Neuba A, Rohrmüller M, Hölscher R, Schmidt WG, Henkel G. A panel of peralkylated sulfur–guanidine type bases: Novel pro-ligands for use in biomimetic coordination chemistry. Inorganica Chimica Acta. 2015;430:225-238. doi:10.1016/j.ica.2015.03.015

Butsch K, Klein A, Bauer M. Highly flexible O,O,N ligands and their Fe, Ni, Cu and Zn complexes. Inorganica Chimica Acta. 2011;374(1):350-358. doi:10.1016/j.ica.2011.02.072