English: Illustration of Fischer, Schrock, and [Co(Por)] orbitals. In Fischer carbenes (a), there is sigma donation from the carbene to the metal, and pi backdonation from the metal to the carbene. The Schrock (b) scenario shows spin-pairing between adjacent orbitals, thus resulting in a covalent interaction. The [Co(Por)]-carbene (c), presented in this work, consists of a doublet metal into which the carbene sigma donates, with pi backdonation from the metal to the carbene, in the case of having a good pi acceptor on the ligand, with the porphyrin ring also serving as an electron "buffer" to keep the pi d-orbitals filled and thus leaving a radical on the carbon.