The reactions of long-chain diazo ketones and azides in adsorbed monolayers on inorganic solids were investigated and compared with the corresponding behaviour in monolayers at the air-water interface. The isolated products indicate that reaction of photochemically generated intermediates occurs both with co-adsorbed water and with hydroxyl groups on the solid surface. In the case of 1-diazo-2-oxoheptadecane, for example, the products of ...