Dimeric Molecular Aggregation Motif in Crystal of 2,7-Diethoxy-1-(4-Nitrobenzoyl)naphthalene: Correlation of Single Molecular Structure, Molecular Accumulation Structure and Non-Covalent-Bonding Interactions

Abstract

Crystal structure of 2,7-diethoxy-1-(4-nitrobenzoyl)naphthalene C21H19NO5, is reported and discussed on the characteristics of the spatial organization of single molecule and molecular aggregation as contrasted with a homologous compound. The molecular structures of these compounds differ only in the kind of alkoxy group of 2,7-positions of the naphthalene rings, i.e., ethoxy groups for title compound and methoxy groups for homologue. In single molecular crystal structures of these compounds, 4-nitrobenzoyl group is non-coplanarly attached to the naphthalene ring. The molecules exhibit axial chirality, with either R or S stereogenic axis. The two pairs of the enantiomeric molecules are related by twofold helical axis in the asymmetric unit of P21/n space group for title compound and P21/c one for homologue, showing the number of molecules (Z) is four for both compounds. In their molecular packing structures, (R)-and (S)enantiomers are connected to each other by … stacking interactions, forming centrosymmetric dimeric molecular aggregates. However, the aggregation structures of the dimers are apparently different between title compound and homologue. The dimeric units of title compound are stacked into columnar structure with (sp 2)C-H…O=C non-classical hydrogen bonds between identical enantiomers along aaxis. The columns are connected by (sp 2)C-H…OEt non-classical hydrogen bonds between identical enantiomers along c-axis to give sheet-like aggregation spreading on ac-plane. The sheets are piled up through (sp 3)C-H… non-classical hydrogen bonds between opposite enantiomeric molecules of next dimeric aggregates along b-axis giving layers. On the other hand, the dimeric molecular aggregates of homologue are connected into flattish column by (sp 3)C-H…O=C non-classical hydrogen bonds and (sp 3)C-H… nonclassical hydrogen bonds between identical enantiomers. The columns are linked into waving plate through weak (sp 2)C-H… nonclassical hydrogen bonds. In title compound, difference between … stacking interactions and non-classical hydrogen bonds is smaller than homologue in contribution to the whole of molecular packing structure.

Crystal structure and Hirshfeld surface analysis of 2-hydroxy-7-methoxy-1,8-bis(2,4,6-trichlorobenzoyl)naphthalene

“…Conformational studies of hydroxyaryl ketones in the solid state and in solution have attracted considerable interest (Siskos et al, 2015;Nonhebel, 1968). Since the discovery of an effective method for diaroylation at the 1,8(peri)-positions of the naphthalene ring core and the related reactions (Okamoto & Yonezawa, 2009;Okamoto et al, 2011;Okamoto, Mitsui et al, 2012), we have reported on the spatial organization of 1,8-diaroylated naphthalenes and homologous compounds in both the solid state and solution Yoshiwaka et al, 2015;Okamoto et al, 2015;Ohisa et al, 2018). In the crystal structures of these compounds, which have non-coplanar accumulated aromatic rings, molecules are arranged by weak ISSN 2056-9890 intermolecular interactions, such as non-classical hydrogen bonds and van der Waals interactions.…”