Crystal Structures and Conformational Analysis of the bis(pyrazolyl)Propanone Derivatives

The crystal structures of 3,3-bis(3,5-dimethyl-1H-pyrazol-1-yl)-1-phenylpropan-1-one (1) and 3,3-bis(3,5- dimethyl-1H-pyrazol-1-yl)-1-(furan-2-yl)propan-1-one (2) are determined by single crystal X-ray diffraction (XRD). According to the single crystal XRD data, in the crystalline phases, the molecules of 1 and 2 are in the form of different conformers (cis and trans respectively), which is due to different orientations of pyrazolyl moieties. The rotational barriers of these moieties are estimated by quantum chemical calculations: they are 2.6 kcal/mol and 2.5 kcal/mol for 1 and 2 respectively. The contributions of different interatomic contacts to the crystal packings are estimated by the Hirshfeld surface analysis.