Search results for "Oxalate"

Ferromagnetic coupling and magnetic anisotropy in oxalato-bridged trinuclear chromium(iii)-cobalt(ii) complexes with aromatic diimine ligands

2010

Two novel heterotrinuclear chromium(III)-cobalt(II) complexes of formula {[Cr(III)(bpy)(ox)(2)](2)Co(II)(Me(2)bpy)}.2H(2)O (1) and {[Cr(III)(phen)(ox)(2)](2)Co(II)(Me(2)bpy)}.1.5H(2)O (2) [ox = oxalato, bpy = 2,2'-bipyridine, Me(2)bpy = 6,6'-dimethyl-2,2'-bipyridine, and phen = 1,10-phenanthroline] have been synthesized using the "complex-as-ligand/complex-as-metal" strategy. The X-ray crystal structure of 2 consists of neutral oxalato-bridged Cr(III)(2)Co(II) bent entities formed by the coordination of two anionic [Cr(III)(phen)(ox)(2)](-) complexes through one of their oxalato groups toward a cationic cis-[Co(II)(Me(2)bpy)](2+) complex. The three tris(chelated), six-coordinated metal atom…

Summary of the Discussion on the Theme “Recommendations for Parenteral Nutrition in Clinical Practice”

1976

Modeling the magnetic properties and Mössbauer spectra of multifunctional magnetic materials obtained by insertion of a spin-crossover Fe(III) comple…

2013

In this article, we present a theoretical microscopic approach to describe the magnetic and spectroscopic behavior of multifunctional hybrid materials which demonstrate spin crossover and ferromagnetic ordering. The low-spin to high-spin transition is considered as a cooperative phenomenon that is driven by the interaction of the electronic shells of the Fe ions with the full symmetric deformation of the local surrounding that is extended over the crystal lattice via the acoustic phonon field. The proposed model is applied to the analysis of the series [Fe(III)(sal2-trien)] [Mn(II)Cr(III)(ox)3]·solv, in short 1·solv, where solv = CH2Cl2, CH2Br2, and CHBr3.

The odd association of a C3h trisamidinium cation and tosylate anion with a series of linear oxalate-bridged trinuclear heterometallic complexes

2013

A series of six isostructural heterometallic trinuclear oxalate-bridged complexes of the formula (TDbenz)(2)(TsO)(2)[M(II)(H(2)O)(2){(μ-ox)M(III)(ox)(2)}(2)]·6H(2)O·2CH(3)OH (TDbenz = 1,3,5-tris[2-(1,3-diazolinium)]benzene; TsO = 4-methylbenzenesulfonate; ox = oxalate; M(III) = Fe, M(II) = Mn (1), Fe (2), Co (3); M(III) = Cr, M(II) = Mn (4), Fe (5), Co (6)) have been synthesized from (NH(4))(3)[M(III)(ox)(3)]·3H(2)O, the chloride salts of the divalent metal ions and the tosylate salt of 1,3,5-tris[2-(1,3-diazolinium)]benzene (trisamidinium). Whereas the crystal structures of compounds 2, 3, 4 and 5 have been investigated by single-crystal X-ray diffraction, the structures of 1 and 6 have be…

Copper(II) complexes of 1,4,5,8,9,12-hexaazatriphenylene with oxalate, squarate, perchlorate as auxiliary ligands or counter ion

2002

Abstract The crystal structures of [Cu(hat)(H2O)(ox)]·H2O (I), [Cu(hat)(H2O)3(sq)]·3H2O (II) and [Cu(hat)(H2O)2](ClO4)2·4H2O (III) have been determined from X-ray single crystal diffraction data (hat=1,4,5,8,9,12-hexaazatriphenylene, ox=oxalate, sq=squarate=dianion of 3,4-dihydroxy-cyclobut-3-ene-1,2-dione). Compound I crystallises in the triclinic system, space group P 1 with a=6.6626(10), b=9.2001(14), c=12.9954(19) A , α=103.301(15), β=91.414(21), γ=105.523(13)°, Z=2; compound II in the orthorhombic system, space group P212121 with a=6.9274(2), b=8.4327(3), c=34.0577(14) A , Z=4; and compound III in the monoclinic system, space group C2/c with a=22.6652(10), b=9.2220(10), c=16.1400(10) A…

One-dimensional oxalato-bridged copper(II) complex possessing two structurally different metallic centres

2001

Abstract The crystal structure of the oxalato-bridged copper(II) compound [Cu2(μ-ox)2(ampy)3]n 1 (ox=oxalate dianion, ampy=2-amino-3-methylpyridine) consists of infinite corrugated one-dimensional chains in which two types of copper(II) centres, five- and six-coordinated, are bridged sequentially by asymmetric bis-bidentate oxalato ligands. Magnetic susceptibility measurements show the occurrence of a significant intrachain antiferromagnetic coupling (J=−22.9 cm −1 ) .

Transition-Metal-Free Decarboxylative Photoredox Coupling of Carboxylic Acids and Alcohols with Aromatic Nitriles.

2016

A transition-metal-free protocol for the redox-neutral light-induced decarboxylative coupling of carboxylic acids with (hetero)aromatic nitriles at ambient temperature is presented. A broad scope of acids and nitriles is accepted, and alcohols can be coupled in a similar fashion through their oxalate half esters. Various inexpensive sources of UV light and even sunlight can be used to achieve this C–C bond formation proceeding through a free radical mechanism.

ChemInform Abstract: Transition-Metal-Free Decarboxylative Photoredox Coupling of Carboxylic Acids and Alcohols with Aromatic Nitriles.

2016

A transition-metal-free protocol for the redox-neutral light-induced decarboxylative coupling of carboxylic acids with (hetero)aromatic nitriles at ambient temperature is presented. A broad scope of acids and nitriles is accepted, and alcohols can be coupled in a similar fashion through their oxalate half esters. Various inexpensive sources of UV light and even sunlight can be used to achieve this C–C bond formation proceeding through a free radical mechanism.

Polymetallic oxalate-based 2D magnets: Soluble molecular precursors for the nanostructuration of magnetic oxides

2010

Here we describe the synthesis and magnetic characterization of a family of 2D polymetallic oxalate-bridged polymeric networks with general formula [M(II)(H(2)O)(2)](3)[M(III)(ox)(3)](2)(18-crown-6)(2) (M(III) = Cr, Fe; M(II) = Mn, Fe, Co, Ni; 18-crown-6 = C(12)H(24)O(6)). Depending on the nature of the trivalent metal ion, they exhibit ferro- (Cr(3+)) or ferrimagnetic (Fe(3+)) ordering in the 3.6-20 K interval. In contrast with most of the oxalate-bridged CPs reported so far, these complexes do not need any additional templating cation for their assembly and represent the first series of oxalate-based polymeric networks which can be considered intrinsically neutral. As previously observed …

2D and 3D mixed MII/CuIImetal–organic frameworks (M = Ca and Sr) withN,N′-2,6-pyridinebis(oxamate) and oxalate: preparation and magneto-structural st…

2018

Three heterobimetallic complexes of formula [Ca2Cu3(mpyba)2(2-apyma)(H2O)7]·8.3H2O (1), [Sr2Cu3(mpyba)2(2-apyma)(H2O)8]·11.6H2O (2) and [Sr4.5Cu4(mpyba)4(ox)(H2O)20]·8.5H2O (3) [H4mpyba = N,N'-2,6-pyridinebis(oxamic acid), 2-apyma = 2-(6-aminopyridinyl)oxamate and ox = oxalate] have been synthesized and structurally characterized. Complexes 1 and 2 are isostructural compounds, with tricopper(ii) units having mpyba and its hydrolytic product (2-apyma) as ligands. They are interlinked through strontium(ii) (1) and calcium(ii) (2) ions to afford neutral two-dimensional networks. Two of the copper(ii) ions are five-coordinate in distorted square pyramidal (Cu3) and trigonal bipyramidal (Cu1) su…