Rei Sakamoto

Bio: Rei Sakamoto is an academic researcher from Tokyo University of Agriculture and Technology. The author has contributed to research in topics: Ring (chemistry) & Dihedral angle. The author has an hindex of 2, co-authored 12 publications receiving 17 citations.

1,8-Dibenzoyl-naph-tha-lene-2,7-diyl dibenzoate.

Abstract: In the title compound, C38H24O6, the phenyl rings of the benzoyl and benzo­yloxy groups make dihedral angles of 67.12 (5), 85.15 (5), 76.41 (5) and 71.47 (5)° with the naphthal­ene ring system. In the crystal, C—H⋯O hydrogen bonds link mol­ecules into chains parallel to the b axis. The structure also features C—H⋯π and π–π stacking inter­actions, with centroid–centroid distances in the range 3.6441 (7)–3.9197 (8) A.

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

Abstract: In crystal of 1,8-bis(4-fluorobenzoyl)naphthalene-2,7-diyl dibenzoate, C 38 H 22 O 6 F 2 , 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 group s has three effective intra molecular 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 intra molecular 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.

{2,7-Dimeth-oxy-8-[4-(2-methyl-prop-yl)benzo-yl]naphthalen-1-yl}[4-(2-methyl-prop-yl)phen-yl]methanone.

Abstract: In the mol­ecule of the title compound, C34H36O4, the two 4-isobutyl­benzoyl groups at the 1- and 8-positions of the naphthalene ring system are aligned almost anti­parallel, and the benzene rings make a dihedral angle of 21.59 (7)°. The dihedral angles between the benzene rings and the naphthalene ring system are 69.26 (6) and 64.29 (5)°. There are no classical hydrogen bonds in the structure, but inversion-related mol­ecules engage in π–π stacking, with an inter­planar spacing between related naphthalene groups of 3.4120 (16) A.

[2,7-Dimeth-oxy-8-(4-propyl-benzo-yl)naphthalen-1-yl](4-propyl-phen-yl)methanone.

Abstract: In the title compound, C32H32O4, the 4-propyl­benzoyl groups at the 1- and 8-positions of the naphthalene ring system are aligned almost anti­parallel, and their benzene rings make a dihedral angle of 8.64 (10)°. The dihedral angles between the naphthalene ring system and the benzene rings are 69.37 (8) and 69.45 (8)°. In the crystal, C—H⋯O inter­actions link adjacent mol­ecules via their aroyl groups.

{2,7-Dimeth-oxy-8-[4-(propan-2-yl-oxy)benzo-yl]naphthalen-1-yl}[4-(propan-2-yl-oxy)phen-yl]methanone.

Abstract: The title compound, C32H32O6, crystallized with two independent molecules in the asymmetric unit. Each molecule has essentially the same feature of non-coplanar aromatic rings whereby the two 4-isopropoxybenzoyl groups are twisted in a perpendicular manner to the naphthalene ring and oriented in the same direction (syn-orientation). The benzene rings of the aroyl groups make dihedral angles of 16.13 (7) and 25.31 (7)° in the two molecules. These benzene rings make dihedral angles of 88.38 (8) and 75.32 (7)° with the naphthalene ring system in one molecule, and 89.71 (7) and 82.11 (7)° in the other. In the crystal, mol­ecules are linked via C—H⋯O hydrogen bonds, forming a three-dimensional network. In one independent molecule, the 2-propyl groups of both isoprop­oxy groups are disordered over two positions with site occupancies of 0.512 (3) and 0.488 (3).

Crystal Structure and Solution Structural Dynamic Feature of 1,8-Dibenzoyl-2,7-Dimethoxynaphthalene

Abstract: The crystal structure and the dynamic feature of molecular structure in solution for 1,8-dibenzoyl-2,7-dimethoxynaph-thalene are revealed by X-ray crystallographic analysis and VT-NMR measurements. In crystal, the molecule of the title compound is located on a twofold rotation axis. The two benzoyl groups are situated in an opposite direction. The dihedral angle between the mean planes of the phenyl ring and the naphthalene ring system is 80.25(6). The benzene ring and carbonyl moiety in each benzoyl group are almost coplanar. The molecular packing is stabilized by weak C–H…O hydrogen bonds and aπ-πstacking interaction between the benzene rings [centroid-centroid and interplanar distances of 3.6383(10) and 3.294 , respectively]. In solution, the temperature-dependent rotation behavior of the C–C bond between the benzene ring and the ketonic carbonyl group has been observed by1H VT-NMR measurements. Furthermore, comparison of the C–C bond rotation behavior between the benzene ring and the carbonyl group with 1-ben-zoyl-2,7-dimethoxynaphthalene has clarified that the C–C bond between the ketonic carbonyl group and the naphthalene ring rotates slower than the 1,8-dibenzoylated homologue.

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, C 21 H 19 NO 5 , 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 naphthalene rings, i.e. , ethoxy groups for title compound and methoxy ones for homologue. In single molecular crystal structure, the 4-nitrobenzoyl groups of these molecules are attached non-coplanarly to the naphthalene ring. The congested situation makes bonds connecting naphthalene ring and carbonyl group fixed to turn stereogenetic, which allow the independent existence of atrope stereoisomers of ( R )- and ( S )-enantiomeric conformer molecules, contrary to their solute state where the fast interconversion disturbs the distinction of the enantiomeric molecules. The two pairs of the enantiomeric molecules are related by two-fold helical axis in the asymmetric unit of P 2 1 /n space group for title compound and P 2 1 /c for homologous compound, exhibiting the number of molecules ( Z ) is four for both compounds. In crystal of title compound, ( R )- and ( S )-enantiomers are connected to each other by pi…pi stacking interaction and two types of C–H…O=N non-classical hydrogen bonds, (sp 2 )C–H…O=N and (sp 3 )C–H…O=N non-classical hydrogen bonds along b -axis, forming centrosymmetric dimeric molecular aggregates. The dimeric units are stacked into columnar structure by (sp 2 )C–H…O=C non-classical hydrogen bonds between molecular unit of identical enantiomeric configuration along a -axis. The columns are also connected by (sp 2 )C–H…OEt non-classical hydrogen bonds between molecular unit of identical enantiomeric configuration along c -axis to give sheet-like aggregate composed of molecules of same enantiomeric configuration spreading on ac -plane. The sheets are piled up through (sp 3 )C–H…pi non-classical hydrogen bonds between opposite enantiomeric molecular units of next dimeric aggregates along b -axis. In crystal of the homologous compound, 2,7-dimethoxy-1-(4-nitrobenzoyl)naphthalene, centrosymmetric dimeric aggregate resulted from the association of ( R )- and ( S )-enantiomers via pi…pi stacking interactions are also observed. The centrosymmetric dimeric aggregates are unidirectionally lined by two kinds of non-classical hydrogen bonds between molecular unit of identical enantiomeric configuration, (sp 3 )C–H…O=C and (sp 3 )C–H…pi non-classical hydrogen bonds, giving columnar structure. The columns are accumulated giving a wavy sheet structure composed of stripes of respective enantiomeric configuration oriented alternatively and anti-parallelly through weak (sp 2 )C–H…pi non-classical hydrogen bonds. The difference of higher ordered structure between title compound and homologue is plausibly explained according to one CH 2 margin in 2,7-dialkoxy groups, i.e. , elongation of the least length in alkyl group of title compound compared to homologue brings about the sterically significant hindrance among dimeric aggregates that makes rather anisotropic intermolecular non-covalent bonding interactions resulting in accumulating sheet structure. For 1-monoaroylnaphthalene compounds, the most stabilized single molecular structure on condition that the sufficiently effective intermolecular interaction is absent is proposed the perpendicular alignment of naphthalene and benzene rings to prevent the steric repulsion of two aromatic rings. The smaller spatial volume of methyl group in homologue molecule is plausibly able to be merged without large alternation in the single molecular structure most stabilized. Contrarily, the additional methylene unit at 2,7-alkoxy group probably requires the rather large perturbation from the supposed structure most stabilized.

{2,7-Dimeth-oxy-8-[4-(2-methyl-prop-yl)benzo-yl]naphthalen-1-yl}[4-(2-methyl-prop-yl)phen-yl]methanone.

Abstract: In the mol­ecule of the title compound, C34H36O4, the two 4-isobutyl­benzoyl groups at the 1- and 8-positions of the naphthalene ring system are aligned almost anti­parallel, and the benzene rings make a dihedral angle of 21.59 (7)°. The dihedral angles between the benzene rings and the naphthalene ring system are 69.26 (6) and 64.29 (5)°. There are no classical hydrogen bonds in the structure, but inversion-related mol­ecules engage in π–π stacking, with an inter­planar spacing between related naphthalene groups of 3.4120 (16) A.