About 18 months ago, there was much discussion on this blog about a system reported by Bob Pascal and co-workers containing a short H…H contact of ~1.5Å[cite]10.1021/ja407398w[/cite]. In this system, the hydrogens were both attached to Si as Si-H…H-Si and compressed together by rings. Now a new report[cite]10.1021/jacs.7b01879[/cite] and commented upon by Steve Bachrach, claims a similar distance for hydrogens attached to carbon, i.e. C-H…H-C, but without the ring compression.
Posts Tagged ‘10.1021’
Dispersion “bonds”: a new example with an ultra-short H…H distance.
Monday, June 26th, 2017The “hydrogen bond”; its early history.
Saturday, December 31st, 2016My holiday reading has been Derek Lowe’s excellent Chemistry Book setting out 250 milestones in chemistry, organised by year. An entry for 1920 entitled hydrogen bonding seemed worth exploring in more detail here.
How does an OH or NH group approach an aromatic ring to hydrogen bond with its π-face?
Wednesday, June 22nd, 2016I previously used data mining of crystal structures to explore the directing influence of substituents on aromatic and heteroaromatic rings. Here I explore, quite literally, a different angle to the hydrogen bonding interactions between a benzene ring and OH or NH groups.
The solvation of ion pairs.
Thursday, November 6th, 2014Solvolytic mechanisms are amongst the oldest studied, but reproducing their characteristics using computational methods has been a challenging business. This post was inspired by reading Steve Bachrach’s post, itself alluding to this aspect in the title “Computationally handling ion pairs”. It references this recent article on the topic[cite]10.1021/jo501012s[/cite] in which the point is made that reproducing the features of both contact and solvent-separated ion pairs needs a model comprising discrete solvent molecules (in this case four dichloromethane units) along with a continuum model.
How to predict the regioselectivity of epoxide ring opening.
Sunday, April 28th, 2013I recently got an email from a student asking about the best way of rationalising epoxide ring opening using some form of molecule orbitals. This reminded me of the famous experiment involving propene epoxide.[cite]10.1021/ja01208a047[/cite]
Secrets of a university tutor: (curly) arrow pushing
Thursday, October 28th, 2010Curly arrows are something most students of chemistry meet fairly early on. They rapidly become hard-wired into the chemists brain. They are also uncontroversial! Or are they? Consider the following very simple scheme.