Synthesis of C2-Symmetrical Bis-(β-Enamino-Pyran-2,4-dione) Derivative Linked via 1,6-Hexylene Spacer: X-ray Crystal Structures, Hishfeld Studies and DFT Calculations of Mono- and Bis-(Pyran-2,4-diones) Derivatives

The synthesis of C2-symmetrical bis(β-enamino-pyran-2,4-dione) derivative 3 connected via 1,6-hexylene linker was reported for the first time. X-ray structures and Hirshfeld studies new bis- β-enamino-pyran-2,4-dione along with two structurally related pyran-2,4-dione derivatives 2a,b were discussed. A comparative analysis different intermolecular contacts affecting crystal stability presented. Generally, H…H, O…H, H…C interactions are common in all compounds considered most abundant contacts. In addition, DFT calculations used to compute electronic properties as well 1H 13C NMR spectra studied systems. All (except 3) polar where 2a (3.540 Debye) has a higher dipole moment than 2b (2.110 Debye). chemical shifts calculated excellent correlations between experimental data obtained (R2 = 0.93–0.94).