Search results for "molecular interaction"
showing 10 items of 70 documents
Halogen...halogen interactions in pressure-frozen ortho- and meta-dichlorobenzene isomers.
2007
Isomers 1,2-dichlorobenzene (o-DCB) and 1,3-dichlorobenzene (m-DCB) were high-pressure frozen in-situ in a Merrill–Bassett diamond–anvil cell and their structures determined at room temperature and at 0.18 (5) GPa for o-DCB, and 0.17 (5) GPa for m-DCB by single-crystal X-ray diffraction. The patterns of halogen...halogen intermolecular interactions in these structures can be considered to be the main cohesive forces responsible for the molecular arrangements in these crystals. The molecular packing of dichlorobenzene isomers, including three polymorphs of 1,4-dichlorobenzene (p-DCB), have been compared and relations between their molecular symmetry, packing arrangements, intermolecular inte…
Dissection of Genetic Cell Programmes Driving Early Arbuscular Mycorrhiza Interactions
2008
The persistence through evolution of the arbuscular mycorrhiza (AM) symbiosis between Glomeromycota and plants is probably due to a widespread molecular dialogue between the two partners. Most studies have focussed on established mycorrhizal systems whilst evidence for cellular commitment of the symbiotic partners during early developmental phases is recent. Whereas spore germination by AM fungi can occur spontaneously, subsequent hyphal branching, appressoria differentiation, root penetration and intraradical development leading to symbiosis establishment are under the control of molecular interactions between the two partners. In this chapter, recent work on AM fungus–plant interactions i…
Solid state conformational behavior and interactions of a series of aromatic oligoamide foldamers
2016
The topic of this thesis is aromatic oligoamide foldamers. The literary review of the thesis discusses the general features of foldamers and their design and then focuses on the specific examples of aromatic oligoamide foldamers. The experimental part of the thesis discusses the design and preparation of a family of aromatic oligoamide foldamers that can adopt a helical conformation. The folding is directed by intramolecular hydrogen bonding and stabilized by intramolecular aromatic interactions. The focus of the thesis is the analysis of the solid state conformations of ten foldamer analogues. The analysis is based on forty different crystal structures which are determined using single cry…
Theoretical and experimental studies of some main group compounds : from closed shell interactions to singlet diradicals and stable radicals
2012
Acquiring knowledge of different interactions within and between molecules is a fascinating undertaking as it not only deepens our understanding of chemical bonding but also offers insight into electronic structures, molecular properties and the connections between these two. This dissertation combines together three main group chemistry related topics within the aforementioned theme. Research presented in the first third of this dissertation describes wave function and density functional theory studies of weak inter- and intramolecular interactions in pnictogen-based dimers X3Pn···PnX3 (Pn = N-Bi; X = F-I), dithallenes RTlTlR (R = H, Me, tBu, Ph) and octachalcogen dications Ch82+ (Ch = S, …
Spectrophotometric determinations of binding constants between cyclodextrins and aromatic nitrogen substrates at various pH values
2001
The inclusion capacity of native β-cyclodextrin (1) and mono-(6-amino-6-deoxy)-β-cyclodextrin (2) versus aromatic compounds having a nitro or an amino group or both has been investigated at three different pH values. Molecular interactions in inclusion complexes have also been investigated by means of molecular mechanics (MM2/QD) models. Electrostatic and van der Waals interactions and the formation of a hydrogen bond between the donor amino group and the oxygen atom of the secondary hydroxyl group seem to be the more important contributions in determining complex stability. The inclusion capacity of two different cyclodextrins versus aromatic compounds has been investigated at three differ…
Brownian dynamics simulation of grafted polymer brushes
1995
We present results of computer simulations by the method of Brownian dynamics of polymeric brushes attached to impenetrable planes. For testing both model and method we have used one polymer brush attached to a repulsive plane and compare some results with Monte Carlo results of Lai and Binder on the bond fluctuation model. We have also studied two polymeric brushes attached to two parallel planes at different distances between planes, and investigate the interplay between the interpenetration of the brushes and the configurational properties of the grafted chains.
Crystal structure, Hirshfeld surface analysis and HOMO–LUMO analysis of (E)-4-bromo-N′-(4-methoxybenzylidene)benzohydrazide
2018
The title Schiff base compound, C15H13BrN2O2, displays an E configuration with respect to the C=N double bond, which forms a dihedral angle of 58.06 (9)° with the benzene ring. In the crystal, the molecules are linked into chains parallel to the b axis by N—H...O and C—H...O hydrogen bonds, giving rise to rings with an R 2 1(6) graph-set motif. The chains are further linked into a three-dimensional network by C—H...π interactions. A Hirshfeld surface analysis indicates that the most important contributions to the crystal packing are from C...H (33.2%), H...H (27.7%), Br...H/H...Br (14.2%) and O...H/H...O (13.6%) interactions. The title compound has also been characterized by frontier molecu…
Crystal structure, Hirshfeld surface analysis and HOMO–LUMO analysis of (E)-N′-(3-hydroxy-4-methoxybenzylidene)nicotinohydrazide monohydrate
2019
The title Schiff base compound displays an E configuration with respect to the C=N double bond. The pyridine and benzene rings subtend a dihedral angle of 29.63 (7)°. In the crystal, the molecules are linked by N—H⋯O, C—H⋯O, O—H⋯O and O—H⋯N hydrogen-bonding interactions.
Intramolecular 1,5-S...N σ-hole interaction in (E)-N′-(pyridin-4-ylmethylidene)thiophene-2-carbohydrazide
2020
The hydrazide-hydrazone forms inverse dimers via hydrogen bonding, but its conformation is defined by the presence of an intramolecular chalcogen bond. Electrostatic forces dominate in the crystal packing and give rise to a layered supramolecular structure.
Bis{4-[(2-hydroxy-5-methoxy-3-nitrobenzylidene)amino]phenyl} ether
2020
The molecule of the title oxybis compound lies on a twofold rotational axis. The conformation of the title compound is discussed and compared to those of related structures. In the crystal, molecules of the title compound are assembled into layers parallel to the ab plane through C—H⋯O hydrogen bonds.