Size matters: Computational insight into magnetic properties of extended acenes

A DFT study of a series of extended acenes comprising from 7 to 35 conjugated six-membered rings (n) predicted their polyradical character and ascertained correlation between the length and magnetic properties of these compounds. A regularity was revealed indicating that increasing the chain length by every seven rings bring into the formation of two additional paramagnetic centers, leading to the presence of ten unpaired electrons in the acene, for which n = 35. The computational results obtained allow one to expect increasing the number of unpaired electrons with a further (n > 35) expanding the acene length.