Search results for "bond."
showing 10 items of 3516 documents
3,4-Dimethoxy-4'-methylbiphenyl
2013
In the title compound, C15H16O2, the dihedral angle between the planes of the aromatic rings is 30.5 (2). In the crystal, molecules are linked via C—HO hydrogen bonds and C— H interactions, forming a two-dimensional network lying parallel to (100). peerReviewed
Methyl 3',5'-dimethoxybiphenyl-4-carboxylate
2013
In the title compound, C16H16O4, the dihedral angle between the benzene rings is 28.9 (2)°. In the crystal, molecules are packed in layers parallel to the b axis in which they are connected via weak intermolecular C-H...O contacts. Face-to-face π-π interactions also exist between the benzene rings of adjacent molecules, with centroid-centroid and plane-to-plane shift distances of 3.8597 (14) and 1.843 (2) Å, respectively.
Methyl 3',4',5'-trimethoxybiphenyl-4-carboxylate
2013
In the title compound, C17H18O5, the dihedral angle between the benzene rings is 31.23 (16)°. In the crystal, the molecules are packed in an antiparallel fashion in layers along the a axis. In each layer, very weak C-H...O hydrogen bonds occur between the methoxy and methyl ester groups. Weak C-H...[pi] interactions between the 4'- and 5'-methoxy groups and neighbouring benzene rings [methoxy-C-ring centroid distances = 4.075 and 3.486 Å, respectively] connect the layers.
1,1,4,4-Tetramethylpiperazinediium dibromide
2009
A small quantity of the title compound, C8H20N22+·2Br−, was formed as a by-product in a reaction between a diamine and an alkyl bromide. The asymmetric unit contains half of a centrosymmetric dication and a bromide anion. In the crystal, weak intermolecular C—H...Br hydrogen bonds consolidate the crystal packing.
Controlling the crystal growth of potassium iodide with a 1,1'-bis(pyridin-4-ylmethyl)-2,2'-biimidazole ligand (L) – formation of a linear [K4I4L4]n …
2018
The crystal growth of potassium iodide was controlled by using the neutral organic 1,1′-bis(pyridin-4-ylmethyl)-2,2′-biimidazole (L) ligand as a modifier. The selected modifier allows the preservation of original cubic [K4I4] units and their arrangement into a linear ligand-supported 1D chain. The supported [K4I4] cubes are only slightly distorted compared to the cubes found in pure KI salt. The N–K binding of the ligand to the KI salt, as well as weak I⋯H, N⋯H, and N⋯I interactions, stabilizes the structure to create a unique 1D polymer of neutral potassium iodide ionic salt inside the [K4I4L4]n complex.
The Institution of Security Agent: A Comparative Study of Polish and French Laws
2022
In many continental legal systems it was often problematic to grant a security right to an entity separate from the holder(s) of the secured receivables. Such arrangement was especially desired by the parties in complex lending structures with many creditors. To solve this problem various legal solutions have been created in different countries. In Poland and in France the special institution of a security agent has been introduced. Aim of this article is to compare those two regulations. The conclusion is that the French provisions better deals with the challenges posed by the entity separation problem. Security agent, collective security arrangements, entity separation, unity principle, s…
Formation, Structural Characterization, and Calculated NMR Chemical Shifts of Selenium-Nitrogen Compounds from SeCl4 and ArNHLi (Ar = supermesityl, m…
2004
Supermesityl selenium diimide [Se{N(C6H2tBu3-2, 4, 6)}2; Se{N(mes*)}2] can be prepared in a good yield from the reaction of SeCl4 and (mes*)NHLi. The molecule adopts an unprecedented anti, anti-conformation, as deduced by DFT calculations at PBE0/TZVP level of theory and supported by 77Se NMR spectroscopy and a crystal structure determination. An analogous reaction involving (C6H2Me3-2, 4, 6)NHLi [(mes)NHLi] unexpectedly lead to the reduction of selenium and afforded the selenium diamide Se{NH(mes)}2 that was characterized by X-ray crystallography and 77Se NMR spectroscopy. The Se-N bonds of 1.847(3) and 1.852(3) A show normal single bond lengths. The <NSeN bond angle of 109.9(1)° also indi…
L2 or L3? Foreign Language Enjoyment and Proficiency
2017
Enjoyment is among the achievement emotions encountered in school and university settings. While often identified with a sense of belonging not necessarily connected with learning (Lumby, 2011), foreign language enjoyment (FLE) in SLA has been found to correlate with teachers’ professional and affective skills, and the existence of a supportive peer group. The risk involved with meeting the challenges of the SLA process induces both private and social feelings of FLE (Dewaele & MacIntyre, 2016). This study hypothesizes that a good command of language may be a source of elevated levels of enjoyment, because greater language proficiency is connected with greater control perception, especially…
A Model for the Study of Sheath Currents in Medium Voltage Cables for Industrial Application
2020
In this paper, the implementation of a simulation model for studying the effect of cross-bonding of metallic sheaths and/or non-magnetic armor of single-core medium voltage cables in the same circuit is discussed. With the use of single-core cables, the resistive losses due to the induced circulating currents in cable sheaths or armors causes an increase of cable temperature that reduces its ampacity. In addition, the risk of electric shock due to induced voltages may be present if a person is exposed to the armor/sheath at the unbounded end. For this reason, special bonding techniques are used to significantly reduce these currents. The authors have implemented a model that could be used t…
The structural disorder of a silica network probed by site selective luminescence of the nonbridging oxygen hole centre
2011
We studied the inhomogeneous distribution of the luminescence band associated with the nonbridging oxygen hole centre in silica through site selective excitation/detection of the zero phonon line by a tunable laser source. Defects induced in the bulk of synthetic samples by γ and β exposure exhibit an increase of the inhomogeneous width from 0.071 to 0.086 eV on increasing the irradiation dose from 2 × 10(6) to 5 × 10(9) Gy. We also investigated two defect variants stabilized at the surface of the silica nanoparticles, (≡ Si-O)3 Si–O* and (≡ Si-O)2(H-O)Si-O*, whose inhomogeneous width was measured to be 0.042 eV and 0.060 eV, respectively. These results can be accounted for by the structura…