FTIR and DFT-D investigation of the structure of ruthenium pentacarbonyl in small alcohol solvents

The equilibrium structure of Ru(CO)5 in butanol, ethanol and isopropanol has been investigated using FTIR spectroscopy and DFT-D calculations. It was determined that 88–100% of the Ru(CO)5 molecules form a weak hexacoordinated complex with a single alcohol molecule under ambient conditions. Complexation of Ru(CO)5 is more favorable than Fe(CO)5 in all solvents studied. The DFT-D calculations predict that the complex formation occurs via electron donation from the complexing alcohol molecule to Ru(CO)5 at an equilibrium distance of ∼375 pm from the metal center to the hydroxyl oxygen.