Non-aromatic stabilised form of 3,4-difluoropyrrole at triosmium clusters: N–H and C–H versus C–F activation

Reaction of 3,4-difluoropyrrole with the labile triosmium cluster [Os3(CO)10(CH3CN)2] affords products in which C–H, N–H and C–F bonds are cleaved under mild conditions. C–H and N–H bonds are cleaved to give [Os3H(Ndouble bond; length as m-dashCCFdouble bond; length as m-dashCFCH2)(CO)10] (1) a non-aromatic stabilised form of 3,4-difluoropyrrole. Thermolysis of 1 affords in moderate yields the compounds [Os3H2(Cdouble bond; length as m-dashCCFdouble bond; length as m-dashCHNH)(CO)9] (2) and [Os3H2(Ndouble bond; length as m-dashCHCFdouble bond; length as m-dashCFC)(CO)9] (3). For compound 3, C–H and N–H bonds are cleaved with concomitant migration of H atoms to the metal framework. In contrast, for compound 2 activation of C–H and C–F bonds leads to coordination of the ligand through the carbon atoms, acting as a four-electron donating species.