I do not play poker, ‡ and so I had to look up a 5-4-3- 2 -1(A), which Wikipedia informs me is a 5-high straight flush , also apparently known as a steel wheel . In previous posts I have suggested acids which can be ionised by (probably) 5, 4, 3 or 1 discrete water molecules in the gas phase;
My previous posts have covered the ionization by a small number of discrete water molecules of the series of halogen acids, ranging from HI (the strongest, pKa -10) via HF (weaker, pKa 3.1) to the pseudo-halogen HCN (the weakest, pKa 9.2). Here I try out some even stronger acids to see what the least number of water […]
HCN is a weak acid (pKa +9.2, weaker than e.g. HF), although it does have an isomer, isocyanic acid or HNC (pka < +9.2 ?) which is simultaneously stronger and less stable. I conclude my halide acid series by investigating how many water molecules (in gas phase clusters) are required for ionisation of this “pseudo-halogen” acid.
Why is this post orphaned from the previous? In order to have the opportunity of noting that treating iodine computationally can be a little different from the procedures used for F, Cl and Br.
No doubt answers to the question posed in the previous post are already being obtained by experiment. Just in case that does not emerge in the next day or so, I offer a prediction here.
According to Guggemos, Slavicek and Kresin, about 5-6!. This is one of those simple ideas, which is probably quite tough to do experimentally. It involved blasting water vapour through a pinhole, adding HCl and measuring the dipole-moment induced deflection by an electric field. They found “evidence for a noticeable rise in the dipole moment occurring at n≈5–6“.
The title of this post refers to the site http://howopenisit.org/ which is in effect a license scraper for journal articles.
Steganone is an unusual natural product, known for about 40 years now. The assignment of its absolute configurations makes for an interesting, on occasion rather confusing, and perhaps not entirely atypical story. I will start with the modern accepted stereochemical structure of this molecule, which comes in the form of two separately isolable atropisomers.
The journal of chemical education has many little gems providing inspiration for laboratory experiments. Jonathan Piard reports one based on the reaction below; here I investigate the mechanism of this transformation.
Sometimes you come across a bond in chemistry that just shouts at you. This happened to me in 1989 with the molecule shown below. Here is its story and, 26 years later, how I responded.
Derek Lowe in his In the Pipeline blog is famed for spotting unusual claims in the literature and subjecting them to analysis. This one is entitled Odd Structures, Subjected to Powerful Computations. He looks at this image below, and finds the structures represented there might be a mistake, based on his considerable experience of these kinds of molecules. I expect he had a gut feeling within seconds of seeing the diagram.