Archive for September, 2017
Thursday, September 21st, 2017
A recent article reports, amongst other topics, a computationally modelled reaction involving the capture of molecular hydrogen using a substituted borane (X=N, Y=C).[1] The mechanism involves an initial equilibrium between React and Int1, followed by capture of the hydrogen by Int1 to form a 5-coordinate borane intermediate (Int2 below, as per Figure 11).‡ This was followed by assistance from a proximate basic nitrogen to complete the hydrogen capture via a TS involving H-H cleavage. The forward free energy barrier to capture was ~11 kcal/mol and ~4 kcal/mol in the reverse direction (relative to the species labelled Int1), both suitably low for reversible hydrogen capture. Here I explore a simple variation to this fascinating reaction.∞
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References
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L. Li, M. Lei, Y. Xie, H.F. Schaefer, B. Chen, and R. Hoffmann, "Stabilizing a different cyclooctatetraene stereoisomer", Proceedings of the National Academy of Sciences, vol. 114, pp. 9803-9808, 2017. http://dx.doi.org/10.1073/pnas.1709586114
Tags:Ammonia borane, animation, Boranes, Chemistry, Cleaning Services, Company: React Group, free energy barrier, Hydroboration, Hydrogen, Matter
Posted in reaction mechanism | 1 Comment »
Saturday, September 16th, 2017
Early in 2011, I wrote about how the diatomic molecule Be2 might be persuaded to improve upon its normal unbound state (bond order ~zero) by a double electronic excitation to a strongly bound species. I yesterday updated this post with further suggestions and one of these inspired this follow-up.
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Tags:Be-Be double bond, Be-Be triple bond, Chemical bond, Chemistry, Cs-Cs double bond, Diatomic molecule, free energy, General chemistry, Interesting chemistry, K-K double bond, Li-Li double bond, Molecular geometry, Oxygen, Province/State: Be2, Quantum chemistry, Rb-Rb double bond, Stereochemistry
Posted in Uncategorised | 3 Comments »
Wednesday, September 6th, 2017
Tags:bond, Chemical bond, chemical bond zoo, City: Aachen, Concepts, Dialectic, Fuzzy concept, Interesting chemistry, Non-classical logic, Psychometrics, triplet excitation energy
Posted in Bond slam | No Comments »