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Silole- and phosphole-containing polycyclic aromatic compounds have attracted significant attention in the field of organic functional materials. The structure of the aromatic units has great impact on the photophysical properties of the resulting silole- and phosphole-containing polycyclic aromatic compounds. Here, dibenzo-fused naphtho[2,3-b:6,7-b′]disilole (NDS) and naphtho[2,3-b:6,7-b′]diphosphole (NDP), where a naphthalene unit is arranged between two silole and phosphole units, respectively, were designed and synthesized. The solid-state structures of them were confirmed by X-ray crystallographic analysis. The photophysical properties were evaluated by UV−vis absorption and photoluminescence spectroscopies and compared with those of their related compounds, such as dibenzo-fused silolo[3,2-b]silole and benzo[1,2-b:4,5-b′]disilole, ever reported. The longest wavelength absorption band of a series of silole-fused compounds was found to be red-shifted in the order benzo[1,2-b:4,5-b′]disilole < NDS < silolo[3,2-b]silole derivatives. For a series of phosphole-fused compounds, π-extension from phospholo[3,2-b]phosphole to NDP derivatives induces the lower absorption coefficient of the longest wavelength absorption band and the red-shift of the second longest wavelength absorption band. Both NDS and NDP exhibit much lower fluorescence quantum yields than their related compounds.

We isolated a stress-tolerance-related gene from a genome library of Synechococcus sp. NKBG15041c. The expression of the gene in E. coli confers resistance against various stresses. The gene encodes a MoxR AAA+ ATPase, which was designated SyMRP since it belongs to the MRP subfamily. The recombinant SyMRP showed weak ATPase activity and protected citrate synthase from thermal aggregation. Interestingly, the chaperone activity of SyMRP is ATP-dependent. SyMRP exists as a stable hexamer, and ATP-dependent conformation changes were not detected via analytical ultracentrifugation (AUC) or small-angle X-ray scattering (SAXS). Although the hexameric structure predicted by AlphaFold 3 was the canonical flat-ring structure, the structures observed by atomic force microscopy (AFM) and transmission electron microscopy (TEM) were not the canonical ring structure. In addition, the experimental SAXS profiles did not show a peak that should exist in the symmetric-ring structure. Therefore, SyMRP seems to form a hexameric structure different from the canonical hexameric structure of AAA+ ATPase.

Refolding multi-disulfide bonded proteins expressed in E. coli into their native structure is challenging. Nevertheless, because of its cost-effectiveness, handiness, and versatility, the E. coli expression of viral envelope proteins, such as the RBD (Receptor-Binding Domain) of the influenza Hemagglutinin protein, could significantly advance research on viral infections. Here, we show that H1N1-PR8-RBD (27 kDa, containing four cysteines forming two disulfide bonds) expressed in E. coli and was purified with nickel affinity chromatography, and reversed-phase HPLC was successfully refolded into its native structure, as assessed with several biophysical and biochemical techniques. Analytical ultracentrifugation indicated that H1N1-PR8-RBD was monomeric with a hydrodynamic radius of 2.5 nm. Thermal denaturation, monitored with DSC and CD at a wavelength of 222 nm, was cooperative with a midpoint temperature around 55 °C, strongly indicating a natively folded protein. In addition, the 15N-HSQC NMR spectrum exhibited several 1H-15N resonances indicative of a beta-sheeted protein. Our results indicate that a significant amount (40 mg/L) of pure and native H1N1-PR8-RBD can be produced using an E. coli expression system with our refolding procedure, offering potential insights into the molecular characterization of influenza virus infection.

The phosphole ring is known as a useful building block for constructing π-conjugated organic materials. Here, we report ladder-type benzophospholo[3,2-b]indole (BPI) derivatives where the phosphole and the pyrrole rings are directly fused. Compounds 8a–8d with different aryl groups on the phosphorous center were successfully synthesized, and the solid-state structure of 8a was confirmed using X-ray crystallographic analysis. The BPIs exhibit relatively high fluorescence quantum yield (Φ 0.50−0.72) and demonstrate a larger Stokes shift compared with a series of benzophospholo[3,2-b]benzoheteroles. The benzophospholo[3,2-b]carbazole derivative 9, which possesses a benzene ring between the phosphole and the pyrrole rings of the BPI, was also synthesized, and its solid-state structure was confirmed using X-ray crystallographic analysis. Compound 9 was found to show a smaller Stokes shift compared with the BPI.

Abstract Lignin-free wood has been successfully developed via a two-step chemical treatment while maintaining its inherent hierarchical structure. The first step was alcoholysis which was conducted using ethylene glycol, and whose condition was optimized by monitoring the removal of lignin using infrared spectroscopy. The second step was bleaching wherein the delignification proceeded from the surface to the core of the wood block, and finally resulted in complete decolorization. Although the wood block was free from lignin and hemicellulose as approximately confirmed by the chemical composition analysis, the 3-dimensional colorless wood block was almost unaltered, even after freeze–drying. Then, multidirectional observation was performed to investigate whether the natural hierarchical structure from anatomical- to nano-level was maintained. Optical microscopy, X-ray microcomputed tomography, X-ray diffractometry, and transmission electron microscopy demonstrated that all the stages of hierarchical structure were maintained. The lignin-free wood block has great potential for novel materials that are supported by a 3-dimensional wooden architecture. The derived lignin-free wood is also a suitable specimen that can be used to understand the formation and functionality of the anatomical structure and lignified cell wall.

Spiro-fused polycyclic aromatic compounds (PACs) have received growing interest as rigid chiral scaffolds. However, furan-containing spiro-fused PACs have been quite limited. Here, we design spiro[indeno[1,2-b][1]benzofuran-10,10′-indeno[1,2-b][1]benzothiophene] as a new family of spiro-fused PACs that contains a furan unit. The compound was successfully synthesized in enantiopure form and also transformed to its S,S-dioxide derivative and the pyrrole-containing analog via aromatic metamorphosis. The absorption and emission properties of the obtained furan-containing chiral spiro-fused PACs are apparently different from those of their thiophene analogs that have been reported, owing to the increased electron-richness of furan compared to thiophene. All of the furan-containing chiral spiro-fused PACs were found to be circularly polarized luminescent materials.

In the title compound, C25H12Cl6O4, the two carbonyl groups are oriented in a same direction with respect to the naphthalene ring system and are situated roughly parallel to each other, while the two 2,4,6-trichlorobenzene rings are orientated in opposite directions with respect to the naphthalene ring system: the carbonyl C—(C=O)—C planes subtend dihedral angles of 45.54 (15) and 30.02 (15)° to the naphthalene ring system are. The dihedral angles formed by the carbonyl groups and the benzene rings show larger differences, the C=O vectors being inclined to the benzene rings by 46.39 (16) and 79.78 (16)°. An intramolecular O—H...O=C hydrogen bond forms an S(6) ring motif. In the crystal, no effective intermolecular hydrogen bonds are found; instead, O...Cl and C...Cl close contacts are observed along the 21 helical-axis direction. The Hirshfeld surface analysis reveals several weak interactions, the major contributor being Cl...H/H...Cl contacts.

Here, we investigated whether the optimal threonine (Thr) to lysine (Lys) ratio in high Lys diet improves the growth performance of modern broiler chickens at finisher period and determined the possible mechanism underlying improvement in the growth performance of chickens fed with high Lys or Lys + Thr diet using metabolome analyses. Eighteen 21-day-old chickens housed in individual cages were randomly divided into three groups of six chickens fed with different diets as follows: control diet, high Lys diet (150% Lys content of National Research Council requirement), and high Lys + Thr diet (0.68 of Thr/Lys in high Lys diet). Body weight gain (BWG) increased in chickens receiving high Lys diet as compared with those fed with the control diet (P

[n]Helicenes with helically twisted structures have attracted increasing interest owing to their unique properties. Therefore, it has been an important issue to develop facile synthetic methodologies which allow access to a variety of [n]helicenes. Here we report the synthesis of [7]helicenes and [7]helicene-like compounds from the thia[7]helicene as a common starting material. Desulfurative dilithiation of the thia[7]helicene and the subsequent reaction with silicon and phosphorus electrophiles afforded the silole- and phosphole-fused [7]helicene-like compounds, respectively. The cyclopentadiene-fused [7]helicene-like compound and the pyrrole-fused aza[7]helicenes were also successfully synthesized via twofold SNAr reactions of the thia[7]helicene S,S-dioxide with the carbon and nitrogen nucleophiles, respectively. The thia[7]helicene S,S-dioxide showed a slightly red-shifted absorption spectrum than the parent thia[7]helicene, which was well demonstrated by the theoretical calculations. The substituents on the silicon atom of silole-fused [7]helicene-like compounds have little impact on the longest absorption maximum. Such little effect of the substituents on absorption properties was also observed for cyclopentadiene-fused [7]helicene-like compounds and aza[7]helicenes and was well demonstrated by the theoretical calculations. The thia[7]helicene S,S-dioxide and the silole-fused [7]helicene-like compound exhibited bright blue emission, and the cyclopentadiene-fused [7]helicene-like compound and the aza[7]helicenes showed strong violet emission. Each single enantiomer of the aza[7]helicenes showed circularly-polarized luminescence with the dissymmetry factors of 4.2~4.4 × 10−3.

The kelulut bee (Meliponini) is a subfamily of stingless bees that produce honey. A total of 89 species out of a total of 500 species of kelulut bees are known to originate from the Indo-Australian region. Kelulut bees do not have quality standards so they still refer to the Codex and EU Directive which basically only applied for Apis honey. The Codex and EU Directive are formed by several psychochemical parameters, one of it is diastase activity. Diastase activity in kelulut honey is known not to meet existing standards or even undetectable. Therefore, this study aimed to explore proteins inside kelulut honey and investigate the possibility of using a specific protein as a biomarker to differentiate honey produced by kelulut bee from other honey. This research can also be considered as an initial step to optimize the exploration of protein in kelulut honey. This research is divided into two sections which are the preliminary research and the research expansion. From preliminary section, glucose dehydrogenase enzyme (GDH) was found to be present inside Tetragonula spp honey. A further examination of GDH enzyme was made in four kelulut bee honeys namely Tetragonula leaviceps, T. biroi, Heterotrigona itama, and Geniotrigona thoracica. The preliminary research has five stages that are exactly the as expansion research section except it didn't include GDH activity measurement. The research includes seven main stages. First honeys were dialyzed to remove the sugar content followed by centrifugation. The samples were then purified using liquid chromatography with anion exchanger column. The molecular weight of proteins was analysed by SDS-PAGE method. The GDH activity was measured using spectrophotometer followed by qualitative analysis using LC-MS/MS. The peptide sequences resulted from LC-MS/MS were then matched with Uniprot to identify the unknow protein. The results showed that only T. biroi and T. laeviceps had GDH enzyme activity of 0,1891 U/mL and 0,1652–1,579 U/mL, respectively. Bands from both species were also qualitatively identified as GDH. With these results, it can be concluded that the GDH enzyme cannot be used as a biomarker to distinguish the kelulut honey.

[Bis(trifluoroacetoxy)iodo]benzene (BTI) and (diacetoxyiodo)benzene (DIB) efficiently promote the formation of acylnitroso species from hydroxamic acids in the presence of various dienes to give the corresponding hetero-Diels–Alder (HDA) adducts in moderate to high yields. The present method could be applied to the HDA reactions of acylnitroso species with o-benzoquinones generated by the oxidative dearomatization of guaiacols.

Vertebrate animals detect odors through olfactory receptors (ORs), members of the G protein-coupled receptor (GPCR) family. Due to the difficulty in the heterologous expression of ORs, studies of their odor molecule recognition mechanisms have progressed poorly. Functional expression of most ORs in heterologous cells requires the co-expression of their chaperone proteins, receptor transporting proteins (RTPs). Yet, some ORs were found to be functionally expressed without the support of RTP (RTP-independent ORs). In this study, we investigated whether amino acid residues highly conserved among RTP-independent ORs improve the functional expression of ORs in heterologous cells. We found that a single amino acid substitution at one of two sites (NBW3.39 and 3.43) in their conserved residues (E and L, respectively) significantly improved the functional expression of ORs in heterologous cells. E3.39 and L3.43 also enhanced the membrane expression of RTP-dependent ORs in the absence of RTP. These changes did not alter the odorant responsiveness of the tested ORs. Our results showed that specific sites within transmembrane domains regulate the membrane expression of some ORs.

HspB1 is a mammalian sHsp that is ubiquitously expressed in almost all tissues and involved in regulating many vital functions. Although the recent crystal structure of human HspB1 showed that 24 monomers form the oligomeric complex of human HspB1 in a spherical configuration, the molecular architecture of HspB1 is still controversial. In this study, we examined the oligomeric structural change of CgHspB1 by sedimentation velocity analytical ultracentrifugation. At the low temperature of 4 °C, CgHspB1 exists as an 18-mer, probably a trimeric complex of hexamers. It is relatively unstable and partially dissociates into small oligomers, hexamers, and dodecamers. At elevated temperatures, the 24-mer was more stable than the 18-mer. The 24-mer is also in dynamic equilibrium with the dissociated oligomers in the hexameric unit. The hexamer further dissociates to dimers. The disulfide bond between conserved cysteine residues seems to be partly responsible for the stabilization of hexamers. The N-terminal domain is involved in the assembly of dimers and the interaction between hexamers. It is plausible that CgHspB1 expresses a chaperone function in the 24-mer structure.

Plasmodium falciparum parasitophorous vacuolar protein 1 (PfPV1), a protein unique to malaria parasites, is localized in the parasitophorous vacuolar (PV) and is essential for parasite growth. Previous studies suggested that PfPV1 cooperates with the Plasmodium translocon of exported proteins (PTEX) complex to export various proteins from the PV. However, the structure and function of PfPV1 have not been determined in detail. In this study, we undertook the expression, purification, and characterization of PfPV1. The tetramer appears to be the structural unit of PfPV1. The activity of PfPV1 appears to be similar to that of molecular chaperones, and it may interact with various proteins. PfPV1 could substitute CtHsp40 in the CtHsp104, CtHsp70, and CtHsp40 protein disaggregation systems. Based on these results, we propose a model in which PfPV1 captures various PV proteins and delivers them to PTEX through a specific interaction with HSP101.

Reductive dehalogenase (RDase) consists of two parts, RdhA and RdhB. RdhA is the catalytic subunit, harboring a cobalamin cofactor and two Fe–S clusters. RdhA is anchored to the cytoplasmic membrane via the membrane anchoring subunit, RdhB. There are many genes encoding RDases in the genome of organohalide-respiring bacteria, including Dehalococcoides spp. However, most genes have not been functionally characterized. Biochemical studies on RDases have been hampered by difficulties encountered in their expression and purification. In this study, we have expressed, purified and characterized RdhA of RDase for tetrachloroethene (PceA) from Geobacter sp. PceA was expressed as a fusion protein with a trigger factor tag in Escherichia coli. PceA was purified and denatured in aerobic condition. Subsequently, this protein was refolded in the presence of FeCl3, Na2S and cobalamin in anaerobic condition. The reconstituted PceA exhibited dechlorination ability for tetrachloroethene. UV-Vis spectroscopy has shown that it contains cobalamin and Fe-S clusters. Since this method requires anaerobic manipulation only in the reconstituting process and has a relatively high yield, it will enable further biochemical studies of RDases.

The title compound, C28H22N2O8, possesses crystallographically imposed twofold symmetry, with the two central carbon atoms of the naphthalene unit lying on the rotation axis. The two benzoyl groups in the molecule are twisted away from the attached naphthalene unit with a C—C—C=O torsion angle of 49.05 (15)° between the naphthalene unit and the carbonyl group. The dihedral angle between the naphthalene ring system and the benzene ring is 77.17 (5)°. In the crystal, pairs of C—H...O=C hydrogen bonds link the molecules into a double-column structure along the c axis. The molecules are further linked by C—H...O=N hydrogen bonds, forming a three-dimensional network. C—H...π interactions between the methylene group and the naphthalene unit and π–π interactions between the naphthalene ring systems [centroid–centroid distances of 3.7858 (7)–3.7860 (7) Å] are also observed.

Prefoldin is a hexameric molecular chaperone found in the cytosol of archaea and eukaryotes. Its hexameric complex is built from two related classes of subunits, and has the appearance of a jellyfish: Its body consists of a double β-barrel assembly with six long tentacle-like coiled coils protruding from it. Using the tentacles, prefoldin captures an unfolded protein substrate and transfers it to a group II chaperonin. Based on structural information from archaeal prefoldins, mechanisms of substrate recognition and prefoldin-chaperonin cooperation have been investigated. In contrast, the structure and mechanisms of eukaryotic prefoldins remain unknown. In this study, we succeeded in obtaining recombinant prefoldin from a thermophilic fungus, Chaetomium thermophilum (CtPFD). The recombinant CtPFD could not protect citrate synthase from thermal aggregation. However, CtPFD formed a complex with actin from chicken muscle and tubulin from porcine brain, suggesting substrate specificity. We succeeded in observing the complex formation of CtPFD and the group II chaperonin of C. thermophilum (CtCCT) by atomic force microscopy and electron microscopy. These interaction kinetics were analyzed by surface plasmon resonance using Biacore. Finally, we have shown the transfer of actin from CtPFD to CtCCT. The study of the folding pathway formed by CtPFD and CtCCT should provide important information on mechanisms of the eukaryotic prefoldin–chaperonin system.

In the crystal structure of the title compound, C5H14NO4P·H2O, the zwitterionic phosphocholine molecules are connected by an O—H...O hydrogen bond between the phosphate groups, forming a zigzag chain along the b-axis direction. The chains are further connected through O—H...O hydrogen bonds involving water molecules, forming a layer parallel to (101). Three and one C—H...O interactions are also observed in the layer and between the layers, respectively. The conformation of the N—C—C—O backbone is gauche with a torsion angle of −75.8 (2)°

Whisker-type poly(3-hexylthiophene-2,5-diyl) (P3HT) nanofibers were aligned by restricting their growth direction using an approximately 100–1000 nm wide narrow groove fabricated by thermal nanoimprinting. In grooves made of an amorphous fluoropolymer (CYTOP™) with widths of less than 1500 nm, the nanofibers oriented uniaxially perpendicular to the groove and their length was limited to the width of the groove. This result indicates that the nucleation of nanofibers tends to be selectively promoted near the interface of CYTOP™ with fluoro-groups, and nanofiber growth perpendicular to the wall is promoted because P3HT molecules are supplied more frequently from the center of the groove. Furthermore, the orientation induced anisotropic conductivity, and the conductivity parallel to the oriented nanofibers was more than an order of magnitude higher than that perpendicular to the oriented nanofibers.

Methylenetetrahydrofolate reductase (MTHFR) is one of the enzymes involved in homocysteine metabolism. Despite considerable genetic and clinical attention, the reaction mechanism and regulation of this enzyme are not fully understood because of difficult production and poor stability. While recombinant enzymes from thermophilic organisms are often stable and easy to prepare, properties of thermostable MTHFRs have not yet been reported.MTHFR from Thermus thermophilus HB8, a homologue of Escherichia coli MetF, has been expressed in E. coli and purified. The purified MTHFR was chiefly obtained as a heterodimer of apo- and holo-subunits, that is, one flavin adenine dinucleotide (FAD) prosthetic group bound per dimer. The crystal structure of the holo-subunit was quite similar to the β(8)α(8) barrel of E. coli MTHFR, while that of the apo-subunit was a previously unobserved closed form. In addition, the intersubunit interface of the dimer in the crystals was different from any of the subunit interfaces of the tetramer of E. coli MTHFR. Free FAD could be incorporated into the apo-subunit of the purified Thermus enzyme after purification, forming a homodimer of holo-subunits. Comparison of the crystal structures of the heterodimer and the homodimer revealed different intersubunit interfaces, indicating a large conformational change upon FAD binding. Most of the biochemical properties of the heterodimer and the homodimer were the same, except that the homodimer showed ≈50% activity per FAD-bound subunit in folate-dependent reactions.The different intersubunit interfaces and rearrangement of subunits of Thermus MTHFR may be related to human enzyme properties, such as the allosteric regulation by S-adenosylmethionine and the enhanced instability of the Ala222Val mutant upon loss of FAD. Whereas E. coli MTHFR was the only structural model for human MTHFR to date, our findings suggest that Thermus MTHFR will be another useful model for this important enzyme.

In the title compound, C25H16Cl2O4·C2H6O, the two 4-chlorobenzoyl groups are in syn orientations with respect to the naphthalene ring system and are approximately parallel to each other: the dihedral angle between the benzene rings is 11.43 (16)°. The conformation around each of the carbonyl C—(C=O)—C groups forms a larger angle to the plane of the naphthalene ring system than that to the benzene ring; the angles of the C=O bond vector with the naphthalene ring system and the benzene ring are 55.4 (3) versus 13.5 (3)° and 52.2 (3) versus 17.9 (3)°. An intramolecular O—H...O=C hydrogen bond generates a six-membered ring. In the crystal structure, intermolecular O—H...O hydrogen bonds including the ethanol solvent molecule are observed. A C—H...O interaction also occurs. The ethyl group of the ethanol molecule is disordered over two positions with site occupancies of 0.63 and 0.37. The crystal studied was an inversion twin.

In the title compound, C18H12BrClO3, the naphthalene ring system and the benzene ring make a dihedral angle of 82.18 (9)°. The conformation around the central C=O group is such that the C=O bond vector forms a larger angle to the plane of the naphthalene ring system than to the plane of the benzene ring, viz. 60.91 (16)° versus 13.94 (16)°. In the crystal structure, two π–π interactions formed between the naphthalene ring systems [centroid–centroid distances of 3.8014 (13) and 3.9823 (13) Å] and intermolecular O—H...O and C—H...O hydrogen bonds are present.

Ipidacrine (2,3,5,6,7,8-hexahydro-1H-cyclopenta[b]quinolin-9-amine) was reacted with 4-methoxyphenyl isocyanate to give the title compound, C28H30N4O4. An intramolecular N—H...O hydrogen bond results in an essentially planar [r.m.s. deviation from the mean plane is 0.126 (1) Å] conformation for the biuret unit. The central ring of the quinoline unit is twisted by 78.2 (1)° with respect to the biuret mean plane, whereas the two 4-methoxybenzene rings are twisted out of this plane by 24.3 (1)° and 48.5 (1)°, resulting in an overall propeller-like structure. An intermolecular N—H...N hydrogen bond between the biuret NH atom and the quinoline ring nitrogen defines the crystal packing.

The title compound, C26H18F2O4, is a naphthalene derivative in which the two aroyl groups at the 1- and 8-positions (peri positions) are anti to each other. There is an appreciable difference in the dihedral angles between the naphthalene ring system and the two benzene rings [66.88 (7)° and 88.09 (6)°]. In the crystal, weak C—H...O interactions involving one of the carbonyl groups and an aromatic C—H group ortho to the F atom seem to stabilize the packing of the molecules.

In the title compound, C14H25NO11·2H2O, the primary hydroxyl group connected to the anomeric C atom of the N-acetyl-β-d-glucopyranose residue exhibits positional disorder, with occupancy factors for the α and β anomers of 0.77 and 0.23, respectively. The two torsion angles (Φ and Ψ) and the bridge angle (τ) that describe conformation of the glycosidic linkage between the galactopyranose and glucopyranose rings are Φ = −81.6 (3)°, Ψ = 118.1 (2)° and τ = 115.2 (2)°. Two water molecules stabilize the molecular packing by forming hydrogen bonds with the saccharide residues.

In the cystal structure of the title compound, (2-hydroxyethyl)trimethylammonium dihydrogen phosphate, C5H14NO+·H2PO4−, two anions create dimeric structures via two O—H...O hydrogen bonds. The hydrogen-bonded dimers are connected by another O—H...O hydrogen bond with the hydroxyl groups of the cations, constructing a columner structure along the a axis. A number of C—H...O interactions are also present.

In the crystal structure of the title compound, C4H12N+·H2PO4−·0.5H2O, the anions form an infinite hydrogen-bonded chain along the [1overline{1}0] direction. The anion chains are connected by water molecules, which lie on crystallographic twofold rotation axes, through O—H...O hydrogen bonds. These hydrogen bonds are almost perpendicular to the other hydrogen bonds which create an assembled structure of anions. In addition, C—H...O hydrogen bonds between anions and cations are observed.

The title compound, C18H13ClO3, has an intramolecular O—H...O=C hydrogen bond between the carbonyl group and the hydroxy substituent on the naphthalene ring system. The angle between the C=O bond plane and the naphthalene ring system is relatively small [20.96 (8)°]. The angle between the benzene ring and the carbonyl group is rather large [35.65 (9)°] compared to that in an analogous compound [3.43 (11)°] having a methoxy group instead of a hydroxy substituent.

The molecule of the title compound, C14H14O2, lies on a crystallographic twofold axis perpendicular to the central C—C bond; there is one half-molecule in the asymmetric unit. The angle between the least-squares planes of the two aromatic rings is 66.94 (7)°. The methoxy group, with a twist angle of 10.69 (8)°, is slightly out of the plane of the benzene ring. In the crystal structure, C—H...π interactions are observed between adjacent molecules along the c-axis direction.

In the title compound, C19H15ClO3, the dihedral angle between the naphthalene ring system and the benzene ring is 72.06 (7)°. The 4-chlorophenyl group and the carbonyl group are almost coplanar. An intermolecular C—H...O hydrogen bond is formed between an H atom of the 4-chlorophenyl group and the O atom of one methoxy group, forming a zigzag chain along the a axis.

The molecule of the title compound, C26H20O4, is located on a twofold rotation axis. The two benzoyl groups are situated in an anti orientation. The dihedral angle between the mean planes of the phenyl ring and the naphthalene ring system is 80.25 (6)°. The phenyl and carbonyl groups in each benzoyl group are almost coplanar. The molecular packing is stabilized by weak C—H...O hydrogen bonds and a π–π stacking interaction between the phenyl rings [centroid–centroid and interplanar distances of 3.6383 (10) and 3.294 Å, respectively].

The title compound, C26H20O4, has an asymmetrical conformation at 193 K. The 4-acetylphenyl groups are twisted away from the the naphthalene ring system, with one benzene ring turned towards the 1-position of the naphthalene ring and the other benzene ring turned towards the 6-position. The interplanar angles between the mean planes of the benzene rings and the naphthalene ring system are 68.71 (6) and 74.01 (6)°. The structure displays C—H...O hydrogen bonding and π–π stacking interactions [centroid–centroid and interplanar distances are 3.5938 (9) and 3.517 Å, respectively].

In the title compound, C19H15ClO3, the interplanar angle between the naphthalene and benzene ring systems is 62.67 (6)°. The carbonyl group is twisted from both ring planes, with torsion angles of −44.9 (2)° with respect to the naphthalene ring and −26.7 (2)° with respect to the phenylene ring. There is an intermolecular hydrogen bond between an H atom of one methoxy group and the O atom of the second methoxy group, forming chains along the ac diagonal.