Formation of thermally stable alkylidene layers on a catalytically active surface

Materials containing organic-inorganic interfaces usually display a combina tion of molecular and solid-state properties, which are of interest for app lications ranging from chemical sensing(1) to microelectronics(2) and catal ysis(3). Thiols-organic compounds carrying a SH group-are widely used to an chor organic layers to gold surfaces(6), because gold is catalytically suff iciently active to replace relatively weak S-H bonds with Au-S bonds, yet t oo inert to attack C-C and C-H bonds in the organic layer. But although sev eral methods(4-6) of functionalizing the surfaces of semiconductors, oxides and metals are known, it remains difficult to attach a wide range of more complex organic species. Organic layers could, in principle, be formed on t he surfaces of metals that are capable of inserting into strong bonds, but such surfaces catalyse the decomposition of organic layers at temperatures above 400 to 600 K, through progressive C-H and C-C bond breaking(7). Here we report that cycloketones adsorbed on molybdenum carbide, a material know n to catalyse a variety of hydrocarbon conversion reactions(8-11), transfor m into surface-bound alkylidenes stable to above 900 K. We expect that this chemistry can be used to create a wide range of exceptionally stable organ ic layers on molybdenum carbide.