Search results for "van der Waals force"
showing 10 items of 170 documents
Crystal structure and absolute configuration of (3aR,3′aR,7aS,7′aS)-2,2,2′,2′-tetramethyl-3a,6,7,7a,3′a,6′,7′,7′a-octahydro-4,4′-bi[1,3-benzodioxolyl…
2017
The absolute configuration,i.e.(3aR,3′aR,7aS,7′aS), of the title compound, C18H26O4, synthesizedviaa palladium-catalyzed homocoupling reaction, was determined on the basis of the synthetic pathway and was confirmed by X-ray diffraction. The homocoupled molecule is formed by two chemically identical moieties built up from two five- and six-membered fused rings. The supramolecular assembly is controlled mainly by C—H...O interactions that lead to the formation of hydrogen-bonded chains of molecules along the [001] direction, while weak dipolar interactions and van der Waals forces hold the chains together in the crystal structure.
1,1′-(Diphosphene-1,2-diyl)bis(2,2,6,6-tetramethylpiperidine)
2017
The title compound, C18H36N2P2, crystallizes in the triclinic space groupP-1 with two independent molecules in the asymmetric unit. Both molecules adopt atransconfiguration of the tetramethylpiperidine units along the P=P axis. The crystal packing is stabilized only by van der Waals interactions.
1,1′-[(2,3,5,6-Tetramethyl-1,4-phenylene)bis(methylene)]dipiperidine
2018
The asymmetric unit of the title compound, C22H36N2, comprises one half-molecule, the other half being generated by a center of inversion. The piperidine ring adopts a chair conformation, with the exocyclic N—C bond in an equatorial orientation. A short intramolecular C—H...N hydrogen bond occurs and forms an S(6) motif. No directional interactions beyond van der Waals contacts are observed between the molecules, which form a wave-like supramolecular architecture.
Crystal structure of (E)-2-(tert-butylamino)-4-(tert-butylimino)naphthalen-1(4H)-one
2018
The title compound is the first example of a naphthoquinone imine derivative crystallizing in the 4-imine/2-amine tautomeric form having bulky tert-butyl substituents at the N atoms.
Crystal structure of 4-(4-meth-oxy-phen-yl)-4',4'-dimethyl-3-p-tolyl-3',4'-di-hydro-1'H,3H-spiro-[isoxazole-5,2'-naphthalen]-1'-one.
2015
In the title compound, C28H27NO3, the cyclohexanone and isoxazole rings have envelope conformations, with the methylene and spiro C atoms as the flaps, respectively. The mean plane of the isoxazole ring is inclined slightly to thep-tolyl ring, making a dihedral angle of 14.20 (9)°, and is nearly perpendicular to the mean plane through the tetralone moiety and to the methoxyphenyl ring [dihedral angles = 83.41 (8) and 72.12 (9)°, respectively]. The crystal packing is stabilized mainly by van der Waals forces.
A study of the atmospherically important reactions of dimethylsulfide (DMS) with I2 and ICl using infrared matrix isolation spectroscopy and electron…
2012
The reactions of dimethylsulfide (DMS) with molecular iodine (I(2)) and iodine monochloride (ICl) have been studied by infrared matrix isolation spectroscopy by co-condensation of the reagents in an inert gas matrix. Molecular adducts of DMS + I(2) and DMS + ICl have also been prepared using standard synthetic methods. The vapour above each of these adducts trapped in an inert gas matrix gave the same infrared spectrum as that recorded for the corresponding co-condensation reaction. In each case, the infrared spectrum has been interpreted in terms of a van der Waals adduct, DMS : I(2) and DMS : ICl, with the aid of infrared spectra computed for their minimum energy structures at the MP2 lev…
Crystal structure and Hirshfeld surface analysis of (2E)-3-(3-bromo-4-fluorophenyl)-1-(3,4-dimethoxyphenyl)prop-2-en-1-one
2018
The title compound is constructed from two aromatic rings (3-bromo-4-fluorophenyl and 3,4-dimethoxyphenyl), which are linked by a C=C—C(=O)—C enone bridge and form a dihedral angle of 17.91 (17)°. In the crystal, molecules are linked by C—H⋯O hydrogen bonds enclosing rings of (14) graph-set motif to form layers parallel to (10).
Crystal structure and Hirshfeld surface analysis of [N(CH3)4][2,2′-Fe(1,7-closo-C2B9H11)2]
2017
Abstract This work investigates the meta -ferrabis(dicarbollide) anion that was isolated as salt of tetramethylammonium. The structure of the obtained crystal consisted of discrete [2,2′-Fe(1,7- closo -C 2 B 9 H 11 ) 2 ] − anions and disordered [N(CH 3 ) 4 ] + cations. The anion had a considerable chemical stability ensured by ionic and Van der Waals interactions. Thus, Hirshfeld surfaces and fingerprint plot were used to visualize, explore, and quantify intermolecular interactions in the crystal lattice of the title compound. This investigation proved that close contacts were dominated by H⋯H interactions.
Phonons in MoSe2/WSe2 van der Waals heterobilayer
2021
We report first-principles calculations of the structural and vibrational properties of the synthesized two-dimensional van der Waals heterostructures formed by single-layers dichalcogenides MoSe2 and WSe2. We show that, when combining these systems in a periodic two-dimensional heterostructures, the intrinsic phonon characteristics of the free-standing constituents are to a large extent preserved but, furthermore, exhibit shear and breathing phonon modes that are not present in the individual building blocks. These peculiar modes depend strongly on the weak vdW forces and has a great contibution to the thermal properties of the layered materials. Besides these features, the departure of fl…
Evidence of Weak Halogen Bonding: New Insights on Itraconazole and its Succinic Acid Cocrystal
2012
Exact knowledge of the crystal structure of drugs and lead compounds plays a significant role in the fields of crystal engineering, docking, computational modeling (drug–receptor interactions), and rational design of potent drugs in pharmaceutical chemistry. The succinic acid cocrystal of the systemic antifungal drug, itraconazole, reported by Remenar et al. (J. Am. Chem. Soc.2003, 125, 8456–8457) (CSD: IKEQEU), represents one of the classical examples displaying a molecular fitting mechanism in the solid state. In this work, we disclose the X-ray single-crystal structure of the cis-itraconazole–succinic acid (2:1) cocrystal and found that it differs slightly from the previously reported st…