Hybrid organic–inorganic polymers based on sarcosine: The influence of metal coordination on phase transitions

• amino acid-based hybrid organic–inorganic polymers as cheap bioalternative. • the pseudohexagonal crystal struture resembles the ferroelectric trissarcosine calcium chloride. • temperature-induced phase transitions are majorly induced by the reorganization of the metal coordination. The amino acids (AA) have been considered as building blocks of proteins rather so far than the hybrid organic–inorganic materials (HOIM), like polymers or perovskites (HOIP). Yet, here we present the structure–property relation results for four HOIMs based on a simple AA – sarcosine (N-methylglycine) and metal halides MX 2 , where M=Sr, Ba and X=Cl, Br. The studies reveal a presence of reversible phase transitions above room-temperature in each crystal associated with crystal transformation into different symmetries, caused by a rearrangement of the metal coordination spheres. These materials constitute a cheap, bio-based alternative for organic–inorganic perovskites.