scholarly journals The Helical Structure of Diallylamine in the Solid State

2019 ◽  
Vol 50 (4) ◽  
pp. 422-427
Author(s):  
Chloe J. Pugh ◽  
Craig M. Robertson ◽  
Alexander Steiner
Keyword(s):  
Hydrogen Bonding ◽  
Solid State ◽  
Van Der Waals ◽  
Helical Structure ◽  
Van Der Waals Interactions ◽  
Asymmetric Unit ◽  
Length Scales ◽  
Hexagonal Packing

Abstract In the solid state diallylamine forms supramolecular helices with four molecules per pitch that are held together by hydrogen bonding. The helical structure is the result of competing length scales at which hydrogen bonding and second-neighbour Van-der-Waals interactions occur. The structure features two crystallographically independent helices and four unique molecules in the asymmetric unit (Z′ = 4). The high Z′ value is partly a consequence of the centrosymmetric pseudo-hexagonal packing of helical columns, which is incompatible with helical spacegroup symmetries. Graphic Abstract

scholarly journals Crystal structure of 2-cyano-1-methylpyridinium tetrafluoroborate

2015 ◽  
Vol 71 (10) ◽  
pp. o697-o698 ◽  
Author(s):  
Francesca A. Vaccaro ◽  
Lynn V. Koplitz ◽  
Joel T. Mague
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Solid State ◽  
Three Dimensional ◽  
Asymmetric Unit ◽  
State Structure ◽  
Solid State Structure ◽  
Two Component

The asymmetric unit of the title salt, C7H7N2+·BF4−, comprises two independent but nearly identical formula units. The solid-state structure comprises corrugated layers of cations and anions, formed by C—H...F hydrogen bonding, that are approximately parallel to (010). Further C—H...F hydrogen bonding consolidates the three-dimensional architecture. The sample was refined as a two-component non-merohedral twin.

A topological analysis of the interion interactions of tetraphenylphosphonium squarate

2006 ◽  
Vol 84 (5) ◽  
pp. 804-811 ◽  
Author(s):  
David Wolstenholme ◽  
Manuel AS Aquino ◽  
T Stanley Cameron ◽  
Joseph D Ferrara ◽  
Katherine N Robertson
Keyword(s):  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Electron Density ◽  
Intermolecular Interactions ◽  
Critical Points ◽  
Topological Analysis ◽  
Van Der Waals ◽  
Van Der Waals Interactions ◽  
Multipole Refinement ◽  
Diverse Interactions

The tetraphenylphosphonium squarate salt crystallizes with a number of diverse interactions, which all have the potential to be classified as hydrogen bonds. The squarate anions are found as dimers linked by O-H···O interactions. The multipole refinement of the tetraphenylphosphonium squarate was performed using the Hansen–Coppens model followed by topological analysis of its intermolecular interactions. A total of 28 interactions were found among the symmetry related molecules, which include a number of C-H···Cπ, C-H···O, and C-H···H-C interactions, along with the O-H···O interaction. With the criteria for hydrogen bonding proposed by Popelier and Koch, it is possible to determine which of these interactions are hydrogen bonds and which are van der Waals interactions. Both linear and exponentially dependent correlations can be seen for the properties of the bond critical points involving the intermolecular interactions that fulfill these criteria. All this leads to a better understanding of the role that hydrogen bonds play in the formation of small organic compounds.Key words: electron density, multiple refinement, hydrogen bonds.

Competition and cooperativity of hydrogen-bonding and tetrel-bonding interactions involving triethylene diamine (DABCO), H2O and CO2 in air

2020 ◽  
Vol 44 (6) ◽  
pp. 2328-2338 ◽  
Author(s):  
Jianming Yang ◽  
Qinwei Yu ◽  
Fang-Ling Yang ◽  
Ka Lu ◽  
Chao-Xian Yan ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Van Der Waals ◽  
Van Der Waals Interactions ◽  
Tetrel Bond

Triethylene diamine (DABCO) can interact with H2O and CO2 in air to form dimeric and trimeric complexes via hydrogen bond, tetrel bond as well as van der Waals interactions.

2-Phenyl-4-hydroxyphthalazin-1-one: A Benzoannelated Derivative of Maleic Hydrazide

1998 ◽  
Vol 54 (5) ◽  
pp. 671-676 ◽  
Author(s):  
D. Becker ◽  
M. Botoshansky ◽  
N. Gasper ◽  
F. H. Herbstein ◽  
M. Karni
Keyword(s):  
Hydrogen Bonding ◽  
Electron Correlation ◽  
Maleic Hydrazide ◽  
Van Der Waals Interactions ◽  
Asymmetric Unit ◽  
Parent Molecule ◽  
Molecular Arrangement ◽  
Independent Molecules ◽  
High Level ◽  
Good Agreement

The monoclinic crystals (space group P21/a, Z = 8) of 2-phenyl-4-hydroxyphthalazin-1-one, C14H10N2O2, have two independent molecules (A and B) in the asymmetric unit. Both occur as the lactim–lactam (hydroxy–one) structure, which is also found in the parent molecule maleic hydrazide (both triclinic and monoclinic polymorphs), dichloromaleic hydrazide and luminol (3-aminophthalhydrazide). The molecular arrangement is based on strings of alternating A and B molecules linked by hydroxyl...carbonyl hydrogen bonds, with only van der Waals interactions between adjacent strings. Comparison is made of the measured bond lengths for (monoclinic) maleic hydrazide and values from high-level ab initio calculations, and reasonably good agreement is obtained, with indications of improvements when allowance is made for electron correlation and hydrogen bonding.

scholarly journals Crystal structure of dibromidotetrakis(propan-2-ol-κO)nickel(II)

2015 ◽  
Vol 71 (12) ◽  
pp. m263-m264
Author(s):  
Yaokang Lv ◽  
Mingxian Liu ◽  
Lvlv Ji ◽  
Cheng Zhang ◽  
Mi Ouyang
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Van Der Waals ◽  
Van Der Waals Forces ◽  
Title Complex ◽  
Asymmetric Unit ◽  
Hexagonal Packing

The asymmetric unit of the mononuclear title complex, [NiBr2(C3H8O)4], comprises a NiIIcation located on a centre of inversion, one Br−anion and two propan-2-ol ligands. The NiIIcation exhibits a distortedtrans-Br2O4environment. There are O—H...Br hydrogen bonds connecting neighbouring molecules into rows along [100]. These rows are arranged in a distorted hexagonal packing and are held together by van der Waals forces only.

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