Synthesis of IrIII Hydrido Complexes by Oxidative Addition of Halogenated Theophylline and Adenine Derivatives

The Ir III hydrido complexes [ 1 ] and [ 2 ] have been synthesized by the regioselective oxidative addition of the N7-H bond of 8-halogenotheophyllines to [IrCl(coe) 2 ] 2 in the presence of PPh 3 . The use of dppf in this reaction yielded the bimetallic Ir III /Fe II hydrido complexes [ 3 ] and [ 4 ]. X-ray diffraction studies confirmed that complexes [ 1 ]-[ 4 ] feature a theophyllinato ligand coordinated to the metal center in the rarely observed, chelating fashion via the N7 and O1 atoms. In addition, 8-bromoadenine reacts with [IrCl(coe) 2 ] 2 in the presence of PPh 3 to form the Ir III hydrido complex [ 5 ] which features one anionic 8-bromoadeninato and one neutral 8-bromoadenine ligand linked by an intramolecular hydrogen bond. Complex [ 5 ] was characterized by high-resolution mass spectrometry and an X-ray diffraction analysis but could not be analyzed by nuclear magnetic resonance spectroscopy because of its low solubility.