Packing structure and non-classical hydrogen bonding interactions of the toluene solvate crystal of 1,8-bis(4-methylbenzoyl)naphthalene-2,7-diyl dibenzoate: Role of toluene molecule in determination of the spatial arrangement of the major constituent molecules

The toluene solvate crystal of the titled highly congested aromatic ketone-ester compound has been subjected to crystal structural analysis from the viewpoints of the clarification of distribution feature of effective non-classical hydrogen bonds and the retention and perturbation of the symmetric nature. The two independent molecules of the title naphthalene derivative, which bears two aroyl groups at the adjacent inner positions and two benzoyloxy groups at the neighboring beta-positions, and one disordered solvent toluene molecule are incorporated in the asymmetric unit of P2(1)/c (Z '= 2). In the packing of the solvate crystal, the solvent toluene molecule plays the multi roles of hydrogen donor/acceptor for C-H horizontal ellipsis pi non-classical hydrogen bonds and hydrogen donor for C-H horizontal ellipsis O = C ones. On the other hand, the role of other benzene rings of the parts of the title compound molecules is confined. The 4-methylbenzoyl groups situated at the molecular inner positions mainly play the role of the hydrogen donor of C-H horizontal ellipsis pi non-classical hydrogen bond. The benzoyloxy groups that extend outward from the molecular body mainly act as the hydrogen acceptors of C-H horizontal ellipsis O and C-H horizontal ellipsis pi non-classical hydrogen bonds. The naphthalene ring moderately contributes as the hydrogen acceptor for C-H horizontal ellipsis pi non-classical hydrogen bonds and as the hydrogen donor for C-H horizontal ellipsis O non-classical hydrogen bonds. The roles of the toluene molecule are not limited to a simple filler for the void among the major constituent molecules but proved to position at the pseudo-centrosymmetric center of the counter-configurated pair of molecules of the independent major component compounds to concentrate the effective non-classical hydrogen bonds.