Highly active group 11 metal complexes with α-hydrazidophosphonate ligands.

α-Hydrazidophosphonates are interesting scaffolds that could combine the biological properties of hydrazones and phosphonyl species, and their coordination properties remain unknown. The coordination chemistry of these ligands towards group 11 metals has been studied. A series of novel gold(i), silver(i) and copper(i) complexes with α-hydrazidophosphonate ligands have been prepared and characterised. The coordination geometries obtained vary from linear to trigonal planar for gold(i) to distorted trigonal planar or tetrahedral for silver(i) and copper(i). Structural characterisation of two silver derivatives shows the ligands in an O^N^O tridentate fashion, with dissimilar bond lengths. These compounds were screened for the in vitro cytotoxic activity against two tumour human cell lines such as HeLa (cervical carcinoma) and A549 (lung carcinoma). The IC values reveal an excellent cytotoxic activity of the metal complexes compared with the α-hydrazidophosphonate ligands alone and cisplatin.