Chem. Phys. Lett. 694, 48–52 (2018)

DOI: 10.1016/j.cplett.2018.01.039

Remote modulation of singlet–triplet gaps in carbenes

The modulation of the singlet-triplet (S/T) gap of phenyl-carbene derivatives by hydrogen bond formation has been studied using the G4(MP2) computational method. The complexation of the aromatic ring substituents (–NH2, –OH, –PH2, –SH) in meta- and para-positions with water and the protonation or deprotonation of such groups have a remarkable influence on the S/T gaps, reaching S/T gap variations from 25.7 to 93.7 kJ mol−1. This variation is linearly related to the binding energy difference of the S/T configurations. Importantly, the triplet and singlet electronic configurations are systematically favored in the protonated and deprotonated forms, respectively, in all cases.