A Matryoshka doll is better known as a Russian nesting doll. They can have up to eight layers. Molecules can only emulate two layers, although see here for a good candidate for making a three-layered example (the inside layer is C 60 , which itself might encapsulate a small molecule. See also DOI: 10.1021/ja991747w). These molecular dolls can be created out of quite simple molecules.
Organic chemistry has some no-go areas, where few molecules dare venture. One of them is described by a concept known as anti-aromaticity. Whereas aromatic molecules are favoured species, their anti-equivalent is avoided. I previously illustrated this (Hückel rule) with cyclopropenium anion.
The (hopefully tongue-in-cheek) title Mindless chemistry was given to an article reporting[cite]10.1021/jp057107z[/cite] an automated stochastic search procedure for locating all possible minima with a given composition using high-level quantum mechanical calculations. “Many new structures, often with nonintuitive geometries, were found”. Well, another approach is to follow unexpected hunches.
I have mentioned Lewis a number of times in these posts; his suggestion of the shared electron covalent bond still underpins much chemical thinking. Take for example mechanistic speculations on the course of a reaction, a very common indulgence in almost all articles reporting such, and largely based on informed * arrow pushing*. This process is bound to follow the rules of reasonable Lewis structures for any putative intermediates.
I have often heard the question posed “ how much of chemistry has been discovered? ” Another might be “ has most of chemistry, like low-hanging fruit, already been picked? ”. Well, time and time again, one comes across examples which are only a simple diagram or so away from what might be found in any introductory chemistry text, and which would tend to indicate the answers to these questions is a
Unusual bonds are always intriguing, and the Xe-Xe bond is no exception.
In 1986 or so, molecular modelling came of age. Richard Counts, who ran an organisation called QCPE (here I had already submitted several of the program codes I had worked on) had a few years before contacted me to ask for my help with his Roadshow. He had started these in the USA as a means of promoting QCPE, which was the then main repository of chemistry codes, and as a means of showing people how to use the codes.
Steve Bachrach has blogged on the reaction shown below. If it were a pericyclic cycloaddition, both new bonds would form simultaneously, as shown with the indicated arrow pushing. Ten electrons would be involved, and in theory, the transition state would have 4n+2 aromaticity.
It is not often that an article on the topic of illusion and deception makes it into a chemical journal.
The interface between physics, chemistry (and materials science) can be a fascinating one. Here I show a carbon nanotorus, devised by physicists[cite]10.1103/PhysRevLett.88.217206[/cite] a few years ago. It is a theoretical species, and was predicted to have a colossal paramagnetic moment . Carbon nanotorus.
