Synthesis, Characterization and Biological evaluation of novel thiosemicarbazide and thiosemicarbazone functionalized calix[4]arene ligands and related transition metal complexes

Calixarenes as the third generation of supramolecular hosts have attracted considerable attention among common molecules due to their easy synthesis from p-tertbutylphenol and formaldehyde via base-catalyzed condensation [1,2]. The flexibility of calixarene frame and capability of upper rim and lower rim for different functionalization make them an ideal candidate for use as coordinating ligand to different metal centers. With this regard, couple of the most important functional groups which can be introduced on calixarenes molecule are thiosemicarbazide and thiosemicarbazone with effective complexation capability [3], anti-cancer [4], antiviral and anti-bacterial [5] activities. we herein synthesized novel thiosemicarbazide L1 and thiosemicarbazone L2 functionalized calix[4]arene as ligand and their corresponding transition metal complexes for the first time. The synthesized compounds were characterized by FT-IR, 1HNMR and ESI-Mass spectroscopy, elemental analysis and the structure of L2 were studied by single-crystal diffraction method. coumponds L1 and L2 act as four-coordinated and six-coordinated ligand respectively (fig. 1). The compounds were evaluated for their antimicrobial activity, biocompatibility and anticancer activity in a panel of human breast cancer and bone cancer cell lines.