The invention relates to a combustion gas seal for injectors and to a seal structure disposed therewith, for preventing leakage of combustion gas in a state in which an injector is mounted to an engine head. For example, cobalt-ruthenium-bidentate, bisalkane catalyst precursors in ether solvents provide good yields of 1,3-PDO in a one step synthesis. The panels are adapted for interconnecting to adjacent panels, and for connection to an edge finishingedge termination system and support structure to enable provision of non-panel areas of the green roof, and above-panel structures.