Does aromaticity have a size limit? Evidence is presented for global aromaticity in porphyrin nanorings with circuits of up to 162 π-electrons. The conformation of the nanoring can be altered by changing the template, which in turn controls the …
Break down of the Born–Oppenheimer approximation is caused by mixing of electronic and vibrational transitions in the radical cations of some conjugated polymers, resulting in unusually intense vibrational bands known as infrared active vibrations …
The design of molecular structures inspired by naturally occuring light harvesting systems has been intensely pursued over the last couple of decades. Interesting new structures include the π-conjugated porphyrin nanorings, which show promising …
Aromaticity can be a useful concept for predicting the behavior of excited states. Here we show that π-conjugated porphyrin nanorings exhibit size-dependent excited-state global aromaticity and antiaromaticity for rings containing up to eight …
Doping, through oxidation or reduction, is often used to modify the properties of π-conjugated oligomers. In most cases, the resulting charge distribution is difficult to determine. If the oligomer is cyclic and doping establishes global aromaticity …
We compare the absorption and magnetic circular dichroism (MCD) spectra of a series of porphyrin oligomers – dimer, tetramer, and hexamer – bound in a linear or cyclic fashion. The MCD signal is extremely weak for low energy transitions in the linear …
The radical cations of a family of π-conjugated porphyrin arrays have been investigated: linear chains of N = 1–6 porphyrins, a 6-porphyrin nanoring and a 12-porphyrin nanotube. The radical cations were generated in solution by chemical and …
Aromatic and antiaromatic molecules—which have delocalized circuits of [4n + 2] or [4n] electrons, respectively—exhibit ring currents around their perimeters1,2,3,4. The direction of the ring current in an aromatic molecule is such as to generate a …
Solution-state NMR spectroscopy remains the primary method for characterising synthetic supramolecular assemblies. Yet, in their NMR spectra, relaxation interference effects can significantly alter peak intensities hindering interpretation. Here, we …
The barrier to torsional rotation in a butadiyne-linked porphyrin dimer has been determined in solution using variable temperature UV-vis-NIR spectroscopy: ΔH = 5.27 ± 0.03 kJ mol−1, ΔS = 10.69 ± 0.14 J K−1 mol−1. The value of ΔH agrees well with …