Supramolecular interactions in boron hydrides: how non-classical bonding directs their crystal architecture

CrystEngComm ◽  
2015 ◽  
Vol 17 (40) ◽  
pp. 7623-7627 ◽  
Author(s):  
David J. Wolstenholme ◽  
Eric J. Fradsham ◽  
G. Sean McGrady
Keyword(s):  
Driving Forces ◽  
Supramolecular Interactions ◽  
Boron Hydrides ◽  
Dihydrogen Bonds

The nature and driving forces behind the formation of dihydrogen bonds are explored for several textbook boranes, and their influence on the crystalline architecture is revealed.

Chemistry of boron hydrides orchestrated by dihydrogen bonds

2013 ◽  
Vol 747 ◽  
pp. 30-42 ◽  
Author(s):  
Oleg A. Filippov ◽  
Natalia V. Belkova ◽  
Lina M. Epstein ◽  
Elena S. Shubina
Keyword(s):  
Boron Hydrides ◽  
Dihydrogen Bonds

ChemInform Abstract: Chemistry of Boron Hydrides Orchestrated by Dihydrogen Bonds

ChemInform ◽  
2014 ◽  
Vol 45 (5) ◽  
pp. no-no
Author(s):  
Oleg A. Filippov ◽  
Natalia V. Belkova ◽  
Lina M. Epstein ◽  
Elena S. Shubina
Keyword(s):  
Boron Hydrides ◽  
Dihydrogen Bonds

Study of Proton-Deuterium Exchange in Ten-Vertex Boron Hydrides

2007 ◽  
Vol 72 (12) ◽  
pp. 1725-1739 ◽  
Author(s):  
Igor B. Sivaev ◽  
Vikentii I. Bragin ◽  
Alexander V. Prikaznov ◽  
Pavel V. Petrovskii ◽  
Vladimir I. Bregadze ◽  
...  
Keyword(s):  
Alkoxy Group ◽  
Deuterium Exchange ◽  
Apical Position ◽  
Boron Hydrides ◽  
Dihydrogen Bonds ◽  
General Order ◽  
Derivatives Of ◽  
Electron Withdrawing Substituents

The effect of electron-donating and electron-withdrawing substituents on the proton-deuterium exchange in derivatives of the closo-decaborate anion in methanol-d4 was studied. Introduction of the electron-donating hydroxy (alkoxy) group into the apical position of the boron cage strongly promotes the H-D exchange at the antipodal apical vertex, whereas introduction of the electron-withdrawing diazonium group stops the H-D exchange completely. The general order of the proton-deuterium exchange in equatorially-substituted derivatives [2-B10H9R]n- is 10 > 1 >> 7,8 > 4 > 3,5 ≈ 6,9. Formation of dihydrogen bonds between 1- and 2-hydroxy derivatives of the closo-decaborate anion and alcohols was investigated and their possible role in the H-D exchange was discussed.

scholarly journals Dimeric and Trimeric Catenation of Giant Chiral [8+12] Imine Cubes Driven by Weak Supramolecular Interactions

2021 ◽  
Author(s):  
Bahiru Punja Benke ◽  
Tobias Kirschbaum ◽  
Jürgen Graf ◽  
Michael Mastalerz
Keyword(s):  
Driving Forces ◽  
Three Dimensional ◽  
Molecular Switches ◽  
Supramolecular Interactions ◽  
Reaction Conditions ◽  
Π Stacking ◽  
Methoxy Groups ◽  
Dimensional Shape ◽  
First Time ◽  
Three Dimensional Shape

Mechanically interlocked structures, such as catenanes or rotaxanes are fascinating synthetic targets and are the basis of molecular switches and machines. Today, the vast majority of catenated structures are built upon macrocycles and only a very few examples of three?dimensional shape-persistent organic cages forming such structures are reported. However, the catenation in all these cases was based on a thermodynamically favoured π-π stacking under certain reaction conditions. Here, we present our findings that catenane formation can be driven by even less directional dispersion (Keesom) interactions of methoxy-groups during the synthesis of chiral [8+12] imine cubes, giving dimeric and also for the first time trimeric catenated organic cages. To further elucidate the underlying driving forces, twelve differently 1,4-substituted benzene dialdehydes have been reacted with a chiral triamino tribenzotriquinacene under various conditions to study whether monomeric cages or catenated cage dimers are the preferred products.

scholarly journals Dimeric and Trimeric Catenation of Giant Chiral [8+12] Imine Cubes Driven by Weak Supramolecular Interactions

2021 ◽  
Author(s):  
Bahiru Punja Benke ◽  
Tobias Kirschbaum ◽  
Jürgen Graf ◽  
Michael Mastalerz
Keyword(s):  
Driving Forces ◽  
Three Dimensional ◽  
Molecular Switches ◽  
Supramolecular Interactions ◽  
Reaction Conditions ◽  
Π Stacking ◽  
Methoxy Groups ◽  
Dimensional Shape ◽  
First Time ◽  
Three Dimensional Shape

Mechanically interlocked structures, such as catenanes or rotaxanes are fascinating synthetic targets and are the basis of molecular switches and machines. Today, the vast majority of catenated structures are built upon macrocycles and only a very few examples of three?dimensional shape-persistent organic cages forming such structures are reported. However, the catenation in all these cases was based on a thermodynamically favoured π-π stacking under certain reaction conditions. Here, we present our findings that catenane formation can be driven by even less directional dispersion (Keesom) interactions of methoxy-groups during the synthesis of chiral [8+12] imine cubes, giving dimeric and also for the first time trimeric catenated organic cages. To further elucidate the underlying driving forces, twelve differently 1,4-substituted benzene dialdehydes have been reacted with a chiral triamino tribenzotriquinacene under various conditions to study whether monomeric cages or catenated cage dimers are the preferred products.

Solute redistribution during in-situ irradiation of alloys in the high voltage electron microscope

1978 ◽  
Vol 36 (1) ◽  
pp. 370-371
Author(s):  
P. R. Okamoto ◽  
N.Q. Lam ◽  
R. L. Lyles
Keyword(s):  
Electron Microscope ◽  
High Voltage ◽  
Driving Forces ◽  
Solute Diffusion ◽  
Solute Redistribution ◽  
Voltage Electron ◽  
High Voltage Electron Microscope ◽  
High Voltage Electron ◽  
Thin Foils ◽  
Solute Atoms

During irradiation of thin foils in a high voltage electron microscope (HVEM) defect gradients will be set up between the foil surfaces and interior. In alloys defect gradients provide additional driving forces for solute diffusion since any preferential binding and/or exchange between solute atoms and mobile defects will couple a net flux of solute atoms to the defect fluxes. Thus, during irradiation large nonequilibrium compositional gradients can be produced near the foil surfaces in initially homogeneous alloys. A system of coupled reaction-rate and diffusion equations describing the build up of mobile defects and solute redistribution in thin foils and in a semi-infinite medium under charged-particle irradiation has been formulated. Spatially uniform and nonuniform damage production rates have been used to model solute segregation under electron and ion irradiation conditions.An example calculation showing the time evolution of the solute concentration in a 2000 Å thick foil during electron irradiation is shown in Fig. 1.

Chronic Pain: Fundamental Scientific Considerations, Specifically for Legal Claims

2013 ◽  
Vol 18 (1) ◽  
pp. 1-18 ◽  
Author(s):  
Robert J. Barth
Keyword(s):  
Health Outcomes ◽  
Pain Perception ◽  
Driving Forces ◽  
Psychological Treatment ◽  
Dominant Role ◽  
Meta Analysis ◽  
General Medicine ◽  
Pain Syndrome ◽  
Problematic Relationship

Abstract Scientific findings have indicated that psychological and social factors are the driving forces behind most chronic benign pain presentations, especially in a claim context, and are relevant to at least three of the AMA Guides publications: AMA Guides to Evaluation of Disease and Injury Causation, AMA Guides to Work Ability and Return to Work, and AMA Guides to the Evaluation of Permanent Impairment. The author reviews and summarizes studies that have identified the dominant role of financial, psychological, and other non–general medicine factors in patients who report low back pain. For example, one meta-analysis found that compensation results in an increase in pain perception and a reduction in the ability to benefit from medical and psychological treatment. Other studies have found a correlation between the level of compensation and health outcomes (greater compensation is associated with worse outcomes), and legal systems that discourage compensation for pain produce better health outcomes. One study found that, among persons with carpal tunnel syndrome, claimants had worse outcomes than nonclaimants despite receiving more treatment; another examined the problematic relationship between complex regional pain syndrome (CRPS) and compensation and found that cases of CRPS are dominated by legal claims, a disparity that highlights the dominant role of compensation. Workers’ compensation claimants are almost never evaluated for personality disorders or mental illness. The article concludes with recommendations that evaluators can consider in individual cases.

Thermodynamics of dihydrogen bonds (A—H…H—B)

1998 ◽  
Vol 94 (5) ◽  
pp. 839-842
Author(s):  
MILAN REMKO
Keyword(s):  
Dihydrogen Bonds
Sign in / Sign up

Export Citation Format

Share Document