Hydrogen-bonded complexes with carbenes as electron-pair donors
Ab initio MP2/aug′-cc-pVTZ calculations have been performed to investigate X-H⋯C hydrogen-bonded complexes involving eleven different carbene molecules as electron-pair donors and the acids FH, CNH, and NCH. Binding energies and charge-transfer energies increase as the X-C distances decrease, and exhibit an exponential dependence on these distances. EOM-CCSD spin-spin coupling constants 2hJ(X-C) increase quadratically in absolute value as the corresponding X-C distance decreases. 1J(F-H) and 1J(N-H) decrease as the F-H and N-H distances, respectively, increase, but 1J(C-H) shows little dependence on distance. All of these carbene complexes are stabilized by traditional hydrogen bonds.