Through-space Electrostatic Interaction between the Electron-donating 1,3-Diphosphacyclobutane-2,4-diyl Units

Catenation of stable 1,3-diphopsphacyclobutane-2,4-diyl units with biphenyl-, diphenyl ether-, and diphenylmethane-based bridging groups were utilized for evaluation of the distinct through-space interaction between the electron-donating P-heterocyclic biradical chromophores. Structural properties of the oligo(biradicals), characterized by X-ray crystallography and DFT calculation, suggest a possible distance between the biradical units for the through-space interaction.