Theoretical investigation of the thermodynamics on monomerization of a rhenium(V) dimer with imidazole-based ligands

The thermodynamics of the monomerization of a Re(V) dithiolato dimer, {MeReO(edt)}2 (D; edt = 1,2-ethanedithiolate) with imidazole-based ligands (L = imidazole, 1-methylimidazole, 1-ethylimidazole, benzimidazle, indazole and pyrazole), giving the monomer [MeReO(edt)L] (=ML) is investigated by density functional theory (DFT) calculations in the gas phase and in benzene and acetone solutions. The negative values obtained for the enthalpy and entropy of the monomerization reaction mean this process is enthalpy-driven. A successful correlation of enthalpy and free energy is realized and the results are discussed in terms of different basicities of the ligands L and solvent polarity.

The thermodynamics of the monomerization of the {MeReO(edt)}2 dimer (edt = 1,2-ethanedithiolate) with imidazole-based ligands, giving the monomer [MeReO(edt)L] is investigated by DFT calculations.Figure optionsDownload as PowerPoint slideHighlights
► We investigated the thermodynamics of the monomerization of a Re dimer by imidazole.
► Negative values for ΔH and ΔS were obtained.
► A successful correlation of enthalpy and free energy with pKa of L was realized.
► Solvent affects on the values of enthalpy and free energy were investigated.