Change in the hybridization of the N→O group oxygen atom upon complex formation of pyridine and quinoline N-oxides with v-acceptors

2008 ◽  
Vol 78 (5) ◽  
pp. 973-983 ◽  
Author(s):  
V. P. Andreev ◽  
V. V. Vapirov ◽  
Ya. P. Nizhnik ◽  
L. A. Aleshina ◽  
T. A. Semenova
Keyword(s):  
Complex Formation ◽  
Oxygen Atom ◽  
Group Oxygen ◽  
Group Oxygen Atom

Halogen bonding of the aldehyde oxygen atom in cocrystals of aromatic aldehydes and 1,4-diiodotetrafluorobenzene

CrystEngComm ◽  
2019 ◽  
Vol 21 (21) ◽  
pp. 3251-3255 ◽  
Author(s):  
Vinko Nemec ◽  
Luka Fotović ◽  
Toni Vitasović ◽  
Dominik Cinčić
Keyword(s):  
Oxygen Atom ◽  
Halogen Bond ◽  
Halogen Bonding ◽  
Aromatic Aldehydes ◽  
Aldehyde Group ◽  
Group Oxygen ◽  
Group Oxygen Atom

Novel halogen bonded cocrystals of aromatic aldehydes have been synthesized. We present the halogen bond acceptor potential of the aldehyde group oxygen atom in competition with the hydroxy, methoxy and pyridine groups.

scholarly journals Synthesis, crystal structure, and magnetic properties of a nitronyl nitroxide biradical-coordinated copper(II) complex

2020 ◽  
pp. 174751982098253
Author(s):  
Yan-Li Gao ◽  
Pingqiang Gao ◽  
Ying Gong ◽  
Guoyu Ren
Keyword(s):  
Crystal Structure ◽  
Oxygen Atom ◽  
Coordination Compound ◽  
Building Blocks ◽  
Nitronyl Nitroxide ◽  
Single Crystal Diffraction ◽  
Group Oxygen ◽  
Group Oxygen Atom ◽  
Susceptibility Study ◽  
Ferromagnetic Interactions

A coordination compound constructed from a nitronyl nitroxide biradical NITPh(3-NIT) and CuII(hfac)2(H2O)2 building blocks [NITPh(3-NIT) = 1,3-bis(1′-oxyl-3′-oxido-4′,4′, 5′, 5′-tetramethyl-4,5-dihydro-1 H-imidazol-2-y1)-benzene, hfac = hexafluoroacetylacetonato] is successfully synthesized. The crystal structure is determined by X-ray single-crystal diffraction. The asymmetric complex {[(NITPh(3-NIT)]Cu(hfac)2} consists of one Cu(II) ion and two >N–O• groups and adopts a distorted triangular bipyramid with a penta-coordinated central copper(II) atom and three hfac oxygen atoms at the base and a >N–O• oxygen atom and one hfac oxygen atom at the apices. Intramolecular O. . .O bonding and π–π stacking interactions are observed between molecules. A magnetic susceptibility study of the coordination compound shows antiferromagnetic interactions between Cu(II) ions and >N–O• groups and very weak ferromagnetic interactions between Cu(II) ions and the free >N–O• group through O. . .O bonding between the nitroxide group oxygen atom and the oxygen atom of hfac.

INFRARED SPECTRA OF 2,6-DIMETHYL-4-PYRONE COMPLEXES

1961 ◽  
Vol 39 (6) ◽  
pp. 1184-1189 ◽  
Author(s):  
Denys Cook
Keyword(s):  
Complex Formation ◽  
Oxygen Atom ◽  
Carbonyl Group ◽  
Lewis Acid ◽  
Frequency Band ◽  
Infrared Spectra ◽  
Donor Site ◽  
Carbonyl Oxygen ◽  
Acid Strength ◽  
Group A

The infrared spectra of 2,6-dimethyl-4-pyrone in solution, and in complexes with HgCl2, ZnCl2, BF3, SbCl5, and HBr have been recorded. A band at 1639 cm−1 in the free pyrone moves to progressively lower frequencies in the complexes as the Lewis acid strength increases, identifying this band as the carbonyl stretching frequency and the donor site as the carbonyl group. A higher-frequency band, at 1678 cm−1 in the free pyrone, moves to lower frequency on complex formation, but to a much smaller extent, and is to be identified with a stretching mode of the ring. The site of protonation in 2,6-dimethyl-4-pyrone salts has been unequivocally shown to be the carbonyl oxygen atom.

Structural Systematics of Rare Earth Complexes. I. Structural Characterization of Lanthanoid(III) Picrate Hydrates: Monoclinic (P21/C) (Quasi-)Dodecahydrates of the Related La → Pr and Nd → Tb Families

1994 ◽  
Vol 47 (2) ◽  
pp. 321 ◽  
Author(s):  
JM Harrowfield ◽  
WM Lu ◽  
BW Skelton ◽  
AH White
Keyword(s):  
Type A ◽  
Water Molecules ◽  
Complex Species ◽  
X Ray ◽  
Structural Types ◽  
Group Oxygen ◽  
Group Oxygen Atom ◽  
History Of ◽  
Similar Complex

Single-crystal room-temperature X-ray studies on hydrated specimens (deposited from aqueous solutions) of the sequence of trivalent lanthanoid picrates La → Tb have shown, with certain qualifications/reservations discussed herein and in Parts III and IV following, their existence as dodecahydrates in two closely related but subtly different monoclinic P21/c structural types. Nd → Tb generally conform to a 'low-β' type: a 7.767(1) → 7.603(3), b 27.525(9) → 27.440(10), c 18.198(11) → 18.182(8) Ǻ, β 105.11(3) → 105.18(4)°, V 3712(3) → 3674(3) Ǻ3, Z = 4 formula units, while La → Pr are a 'higher-β' type: a 7.933(1) → 7.9435(9), b 26.856(6) → 26.74(1), c 18.244(6) → 18.215(2) Ǻ, β 107.96(2) → 108.238(8)°, V 3697(2) → 3675(2) Ǻ3, Z = 4 formula units; the latter form is frequently found partially desolvated toward the undecahydrate without loss of crystal integrity, as water is lost from tunnels in the lattice, with the actual hydrate stoichiometry dependent on the history of the specimen. In both sets of compounds, similar complex species [ Ln ( pic )2(OH2)6]+ are observed, with one picrate uncoordinated as counter ion, and six lattice water molecules. The lanthanoid ion is >8-coordinate, one of the coordinated picrate moieties being quasi-bidentate , with an ortho-nitro group oxygen atom having a long contact to the metal atom in both series.

A study of twinning in YBa2Cu3O7−x by large-angle convergent-beam electron diffraction

1990 ◽  
Vol 48 (4) ◽  
pp. 20-21
Author(s):  
P.A. Midgley ◽  
R. Vincent ◽  
D. Cherns
Keyword(s):  
Electron Diffraction ◽  
Oxygen Atom ◽  
Strain Field ◽  
Large Angle ◽  
Convergent Beam Electron Diffraction ◽  
Orthorhombic Distortion ◽  
Beam Electron ◽  
Resultant Powder ◽  
Convergent Beam ◽  
Mesh Grid

The oxygenation of YBa2Cu3O7−x (YBCO) leads to an orthorhombic distortion of the unit cell to accommodate the extra oxygen atom. This makes the formation of twins energetically favourable with CuO4 planar unit chains running alternately along the a and b axes of the parent tetragonal structure. The geometry of this twinning is such that four possible twin variants may co-exist with the twin boundaries lying in the (110) or (110) planes of the deformed structure. The traces of these planes are not mutually perpendicular and thus the crystal is strained to allow for the mismatch. It is to the nature of this strain field that this work has been addressed.Sintered samples were prepared by crushing and dispersing the resultant powder onto a very fine Cu mesh grid. Single crystals were chemically thinned to perforation. No discernible artefacts were seen and similar results were obtained with either method.

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