TY - JOUR
T1 - Hydride donor abilities and bond dissociation free energies of transition metal formyl complexes
AU - Ellis, William W.
AU - Miedaner, Alex
AU - Curtis, Calvin J.
AU - Gibson, Dorothy H.
AU - DuBois, Daniel L
PY - 2002/3/6
Y1 - 2002/3/6
N2 - The hydride complex [Pt(dmpe)2H]+ (dmpe = 1,2-bis(dimethylphosphino)ethane) reversibly transfers H- to the rhenium carbonyl complex [CpRe(PMe3)(NO)(CO)]+, giving the formyl CpRe(PMe3)(NO) (CHO). From the equilibrium constant for the hydride transfer (16.2), the ΔG° for the reaction was determined (-1.6 kcal/mol), as was the hydride-donating ability of the formyl (44.1 kcal/mol). The hydride-donating donating ability, ΔG°H-, is defined as the energy required to release the hydride ion into solution by the formyl complex [i.e. M(CHO) → M(CO)+ + H-]. Subsequently, the hydride-donating ability of a series of formyl complexes was determined, ranging from 44 to 55 kcal/mol. With use of this information, two rhenium carbonyl complexes, [CpRe(NO)(CO)2]+and [Cp*Re(NO)(CO)2]+, were hydrogenated to formyls, employing [Pt(dmpp)2]2+ and Proton-Sponge. Finally, the E1/2(I/0) values for five rhenium carbonyl complexes were measured by cyclic voltammetry. Combined with the known ΔG°H- values for the complexes, the hydrogen atom donating abilities could be determined. These values were all found to be approximately 50 kcal/mol.
AB - The hydride complex [Pt(dmpe)2H]+ (dmpe = 1,2-bis(dimethylphosphino)ethane) reversibly transfers H- to the rhenium carbonyl complex [CpRe(PMe3)(NO)(CO)]+, giving the formyl CpRe(PMe3)(NO) (CHO). From the equilibrium constant for the hydride transfer (16.2), the ΔG° for the reaction was determined (-1.6 kcal/mol), as was the hydride-donating ability of the formyl (44.1 kcal/mol). The hydride-donating donating ability, ΔG°H-, is defined as the energy required to release the hydride ion into solution by the formyl complex [i.e. M(CHO) → M(CO)+ + H-]. Subsequently, the hydride-donating ability of a series of formyl complexes was determined, ranging from 44 to 55 kcal/mol. With use of this information, two rhenium carbonyl complexes, [CpRe(NO)(CO)2]+and [Cp*Re(NO)(CO)2]+, were hydrogenated to formyls, employing [Pt(dmpp)2]2+ and Proton-Sponge. Finally, the E1/2(I/0) values for five rhenium carbonyl complexes were measured by cyclic voltammetry. Combined with the known ΔG°H- values for the complexes, the hydrogen atom donating abilities could be determined. These values were all found to be approximately 50 kcal/mol.
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U2 - 10.1021/ja0116831
DO - 10.1021/ja0116831
M3 - Article
C2 - 11866605
AN - SCOPUS:0037029009
VL - 124
SP - 1926
EP - 1932
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 9
ER -