Thermodynamic considerations regarding critical hydrogenation reactions have not been well studied. We report a rhenium(I) pincer carbonyl complexes have been synthesized. Hydricity values, as well as the enthalpy and entropy of H2 heterolysis, have been experimentally determined in various solvents (THF, MeCN, toluene). Preliminary catalytic hydrogenation reactions of CO2 have been carried out using (tBuPOCOP)(Re)(CO)2(H)-.Bachelor of Scienc