Convenient synthesis of zwitterionic calcium(II)-carboxylate metal organic frameworks with efficient activities for the treatment of osteoporosis.

Calcium supplementation is effective in alleviating the process of osteoporosis and the occurrence of osteoporotic fractures for people with long-term calcium deficiency. Herein, five water-stable calcium carboxylate compounds, that is, mononuclear coordination compound [Ca(Cbdcp)(HO)]·0.5HO (1, HCbdcpBr = N-(4-carboxybenzyl)-(3,5-dicarboxyl)pyridinium bromide), and metal organic frameworks (MOFs) {[Ca(Dcbdcp)(HO)]·2HO} (2, HDcbdcpBr = N-(3,5-dicarboxybenzyl)-(3,5-dicarboxyl)pyridinium bromide), {[Ca(Cmdcp)(HO)]·3HO} (3, HCmdcpBr = N-carboxymethyl-(3,5-dicarboxyl)pyridinium bromide), {[Ca(Cdcbp)]·2HO} (4, HCdcbpBr = 3-carboxyl-(3,5-dicarboxybenzyl)-pyridinium bromide) and {[Ca(Cmcp)]·2HO} (5, HCmcpBr = N-carboxymethyl-(3-carboxyl)pyridinium bromide), were synthesized from the reaction of CaCl with five different kinds of zwitterionic carboxylate ligands in the presence of NaOH, respectively.