Fig. 15. Comparison of the IR spectra of reactions after 2 days of 4Mes and 4Mes-13C under an atmosphere of CO or 13CO. All reactions performed in C6H6. Left, metal carbonyl and ketene region. Right, region for squaraine. Circles signify 12C products, triangles signify mixed 12C/13C and square signifies 13C products. Signals in green are for ketene (8). Signals in red are squaraine (2Mes). Signals in black are Fe(CO)5.
