Cationic palladium(ii)-indenyl complexes bearing phosphines as ancillary ligands: synthesis, and study of indenyl amination and anticancer activity. Issue 29 (8th July 2022)

• Record Type: Journal Article
• Authors: Bortolamiol, Enrica; Fama, Francesco; Zhang, Ziyun; Demitri, Nicola; Cavallo, Luigi; Caligiuri, Isabella; Rizzolio, Flavio; Scattolin, Thomas; Visentin, Fabiano
• Is Part Of: Dalton transactions. Volume 51:Issue 29(2022)
• Page Start: 11135
• Page End: 11151
• Publication Date: 2022-07-08
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/d2dt01821g
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : Palladium-indenyl complexes bearing phosphine ligands were prepared to explore nucleophilic addition to the indenyl fragment and their promising anticancer properties. Abstract : The reactivity of palladium(ii ) indenyl derivatives and their applications are topics relatively less studied, though in recent times these compounds have been used as pre-catalysts able to promote challenging cross-coupling processes. Herein, we propose the first systematic study concerning the nucleophilic attack on the palladium(ii ) coordinated indenyl fragment and, for this purpose, we have prepared a library of new Pd-indenyl complexes bearing mono- or bidentate phosphines as spectator ligands, developing specific synthetic strategies. All novel compounds are thoroughly characterized, highlighting that the indenyl ligand presents always a hapticity intermediate between η 3 and η 5 . Secondary amines have been chosen as nucleophiles for the present study and indenyl amination has been monitored by UV-Vis and NMR spectroscopies, deriving a second order rate law, with dependence on both complex and amine concentrations. The rate-determining step of the process is the initial attack of the amine to the coordinated indenyl fragment, and this conclusion has been supported also by DFT calculations. The determination of second order rate constants has allowed us to assess the impact of the phosphine ligands on the kinetics of the process and identify the steric and electronic descriptors most suitable for predicting the reactivity of these systems. Finally, in vitro tests have proven that these organometallic compounds promote antiproliferative activity towards ovarian cancer cells better than cisplatin and possibly by adopting a different mechanism of action.