Synthetic Strategy Towards Heterodimetallic Half-Sandwich Complexes Based on a Symmetric Ditopic Ligand

Lewis P M Green; Tasha R Steel; Mie Riisom; Muhammad Hanif; Tilo Söhnel; Stephen M F Jamieson; L James Wright; James D Crowley; Christian G Hartinger

doi:10.3389/fchem.2021.786367

Synthetic Strategy Towards Heterodimetallic Half-Sandwich Complexes Based on a Symmetric Ditopic Ligand

Front Chem. 2021 Dec 3:9:786367. doi: 10.3389/fchem.2021.786367. eCollection 2021.

Authors

Lewis P M Green¹, Tasha R Steel¹, Mie Riisom^{1

2}, Muhammad Hanif¹, Tilo Söhnel¹, Stephen M F Jamieson², L James Wright¹, James D Crowley³, Christian G Hartinger¹

Affiliations

¹ School of Chemical Sciences, University of Auckland, Auckland, New Zealand.
² Auckland Cancer Society Research Centre, University of Auckland, Auckland, New Zealand.
³ Department of Chemistry, University of Otago, Dunedin, New Zealand.

Abstract

Multimetallic complexes have been shown in several examples to possess greater anticancer activity than their monometallic counterparts. The increased activity has been attributed to altered modes of action. We herein report the synthesis of a series of heterodimetallic compounds based on a ditopic ligand featuring 2-pyridylimine chelating motifs and organometallic half-sandwich moieties. The complexes were characterized by a combination of ¹H NMR spectroscopy, electrospray ionization mass spectrometry, elemental analysis and single crystal X-ray diffraction. Investigations into the stability of representative complexes in DMSO-d ₆ and 10% DMSO-d ₆ /D₂O revealed the occurrence of solvent-chlorido ligand exchange. Proliferation assays in four human cancer cell lines showed that the Os-Rh complex possessed minimal activity, while all other complexes were inactive.

Keywords: anticancer activity; bioorganometallics; heterodimetallic complexes; ligand exchange reactions; structural characterization.