Coupling of Nitric Oxide and Release of Nitrous Oxide from Rare-Earth-Dinitrosyliron Complexes

Addition
of Lewis acidic [Cp*2M]+ (M = Y,
Gd) to the dinitrosyliron complexes (DNICs) [(NacNacAr)­Fe­(NO)2]− (Ar = mesityl, 2,6-diisopropylphenyl)
results in formation of the isonitrosyl-bridged DNICs [(Cp*)2M­(μ-ON)2­Fe­(NacNacAr)]. When Ar
= 2,6-diisopropylphenyl, coupling of the NO ligands and release of
N2O occur. Two factors contribute to this previously unobserved
DNIC reactivity mode. First, the oxophilic rare-earth elements drive
the formation of isonitrosyl bonds, forcing the DNIC nitrogen atoms
into proximity. Second, the bulky substituents further squeeze the
DNIC, which ultimately overcomes the barrier to NO coupling, demonstrating
that N2O elimination can occur from a single iron center.