Synthesis and anticancer property of three new Ca (II) compounds derived from tetrazole carboxylate ligands

Three new Ca (II) coordination polymers derived from different tetrazole-carboxylate ligands, namely [Ca(pztzma)2(H2O)2] (1), [Ca(pytza)2(H2O)2] (2), [Ca(tzpha)(4,4′-bipy)3/2(H2O)]·2H2O (3) have been prepared and characterized, where pztzma (pztzma = 2-(5-pyrazin-2-yl-tetrazol-2-yl)-propionic anion, pytza (pytza = 2-(5-pyridin-4-yl-tetrazol-2-yl)-propionic anion), tzpha (tzpha = {5-[3,5-Bis-(2-methoxycarbonylmethyl-2H-tetrazol-5-yl)-phenyl]-tetrazol-2-yl}-acetato). Nanoparticles (NPs) of the three compounds can be prepared by PEG-5000 (Polyethylene glycol-5000) co-precipitation method. And [Ca(tzpha)(4,4′-bipy)3/2(H2O)]·2H2O (3) NPs has a relatively low IC50 (half maximal inhibitory concentration) of 42 μg/mL (5.6 μM) on HeLa cells is superior to [Ca(pytza)2(H2O)2] (2) 40 μg/mL (7.8 μM) and [Ca(pztzma)2(H2O)2] (1) NPs of 33 μg/mL (6.4 μM). The migration of HeLa cells is inhibited by NPs of the three compounds. The results show that [Ca(pztzma)2 (H2O)2] (1), [Ca(pytza)2(H2O)2] (2) and [Ca(tzpha)(4,4′-bipy)3/2(H2O)]·2H2O (3) NPs can inhibit cell proliferation and migration in vitro.