The 1,1'-trimethylenebis(pyridinyl) diradical and its photosensitive cyclomers.
Reduction of 1,1′-trimethylenebis(pyridinium) dibromide with sodium amalgam produces the cyclomers of 1,1′-trimethylene-bis(pyridinyl) diradical. Meso and dl forms of the cyclomers are convertible to each other. Two conformations of the diradical are observed in the triplet ESR spectrum at 77 K.