CRYSTAL STRUCTURE OF 1,8-BIS(4-FLUOROBENZOYL)NAPHTHALENE-2,7-DIYL DIBENZOATE: ROLE OF (SP2)C–H…F HYDROGEN BONDING AS DISTINCTLY STRONG INTERACTION AMONG NON-CLASSICAL HYDROGEN BONDS CONTRIBUTING STABILITY OF THE CRYSTAL
In crystal of 1,8-bis(4-fluorobenzoyl)naphthalene-2,7-diyl dibenzoate, C38H22O6F2, the phenyl rings of benzoyloxy groups and the naphthalene ring demonstrate largely disproportionate interplanar angles [38.97 (7)° and 52.62 (6)°] different from those between 4-fluorobenzoyl group and the naphthalene ring core [71.24 (5)° and 78.85 (6)°]. One of two benzoyloxy groups has three effective intramolecular interactions [(benzoyloxy) C―H(o-)···O (benzoyloxy), (naphthalene) C―H(6-)···O=C (benzoyloxy), and (benzoyloxy) C―H(o-)···π (4-fluorobenzoyl) hydrogen bonds] and the other has no intramolecular interactions. In crystal, the molecules of identical enantiomeric isomer are unidirectionarly arranged along the b axis through (4-fluorobenzoyl)C―H(m-)···O=C(4-fluorobenzoyl) hydrogen bonding interactions forming columnar structure. Moreover, a column is connected with the mirror imaged column composed of the opposite enantiomeric isomers into centrosymmetric dimer aggregates by three types of complementary interactions, i.e., (benzoyloxy)C―H(m-)···F, (4-fluorobenzoyl)C―H(m-)···π(4-fluorobenzoyl), and (4-fluorobenzoyl)C―H(m-)···π(benzoyloxy) hydrogen bondings. The tubular structures thus formed are stacked parallel to the ac plane via (benzoyloxy)C―H(p-)…F, (benzoyloxy)C―H(m-)…π(benzoyloxy), (naphthalene)C―H(6-)…O=C(4-fluorobenzoyl), and (4-fluorobenzoyl)C―H(o-)…O=C(benzoyloxy) hydrogen bonds. In homologous compound, a fluoro group-free derivative for title compound, the enantiomeric isomer and the opposite enantiomeric counterpart isomer are alternately arranged in a head-to-tail fashion through (benzoyl)C–H(p-)…O=C(benzoyl)hydrogen bonds along b-axis. The zigzagged columns are aligned along a-axis with inversion center to form a sheet structure. However, there are no effective non-covalent bonding interactions between the zigzagged columns. In other words, the molecular packing structure of the homologous compound is governed by solely one strong (benzoyl)C–H(p-)…O=C(benzoyl) hydrogen bonds, contrary to the organization of supramolecular architecture in title compound ascribed to cooperative unidirectional (4-fluorobenzoyl)C–H(m-)…O=C(4-fluorobenzoyl) hydrogen bonds and bidirectional (benzoyloxy)C–H(m-/p-)…F hydrogen bonds.
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