One-dimensional alkylate-bridged Wiirster＇s blue-based diradical dications

By using weakly coordinating anions we succeeded in the stabilization and isolation of two Wfirster＇s blue-based diradicaloid dications with saturated spacers. Their geometries and electronic structures were investigated by various experiments in conjunction with DFT calculations. Both one-dimensional alkylate-bridged dications show considerable diradical character with spacer-dependent singlet-triplet energy gaps. One of them displays a much enhanced diradical character and could basically be viewed as a pure diradical with degeneracy of singlet and triplet states.