I have written a few times about the so-called “anomeric effect“, which relates to stereoelectronic interactions in molecules such as sugars bearing a tetrahedral carbon atom with at least two oxygen substituents. The effect can be detected when the two C-O bond lengths in such molecules are inspected, most obviously when one of these bonds has a very different length from the other. The effect originates when one of the lone pair of electrons on one oxygen atom uniquely overlaps with the C-O antibonding σ* on another oxygen, thus shortening the length of the donating oxygen-carbon length and ..read more

The recent release of the DataCite Data Citation corpus, which has the stated aim of providing “a trusted central aggregate of all data citations to further our understanding of data usage and advance meaningful data metrics” made me want to investigate what the current state of citing data in the area of chemistry might be. Chemistry is known to be a “data rich” science (as most of the physical sciences are) and  here on this very blog I try to cite whenever possible the source(s) of the data that  I often use when discussing a topic. Such citations are not necessarily the same as ..read more

Following on from my template exploration of the Wilkinson hydrogenation catalyst, I now repeat this for the Grubbs variant of the Alkene metathesis reaction. As with the Wilkinson, here I focus on the stereochemistry of the mechanism as first suggested by Chauvin[1], an aspect lacking in eg the Wikipedia entry. As before, the diagram below is hyperlinked to the appropriate data repository identifier so that you can go straight from the scheme to the data (Top level Data DOI: 10.14469/hpc/13796). The essence of the reaction is the formation of a metallacyclobutane intermediate, which being a ..read more

In the late 1980s, as I recollected here[1] the equipment needed for real time molecular visualisation as it became known as was still expensive, requiring custom systems such as Evans and Sutherland PS390 workstations. One major breakthrough in making such techniques generally available on less specialised equipment was achieved by Roger Sayle[2], then working at Imperial College around 1990 and using a Silicon Graphics workstation. He greatly optimised up the rendering algorithms by creating a program called RasMol (after his initials), which meant such visualisations could very r ..read more

On 24th January 1984, the Macintosh computer was released, as all the media are informing us. Apparently, some are still working. I thought I would give my own personal recollections of that period. In fact, the Mac reached UK stores via a dealership only in 1985. What brought it to the attention of our university chemistry department was that also in 1985 the Chemdraw program was released and visitors to e.g. ACS meetings that year (probably the spring meeting) brought news of it back. A third piece of the puzzle, the Laserwriter also appeared that year. What difference would all this make ..read more

Geoffrey Wilkinson first reported his famous work on the hydrogenation catalyst that now bears his name in 1965[1] and I met him at Imperial College around 1969 and again when I returned there in 1977. He was still working on these catalysts then and I was privileged to collaborate with him on unravelling the NMR spectra of some of these compounds.[2],[3],[4]. During that period, computational modelling of the mechanisms of molecules containing transition elements was still in its infancy and I never extended my collaboration into this area at that time. Now, even if belatedly, I decided ..read more

First, a very brief history of scholarly publishing, starting in 1665[1] when scientific journals started to be published by learned societies. This model continued until the 1950s, when commercial publishers such as Pergamon Press started with their USP (unique selling point) of rapid time to publication of ~3 months,[2] compared to typical times for many learned society publishers of 2 years or longer. Fast forward another 50 years or so, and the commercial publishers were now dominating the scene, but the business model was still based on institutional subscriptions, whereby the institutio ..read more

I will approach this example of a molecule-of-the-year candidate – in fact the eventual winner in the reader poll – from the point of view of data. Its a metallocene arranged in the form of a ring comprising 18 sub-units.[1] Big enough to deserve a 3D model rather than the static images you almost invariably get in journals (and C&EN). So how does one go to the journal and acquire the coordinates for such a model? Well, nowadays most reputable journals include a “data availability” statement, which in this case is indicated using a URL-style identifier for supporting information. This me ..read more

The Science education unit at the ACS publication C&EN publishes its list of molecules of the year (as selected by the editors and voted upon by the readers) in December. Here are some observations about three of this year’s batch. Diberyllocene[1] with its unusual Be-Be bond has already beeen covered on this blog.[2], where I commented that lithioborocene should be possible to make as well. The second in the list is the synthesis of the chiral triaryloxonium ion[3] HICBUU(Crystal DOI: 10.5517/ccdc.csd.cc2cjynj). Curiously, this combines the features of two of our recent publications (w ..read more

In 2023, we very much take for granted that everyone and pretty much everything is online. But it was not always so and when I came across an old plan indicating how the chemistry department at Imperial College was connected in 1989, I was struck by how much has happened in the 34 years since. Nowadays all the infrastructures needed are effectively “built in” to the building when it is constructed and few are even aware of them. But in 1989 that was not at all true. To introduce the plan I discovered, I will first try to very briefly summarise the evolution of computing and IT infrastructures ..read more