Halogenation of Ru(COD)(8-quinolinolate)2 and Ru(COD)(5-formyl-8-quinolinolate)2

An improved synthesis of Ru(COD)(8-quinolinolate)2 (COD = 1,5-cyclooctadiene) and the synthesis of Ru(COD)(5-formyl-8-quinolinolate)2 is reported. Electrophilic halogenation of these complexes with N-halosuccinimides proceeded smoothly resulting in 5,7-dihalogenation of the quinolinolate ligands in Ru(COD)(8-quinolinolate)2 and in 7-halogenation of Ru(COD)(5-formyl-8-quinolinolate)2. All compounds exhibit strong absorbance in the visible up to 500 nm, resulting in an intensively yellow colour. With all complexes no luminescence was observed.