Table 2.
Electrochemical data for dimeric and monomeric 2-Y-DMBI compounds,[a] and adiabatic ionization energies (IEs) and dissociation energies obtained from M06/LANL2DZ/6-31G(d,p) calculations for various 2-Y-DMBI species.
E vs. FeCp2
+/0 / V [a] |
IE / eV[d] |
ΔUdiss / kJ mol−1 (eV)[d] |
|||||
---|---|---|---|---|---|---|---|
Y | Epa(D2 +/0)[b] | Epc(D+/0)[c] | D2→D2•++e[e] | D•→D++e | 0.5D2→D++e[f] | D2→2D• | D2•+ →D+ + D •[e] |
Cyc | −0.64 | −2.45 | 5.06 | 3.72 | 4.81 | 210 (2.17) | 81 (0.84) |
Fc | −0.89 | −2.24 | 4.69 | 3.93 | 4.79 | 165 (1.71) | 91 (0.94) |
Rc | −0.59 | −2.29 | 4.68 | 3.80 | 4.73 | 181 (1.87) | 97 (1.00) |
In THF / 0.1 M nBu4NPF6.
Peak potential for the irreversible oxidation of D2 measured at 100 mV s−1.
Peak potential for the partially reversible reduction of D+ at 100 mV s−1.
Gas-phase adiabatic IEs and dissociation energies obtained from DFT calculations.
These results should be treated with caution owing to the tendency of DFT to artificially over-delocalize odd-electron systems such as these cations due to self-interaction error[22] Indeed the optimized structures for the D2 •+species are all characterized by spuriously long central C—C bonds (3.23-3.34 Å).
IEeff(0.5D2→D++e) = IE(D) + 0.5ΔUdiss(D2).