Knowledge Bank

Laser-ablated chromium atoms have been reacted with NO molecules during condensation in excess argon. Absorptions due to NCrO $(976.1,866.2cm-1),Cr-\eta 1-NO(1614.3,541.1cm-1)$ and $Cr-\eta 2-NO(1108.8,528.2,478.0cm-1)$ are observed and identified via isotopic substitutions and DFT calculations. Formation of the more stable NCrO insertion product requires activation energy, while $Cr-\eta 1-NO$ and $Cr-\eta 2-NO$ can be formed on diffusion of cold reagents in solid argon. High nitrosyls are also formed on annealing. Based on the observation of mixed isotopic multiplets, a $1623.3cm-1$ absorption is assigned to $Cr-\eta 1(NO)2$, a $1663.5cm-1$ absorption to $Cr-\eta 1-(NO)3$, and absorptions at 1726.0, 633.0 and $506.1cm-1$ are assigned to $Cr-\eta 1-(NO)4$.