HAT by benzophenone occurs. Under basic conditions, dimethyl malonate and [Co III (TPP)Cl] were mixed and the formed complex was characterized by NMR spectroscopy and high resolution mass spectrometry (HRMS) (see supporting information). The 1 H NMR spectrum showed a signal at -3.16 ppm, which is indicative for a single proton on a carbon atom that is attached to a cobalt porphyrin complex. In combination with HRMS measurements that showed a mass of 802.1984 [M+], the formed complex was identified as [Co III (TPP)(CH(CO2Me)2] (complex 1). Contrarily, by exposing [Co II (TPP)] to the same conditions, no adduct was formed as indicated by the lack of signal in the negative region of the 1 H NMR spectrum (see supporting information, Figure ). This confirms that [Co II (TPP)] is indeed unable to bind the dimethyl malonate anion.