Synthesis and identification of a trimethylenemethane derivative π-extended with three pyridinyl radicals

Article abstract of DOI:10.1021/ol902937k

A trimethylenemethane (TMM) derivative 1^2., In which the parent TMM is π-extended by the symmetric Insertion of three pyridine rings Into the C-C bonds of TMM, has been synthesized by the alkali metal reduction of the Isolated corresponding dication. Although the frozen-glass X-band cw-ESR spectrum of 1^2. gave unresolved fine structures due to the small ZFS parameters, pulsed ESR two-dimensional electron spin transient nutation (2D-ESTN) spectroscopy unambiguously can afford to Identify diradical 1 ^2. as a triplet species.