Molecular and crystal structure of water-soluble 25,57 bis(dihydroxy-phosphoryloxy)calix[4]arene

The molecule of 25,27-bis(dihydroxyphosphoryloxy)calix[4]arene possessing t wo proton-ionizable dihydroxyphosphoryl groups at the lower rim of macrocyc le exists in the cone conformation in which diametrically opposite phenolic rings form with main plane of the molecule dihedral angles of 40.4 and 32. 10 degrees, The phosphorylaed phenolic fragments are approximately perpendi cular to this plane (82.2 and 75.5 degrees respectively). Two calixarene mo lecules form a centrosymmetrycal dimeric unit via intermolecular hydrogen b onds between the peripheral dihydroxyphosphoryl groups, The compound crysta llized as a solvate with methanol (1:4 ratio).