2 O)]·4H 2 O ( II ). Both compounds were characterized by TG-DTA analysis, spectral properties (IR, reflectance and RSE) and X-ray diffraction. In I the copper(II) atom exhibits a distorted square-base coordination (type 4+1) by chelation of one H 2 CDTA 2− ligand through two N and two O (carboxylate) at the square base and one O (carboxylic) at the apex of the coordination polyhedron; a second carboxymethyl group of H 2 CDTA 2− remains free. In II the H 2 CDTA 2− chelating …
The ferrimagnetic compounds CoM[M’(EDTA)]2⋅4H2O(M,M’=Co,Ni): Magnetic characterization of CoCo[Ni(EDTA)2]⋅4H2O
1990
Under the terms of the Creative Commons Attribution (CC BY) license to their work.
Magnetic exchange interactions in the heteropoly complexes [M4(H2O)2(PW9O34)2]10− [M=Co(II) and Cu(II)]
1990
The magnetic properties of the heteropolyanions [M4(H2O)2(PW9O34)2]10− [M=Co(II) and Cu(II)] down to 4 K are reported. Their individual heteropoly molecules contain a rhomblike arrangement formed by four coplanar MO6 octahedra sharing edges. The magnetic properties support an intramolecular ferromagnetic exchange in the Co(II) tetramer, and antiferromagnetic exchange in the Cu(II) tetramer. These behaviors are discussed assuming anisotropic exchange in the Co(II) compound, and Heisenberg exchange in the Cu(II) compound. Carlos.Gomez@uv.es
Crystal structure and magnetism of Co(HPO3)⋅H2O : A novel layered compound of Co(II)
1990
Under the terms of the Creative Commons Attribution (CC BY) license to their work.-- et al.
Methylresorcinarene: a reaction vessel to control the coordination geometry of copper(II) in pyridine N-oxide copper(II) complexes
2015
Pyridine and 2-picolinic acid N-oxides form 2 : 2 and 2 : 1 ligand : metal (L : M) discrete L2M2 and polymeric complexes with CuCl2 and Cu(NO3)2, respectively, with copper(ii) salts. The N-oxides also form 1 : 1 host-guest complexes with methylresorcinarene. In combination, the three components form a unique 2 : 2 : 1 host-ligand-metal complex. The methylresorcinarene acts as a reaction vessel/protecting group to control the coordination of copper(ii) from cis-see-saw to trans-square planar, and from octahedral to square planar coordination geometry. These processes were studied in solution and in the solid state via(1)H NMR spectroscopy and single crystal X-ray diffraction.
Two polymorphs Ni(II) complexes containing the dicyanamide ligand: syntheses, structures and magnetic properties of {[Ni(meso-CTH)(μ1,5-dca)]ClO4}n a…
2004
Abstract Two polymorphs Ni(II) complexes {[Ni(meso-CTH)(μ1,5-dca)]ClO4}n (1) and [Ni(meso-CTH)][Ni(meso-CTH)(dca)2](ClO4)2 (2) have been obtained in the same synthesis from dicyanamide (dca) and [Ni(meso-CTH)](ClO4)2 and have been characterized by X-ray crystallography and magnetic measurements. Complex 1 is a 1D cationic polymeric zig-zag chain with single end-to-end dca bridges connecting Ni(II) ions in trans positions, whereas in compound 2 coexist two different types of Ni(II) mononuclear units, cationic square-planar and neutral octahedral. Variable-temperature magnetic measurements reveal weak ferromagnetic interactions across the single end-to-end dca bridges in 1, while for 2 the ma…