A new family of oxime palladacycles mixed with unsymmetrical phosphorus ylides; synthesis, structural, cytotoxicity and catalytic activity studies

Abstract

In the present investigation, the reactivity of an oxime-derived palladacycle [Pd{C,N–C6H4{C(Me) = NOH}-2}(μ-Cl)]2 toward various unsymmetrical phosphorus ylides has been studied. When the ylide was added to a solution of oxime complex in dichloromethane (2:1 ratio), the new oxime palladacycles of the types [Pd{C,N–C6H4{C(Me) = NOH}-2}(Ph2PCH2PPh2C(H)C(O)C6H4X)]ClO4 (X = Cl (1), Br (2), NO2(3) or OCH3 (4)) were formed by means of bridge-splitting reaction. These are the first description of oxime-based palladacycles mixed with phosphorus ylides. All of complexes were fully characterized by elemental analysis, IR and NMR spectroscopies. The crystal structure of 3 were determined by single-crystal X-ray diffraction analysis that confirmed breaking of Pd–Cl bonds in the initial precursor and allowing phosphorus ylide act as P,C-chelating ligand. In addition, the catalytic activity of 3 was evaluated in the Suzuki cross-coupling reactions of a variety of arylbromides with phenylboronic acid. This complex was also used for the assessment of their anticancer activities against three human carcinoma cell lines: A549 (human lung carcinoma), HT29 (human colon carcinoma), and HeLa (human cervical carcinoma). The results show that the new family of oxime-derived palladacycles could be introduced as promising innovative anticancer complexes and considered as an efficient catalyst in the cross coupling reactions.