Intermolecular interactions in multi-component crystals of acridinone/thioacridinone derivatives: Structural and energetics investigations

• Multi-component crystals consisting of acridinone/thioacridinone and solvent moiety have been characterized.
• Different theoretical approaches were undertaken to asses the intermolecular interactions within the crystal.
• Coulombic and specific interactions stabilize crystal lattice and influence mutual arrangement of crystal packing.

A single crystal X-ray analysis of two multi-component crystals consisting of an acridinone/thioacridinone moiety and a solvent moiety – water and ammonia (1 and 2), respectively, was carried out to determine the crystal structures of obtained crystals. A theoretical approach was undertaken – using the DFT method, lattice energies calculations and Hirshfeld surfaces (HS) – to qualitatively and quantitatively assess the intermolecular interactions within the crystal. HS analysis was showed that the H⋯H, C⋯H/H⋯C and C⋯C contacts for both structures (altogether 81.6% of total Hirshfeld surface area for 1 and 79.3% for 2) and the O⋯H/H⋯O (14.3%) for 1 and the S⋯H/H⋯S (15.2%) contacts for 2 were the characteristic intermolecular contacts in the related crystal structures. Using a computational methods were confirmed that the main contribution to the stabilization of the crystal lattice of compound 1 comes from the Coulombic interactions, whereas in compound 2 electrostatic and van der Waals appear to have similar contribution to the crystal lattice energy. Theoretical calculations of the investigated compounds have also allowed to determine the energy of a single specific intermolecular interaction.

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