Conference report: an example of collaborative open science (reaction IRCs).

May 25th, 2017
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It is a sign of the times that one travels to a conference well-connected. By which I mean email is on a constant drip-feed, with venue organisers ensuring each delegate receives their WiFi password even before their room key. So whilst I was at a conference espousing the benefits of open science, a nice example of open collaboration was initiated as a result of a received email.

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Conference report: OPEN SCIENCE AND THE CHEMISTRY LAB OF THE FUTURE

May 23rd, 2017
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This is taking place in the idyllic surroundings of the Niederwald forest, Rüdesheim, Germany. Here I highlight only aspects of the first three talks.

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How does carbon dioxide coordinate to a metal?

May 6th, 2017
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Mention carbon dioxide (CO2) to most chemists and its properties as a metal ligand are not the first aspect that springs to mind. Here thought I might take a look at how it might act as such.

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The challenges in curating research data: one case study.

April 28th, 2017
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Research data (and its management) is rapidly emerging as a focal point for the development of research dissemination practices. An important aspect of ensuring that such data remains fit for purpose is identifying what curation activities need to be associated with it. Here I revisit one particular case study associated with the molecular structure of a product identified from a photolysis reaction[1] and the curation of the crystallographic data associated with this study.

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References

  1. Y. Legrand, A. van der Lee, and M. Barboiu, "Single-Crystal X-ray Structure of 1,3-Dimethylcyclobutadiene by Confinement in a Crystalline Matrix", Science, vol. 329, pp. 299-302, 2010. http://dx.doi.org/10.1126/science.1188002

π-Facial hydrogen bonds to alkynes (revisited): how close can an acidic hydrogen approach?

April 17th, 2017
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Following on from my re-investigation of close hydrogen bonding contacts to the π-face of alkenes, here now is an updated scan for H-bonds to alkynes. The search query (dataDOI: 10.14469/hpc/2478) is similar to the previous one:

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π-Facial hydrogen bonds to alkenes (revisited): how close can an acidic hydrogen approach?

April 15th, 2017
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Back in the early 1990s, we first discovered the delights of searching crystal structures for unusual bonding features.[1] One of the first cases was a search for hydrogen bonds formed to the π-faces of alkenes and alkynes. In those days the CSD database of crystal structures was a lot smaller (<80,000 structures; it’s now ten times larger) and the search software less powerful. So here is an update. 

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References

  1. H.S. Rzepa, M.H. Smith, and M.L. Webb, "A crystallographic AM1 and PM3 SCF-MO investigation of strong OH ⋯π-alkene and alkyne hydrogen bonding interactions", J. Chem. Soc., Perkin Trans. 2, pp. 703-707, 1994. http://dx.doi.org/10.1039/P29940000703

The π-π stacking of aromatic rings: what is their closest parallel approach?

April 13th, 2017
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Layer stacking in structures such as graphite is well-studied. The separation between the π-π planes is ~3.35Å, which is close to twice the estimated van der Waals (vdW) radius of carbon (1.7Å). But how much closer could such layers get, given that many other types of relatively weak interaction such as hydrogen bonding can contract the vdW distance sum by up to ~0.8Å or even more? This question was prompted by the separation calculated for the ion-pair cyclopropenium cyclopentadienide (~2.6-2.8Å).

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The conformation of carboxylic acids revealed.

April 11th, 2017
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Following my conformational exploration of enols, here is one about a much more common molecule, a carboxylic acid.

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Cyclopropenium cyclopentadienide: a strangely neutral ion-pair?

April 9th, 2017
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Both the cyclopropenium cation and the cyclopentadienide anion are well-known 4n+2-type aromatic ions, but could the two together form an ion-pair?

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The conformation of enols: revealed and explained.

April 6th, 2017
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Enols are simple compounds with an OH group as a substituent on a C=C double bond and with a very distinct conformational preference for the OH group. Here I take a look at this preference as revealed by crystal structures, with the theoretical explanation.

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