Isomeric pyridylcarbenes and their Si and Ge heavier analogues at DFT: stabilization through π–p or n–p interaction

Heteroarylcarbenes

“…Amani and co-workers reported B3LYP investigations of the different geometries and electronics in these systems and compared them to Si and Ge relatives. 53 They found that the triplet carbenes at the 2-, 3-, and 4-positions of pyridine have approximately the same energy, but the higher energy singlet carbenes vary by several kcal/mol among the three isomers. They find that all ST energy gaps are larger than that of phenylcarbene (7.3 kcal/mol), calculated at the same level of theory, which they attribute to the larger electron-donating effect of the phenyl ring compared to pyridyl.…”

“…Perhaps the most extensive theoretical analysis of the electronic states of the isomeric pyridylcarbenes appeared in 2012. Amani and co-workers reported B3LYP investigations of the different geometries and electronics in these systems and compared them to Si and Ge relatives . They found that the triplet carbenes at the 2-, 3-, and 4-positions of pyridine have approximately the same energy, but the higher energy singlet carbenes vary by several kcal/mol among the three isomers.…”