First, Open Access, then Open (and FAIR) Data, now Open Citations.

February 3rd, 2018
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The topic of open citations was presented at the PIDapalooza conference and represents a third component in the increasing corpus of open scientific information.

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PIDapalooza 2018. A conference like no other!

January 23rd, 2018
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Another occasional conference report (day 1). So why is one about “persistent identifiers” important, and particularly to the chemistry domain?

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Silicon drug analogues.

January 14th, 2018
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I don’t normally write about the pharmaceutical industry, but I was intrigued by several posts by Derek Lowe (who does cover this area) on the topic of creating new drugs by deuterating existing ones. Thus he covered the first deuterated drug receiving FDA approval last year, having first reviewed the concept back in 2009. So when someone introduced me to sila-haloperidol, I checked to see if Derek had written about it. Apparently not, so here are a few details.

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Hypervalent hydrogen?

January 13th, 2018
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I discussed the molecule the molecule CH3F2- a while back. It was a very rare computed example of a system where the added two electrons populate the higher valence shells known as Rydberg orbitals as an alternative to populating the C-F antibonding σ-orbital to produce CH3 and F. The net result was the creation of a weak C-F “hyperbond”, in which the C-F region has an inner conventional bond, with an outer “sheath” encircling the first bond. But this system very easily dissociates to CH3 and F and is hardly a viable candidate for experimental detection.  In an effort to “tune” this effect to see if a better candidate for such detection might be found, I tried CMe3F2-. Here is its story.

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Multispectral Chiral Imaging with a Metalens.

January 6th, 2018
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The title here is from an article on metalenses[1] which caught my eye.

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References

  1. M. Khorasaninejad, W.T. Chen, A.Y. Zhu, J. Oh, R.C. Devlin, D. Rousso, and F. Capasso, "Multispectral Chiral Imaging with a Metalens", Nano Letters, vol. 16, pp. 4595-4600, 2016. http://dx.doi.org/10.1021/acs.nanolett.6b01897

Are diazomethanes hypervalent molecules? An attempt into more insight by more “tuning” with substituents.

December 26th, 2017
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Recollect the suggestion that diazomethane has hypervalent character[1]. When I looked into this, I came to the conclusion that it probably was mildly hypervalent, but on carbon and not nitrogen. Here I try some variations with substituents to see what light if any this casts.

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References

  1. M.C. Durrant, "A quantitative definition of hypervalency", Chemical Science, vol. 6, pp. 6614-6623, 2015. http://dx.doi.org/10.1039/C5SC02076J

Can any hypervalence in diazomethanes be amplified?

December 23rd, 2017
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In the previous post, I referred to a recently published review on hypervalency[1] which introduced a very simple way (the valence electron equivalent γ) of quantifying the effect. Diazomethane was cited as one example of a small molecule exhibiting hypervalency (on nitrogen) by this measure. Here I explore the effect of substituting diazomethane with cyano and nitro groups.

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References

  1. M.C. Durrant, "A quantitative definition of hypervalency", Chemical Science, vol. 6, pp. 6614-6623, 2015. http://dx.doi.org/10.1039/C5SC02076J

Are diazomethanes hypervalent molecules? Probably, but in an unexpected way!

December 23rd, 2017
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A recently published review on hypervalency[1] introduced a very simple way of quantifying the effect. One of the molecules which was suggested to be hypervalent using this method was diazomethane. Here I take a closer look.

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References

  1. M.C. Durrant, "A quantitative definition of hypervalency", Chemical Science, vol. 6, pp. 6614-6623, 2015. http://dx.doi.org/10.1039/C5SC02076J

Ammonide: an alkalide formed from ammonia and resembling an electride.

December 17th, 2017
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Alkalides are anionic alkali compounds containing e.g. sodide (Na), kalide (K), rubidide (Rb) or caeside (Cs). Around 90 examples can be found in the Cambridge structure database (see DOI: 10.14469/hpc/3453  for the search query and results). So what about the ammonium analogue, ammonide (NH4)? A quick search of Scifinder drew a blank! So here I take a look at this intriguingly simple little molecule.

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Identification of a simplest hypervalent hydrogen fluoride anion.

December 8th, 2017
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An article with the title shown above in part recently appeared.[1] Given the apparent similarity of HF1- to CH3F1- and CH3F2-, the latter of which I introduced on this blog previously, I thought it of interest to apply my analysis to HF1-.

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References

  1. M. Liu, H. Chen, C. Chin, T. Huang, Y. Chen, and Y. Wu, "Identification of a Simplest Hypervalent Hydrogen Fluoride Anion in Solid Argon", Scientific Reports, vol. 7, 2017. http://dx.doi.org/10.1038/s41598-017-02687-z