Compounds having two reactive functional groups are described that can be used to provide a connector group between a substrate and an amine-containing material. The first reactive functional group can be used to provide attachment to a surface of a substrate. The second reactive functional group is a N-sulfonylaminocarbonyl group that can be reacted with an amine-containing material, particularly a primary aliphatic amine, to form a carbonylimino-containing connector group. The invention also provides articles and methods for immobilizing amine-containing materials to a substrate.