Two isomeric products [Os3(μ-H)(C14H9N4)(CO)9] formed by orthometallation of the cluster [Os3(C14H10N4)(CO)10] containing the chelating ligand 2,3-bis(2-pyridyl)pyrazine

Thermolysis of complex [Os3(C14H10N4)(CO)10] (1) yields two structural isomers formulated as [Os3(μ-H)(μ,η3-C14H9N4)(CO)9] (2) and (3). Isomer 2 is of particular interest since to the best our knowledge is first example of a osmium trinuclear that contains an orthometallated pyridine ligand system that is also part of a seven-membered chelate ring.