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Henry Rzepa's Blog

Henry Rzepa's Blog
Chemistry with a twist
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Chemical ITCarbonChemical DatabasesChemical GraveyardChemical SpectraChimieAnglais
Publié

Nowadays, data supporting most publications relating to the synthesis of organic compounds is more likely than not to be found in associated “supporting information” rather than the (often page limited) article itself. For example, this article has an SI which is paginated at 907;

Chemical ITAcquisitionArchival ScienceAuthorCollection SoftwareChimieAnglais
Publié

In an era when alternative facts and fake news afflict us, the provenance of scientific data becomes ever more important. Especially if that data is available as open access and exploitable by others for both valid scientific reasons but potentially also by those with other motives.

Bond SlamCrystal_structure_miningHypervalencyInteresting ChemistryAromatic SystemsChimieAnglais
Publié

A few years back I followed a train of thought here which ended with hexacoordinate carbon, then a hypothesis rather than a demonstrated reality. That reality was recently confirmed via a crystal structure, DOI:10.5517/CCDC.CSD.CC1M71QM. Here is a similar proposal for penta-coordinate nitrogen.

Crystal_structure_mining2-Norbornyl CationCarbocationsChemical BondingChemistryChimieAnglais
Publié

It is not only the non-classical norbornyl cation that has proved controversial in the past. A colleague mentioned at lunch (thanks Paul!) that tri-coordinate group 14 cations such as R3Si+ have also had an interesting history. Here I take a brief look at some of these systems.

Reaction MechanismAnimationChemical ReactionChemistryComputational ChemistryChimieAnglais
Publié

The example a few posts back of how methane might invert its configuration by transposing two hydrogen atoms illustrated the reaction mechanism by locating a transition state and following it down in energy using an intrinsic reaction coordinate (IRC). Here I explore an alternative method based instead on computing a molecular dynamics trajectory (MD).

Reaction MechanismChemistryMethaneMolecular GeometryOrbital HybridisationChimieAnglais
Publié

This is a spin-off from the table I constructed here for further chemical examples of the classical/non-classical norbornyl cation conundrum. One possible entry would include the transition state for inversion of methane via a square planar geometry as compared with e.g. NiH4 for which the square planar motif is its minimum.