Sustainable by (crystal) design: novel materials for agriculture via active ingredient cocrystallization

Novel material design for sustainable development of agriculture is of key importance. In this regard, cocrystallization emerged as an effective laboratory synthesis as well as large-scale agricultural material production technique to enhance the efficiency of active ingredients by forming cocrystals with agriculturally compatible molecules and thereby improving their properties, such as moisture resistance, enzyme inhibition or nitrogen efficiency. This review provides a state of the art of this quickly developing area from the material design perspective and examines cocrystallized products for emerging applications in sustainable agriculture, such as novel fertilizer formulations that incorporate essential nutrients, as well as cocrystals for other applications, such as pest control. The chemical and crystal structures, bonding mechanisms, and the resulting properties of these cocrystals are discussed. Special attention is given to urea-based cocrystals. By integrating macro- (e.g., N, P, K, Ca, Mg and S) and micro-nutrients (e.g., Fe, Mn, Cu, Zn, B, Mo, Cl and Ni), these cocrystals provide novel nutrient delivery and management strategies. We then explore existing cocrystals that assist sustainable agriculture beyond nutrient delivery, e.g. herbicides, insecticides and fungicides. Finally, we discuss the potential routes to enhance agricultural cocrystal sustainability, such as novel methods of their synthesis, including mechanochemical processes.