Pyridazines in Crystal Engineering. A Systematic Evaluation of the Role of Isomerism and Steric Factors in Determining Crystal Packing and Nano/Microcrystal Morphologies

The present study focuses on understanding hydrogen bond patterns in a series of variably substituted pyridyl-pyridazines as a function of positional isomerism and steric factors. A relatively uncommon multiple hydrogen bond acceptor nature of pyridazine has been observed in the di- and tripyridazine compounds. With increasing aromatic substitution and thereby steric hindrance, a systematic transition has been observed from close-packed to porous solvated assemblies. Distinct morphologies of the organic nano/microparticles, obtained by the precipitation method, indicate that the molecules interact with the solvent system in different ways.