Crystal-Engineered Three-Dimensional Hydrogen-Bonding Networks Built with 1,3,5-Benzenetri(phosphonic acid) and Bipyridine Synthons Academic Article uri icon


  • The phosphonic acid 1,3,5-benzenetri(phosphonic acid) (BTP; 1,3,5-[(OH) 2PO] 3-C 6H 3) can act as both a hydrogen bond donor and acceptor. BTP was reacted with two organic bases, 2,2′-bipyridine and 4,4′-bipyridine, in a 1:1 molar ratio. The bis-deprotonation and tris-deprotonation trigger the formation of self-complementary 3D hydrogen bonding architectures. Layers of the 2,2′-bipyridine compound are formed through hydrogen bonding of the phosphonic acid groups existing in the dianionic motif {1,3-[(OH)PO 2] 2-5-[PO(OH) 2]-C 6H 3} 2-. The ratio of BTP to 2,2′-bipyridine is 1:1.5, with two of the phosphonic acid protons being transferred to the nitrogen atoms, leaving a negatively charged oxygen and a proton on each of the phosphonic acid groups. Discrete dimers are formed by three very short PO-H⋯O-P type hydrogen bonds (2.45-2.48 A°) and one short PO-H⋯O=P hydrogen bond at 2.56 Å interconnecting all dimers into extended layers in the bc plane. The protonated bipyridyls penetrated into the layers by formation of two NH +⋯O-P hydrogen bonds (2.72, 3.14 A°) to complete the 3D network. The compound with 4,4′-bipyridine is triclinic P1, in which the ratio of BTP to bipyridine is 1:1. Each amino nitrogen atom is protonated, leaving each phosphonic acid group negatively charged. One additional positive charge is provided by a hydronium ion. The BTP molecules align in hydrogen-bonded staircase chains along the b axis, in which the molecules are bonded together by double hydrogen bonds: P-O -⋯HO-P. The staircases are then interwoven into each other by the NH +⋯O-P hydrogen bonds between the pyridyl and the phosphonic acid groups. © 2005 American Chemical Society.

author list (cited authors)

  • Kong, D., Clearfield, A., & Zoń, J.

citation count

  • 51

publication date

  • August 2005