scholarly journals Binuclear Co(II), Ni(II), Cu(II) and Zn(II) complexes with Schiff-bases derived from crown ether platforms: Rare examples of ether oxygen atoms bridging metal centers

Polyhedron ◽  
2010 ◽  
Vol 29 (11) ◽  
pp. 2269-2277 ◽  
Author(s):  
Lea Vaiana ◽  
Marta Mato-Iglesias ◽  
David Esteban-Gómez ◽  
Carlos Platas-Iglesias ◽  
Andrés de Blas ◽  
...  
Keyword(s):  
Crown Ether ◽  
Schiff Bases ◽  
Metal Centers ◽  
Ether Oxygen ◽  
Oxygen Atoms

scholarly journals Polysulfonylamine, XLIV Synthese von [Na(15-Krone-5)][N(SO2CH3)2] und Kristallstruktur bei –95°C / Polysulfonylamines, XLIV Synthesis of [Na(15-Crown-5)][N(SO2CH3)2] and Crystal Structure at –95°C

1993 ◽  
Vol 48 (7) ◽  
pp. 893-897 ◽  
Author(s):  
Armand Blaschette ◽  
Karl-Heinz Nagel ◽  
Peter G. Jones
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Crown Ether ◽  
Ion Pairs ◽  
Sodium Cation ◽  
Methanol Solution ◽  
Sodium Ion ◽  
Monoclinic Space Group ◽  
Ether Oxygen ◽  
Oxygen Atoms

The complex [Na(15-crown-5)][N(SO2CH3)2] crystallizes at —25°C from a methanol solution containing equimolar amounts of NaN(SO2CH3)2 and 15-crown-S. Its crystallographic data at —95°C are: monoclinic, space group P 21/c, a = 852.1(5), b = 2731.9(12), c = 909.2(4) pm, β = 115.53(4)°, V = 1.910 nm3, Z = 4, Dx = 1.445 Mgm3. The structure in the solid state consists of ion pairs. The sodium cation is coordinated to the five oxygen atoms of the crown ether, one oxygen atom of the anion, and to the nitrogen atom of the anion. The bond distances are Na—O(crown) 238.7-247.2, Na—O(sulfonyl) 234.9, Na—N 275.8 pm. The sodium ion lies 78 pm out of the plane of the crown ether oxygen atoms. The conformation of the coronand is described.

Bildiing und kristallstruktur des (complexes [(18-Krone-6)(CH2Cl2)2] / Formation and Crystal Structure of the Complex [(18-Crown-6)(CH2Cl2)2]

1994 ◽  
Vol 49 (6) ◽  
pp. 852 ◽  
Author(s):  
Peter G. Jones ◽  
Oliver Hiemisch ◽  
Armand Blaschette
Keyword(s):  
Crystal Structure ◽  
Crown Ether ◽  
Sulfur Trioxide ◽  
Title Complex ◽  
Formula Unit ◽  
Dichloromethane Solution ◽  
Triclinic Space Group ◽  
Ether Oxygen ◽  
Ether Molecule ◽  
Oxygen Atoms

Single crystals of the title complex were fortuitously grown from a dichloromethane solution containing 18-crown-6 and sulfur trioxide. Crystallographic data (at -130 °C): triclinic, space group P1̄, a = 819.1(7). b = 860.6(7), c = 905.8(7) pm. a = 63.98(3), β = 66.56(3), y = 74.95(3)°, V = 0.5236 nm3, Z = 1, Dx, = 1.377 Mgm-3. In the centrosymmetric formula unit, the two CH2Cl2 molecules are situated one above and one below the plane of the ether oxygen atoms. They are C-H···O hydrogen-bonded to two opposing oxygen atoms (H-O 237.1 and 270.6 pm, C-O 335.5 and 365.9 pm, C-H···O 171.7 and 161.8°). The crown ether molecule has approximate D3d symmetry

Studies in the stereochemistry of zinc(II). VI. Zinc complexes with quadridentate Schiff bases

1967 ◽  
Vol 20 (5) ◽  
pp. 885 ◽  
Author(s):  
GE Batley ◽  
DP Graddon
Keyword(s):  
Schiff Bases ◽  
Infrared Spectra ◽  
Zinc Complexes ◽  
Steric Effects ◽  
Pyridine Solution ◽  
Carbon Chains ◽  
Tetrahedral Environment ◽  
Oxygen Atoms

Zinc complexes have been prepared with Schiff bases formed from salicylaldehyde and polymethylenediamines with chains of 2-9 carbon atoms. The anhydrous zinc complexes of ligands with 2-3 carbon chains readily form 1 : 1 adducts with water or bases such as pyridine; the ultraviolet and infrared spectra of these anhydrous compounds indicate that they are polymeric with bridging oxygen atoms, the zinc being 5-coordinate. The zinc complexes of ligands with carbon chains of four or more atoms do not form adducts, even in pyridine solution, and their spectra show that none of the oxygen atoms is bridging, the zinc being 4-coordinate. The stereochemistry of the zinc appears to be determined solely by steric effects: when the ligand is such that 4-coordination can produce a tetrahedral environment, further coordination does not occur; when 4-coordination cannot produce a tetrahedral environment, 5- coordination always occurs.

Synthesis, Crystal Structure and Electrochemical Properties of a New Adduct of Benzo-15-crown-5 and H3PMo12O40

2009 ◽  
Vol 64 (3) ◽  
pp. 274-280 ◽  
Author(s):  
Qinghua Du ◽  
Dawei Song ◽  
Wansheng You ◽  
Yi Zhao ◽  
Tingting Gan ◽  
...  
Keyword(s):  
Crown Ether ◽  
Supramolecular Interactions ◽  
Modified Carbon Paste Electrode ◽  
Cyclic Voltammograms ◽  
Molecular Formula ◽  
Carbon Paste ◽  
Acidic Aqueous Solution ◽  
Oxonium Ions ◽  
Paste Electrode ◽  
Oxygen Atoms

A new crown ether-POM (POM = polyoxometalate) adduct with the molecular formula [(C14- H20O5)4(H3O)3]PMo12O40 ・ 0.5CH3CN (1) was isolated from the mixed solvent of acetonitrile and methanol. The adduct is constructed from Keggin [PMo12O40]3− anions and [(C14H20O5)- (H3O+)] and [(C14H20O5)2(H3O+)] cations via electrostatic and hydrogen bonding interactions. The supramolecular interactions combine the crown ether with oxonium ions. In the [(C14H20O5)- (H3O+)] moieties, the oxonium ions reside out of the planes defined by the oxygen atoms of the crown ether. The [(C14H20O5)2(H3O+)] moieties exhibit a sandwich structure. There exist hydrogen bonds between the oxonium ions of the [(C14H20O5)(H3O)]+ cations and the acetonitrile molecules and the terminal and bridging oxygen atoms of the [PMo12O40]3− anions. The adduct has been used as a bulk-modifier to fabricate a chemically modified carbon paste electrode (MCPE), which displays well-defined cyclic voltammograms with three reversible two-electron redox couples in acidic aqueous solution, and electrocatalytic activities towards the reduction of H2O2 and NO2−.

Stabilisierung des reaktiven Methylcarbonat-Ions im Kronenether- Komplex [Cs(18-Krone-6)(CH3CO3)] und dessen Hydrolyseprodukt / Stabilization of the Reactive Methylcarbonate Ion in the Crown Ether Complex [Cs(18-crown-6)(CH3CO3)], and its Hydrolysis Product

2008 ◽  
Vol 63 (9) ◽  
pp. 1101-1106
Author(s):  
Adelė Jonušaite ◽  
Arnold Adam
Keyword(s):  
Crown Ether ◽  
Hydrolysis Product ◽  
Starting Material ◽  
Monoclinic Space Group ◽  
Bidentate Ligands ◽  
Space Group ◽  
Methyl Carbonate ◽  
Hydrolysis Of ◽  
Ether Complex ◽  
Oxygen Atoms

[Cs(18-crown-6)(CH3CO3)] (1) has been obtained by the reaction of CsOCH3 with 18-crown-6 (1,4,7,10,13,16-hexaoxacyclooctadecane) in methanol in a CO2 atmosphere. The compound crystallizes in the monoclinic space group P21/n (no. 14) with a = 12.141(3), b = 8.610(1), c = 17.985(4) Å , β = 91.17(2)° and V = 1879.6(7) Å3. Cs is tenfold coordinated by six oxygen atoms of the crown ether and four oxygen atoms of two methyl carbonate anions which act as bidentate ligands. The slow hydrolysis of the methylcarbonate results in the hydrogencarbonate complex {Cs2(18-crown- 6)2 · [H2(CO3)2] · H2O · CH3OH} (2), the basic structural constitution of the starting material being retained. This new compound crystallizes in the monoclinic space group P21/c with a = 8.657 (7), b = 22.601 (2), c = 19.619 (15) Å, β = 92.09 (6)° and V = 3836.5 (6) Å3.

scholarly journals Raman spectroscopic study of the hydration of short-chain poly(oxyethylene)s C 1EnC 1 (n=1−4)

2004 ◽  
Vol 2 (4) ◽  
pp. 617-626 ◽  
Author(s):  
Mircho Georgiev ◽  
Tatiana Popova ◽  
Zhorro Nickolov ◽  
Nikolay Goutev ◽  
Georgi Georgiev ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Bonding ◽  
Raman Band ◽  
Short Chain ◽  
Water Molecules ◽  
Degree Of Hydration ◽  
Raman Spectroscopic ◽  
Raman Spectroscopic Study ◽  
Ether Oxygen ◽  
Oxygen Atoms

AbstractThe hypothesis that the degree of hydration of poly(oxyethylene) (POE) in aqueous solution depends on the mole ratio of water molecules to ether oxygen atoms in the molecule has been verified by studying the isotropic Raman spectra in the O−H stretching region for four short-chain POEs (C 1EnC 1 withn=1−4). Excellent coincidence of the O−H stretching Raman band for all four POEs studied in the range of mole ratio H2O/Oether from 25 to 0.6 was observed, thus confirming the assumption stated above. A conclusion that all ether oxygen atoms in the POE molecule participate in hydrogen bonding with water molecules has been made.

Synthesen und Kristallstrukturen der Kronenether-Komplexe (18-Krone-6) · 2CH3CN, [Na-15-Krone-5][ReO4] · CH3CN und [Na-15-Krone-5]PF6 / Syntheses and Crystal Structures of the Crown Ether Complexes (18-Crown-6) · 2 CH3CN, [Na-15-Crown-5][ReO4] · CH3CN, and [Na-15-Crown-5]PF6

1989 ◽  
Vol 44 (12) ◽  
pp. 1524-1530 ◽  
Author(s):  
Frank Weller ◽  
Harald Borgholte ◽  
Harald Stenger ◽  
Stefan Vogler ◽  
Kurt Dehnicke
Keyword(s):  
Crown Ether ◽  
Sodium Fluoride ◽  
Ion Pairs ◽  
Sodium Atom ◽  
Acetonitrile Solution ◽  
Space Group ◽  
Crown Ether Complexes ◽  
Water Space ◽  
Ether Molecule ◽  
Oxygen Atoms

Single crystals of (18-crown-6) · 2 CH3CN were obtained by cooling a solution of 18-crown-6 in acetonitrile to 4 °C. Space group P21/n, Z = 2, 629 observed independent reflexions, R = 0.062. Lattice dimensions at 19°C: a = 911.7(1), b = 852.0(1), c = 1370.0(2) pm; β = 104.61(1)°. The compound forms a molecular structure with approximate D3d symmetry of the crown ether molecule, and C—H ··· O interactions of the acetonitrile molecules with the crown ether, the Η···Ο distances being 243, 253, and 267 pm, respectively.[Na-15-crown-5][ReO4] · CH3CN is formed as a by-product of the reaction of ReNCl4 with sodium fluoride in acetonitrile in the presence of 15-crown-5 and traces of water. Space group Ρ 1̄ , Ζ = 2, 3107 observed independent reflexions, R = 0.045. Lattice dimensions at 19°C: a = 823.4(1), b = 1078.8(1), c = 1204.0(1) pm; α = 112.40(1)°, β = 94.35(1)°, γ = 104.63(1)°. The compound forms ion pairs, in which the sodium atom is sixfold coordinated by the five oxygen atoms of the crown ether molecule, as well as by one oxygen atom of the ReO4- ion, which is only slightly distorted. The bond length Na—OReO3 is 237.8(8) pm, the bond angle NaORe is 164.3(5)°.[Na-15-crown-5]PF6 is formed in the reaction of [ReCl3(NSCl)2 · POC13] with sodium fluoride in acetonitrile solution in the presence of 15-crown-5. Space group Pna21, Ζ = 4, 1130 observed independent reflexions, R = 0.123. The high R value is due to disorder of the skeletal atoms of the crown ether molecule. The compound forms ion pairs, in which the sodium atom is sevenfold coordinated by the five oxygen atoms of the crown ether molecule, as well as by two fluorine atoms of the PF6- ion with Na—F bond lengths of 240(2), and 246(2) pm, respectively.

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