Synthesis, molecular structure and vibrational spectra of 1,3-bis(1-adamantyl)-2-phenylpropan-1,3-diones

The interest in the oxo-enol tautomerism of 1,3-dioxo compounds is justified by their usefulness in many synthetic fields. A series of new 1,3-bis(1-adamantyl)propan-1,3-diones with a variably substituted phenyl ring at the C2 position was prepared either by the reaction of an appropriate Grignard reagent with adamatane-1-carbonyl chloride or by SEAr on the unsubstituted 1,3-bis(1-adamanty1)-2-phenylpropan-1,3-dione. In addition to the single crystal X-ray diffraction analysis of three of the prepared compounds, the experimental H-1 and C-13 NMR, IR and Raman spectroscopic data were assigned and compared to those obtained by DFT computations. In the solid state, the syn-dioxo forms were exclusively observed, which are shown to also predominate in CHCl3 solutions. The analysis of the Hirshfeld surface revealed that H center dot center dot center dot H and O center dot center dot center dot H contacts dominate the intermolecular interactions in the solid state, whereas it pi center dot center dot center dot pi stacking plays a marginal role. (C) 2015 Elsevier B.V. All rights reserved.