C-Br bond activation followed by a C-C coupling reaction of the 2-bromo-pyridyl unit of [1-phenyl-2-(6-bromopyridin-2-yl)-benzoimidazole] was performed by Pd(CH(2)CMe(2)-o-C(6)H(4))(η(4)-COD). Two new seven membered palladacycles were obtained. A combined experimental and theoretical DFT study elucidates the mechanism for this reaction.

A small library of seven-membered palladacycles and asymmetric bipyridines was prepared via C–Br activation and C–C coupling reactions.

Rollover palladacycles complexes containing pyridinebenzothiazole fragments were synthetized via remote C−H bond activation by PdCl2 in DMF. The structures of these compounds were proposed based on NMR analysis and high‐resolution mass spectrometry; in selected case of compound 1, its molecular structure was corroborated by single crystal X‐ray diffraction experiment. Upon solubilization in acetonitrile and using ESI‐QTOFMS, this complex was found as unusual tricoordinate cationic complex 1‐NCCH3 with acetonitrile attachment via Pd−Cl bond activation. Of note, synthesis success when PdCl2 was used as the starting material and mild heating (60 °C) of the reaction mixture was necessary to obtain the desired compound in a reasonable time (7 days). Evidence is provided that DMF solvent plays a key mechanistic role enabling the formation of organometallic rollover compounds; whereas using another solvent like DMSO, NCCH3 or acetone, a classic coordination complex is obtained.

The reaction of dinuclear complex [IrCl­(COD)]2 (COD = 1,5-cyclooctadiene) with 1 equiv of 1,3-dimesitylpropane-1,3-dione (H-Acac BiMs ) and an excess of triethylamine in benzene or dichloromethane at room temperature results in the formation of β-diketonate complex [Ir­(Acac BiMs )­(COD)], 1. Further, compound 1 reacts with an equivalent of H-Acac BiMs in dichloromethane under atmospheric conditions to give the new complex with the formula [cis-Ir­(Acac BiMs )2(COE-OH)], 2 (COE-OH = σ,π-hydroxyenediyl), through a formal insertion of a hydroxyl group into a COD ring. All compounds were characterized by melting point, analytical data, and IR and NMR spectroscopy. Additionally, an X-ray crystallographic study was undertaken to corroborate the structure of both complexes.

Three novel platinum(ii) complexes with the general formula [trans-Pt(Br-PyBenz-X)(Cl)2(DMSO)] containing Br-pyridylbenz(imida, oxa or othia)zole derivatives, under an unusual N-κ1-coordination mode were synthesized.