External Heavy-Atom Effect via Orbital Interactions Revealed by Single-Crystal X-ray Diffraction

2016 ◽  
Vol 120 (29) ◽  
pp. 5791-5797 ◽  
Author(s):  
Xingxing Sun ◽  
Baicheng Zhang ◽  
Xinyang Li ◽  
Carl O. Trindle ◽  
Guoqing Zhang
Keyword(s):  
Single Crystal ◽  
Heavy Atom ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heavy Atom Effect ◽  
Orbital Interactions ◽  
Atom Effect

Synthese und Struktur- und Konformationsanalyse von Triphenylphosphonium-bis(diphenylarsino)methylid

1984 ◽  
Vol 39 (11) ◽  
pp. 1456-1462 ◽  
Author(s):  
Hubert Schmidbaur ◽  
Peter Nußstein ◽  
Gerhard Müller
Keyword(s):  
Single Crystal ◽  
Spectroscopic Data ◽  
Heavy Atom ◽  
Lone Pair ◽  
Molar Ratio ◽  
Single Bond ◽  
X Ray Diffraction ◽  
Trans Conformation ◽  
X Ray ◽  
Lone Pairs

Abstract Triphenylphosphonium -diphenylarsinomethylide (1) and -bis-(diphenylarsino)methylide (2) are easily available through transylidation processes using Ph3P = CH2 and Ph2AsCl as the starting materials in the appropriate molar ratio. Analytical and spectroscopic data are presented for both ylides. The structure of 2 was studied in detail by single-crystal X-ray diffraction. The basic PCAs2 skeleton is found to deviate strongly from planarity. The Ph2As-substituents adopt a cis/trans conformation relative to the ylidic P = C bond with the directions of the lone pairs of electrons at the arsenic atoms in the heavy atom plane as expected for a maximum compensation of the electrostatic vectors. For 1, a cis-conformation of the lone pair of electrons and a large PCAs angle are predicted on the basis of NMR analogies with the phosphorus homologues. Single bond rotational barriers appear to be much lower for 1 and 2, however, than for the corresponding phosphino-substituted ylides.

Confacial bioctahedral complexes of tungsten(IV) containing tungsten-to-tungsten bonds: X-ray crystal structures of di-μ-ethanethiolato-μ-sulfidobis[dichloro(dimethyl sulfide)-tungsten(IV) (W—W)] and tetraphenylphosphonium di-μ-ethane thiolato-μ-sulfido- bis[trichlorotungstate(IV) (W—W)]

1982 ◽  
Vol 60 (11) ◽  
pp. 1333-1338 ◽  
Author(s):  
P. Michael Boorman ◽  
Penelope W. Codding ◽  
K. Ann Kerr ◽  
Kelly J. Moynihan ◽  
Vikram D. Patel
Keyword(s):  
Single Crystal ◽  
Bond Length ◽  
Diffraction Study ◽  
Crystal Structures ◽  
Dimethyl Sulfide ◽  
Heavy Atom ◽  
X Ray Diffraction ◽  
Triclinic Space Group ◽  
Space Group ◽  
X Ray

The complex (Me2S)Cl2W(μ-S)(μ-SEt)2WCl2(Me2S), 1, has been prepared by reaction of [WCl4(Me2S)2] with 1 mol-equiv. of SiMe3(SEt) in CH2Cl2 solution. A single-crystal X-ray diffraction study shows that the molecule has a confacial bioctahedral structure with a W—W bond length of 2.526(2) Å. The structure was solved by heavy atom methods and refined to R = 0.061 and Rw = 0.061 for 2715 reflections with I ≥ 3σ(1). Crystals of 1 are triclinic, space group [Formula: see text], with a = 9.661(1), b = 10.695(1), c = 13.253(4) Å, α = 61.84(2), β = 66.98(2), and γ = 66.44(1)°, Z = 2.Reaction of 1with 2 mol-equiv. of Ph4PCl in CH2Cl2 solution yields (Ph4P)2[Cl3W(μ-S)(μ-SEt)2WCl3], 2. Crystals of 2 are triclinic, space group [Formula: see text], with a = 10.153(1), b = 13.043(1), c = 21.876(3) Å, α = 95.16(1), β = 96.48(2), and γ = 108.90(1)°, Z = 2. The structure was refined to R = 0.041, Rw = 0.048 for 2384 reflections with I ≥ 3σ(1); 2 also has a confacial bioctahedral structure with a W—W bond length of 2.522(1) Å.

scholarly journals Unexpectedly Long Lifetime of the Excited State of Benzothiadiazole Derivative and Its Adducts with Lewis Acids

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 2030
Author(s):  
Taisiya S. Sukhikh ◽  
Radmir M. Khisamov ◽  
Sergey N. Konchenko
Keyword(s):  
Lewis Acids ◽  
Bromine Atom ◽  
Heavy Atom ◽  
Intersystem Crossing ◽  
Triplet States ◽  
X Ray Diffraction ◽  
X Ray ◽  
Singlet And Triplet States ◽  
Long Lifetime ◽  
Atom Effect

We report a study of photoluminescent properties of 4-bromo-7-(3-pyridylamino)-2,1,3-benzothiadiazole (Py-btd) and its novel Lewis adducts: (PyH-btd)2(ZnCl4) and [Cu2Cl2(Py-btd)2{PPO}2]·2C7H8 (PPO = tetraphenyldiphosphine monoxide), whose crystal structure was determined by X-ray diffraction analysis. Py-btd exhibits a lifetime of 9 microseconds indicating its phosphorescent nature, which is rare for purely organic compounds. This phenomenon arises from the heavy atom effect: the presence of a bromine atom in Py-btd promotes mixing of the singlet and triplet states to allow efficient singlet-to-triplet intersystem crossing. The Lewis adducts also feature a microsecond lifetime while emitting in a higher energy range than free Py-btd, which opens up the possibility to color-tune luminescence of benzothiadiazole derivatives.

Electron Microscopy of Shock Loaded Polycrystalline Beryllium

1974 ◽  
Vol 32 ◽  
pp. 506-507 ◽  
Author(s):  
J. M. Galbraith ◽  
L. E. Murr ◽  
A. L. Stevens
Keyword(s):  
Electron Microscopy ◽  
Wave Propagation ◽  
Structural Change ◽  
Single Crystal ◽  
Diffraction Pattern ◽  
Shock Loading ◽  
Slip Systems ◽  
Compression Tests ◽  
X Ray Diffraction ◽  
X Ray

Uniaxial compression tests and hydrostatic tests at pressures up to 27 kbars have been performed to determine operating slip systems in single crystal and polycrystal1ine beryllium. A recent study has been made of wave propagation in single crystal beryllium by shock loading to selectively activate various slip systems, and this has been followed by a study of wave propagation and spallation in textured, polycrystal1ine beryllium. An alteration in the X-ray diffraction pattern has been noted after shock loading, but this alteration has not yet been correlated with any structural change occurring during shock loading of polycrystal1ine beryllium.This study is being conducted in an effort to characterize the effects of shock loading on textured, polycrystal1ine beryllium. Samples were fabricated from a billet of Kawecki-Berylco hot pressed HP-10 beryllium.

Isomorphous replacement in electron diffraction of wet crystals of rat hemoglobin

1983 ◽  
Vol 41 ◽  
pp. 446-447
Author(s):  
William F. Tivol ◽  
Murray Vernon King ◽  
D. F. Parsons
Keyword(s):  
Electron Diffraction ◽  
Heavy Atom ◽  
Isomorphous Substitution ◽  
X Ray Diffraction ◽  
Salt Solutions ◽  
X Ray ◽  
Isomorphous Replacement ◽  
Structure Factors ◽  
Diffraction Structure ◽  
The Mean

Feasibility of isomorphous substitution in electron diffraction is supported by a calculation of the mean alteration of the electron-diffraction structure factors for hemoglobin crystals caused by substituting two mercury atoms per molecule, following Green, Ingram & Perutz, but with allowance for the proportionality of f to Z3/4 for electron diffraction. This yields a mean net change in F of 12.5%, as contrasted with 22.8% for x-ray diffraction.Use of the hydration chamber in electron diffraction opens prospects for examining many proteins that yield only very thin crystals not suitable for x-ray diffraction. Examination in the wet state avoids treatments that could cause translocation of the heavy-atom labels or distortion of the crystal. Combined with low-fluence techniques, it enables study of the protein in a state as close to native as possible.We have undertaken a study of crystals of rat hemoglobin by electron diffraction in the wet state. Rat hemoglobin offers a certain advantage for hydration-chamber work over other hemoglobins in that it can be crystallized from distilled water instead of salt solutions.

Crystal structure of an inclusion complex between chiral monoaza-15-crown-5 and S(–)-1-phenyl-ethyl ammonium percholorate

2003 ◽  
Vol 218 (5) ◽  
Author(s):  
Süheyla Özbey ◽  
F. B. Kaynak ◽  
M. Toğrul ◽  
N. Demirel ◽  
H. Hoşgören
Keyword(s):  
Crystal Structure ◽  
Inclusion Complex ◽  
Single Crystal ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
New Type

AbstractA new type of inclusion complex, S(–)-1 phenyl ethyl ammonium percholorate complex of R-(–)-2-ethyl - N - benzyl - 4, 7, 10, 13 - tetraoxa -1- azacyclopentadecane, has been prepared and studied by NMR, IR and single crystal X-ray diffraction techniques. The compound crystallizes in space group

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