Reaction of technetium hexacarbonyl cation with acetonitrile: Kinetics, product structure, DFT calculations

Technetium hexacarbonyl perchlorate was prepared in CH2Cl2 in a reasonable yield. Reaction of this complex with acetonitrile was studied. The only reaction product was [Tc(CO)3(MeCN)3]ClO4. The crystal structure of [Tc(CO)3(MeCN)3]ClO4 was determined by single crystal X-ray diffraction. The kinetics of thermal decarbonylation of [Tc(CO)6]+ in acetonitrile was studied by IR spectroscopy. The rate constants and the activation energy of this reaction were determined. The rate constant is lower by more than an order of magnitude than that of [TcBr(CO)5]. The causes of increased stability of [Tc(CO)6]+ were analyzed by DFT calculations.

[Tc(CO)6][ClO4] reacts with CH3CN to give [Tc(CO)3(MeCN)3]ClO4. The reaction rate constant is lower by more than an order of magnitude than that of [TcBr(CO)5]. DFT calculations show that the CO abstraction from [Tc(CO)6]+ requires higher energy than from [TcBr(CO)5], because of rearrangement of the transition state in the latter case.Figure optionsDownload as PowerPoint slideHighlights
► Thermal stability of [Tc(CO)6]ClO4 in acetonitrile was studied.
► Crystal structure of [Tc(CO)3(CH3CN)3]ClO4 was determined.
► Decarbonylation rate constant and activation energy were calculated.
► DFT analysis of [Tc(CO)6]+ thermal decarbonylation was performed.