This starter grant award of the Chemistry Division to the University of Notre Dame supports the research of Professor Marya Lieberman. The research focuses on crosslinking reactions applied to the synthesis and analysis of layered materials. Initial studies are carried out with layered metal organophosphonates and organophosphates, which consist of layers of metal phosphonate connected by layers of organic spacer molecules. Each organic spacer is synthetically modified to include a photochemically- or electrochemically-activated crosslinker, whose function is to connect a known number of adjacent molecules in a specific manner. The modified spacers are mixed with appropriate metal salts to form layered materials. Activation of the crosslinker forms molecular adducts trapped within the layered material. The study of crosslinking chemistry leads to information on defects, structural rearrangements, and possible metastable materials. This research advances fundamental understanding of the synthesis and structure of layered materials by developing crosslinking reactions as an analytical and a synthetic tool that can be applied to molecular monolayers on surfaces and inside layered materials.