Mechanism of carbene formation from the excited states of diazirine and diazomethane: an MC-SCF study

MC-SCF calculations using 6-31G* basis sets yield three radiation less decay pathways for the photochemical decomposition of diazirine and diazomethane. The triplet pathway starting from a (super 3)pi-pi* diazirine minimum to a (super 3)pi-pi* diazomethane minimum can be accessed from the single manifold via an intersystem exo crossing. Analysis of the crossing reveals the presence of temperature-dependent fluorescence CH2 + N2 direct formation and absence of triplet status in the reactions of both compounds.