Synthesis, Characterization, and Crystal Structure of Dicalcium Glutarylbisphosphonate Dihydrate - Covalently Pillared Layer Structure with the Potential for Epitaxial Growth on Hydroxyapatite.
M Mathew, Bruce O. Fowler, E Breuer, G Golomb, I S. Alferiev, Naomi Eidelman
A new bisacylphosphonate, glutarylbisphosphonate (GlBP) was synthesized. Sodium and calcium salts of the GlBP, disodium dihydrogenglutarylbisphosphonate, NaHO3P-C(O)-(CH2)3C(O)-PO3Hna and dicalcium glutarylbisphosphonate dihydrate, Ca2[O3P-C(O)-(CH2)3-C(O)-PO3] 2H2O were prepared and characterized by chemical analyses, thermogravimetry and Fourier-transform infrared spectroscopy (FTIR). The crystal structure of the Ca salt was determined by single crystal x-ray diffraction. The crystals are orthorhombic with a = 10.970(1) , b = 23.694(2) , c = 5.580(1) , space group Pnma, Z = 4. This study provides the first example of a structure of a calcium complex involving a nongeminal bisphossphonate. The structure can be described in terms of a covalently pillared layer-type arrangement of neutral Ca-GlBP-Ca units along the b-axis. Each oxygen atom of the phosphonate group is bonded to a different Ca ion and each Ca in turn is linked to three phosphonate groups. The Ca-octahedra and the phosphonate tetrahedra form a two dimensional polar sheet perpendicular to the b-axis. The chelate bonds involving the keto groups appear to be important links in the stabilization of the structure and, in turn, to the biological activity of bisacylphosphonates. A near-perfect lattice match, found between the Ca-phosphonate layer and the major crystal faces of hydroxyapatite, indicates that epitaxial growth or incorporation of GlBP can occur on the apatitic surface which may be the mode of action in the inhibition of calcification.
, Fowler, B.
, Breuer, E.
, Golomb, G.
, Alferiev, I.
and Eidelman, N.
Synthesis, Characterization, and Crystal Structure of Dicalcium Glutarylbisphosphonate Dihydrate - Covalently Pillared Layer Structure with the Potential for Epitaxial Growth on Hydroxyapatite., Inorganic Chemistry
(Accessed June 9, 2023)