Isomer directed assembly of two Ca(II) compounds based on 5-(n-pyridyl)tetrazole-2-isopropanoic acid (n = 2, 3) and action against Hela cells

Isomers sometimes play a fundamental role in the formation of coordination architectures. In this article, bifunctional 5-(n-pyridyl)tetrazole-2-isopropanoic acid (n = 2, 3) has been designed and prepared. Then, reactions of Ca(NO3)2·4H2O with isomeric 5-(n-pyridyl)tetrazole-2-isopropanoic acid (denoted as Hn-pytzipa, n = 2, 3) afforded mononuclear [Ca(2-pytzipa)2(H2O)4] (1) and one-dimensional [Ca(3-pytzipa)2(H2O)2]n (2), respectively. In 1, 2-pytzipa is a bidentate ligand which chelates one Ca(II) via the nitrogen atoms of the pyridine and tetrazole rings while in 2, 3-pytzipa bridges adjacent Ca(II) centers in a μ1,1,3-COO mode. PEG-5000 (poly(ethyleneglycol-5000)) coated [Ca(2-pytzipa)2(H2O)4] (1) and [Ca(3-pytzipa)2(H2O)2]n (2) nanoparticles (NPs) show toxicity towards Hela cells, but the ligands are non-toxic in nature and 2 is superior to 1. Furthermore, cell migration across a 2D artificial gap indicates that both NPs can inhibit the migration of Hela cells.