Development of biradical ligands toward [2×2] molecular grids

Introduction of 2p spins into molecular grids is rare. We prepared 4,6-bis{3-(4,4,5,5-tetramethylimidazolin-1-yloxyl-3-oxido-2-yl)-1H-pyrazol-1-yl}pyrimidine (bis‘nitronyl nitroxide’) and its bisdeoxygenated derivative (bis‘imino nitroxide’) as a building block for [2×2] molecular grids. Electron spin resonance spectra were satisfactorily simulated with the corresponding biradical models. The magnetic susceptibility measurements revealed the presence of two radical groups in a molecule. X-Ray crystal structure analysis of the bis‘nitronyl nitroxide’ derivative clarified the molecular structure constructed as designed. However, the geometries around the single bonds between pyrimidine and pyrazole rings were configured to be transoid (anti) in the crystal. A dichloromethane molecule was incorporated as a guest.