Hydrido(acylenolato)cobalt(III)-Verbindungen mit Trimethylphosphan- Liganden: Insertionsreaktionen mit Alkinen und die ersten Carbonylcobalt(III)-Komplexe / Hydrido(acylenolato)cobalt(III) Compounds Containing Trimethylphosphane Ligands: Insertion Reactions with Alkynes and the First Carbonylcobalt(III) Complexes

2000 ◽  
Vol 55 (8) ◽  
pp. 707-717 ◽  
Author(s):  
Hans-Friedrich Klein ◽  
Xiaoyan Li ◽  
Ulrich Flörke ◽  
Hans-Jürgen Haupt
Keyword(s):  
Axial Position ◽  
Coupling Reactions ◽  
Carbonyl Complexes ◽  
Ambient Conditions ◽  
X Ray Diffraction ◽  
Insertion Reactions ◽  
X Ray ◽  
Reversible Transformation ◽  
Tert Butyl ◽  
Trigonal Bipyramidal

Abstract Formal insertion of phenylethyne into Co-H functions of mer-octahedral acyl(enolato)-cobalt(III) hydrides 1-3 proceeds under ambient conditions affording η1-vinylcobalt(III) compounds where the dianionic acyl(enolato) ligands are derived from 2-formyl-4-phenyl-cyclohexanone (4), 1-formyl-cyclohexan-2-one (5), and 3-hydroxo-2,3-diphenyl-propenal (6). Dissociation and association of trimethylphosphane results in a reversible transformation of penta-coordinate complexes 4 -6 into hexa-coordinate ones 7 -9, respectively, involving different tautomeric vinyl species. In toluene solution 9 rearranges by reductive C,C coupling into a 5,6-η2-olefin(enolato)cobalt(I) complex 10. Trimethylsilylethyne undergoes a hydrolytic desilylation reaction which is followed by reductive C,C-coupling reactions of acyl and vinyl functions selectively producing chelating η1-enolato-5,6-η2-olefin ligands in cobalt(I) com ­ pounds 13 -16 where the (ax,eq)chelating ligands are derived from 1-formyl-cyclohexan-2-one (13), 3-hydroxo-2,3-diphenyl-propenal (14), 2-formyl-α-tetralone (15), and 2-formyl-4-tert-butyl-cyclohexanone (16). An axial position of the enolato-O donor in the trigonal bipyramidal configuration of complex 15 has been confirmed by X-ray diffraction analysis. With 1,4-bis(trimethylsilyl)buta-diyne 1,2-addition in cobalt(III) hydrides 2, 3, 11 (as deriverd from 2-formyl-α-tetralone), and 12 (as derived from 2-formyl-4-tert-butyl-cyclohexanone) produces 2-metalated vinyl groups in compounds 17 -20. Dissociation of trimethylphosphane from 17 and 19 does not activate C,C coupling at the cobalt(III) centre of penta-coordinate 21 and 22. Steric congestion in compounds 17, 18, and 20 favours exchange of trimethylphosphine for carbon monoxide affording the first octahedral carbonyl complexes of cobalt (d6) (23 -25). In the crystal and in solution a meridional configuration is adopted by complex 23 with the CO group in a position opposite to the acyl function.

Crystal structure and solution studies of the product of the reaction of β-mercaptoethanol with vanadate

1999 ◽  
Vol 77 (12) ◽  
pp. 2088-2094 ◽  
Author(s):  
Sudeep Bhattacharyya ◽  
Raymond J Batchelor ◽  
Frederick WB Einstein ◽  
Alan S Tracey
Keyword(s):  
Crystal Structure ◽  
Mixed Solvent ◽  
Axial Position ◽  
Acetonitrile Solution ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
X Ray ◽  
Trigonal Bipyramidal ◽  
Solution Studies ◽  
Alkaline Conditions

Reaction of β-mercaptoethanol with vanadate under slightly alkaline conditions provided a crystalline complex that was characterized by X-ray diffraction and FTIR spectroscopy. The complex was dimeric in structure with a central [VO]2 core and a pentacoordinate, crudely trigonal bipyramidal arrangement about each vanadium atom with a sulphur occupying a pseudo-axial position. A single 51V NMR signal was observed for this complex when dissolved in water, chloroform or acetonitrile. A large influence of acetonitrile on the vanadium chemical shift suggested the possibility of reaction with acetonitrile. FTIR showed the presence of two complexes in acetonitrile solution but only one in chloroform or water. Mixed solvent studies were carried out in an effort to further characterize the solution complexes. Crystal structure of [{VO2(OC2H4S)}2][NEt4]2: monoclinic, space group P21/n,. a = 8.3451(17), b = 16.954(4), c = 10. 2064(25) Å; β = 101. 271(18)°; V = 1416.2 Å3; Z = 2; RF = 0.048 for 1355 data (Io 2..5σ (Io) and 147 variables.Key words: mercaptoethanol, vanadate, vanadium NMR, X-ray diffraction, FTIR, thiolate.

The preparation of bis(perfluoroethyl) tellurium difluoride and dichloride, trans perfluoroethyl tellurium monochloride tetrafluoride, trans bis(perfluoroethyl) tellurium tetrafluoride; and the preparation and X-ray crystal structure of perfluoroethyl tellurium trifluoride

1985 ◽  
Vol 63 (8) ◽  
pp. 2273-2280 ◽  
Author(s):  
Clement Lau ◽  
Jack Passmore ◽  
E. Keith Richardson ◽  
Tom K. Whidden ◽  
Peter S. White
Keyword(s):  
Vibrational Spectra ◽  
Electron Pair ◽  
Lone Pair ◽  
Axial Position ◽  
X Ray Diffraction ◽  
Tellurium Atom ◽  
Nmr Spectrum ◽  
X Ray ◽  
R Factor ◽  
Trigonal Bipyramidal

The reaction of (C2F5)2Te and XeF2 in a slurry of SO2ClF yielded (C2F5)2TeF2 essentially quantitatively. Chlorine and (C2F5)2Te gave (C2F5)2TeCl2. Both (C2F5)2TeF2 and (C2F5)2TeCl2 were assigned a trigonal bipyramidal geometry, on the basis of their 19F nmr and vibrational spectra, with the lone pair and C2F5 groups in equatorial, and the halogens in the axial positions. Perfluoroethyl tellurium trifluoride was prepared essentially quantitatively by the reaction of C2F5TeTeC2F5 and XeF2 in liquid SO2F2. The generally inert SO2ClF was found to react with C2F5TeTeC2F5 to give C2F5TeClxF3−x, and sulphur dioxide. The structure of C2F5TeF3 was determined by X-ray diffraction. The crystals are tetragonal with a = 10.129(4), c = 25.561(6) Å, and Z = 16. The structure was refined in space group I41/a to a conventional R factor of 0.051 for 901 observed reflections with I ≥ 3σ(I). Each tellurium atom is surrounded by two terminal fluorine atoms and two bridging fluorine atoms and a C2F5 group in an axial position around the apex of a distorted square pyramid. The square-pyramidal units are linked by symmetrical cis bridging atoms into endless chains with bridging angles of 180° and 177°. The geometry of the (C2F5TeF4) group is consistent with steric activity of the non-bonded electron pair. The 19F nmr and Raman spectra of C2F5TeF3 were recorded and the Raman spectrum assigned. Trans-C2F5TeClF4 was prepared by the reaction of C2F5TeTeC2F5, and an excess of ClF. The trans octahedral geometry of C2F5TeClF4 was unambiguously assigned from its 19F nmr and vibrational spectra. A mixture of trans-(C2F5)2TeF4 and trans-C2F5TeClF4 was obtained from the reaction of (C2F5)2Te and an excess of ClF. Trans geometry of (C2F5)2TeF4 was unambiguously assigned from its 19F nmr spectrum.

scholarly journals Crystal structure of 3-benzyl-2-[(E)-2-(furan-2-yl)ethenyl]-2,3-dihydroquinazolin-4(1H)-one and 3-benzyl-2-[(E)-2-(thiophen-2-yl)ethenyl]-2,3-dihydroquinazolin-4(1H)-one from synchrotron X-ray diffraction

2018 ◽  
Vol 74 (1) ◽  
pp. 10-14
Author(s):  
Flavien A. A. Toze ◽  
Vladimir P. Zaytsev ◽  
Lala V. Chervyakova ◽  
Elisaveta A. Kvyatkovskaya ◽  
Pavel V. Dorovatovskii ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Axial Position ◽  
Isatoic Anhydride ◽  
X Ray Diffraction ◽  
X Ray ◽  
Bond Angles ◽  
Pyramidal Geometry ◽  
Three Component Reaction ◽  
Racemic Crystals

The chiral title compounds, C21H18N2O2, (I), and C21H18N2OS, (II) – products of the three-component reaction between benzylamine, isatoic anhydride and furyl- or thienyl-acrolein – are isostructural and form isomorphous racemic crystals. The tetrahydropyrimidine ring in (I) and (II) adopts a sofa conformation. The amino N atom has a trigonal–pyramidal geometry [sum of the bond angles is 347.0° for both (I) and (II)], whereas the amido N atom is flat [sum of the bond angles is 359.3° for both (I) and (II)]. The furyl- and thienylethenyl substituents in (I) and (II) are planar and the conformation about the bridging C=C bond isE. These bulky fragments occupy the axial position at the quaternary C atom of the tetrahydropyrimidine ring, apparently, due to steric reasons. In the crystals, molecules of (I) and (II) form hydrogen-bonded helicoidal chains propagating along [010] by strong intermolecular N—H...O hydrogen bonds.

Crystal and molecular structure of diorganoammonium oxalatotrimethylstannate, [R2NH2][Me3Sn(C2O4)] (R=i-Bu, cyclohexyl)

2011 ◽  
Vol 34 (5-6) ◽  
pp. 127-130 ◽  
Author(s):  
Yaya Sow ◽  
Libasse Diop ◽  
Kieran C. Molloy ◽  
Gabrielle Kociok-Köhn
Keyword(s):  
Molecular Structure ◽  
Hydrogen Bonds ◽  
Diffraction Study ◽  
Crystal And Molecular Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Trigonal Bipyramidal ◽  
Trans Complex ◽  
A Chain ◽  
Distorted Trigonal Bipyramidal

Abstract The title compounds [R2NH2][C2O4SnMe3](R=i-Bu, Cy), in which tin atoms adopt a distorted trigonal bipyramidal configuration, have been prepared and submitted to an X-ray diffraction study. These compounds have been obtained from the reaction of (Cy2NH2)2C2O4·H2O or (i-Bu2NH2)2C2O4 with SnMe3Cl. In both [R2NH2][C2O4SnMe3] compounds, the trans complex has an almost regular trigonal bipyramidal geometry around the tin atom. The SnMe3 residues are connected as a chain with bridging oxalate anions in a trans-SnC3O2 framework, the oxygen atoms being in axial positions. The cations connect linear adjacent chains through NH…O hydrogen bonds giving layered structures.

scholarly journals Discovery of Fe7O9: a new iron oxide with a complex monoclinic structure

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Ryosuke Sinmyo ◽  
Elena Bykova ◽  
Sergey V. Ovsyannikov ◽  
Catherine McCammon ◽  
Ilya Kupenko ◽  
...  
Keyword(s):  
Applied Sciences ◽  
Crystal Structure ◽  
Iron Oxide ◽  
Iron Oxides ◽  
Industrial Applications ◽  
Ambient Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Pressure High Temperature ◽  
Insight Into

Abstract Iron oxides are fundamentally important compounds for basic and applied sciences as well as in numerous industrial applications. In this work we report the synthesis and investigation of a new binary iron oxide with the hitherto unknown stoichiometry of Fe7O9. This new oxide was synthesized at high-pressure high-temperature (HP-HT) conditions, and its black single crystals were successfully recovered at ambient conditions. By means of single crystal X-ray diffraction we determined that Fe7O9 adopts a monoclinic C2/m lattice with the most distorted crystal structure among the binary iron oxides known to date. The synthesis of Fe7O9 opens a new portal to exotic iron-rich (M,Fe)7O9 oxides with unusual stoichiometry and distorted crystal structures. Moreover, the crystal structure and phase relations of such new iron oxide groups may provide new insight into the cycling of volatiles in the Earth’s interior.

Effect of NABr on the Pore Size and Surface Morphology of Cu Foam Prepared by Hydrogen Bubble Templating

2021 ◽  
Vol 880 ◽  
pp. 83-88
Author(s):  
Mary Donnabelle L. Balela ◽  
Reginald E. Masirag ◽  
Francis O. Pacariem Jr. ◽  
Juicel Marie D. Taguinod
Keyword(s):  
Polyethylene Glycol ◽  
Cuprous Oxide ◽  
Active Material ◽  
Current Collector ◽  
Hydrogen Bubble ◽  
Ambient Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cu Foam ◽  
Interconnected Pores

Binderless supercapacitor electrodes are currently being employed to increase the surface contact between the active material and current collector, leading to enhanced capacitance. In binderless electrodes, the active material is directly grown on the surface of the current collector, omitting the use of insulative polymer-based binders. In this work, Cu foam was successfully electrodeposited on Cu sheet by dynamic hydrogen bubble templating (DHBT) using polyethylene glycol (PEG) and sodium bromide (NaBr) as additives. The current density was set at 3 A·cm-2 and electrodeposition was performed for 20 s. At 200 mg/L PEG, increasing the NaBr concentration from 0 to 80 mM produced Cu foam with decreasing pores sizes of about 75.15 to 34.10 μm. However, the walls of the interconnected pores became thicker as the pore diameters were reduced. This indicates that NaBr promotes Cu deposition rather than hydrogen evolution reaction (HER), leading to smaller pore sizes. X-ray diffraction confirms the oxidation of the Cu foam under ambient conditions forming cuprous oxide (Cu2O). The Cu2O/Cu foam was then utilized as binderless electrode for supercapacitor, resulting to a specific capacitance of 0.815 F·cm-2 at 5 mV·s-1. Results show the potential of the fabricated Cu2O/Cu foam as binderless electrode for pseudo-type supercapacitors.

scholarly journals A Covalent Organic Cage Compound Acting as a Supramolecular Shadow Mask for the Regioselective Functionalization of C60

2020 ◽  
Author(s):  
Viktoria Leonhardt ◽  
Stefanie Fimmel ◽  
Ana-Maria Krause ◽  
Florian Beuerle
Keyword(s):  
Mass Spectrometry ◽  
Single Crystal ◽  
High Selectivity ◽  
Shadow Mask ◽  
X Ray Diffraction ◽  
X Ray ◽  
Trigonal Bipyramidal ◽  
Cage Compound ◽  
Vis Spectroscopy ◽  
Regioselective Functionalization

<div><div><div><p>A trigonal-bipyramidal covalent organic cage compound serves as an efficient host to form stable 1:1-complexes with C60 and C70. Fullerene encapsulation has been comprehensively studied by NMR and UV/Vis spectroscopy, mass spectrometry as well as single-crystal X-ray diffraction. Exohedral functionalization of encapsulated C60 via threefold Prato reaction revealed high selectivity for the symmetry-matched all-trans-3 addition pattern.</p></div></div></div>

scholarly journals Crystal structure refinement of magnesium zinc divanadate, MgZnV2O7, from powder X-ray diffraction data

2021 ◽  
Vol 77 (6) ◽  
pp. 588-591
Author(s):  
Stephanie J. Hong ◽  
Jun Li ◽  
Mas A. Subramanian
Keyword(s):  
Crystal Structure ◽  
Diffraction Data ◽  
Structure Refinement ◽  
Atomic Ratio ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
X Ray ◽  
Trigonal Bipyramidal ◽  
Wyckoff Position ◽  
Distorted Trigonal Bipyramidal

The crystal structure of magnesium zinc divanadate, MgZnV2O7, was determined and refined from laboratory X-ray powder diffraction data. The title compound was synthesized by a solid-state reaction at 1023 K in air. The crystal structure is isotypic with Mn0.6Zn1.4V2O7 (C2/m; Z = 6) and is related to the crystal structure of thortveitite. The asymmetric unit contains two metal sites with statistically distributed magnesium and zinc atoms with the atomic ratio close to 1:1. One (Mg/Zn) metal site (M1) is located on Wyckoff position 8j and the other (M2) on 4h. Three V sites (all on 4i), and eight O (three 8j, four 4i, and one 2b) sites complete the asymmetric unit. The structure is an alternate stacking of V2O7 layers and (Mg/Zn) atom layers along [20\overline{1}]. It is distinct from other related structures in that each V2O7 layer consists of two groups: a V2O7 dimer and a V4O14 tetramer. Mixed-occupied M1 and M2 are coordinated by oxygen atoms in distorted trigonal bipyramidal and octahedral sites, respectively.

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