Solid State Conformational Preferences of a Flexible Molecular Backbone Derived from Acetone: Dependence on Electron Donating/Withdrawing Ability of Substitutions

Conformational preferences, crystal packing, and intermolecular interactions can play a pivotal role in solid state reactions, and in particular for bis(phenyl)acetones, these factors are known to determine the rate of the photodecarbonylation process. In the present work, conformational pliability and the supramolecular synthons present in a series of variably substituted bis(phenyl)acetones have been assessed in terms of the electron donating/withdrawing ability of the substituents. While an exo-exo conformation has been observed in the case of electron donating substituents, electron withdrawing analogues preferred an endo endo arrangement. A linear correlation has been observed between the angular shift and the Hammett constants of the functional groups. The shift in the IR spectra with respect to that of acetone has been used to ascertain the spectral and structural analogy. SEM analysis of the nano-/microparticles of the compounds reveals the direct dependence of the hydrophobic/hydrophilic character of the functional groups on the nature and morphology of the particles.