Spectral and thermal studies on ruthenium carbonyl complexes with 5-trifluoromethyl-2,4-dihydropyrazol-3-one ligands

Reactions of the cluster compound [Ru3(CO)12] with 5-trifluoromethyl-2,4-dihydropyrazol-3-one (HL1), 4-(2,4-dichlorophenylhydrazono)-5-trifluoromethyl-2,4-dihydropyrazol-3-one (H2L2), 4-(3-fluorophenylhydrazono)-5-trifluoromethyl-2,4-dihydropyrazol-3-one (H2L3), 4-(3-trifuoloromethyl-phenylhydrazono)-5-trifluoromethyl-2,4-dihydropyrazol-3-one (H2L4) and 4-(3-nitrophenylhydrazono)-5-trifluoromethyl-2,4-dihydropyrazol-3-one (H2L5) have been carried out in benzene and under reduced pressure. The structures of the isolated complexes were elucidated using elemental analyses, IR, UV–vis, mass and NMR spectroscopy. All the complexes are diamagnetic and have trigonal bipyramidal structures with general formulae [Ru(CO)4(HL1)] and [Ru(CO)3(H2L2–5)]. The thermal decompositions of the complexes were studied in correlation with the mass spectral fragmentation patterns.