No abstract

Keywords: S-shaped tetramer composed of four conformers, pseudo-centrosymmetricity, classical hydrogen bonds, non-classical hydrogen bondsCrystal structure of (1R,2S)-1,2-bis(4-chlorophenyl)-3,8-dimethoxyacenaphthene-1,2-diol, C26H20O4Cl2, is reported and discussed from the viewpoints of characteristics in spatial organization, i.e., single molecular structures of four conformers, tetrameric aggregates, and higher ordered structures, with clarification of a classical and two non-classical hydrogen bonding interactions as the structure determining interactions. The title compound crystallizes with four independent molecules (conformers G, B, R, and Y) in the asymmetric unit. Furthermore, each independent molecule displays a meso configuration, with one 4-chlorophenyl group R and the other S. The four molecules are related by inversion center in the asymmetric unit of P-1 space group, exhibiting the number of molecules is eight, Z = 8. Single molecular structure of each conformer shows that the two benzene rings are bonded with large dihedral angles against the naphthalene plane and the two phenyl rings are oriented in the same direction with respect to the naphthalene ring plane (syn-orientation). The four conformers are classified into two groups according to overlapping feature of phenyl rings, i.e., conformers G and Y have larger slippage of the phenyl rings than conformers B and R. In the molecular packing, four conformers Y, B, R, and G are connected by classical O-H…O(H) hydrogen bonds in head-to-head fashion forming S-shaped tetramer. Tetramers composed of four conformers are stacked into columnar structure along a-axis through non-classical C-H…Cl hydrogen bonds between conformers G. The columns are linked into a sheet structure by non-classical C-H…Cl hydrogen bonds between conformers G and Y along ab-diagonal. The waved sheets are interlocked by two types of non-classical C-H… hydrogen bonds forming the stripe structure along c-axis, i.e., non-classical C-H… hydrogen bonds between conformers R and Y, and those between conformers B and G.

The title compound lies about a crystallographic inversion centre located at the terephthalate moiety. The two peri-benzoylnaphthalene units having atrope chirality are also situated centrosymmetrically. In the two peri-benzoylnaphthalene moieties, two benzoyl groups are substituted at 1 and 8 carbons of the naphthalene ring in anti-orientation. Then two absolute configurations of peri-benzoylnaphthalene moieties are consequently assigned as complementary to each other, i.e., one unit has R,R-configuration and the other S,S-one, respectively. The two benzoyl groups in peri-benzoylnaphthalene moiety and the terephthalate phenylene ring are non-coplanarly located against the naphthalene ring. The dihedral angles of each benzene ring of two benzoyl groups and terephthalate unit with the naphthalene ring are 73.73 and 75.96, and 71.79°. In molecular packing, several kinds of weak interactions are responsible to induce three-dimensional molecular network. Especially, the synergetic effect realized through the bidentate hydrogen acceptor function in bidirectional C-H···π non-classical hydrogen bonds by the terephthalate phenylene ring moiety plausibly plays the determining role.

C26H20F2O4, monoclinic, P21/n (no. 14), a = 10.3707(2) Å, b = 12.0232(2) Å, c = 15.7744(3) Å, β = 90.907(1)°, V = 1966.65(6) Å3, Z = 4, R gt (F) = 0.0371, wR ref (F 2) = 0.1013, T = 193.15 K.

C40H28O8, orthorhombic, Pna21 (no. 33), a = 27.0291(4) Å, b = 14.5593(2) Å, c = 7.95172(10) Å, V = 3129.20(7) Å3, Z = 4, R gt (F) = 0.0276, wR ref (F 2) = 0.0690, T = 193 K.