. Author manuscript; available in PMC: 2015 Jun 25.

Published in final edited form as: J Phys Chem A. 2007 Jun 14;111(26):5729–5742. doi: 10.1021/jp071526+

Table 2. Standard Free Energies (kcal/mol) of Reactions for the Electron and Proton Additions to Lumiflavin in Water at 298 K, Calculated with Implicit Solvent with M06-L/SM6 and B3LYP/SM6 (in Parenthesis) and with Explicit Solvent Treatment with SCC-DFTB/CHARMM.

reactions

M06-L/SM6 (B3LYP/SM6)

SCC-DFTB/MM simulations

ΔG^○(g)

Δ G_{S}^{○} (P)

Δ G_{S}^{○} (R)

ΔG^○(aq)

LF + e⁻ → LF^−•

−43 (−47)

−63 (−67)

−22 (−23)

−84 (−91)

−93

LF^−• + H⁺ → LFH^•

−320 (−318)^a

−22 (−24)

−327 (−331)^b

−15 (−11)

−4

LF + e⁻ + H⁺ → LFH^•

−363 (−365)

−22 (−24)

−286 (−287)

−99 (−102)

−97

LFH^• + e⁻ → LFH⁻

−47 (−51)

−63 (−64)

−22 (−24)

−88 (−91)

−97

LFH^−-+ H⁺ → LFH₂

−316 (−317)^a

−13 (−14)

−327 (−328)^b

−2 (−3)

LFH^• + e⁻ + H⁺ → LFH₂

−363 (−368)

−13 (−14)

−286 (−288)

−90 (−94)

−93

LF + 2e⁻ + 2H⁺ → LFH₂

−726 (−733)

−13 (−14)

−550 (−551)

−189 (−196)

−190

The calculation includes a Gibb's free energy of H⁺ of −6.28 kcal/mol.¹¹⁷

The solvation free energy of a proton, −264.0 kcal/mol in the standard state (1 atm for the gas phase and 1 mol/L for the solution state), is included.^66,94