Posts Tagged ‘Conjugated system’

Dispersion-induced triplet aromatisation?

Thursday, January 3rd, 2019

There is emerging interest in cyclic conjugated molecules that happen to have triplet spin states and which might be expected to follow a 4n rule for aromaticity.[cite]10.1002/anie.201705228[/cite] The simplest such system would be the triplet state of cyclobutadiene, for which a non or anti-aromatic singlet state is always found to be lower in energy. Here I explore some crystal structures containing this motif for possible insights.


Long C=C bonds.

Thursday, December 1st, 2016

Following on from a search for long C-C bonds, here is the same repeated for C=C double bonds.


π-Resonance in amides: a crystallographic reality check.

Saturday, September 5th, 2015

The π-resonance in amides famously helped Pauling to his proposal of a helical structure for proteins. Here I explore some geometric properties of amides related to the C-N bond and the torsions about it.