The topic of this post originates from a recent article which is attracting much attention.[1] The technique uses confined light to both increase the spatial resolution by around three orders of magnitude and also to amplify the signal from individual molecules to the point it can be recorded.

n-Butyl lithium is hexameric in the solid state[1] and in cyclohexane solutions. Why? Here I try to find out some of its secrets. SUHBEC. CLICK FOR 3D. The crystal structure reveals the following points of interest: Six lithium atoms form a cluster with triangular faces. An off-centre carbanion caps a triangular lithium face.

Consider acetaldehyde (ethanal for progressive nomenclaturists). What conformation does it adopt, and why? This question was posed of me by a student at the end of a recent lecture of mine. Surely, an easy answer to give? Read on … There really are only two possibilities, the syn and anti . Well, I have discovered it is useful to start with a search of the Cambridge data base.

The electronic interaction between a single bond and an adjacent double bond is often called σ-π-conjugation (an older term for this is hyperconjugation), and the effect is often used to e.g. explain why more highly substituted carbocations are more stable than less substituted ones.

I previously blogged about anomeric effects involving π electrons as donors, and my post on the conformation of 1,2-difluorethane turned out one of the most popular.

One frequently has to confront the question: will a hydrogen bond form between a suitable donor (lone pair or π) and an acceptor? One of the factors to be taken into consideration for hydrogen bonds which are part of a cycle is the ring size. Here I explore one way of quantifying the effect for the series below, n=1-5 (4-8 membered rings). I will use the NBO approach.

Here is a challenge: what is the longest C-C bond actually determined (in which both carbon termini are sp ³ hybridised)? I pose this question since Steve Bachrach has posted on how to stabilize long bonds by attractive dispersive interactions, and more recently commenting on what the longest straight chain alkane might be before dispersive interaction start to fold it (the answer appears to be C ₁₇ ). A search of the

In the preceding post, I described a fascinating experiment and calculation by Bogle and Singleton, in which the trajectory distribution of molecules emerging from a single transition state was used to rationalise the formation of two isomeric products 2 and **3. ** In the present post, I explore possible consequences of including a sodium cation (X=Na ⁺ below) in the computational

Years ago, I was travelling from Cambridge to London on a train. I found myself sitting next to a chemist, and (as chemists do), he scribbled the following on a piece of paper. When I got to work the next day Vera (my student) was unleashed on the problem, and our thoughts were published[1]. That was then. This is now. I have just finished a post on ring-opening reactions of oxirene, a 4n electron anti-aromatic ring.

A scalemic molecule is the term used by Eliel to describe any non-racemic chiral compound.