The ruthenacyclic carbamoyl complexes [RuBr(2-NHC(O)C5H3N-4-R)(CO)2(MeCN)] in which the 4-position of the pyridinyl ring is derivatized, have been synthesized. These are ruthenium-based structural mimics of the natural [Fe]-hydrogenase metal cofactor. The derivative with R = H reacts with phosphine to form a disubstituted product [RuBr(2-NHC(O)C5H4N)(CO)(PPh2SPh)2]. © 2020 Elsevier Ltd