scholarly journals Antimony lone electronic pair as a stereoelectronic barrier to stibatrane

2021 ◽  
Vol 11 (2) ◽  
pp. 178-186
Author(s):  
V. P. Baryshok ◽  
E. A. Zel'bst
Keyword(s):  
Crystal Structure ◽  
Oxygen Atom ◽  
Bond Length ◽  
Intermolecular Hydrogen Bond ◽  
Valence Bond ◽  
Covalent Bond ◽  
Sodium Methylate ◽  
Antimony Atom ◽  
Nucleophilic Attack ◽  
Coordinate Bond

To examine the effect of 5s2 lone electron pair of antimony atom on the reaction of antimony trifluoride and triethanolamine in the presence of sodium methylate, the crystal structure of the reaction product -2-fluoro-6-(2-hydroxyethyl)-1,3-dioxa-6-aza-2-stibacy-cylooctane (1-fluoro-2-hydrostibatrane) FSb (OCH2CH2)2NCH2CH2OH) was confirmed. In the compound structure, the hydrogen atom of the 2-hydtoxyethyl group of each molecule forms an intermolecular hydrogen bond with the oxygen atom of one of the five-membered SbOCH2CH2N half-cycles in a neighbouring molecule. A geometry of both five-member N-C-C-O-Sb heterocycles, end-capped by transannular N→Sb bond in the 1-fluoro-2-hydrostibatrane molecule, is almost identical. C-O, C-C, N-C interatomic distances and valence angles in two endocyclic units (NCCOSb) are comparable to those observed in RSi(OCH2CH2)3N silatranes. A coordination polyhedron of the Sb atom can be represented as a transition from a bisphenoid to Sb(O3)N trigonal pyramid, with a nitrogen atom at the apex and three oxygen atoms in the base. The N→Sb transannular coordinate bond length is 2.402(4) Å, which is 0.40 Å greater than the Sb-N covalent bond standard length. The Sb-F bond (1.997(4) Å) is 0.12 Å longer than that in the SbF3 molecule, and insignificantly shorter than that of the Sb-Fax (2.028(3) Å) in the SbF3Gly crystalline complex. The fluorine atom substantially strays from the N→Sb axis to the direction of O(1) and O(2) atoms. The oxygen atom of the 2-hydroxyethyl group lies at a distance of 2.899(3) A from that of Sb, intermediate between the valence bond length and the sum of the Van der Waals radii of these atoms. Combined with the F atom position, one can assume the 1-fluoro-2-hydrostibatrane crystal structure as a “frozen” state of the SNi(Sb) type nucleophilic attack of the oxygen atom, uncompleted because of its repulsion by the 5s2 lone electronic pair of antimony atom.

Crystal Structure of α-Zn2V2O7

1973 ◽  
Vol 51 (7) ◽  
pp. 1004-1009 ◽  
Author(s):  
Ramanathan Gopal ◽  
Crispin Calvo
Keyword(s):  
Crystal Structure ◽  
Oxygen Atom ◽  
Bond Length ◽  
Fold Axis ◽  
Full Matrix ◽  
X Ray ◽  
R Value ◽  
The Individual ◽  
Zn Ions ◽  
Oxygen Atoms

α-Zn2V2O7 is monoclinic with lattice parameters a = 7.429(5), b = 8.340(3), c = 10.098(3) Å, β = 111.37(5)°, Z = 4 and space group C2/c. The structure was refined using a full matrix least-squares with 1034 reflections measured with a quarter-circle General Electric automatic X-ray diffractometer to a final R value of 0.066. The anion consists of a pair of VO4 tetrahedra sharing an oxygen atom which lies on a two-fold axis. The bridging V—O bond length is 1.775(4) Å while the three independent terminal ones are 1.728(4), 1.704(7), and 1.658(8) Å long. These bond lengths are consistent with the charge character around the individual oxygen atoms. The Zn ions are coordinated to five oxygen atoms with Zn—O bonds ranging from 1.973 to 2.088°Å. The structure is similar to that of α-CU2P2O7 and transforms to the thortvietite structure at about 615 °C.

scholarly journals Aggregation of Molecules in Liquid Ethylene Glycol and Its Manifestation in Experimental Raman Spectra and Non-Empirical Calculations

2020 ◽  
Vol 65 (4) ◽  
pp. 298
Author(s):  
H. Hushvaktov ◽  
A. Jumabaev ◽  
G. Murodov ◽  
A. Absanov ◽  
G. Sharifov
Keyword(s):  
Hydrogen Bond ◽  
Raman Spectroscopy ◽  
Hydrogen Atom ◽  
Hydrogen Bonds ◽  
Oxygen Atom ◽  
Ethylene Glycol ◽  
Bond Length ◽  
Raman Spectra ◽  
Intermolecular Hydrogen Bond ◽  
The Other

Intra- and intermolecular interactions in liquid ethylene glycol have been studied using the Raman spectroscopy method and non-empirical calculations. The results of non-empirical calculations show that an intermolecular hydrogen bond is formed between the hydrogen atom of the OH group in one ethylene glycol molecule and the oxygen atom in the other molecule. The formation of this bond gives rise to a substantial redistribution of charges between those atoms, which, nevertheless, insignificantly changes the bond length. In the corresponding Raman spectra, the presence of hydrogen bonds between the ethylene glycol molecules manifests itself as the band asymmetry and splitting.

scholarly journals Crystal structure of dichloridobis{μ-2-methoxy-6-[(methylimino)methyl]phenolato}{2-methoxy-6-[(methylimino)methyl]phenolato}cadmium(II)cobalt(III) monohydrate

2018 ◽  
Vol 74 (11) ◽  
pp. 1532-1535 ◽  
Author(s):  
Olga Yu. Vassilyeva ◽  
Katerina V. Kasyanova ◽  
Vladimir N. Kokozay ◽  
Brian W. Skelton
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Oxygen Atom ◽  
Crystal Lattice ◽  
Bond Length ◽  
Title Compound ◽  
Water Molecules ◽  
Cell Parameters ◽  
Solvent Water ◽  
Weak Hydrogen Bonds

The title compound, [CoCd(C9H10NO2)3Cl2]·H2O, is a solvatomorph of the corresponding hemihydrate recently published by us [Nesterova et al. (2018). Appl. Cat. A, 560, 171–184]. The current structure reveals different cell parameters and space group compared with the published one while both are monoclinic with almost the same cell volume. The title compound is formed of discrete neutral dinuclear molecules with no crystallographically imposed symmetry and water molecules of crystallization. The overall geometry about the cobalt(III) ion is octahedral with an N3O3 environment; each ligand acts as a meridional ONO donor. The CdII coordination sphere approximates an irregular square pyramid with a chlorine atom at the apex. There is significant shortening of a Cd—O bond length to the oxygen atom of the methoxo group on one of the ligands [2.459 (3) Å] compared to the corresponding distance in the published structure [2.724 (7) Å], while other Cd—Cl/N/O bonds remain roughly the same. In the crystal lattice, the heterometallic molecules, which are related by the crystallographic n-glide plane and interlinked by weak hydrogen bonds to solvent water molecules, form columns along [101]. Adjacent columns lie antiparallel to each other.

Notizen: Die Kristallstruktur des Rhenium-Tolankomplexes [ReCl4(PhC ≡ CPhXOPCl3)] / The Crystal Structure of the Rhenium-tolane Complex [ReCl4(PhC ≡ CPh)(OPCl3)]

1993 ◽  
Vol 48 (7) ◽  
pp. 1019-1022 ◽  
Author(s):  
Gerlinde Frenzen ◽  
Dorothea Wolff von Gudenberg ◽  
Kurt Dehnicke
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Oxygen Atom ◽  
Bond Length ◽  
Trans Position ◽  
X Ray ◽  
Bond Lengths ◽  
In Trans ◽  
Ray Methods ◽  
Ligand Bond

The crystal structure of [ReCl4(PhC = CPh)(OPCl3)] was solved with X-ray methods. Space group P1̄, Z = 2, 2085 observed unique reflections, R = 0.029. Lattice dimensions at -70°C: a = 857.0(2), b = 937.9(2), c = 1249.6(2) pm, α = 87.43(3)°, β = 83.48(3)°, γ = 89.80(3)°. [ReCl4(PhC ≡ CPh)(OPCl3)] has a molecular structure with the alkyne ligand bonded side-on (bond lengths Re-C 198.9(8) and 198.6(7) pm). The oxygen atom of the solvating POCl3 molecule is coordinated in trans position to the ReC2 unit of the alkyne ligand (bond length Re-O 226.7(5) pm).

Crystal structure of tetraammonium diphosphate, (NH4)4P2O7 at 22 °C

1976 ◽  
Vol 54 (13) ◽  
pp. 2025-2028 ◽  
Author(s):  
Nora Middlemiss ◽  
Crispin Calvo
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Oxygen Atom ◽  
Bond Length ◽  
Fold Axis ◽  
Hydrogen Atoms ◽  
Monoclinic System ◽  
Full Matrix ◽  
R Value ◽  
Oxygen Atoms

Crystals of tetraammonium diphosphate, (NH4)4P2O7, crystallize in the monoclinic system with space group C2/c, Z = 4 and lattice parameters a = 11.758(3), b = 6.486(2), c = 13.659(2) Å and β = 104.81(1)°. The structure was refined using full-matrix least-squares methods with 810 reflections to an R value of 0.092. The diphosphate anion contains a crystallographic two-fold axis, and has a configuration intermediate between staggered and eclipsed. The bridging P—O bond length is 1.624(2) Å and the terminal P—O bonds average 1.507 Å. The diphosphate groups lie in sheets defined by [Formula: see text] and are bridged by NH4+ groups which hydrogen bond to only the terminal oxygen atoms. Each hydrogen is bonded to one oxygen atom but each of the terminal oxygen atoms interacts with either two or three hydrogen atoms.

scholarly journals Role of Chemistry and Crystal Structure on the Electronic Defect States in Cs-Based Halide Perovskites

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1032
Author(s):  
Anirban Naskar ◽  
Rabi Khanal ◽  
Samrat Choudhury
Keyword(s):  
Crystal Structure ◽  
Density Functional ◽  
Covalent Bond ◽  
Density Functional Theory Calculations ◽  
Antisite Defect ◽  
Defect States ◽  
Functional Theory ◽  
Electronic Defect ◽  
Constituent Elements

The electronic structure of a series perovskites ABX3 (A = Cs; B = Ca, Sr, and Ba; X = F, Cl, Br, and I) in the presence and absence of antisite defect XB were systematically investigated based on density-functional-theory calculations. Both cubic and orthorhombic perovskites were considered. It was observed that for certain perovskite compositions and crystal structure, presence of antisite point defect leads to the formation of electronic defect state(s) within the band gap. We showed that both the type of electronic defect states and their individual energy level location within the bandgap can be predicted based on easily available intrinsic properties of the constituent elements, such as the bond-dissociation energy of the B–X and X–X bond, the X–X covalent bond length, and the atomic size of halide (X) as well as structural characteristic such as B–X–B bond angle. Overall, this work provides a science-based generic principle to design the electronic states within the band structure in Cs-based perovskites in presence of point defects such as antisite defect.

WHICH IS THE PROTON-SHUTTLE IN ISOXANTHOPTERIN DEAMINASE? QM/MM MD UNDERSTANDING

2013 ◽  
Vol 12 (08) ◽  
pp. 1341002 ◽  
Author(s):  
XIN ZHANG ◽  
MING LEI
Keyword(s):  
Crystal Structure ◽  
Molecular Dynamics ◽  
Hydrogen Bonds ◽  
Proton Transfer ◽  
Glutamic Acid ◽  
Active Site ◽  
Nucleophilic Attack ◽  
Zinc Ions ◽  
Initial Model ◽  
Dynamics Simulations

The deamination process of isoxanthopterin catalyzed by isoxanthopterin deaminase was determined using the combined QM(PM3)/MM molecular dynamics simulations. In this paper, the updated PM3 parameters were employed for zinc ions and the initial model was built up based on the crystal structure. Proton transfer and following steps have been investigated in two paths: Asp336 and His285 serve as the proton shuttle, respectively. Our simulations showed that His285 is more effective than Aap336 in proton transfer for deamination of isoxanthopterin. As hydrogen bonds between the substrate and surrounding residues play a key role in nucleophilic attack, we suggested mutating Thr195 to glutamic acid, which could enhance the hydrogen bonds and help isoxanthopterin get close to the active site. The simulations which change the substrate to pterin 6-carboxylate also performed for comparison. Our results provide reference for understanding of the mechanism of deaminase and for enhancing the deamination rate of isoxanthopterin deaminase.

The crystal structure of kalsilite, KAlSiO4

1965 ◽  
Vol 35 (272) ◽  
pp. 588-595 ◽  
Author(s):  
A. J. Perrotta ◽  
J. V. Smith
Keyword(s):  
Crystal Structure ◽  
Oxygen Atom ◽  
Crystal Structures ◽  
Bond Angle ◽  
Three Dimensional ◽  
Full Matrix ◽  
Ideal Position ◽  
Wide Range ◽  
The Ideal

SummaryA full-matrix, three-dimensional refinement of kalsilite, KAlSi04 (hexagonal, a 5·16, c 8.69 Å, P6a), shows that the silicon and aluminium atoms are ordered. The respective tetrahedral distances of 1·61 and 1·74 Å agree with values of 1·61 and 1·75 Å taken to be typical of framework structures. As in nepheline, an oxygen atom is statistically distributed over three sites displaced 0·25 Å from the ideal position on a triad axis. This decreases the bond angle from 180° to 163° in conformity with observations on some other crystal structures. The potassiumoxygen distances of 2·77, 2·93, and 2·99 Å are consistent with the wide range normally found for this weakly bonded atom.

scholarly journals Crystal structure and Hirshfeld surface analysis of dichlorido(methanol-κO)bis(2-methylpyridine-κN)copper(II)

2020 ◽  
Vol 76 (11) ◽  
pp. 1771-1774
Author(s):  
J. Prakasha Reddy
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Oxygen Atom ◽  
Rotation Axis ◽  
Hirshfeld Surface ◽  
Title Complex ◽  
Complex Molecules ◽  
Crystal Complex ◽  
Tetragonal Pyramidal ◽  
Cl Atoms

In the title complex, [CuCl2(C6H7N)2(CH3OH)], the copper atom is five-coordinated by two nitrogen atoms of 2-methylpyridine ligands, two chloro ligands and an oxygen atom of the methanol molecule, being in a tetragonal–pyramidal environment with N and Cl atoms forming the basal plane. In the crystal, complex molecules related by the twofold rotation axis are joined into dimeric units by pairs of O—H...Cl hydrogen bonds. These dimeric units are assembled through C—H...Cl interactions into layers parallel to (001).

The synthesis, molecular and crystal structure of the 1:1 adduct of triphenyltin chloride with 2,3-diphenylthiazolidin-4-one

1995 ◽  
Vol 73 (1) ◽  
pp. 95-99 ◽  
Author(s):  
Frank E. Smith ◽  
Rosemary C. Hynes ◽  
John Tierney ◽  
Ying Z. Zhang ◽  
George Eng
Keyword(s):  
Crystal Structure ◽  
Structural Analysis ◽  
Oxygen Atom ◽  
Dutch Elm Disease ◽  
Monoclinic Space Group ◽  
Monodentate Ligand ◽  
X Ray ◽  
Trigonal Bipyramidal ◽  
Triphenyltin Chloride ◽  
Mössbauer Data

The title compound was synthesized as part of an effort to produce a more effective fungicide to combat Dutch Elm Disease (DED), which is caused by the fungus Ceratocystisulmi. A full X-ray structural analysis of the 1:1 adduct has been carried out and the results are reported along with the Mössbauer data for the compound. The crystals are monoclinic, space group P21/a with a = 19.240(3) Å, b = 9.1463(24) Å, c = 19.3512(24) Å, β = 118.874(8)°, V = 2982.0(10) Å3, z = 4, and Dcalc = 1.427 Mg m−3. The final discrepancy factors are RF = 0.056 and Rw = 0.058 for 1915 significant reflections. The QS and IS values in the Mössbauer spectrum of the complex are 3.08 mm s−1 and 1.28 mm s−1, respectively. The 2,3-diphenylthiazolidin-4-one behaves as a monodentate ligand and coordinates to the tin through the oxygen atom. The complex exhibits a trigonal bipyramidal configuration with the three phenyl groups in equatorial positions and the chloride and ligand oxygen occupying the apical sites. Keywords: triorganotin, fungicide, Dutch Elm Disease, thiazolidin-4-one.

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