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Henry Rzepa's Blog

Henry Rzepa's Blog
Chemistry with a twist
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Interesting ChemistryReaction MechanismChimieAnglais
Publié

In this series of posts about the electronic effects in small sulfur rings[cite]10.59350/rzepa.28615[/cite] I have explored increasingly large induced geometric effects. Here is the largest so far, for the compound S 7 I 1+ [cite]10.1021/ic50225a048[/cite] The calculated geometry[cite]10.14469/hpc/15236[/cite] is shown below, with the crystallographic values in parentheses – the two matching very well.

Interesting ChemistryChimieAnglais
Publié

The two previous  posts[cite]10.59350/rzepa.28515[/cite],[cite]10.59350/rzepa.28407[/cite] on the topic of anomeric effects in 7-membered sulfur rings illustrated how orbital interactions between the lone pairs in the molecules and S-S bonds produced widely varying S-S bond lengths in the molecules, some are shorter than normal (which is ~2.05Å for e.g. the S 8 ring) by ~ 0.1Å and some are longer by ~0.24Å.

Interesting ChemistryReaction MechanismChimieAnglais
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The monosulfoxide of cyclo-heptasulfur was reported along with cycloheptasulfur itself in 1977,[cite]10.1002/anie.197707161[/cite] along with the remarks that “ The δ modification of S 7 contains bonds of widely differing length: this has never been observed before in an unsubstituted molecule. and “the same effect having also been observed in other sulfur rings (S 8 O, S 7 I 1+ and S 7 O).”

Crystal_structure_miningInteresting ChemistryChimieAnglais
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Way back in 1977, the crystal structure of the sulfur ring S 7 was reported.[cite]10.1002/anie.197707151[/cite] The authors noted that “ The δ modification of S 7 contains bonds of widely differing length: this has never been observed before in an unsubstituted molecule. ” No explanation was offered, although they note that similar effects have been observed in S 8 O, S 7 I + and

Interesting ChemistryChimieAnglais
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Back in early 2012, I pondered about the relationships between a science-based blog post and a science-based journal article[cite]10.59350/3pbz1-vcd67[/cite]. This was in part induced by my discovering a blog plugin called Kcite , which allow a journal articles to be appended to the blog in the form of a numbered reference list.

Interesting ChemistryChimieAnglais
Publié

X-ray crystallography is the technique of using the diffraction of x-rays by the electrons in a molecule to determine the positions of all the atoms in that molecule. Quantum theory teaches us that the electrons are to be found in shells around the atomic nuclei. There are two broad types, the outermost shell (also called the valence shell) and all the inner or core shells.

Interesting ChemistryChimieAnglais
Publié

Starting around 2016, journal publishers started including mandatory “Data Availability” statements as part of research articles; a typical (dated) example is linked here, including guidelines for how to cite the data itself. I wrote about these aspects last year in a blog post for the RSC journal Digital Discovery[cite]10.26434/chemrxiv-2024-dz2dv[/cite] and here I follow up with more news.

Interesting ChemistryChimieAnglais
Publié

This is another in the C&E News list of candidates for the Molecule of the Year, Molecular shuttle in a box [cite]10.1002/anie.202318829[/cite] Mirror-image cyclodextrin [cite]10.1038/s44160-024-00495-8[/cite] Molecular shuttle in a box [cite]10.1002/anie.202318829[/cite] Rule-bending strained alkene [cite]10.1126/science.adq3519[/cite] First soluble promethium complex [cite]10.1038/s41586-024-07267-6[/cite]