Adjacent Benzene Research Articles

Regional Functionalization Molecular Design Strategy: A Key to Enhancing the Efficiency of Multi-Resonance OLEDs.

Herein, we propose a regional functionalization molecular design strategy that enables independent control of distinct pivotal parameters through different molecule segments. Three novel multiple resonances thermally activated delayed fluorescence (MR-TADF) emitters A-BN, DA-BN, and A-DBN, have been successfully synthesized by integrating highly rigid and three-dimensional adamantane-containing spirofluorene units into the MR framework. These molecules form two distinctive functional parts: part 1 comprises a boron-nitrogen (BN)-MR framework with adjacent benzene and fluorene units forming a central luminescent core characterized by an exceptionally rigid planar geometry, allowing for narrow FWHM values; part 2 includes peripheral mesitylene, benzene, and adamantyl groups, creating a unique three-dimensional "umbrella-like" conformation to mitigate intermolecular interactions and suppress exciton annihilation. The resulting A-BN, DA-BN, and A-DBN exhibit remarkably narrow FWHM values ranging from 18 to 14 nm and near-unity photoluminescence quantum yields. Particularly, OLEDs based on DA-BN and A-DBN demonstrate outstanding efficiencies of 35.0 % and 34.3 %, with FWHM values as low as 22 nm and 25 nm, respectively, effectively accomplishing the integration of high color purity and high device performance.

Regional Functionalization Molecular Design Strategy: A Key to Enhancing the Efficiency of Multi‐Resonance OLEDs

AbstractHerein, we propose a regional functionalization molecular design strategy that enables independent control of distinct pivotal parameters through different molecule segments. Three novel multiple resonances thermally activated delayed fluorescence (MR‐TADF) emitters A‐BN, DA‐BN, and A‐DBN, have been successfully synthesized by integrating highly rigid and three‐dimensional adamantane‐containing spirofluorene units into the MR framework. These molecules form two distinctive functional parts: part 1 comprises a boron‐nitrogen (BN)‐MR framework with adjacent benzene and fluorene units forming a central luminescent core characterized by an exceptionally rigid planar geometry, allowing for narrow FWHM values; part 2 includes peripheral mesitylene, benzene, and adamantyl groups, creating a unique three‐dimensional “umbrella‐like” conformation to mitigate intermolecular interactions and suppress exciton annihilation. The resulting A‐BN, DA‐BN, and A‐DBN exhibit remarkably narrow FWHM values ranging from 18 to 14 nm and near‐unity photoluminescence quantum yields. Particularly, OLEDs based on DA‐BN and A‐DBN demonstrate outstanding efficiencies of 35.0 % and 34.3 %, with FWHM values as low as 22 nm and 25 nm, respectively, effectively accomplishing the integration of high color purity and high device performance.

Antioxidant Activity in Vitro and Immunocompetence in Vivo of Compound Angelica sinensis Tea

To explore the antioxidant in vitro and immunological activities of compound Angelica sinensis tea (CAT), the different concentrations of CAT were prepared, the total antioxidant activity, DPPH radical, superoxide anion radical determination, hydroxyl radical scavenging ability of CAT were measured respectively by molybdenum blue colorimetric method, DPPH analysis method, adjacent benzene three phenol autoxidation and salicylic acid method. The immunological activities of CAT were measured by peritoneal macrophages based on the red blood cells of chicken in mice, serum hemolysin level, and activity of NK cells and mice reticuloendothelial system. The results showed that CAT had certain antioxidant activity in vitro, with the increase of sample concentration, total antioxidant activity increased gradually, CAT was able to scavenge DPPH free radical and·OH free radical obviously, IC50 were 3.2226, 20.8848 mg/mL, but weakly on scavenging O2-·free radicals, peritoneal macrophage phagocytic percentage and phagocytic index were significantly higher in high and middle dose group (p<0.05), serum hemolysin antibody levels were significantly increased in CAT high dose group (p<0.01), NK cell activity in mice were significantly higher in high or middle dose group (p<0.05), spleen index were significantly higher in high dose group (p<0.05), K and α values were significantly increased in high and middle dose group (p<0.01, p<0.05). Comprehensive analysis found that CAT had certain antioxidant activity and non-specific immune enhancement effect.

Direct Synthesis of Crystalline Graphtetrayne—A New Graphyne Allotrope

We report a bottom-up synthesis of a new graphyne allotrope-graphtetrayne (GTTY), which features four acetylene linkages between the adjacent benzene on the surface of copper under low temperature....

Facile Synthesis of Aromatic Porous Organic Polymer for Highly Selective Capture of CO2 via Enhanced Local Dipole-π and Dipole-Quadrupol Interactions by Adjacent Benzene

A new aromatic porous organic polymeric material named as N-PKIN has been successfully constructed. The electron-rich benzene in its microstructure can donate the electron density to the neighboring indole and carbonyl groups to further enhance the local dipole-π and dipole-quadrupole binding abilities to the CO2 molecules for effectively facilitating the adsorbent to attract CO2 selectively. As a result, this porous organic polymer showed outstanding CO2 absorption capacity and high CO2/N2, CO2/CH4 selectivity. In addition, upon exposure to humid condition, the porous organic polymer still kept high CO2 capture capacity and selectivity. Moreover, we have demonstrated that the CO2 absorption process is fully reversible.

(4-Aminosulfonylphenyl)[(2-oxidonaphthalen-1-yl)imino]azanium

The crystal structure of the title compound, C16H13N3O3S, shows that the two independent zwitterions in the asymmetric unit are approximately planar. Intramolecular N—H...O hydrogen bonds occur and the aromatic rings have atransconfiguration with respect to the azo double bond. In the crystal, the molecules are linkedviaN—H...O hydrogen bonds and π–π stacking, forming a three-dimensional supramolecular network, the π–π stacking interactions between adjacent benzene and naphthalene rings having centroid-to-centroid distances of 3.764 (3) and 3.775 (3) Å.

Noncatalytic bromination of benzene: A combined computational and experimental study.

The noncatalytic bromination of benzene is shown experimentally to require high 5-14 M concentrations of bromine to proceed at ambient temperatures to form predominantly bromobenzene, along with detectable (<2%) amounts of addition products such as tetra and hexabromocyclohexanes. The kinetic order in bromine at these high concentrations is 4.8 ± 0.06 at 298 K and 5.6 ± 0.11 at 273 K with a small measured inverse deuterium isotope effect using D6 -benzene of 0.97 ± 0.03 at 298 K. These results are rationalized using computed transition states models at the B3LYP+D3/6-311++G(2d,2p) level with an essential continuum solvent field for benzene applied. The model with the lowest predicted activation free energies agrees with the high experimental kinetic order in bromine and involves formation of an ionic, concerted, and asynchronous transition state with a Br8 cluster resembling the structure of the known Br9 (-). This cluster plays three roles; as a Br(+) donor, as a proton base, and as a stabilizing arm forming weak interactions with two adjacent benzene CH hydrogens, these aspects together combining to overcome the lack of reactivity of benzene induced by its aromaticity. The computed inverse kinetic isotope effect of 0.95 agrees with experiment, and arises because C-Br bond formation is essentially complete, whereas C-H cleavage has not yet commenced. The computed free energy barriers for the reaction with 4Br2 and 5Br2 for a standard state of 14.3 M in bromine are reasonable for an ambient temperature reaction, unlike previously reported theoretical models involving only one or two bromines.

(E)-2-{[1-(3,11-Dimethyl-4-methylene-10-oxo-1-phenyl-4,5,10,11-tetrahydro-1H-benzo[b]pyrazolo[3,4-f][1,5]diazocin-5-yl)ethylidene]amino}-N-methyl-N-(3-methyl-1-phenyl-1H-pyrazol-5-yl)benzamide

The central eight-membered ring of the title compound, C40H36N8O2, deviates from the ideal boat conformation because the bond between the exo-ethyl­ene group and the adjacent N atom is twisted by 60.0 (4)° due to steric hindrance. Its adjacent benzene and pyrazole rings are oriented almost perpendicular to each other, making a dihedral angle of 85.8 (3)°. In the crystal, the mol­ecules are linked by C(ar)—H⋯O hydrogen bonds, generating a three-dimensional network.

2-Anilino-4-(1,3-benzothiazol-2-yl)-5-(4-chlorobenzoyl)thiophene-3-carbonitrile

In the title compound, C25H14ClN3OS2, the central thio­phene ring [maximum deviation = 0.011 (1) Å] makes dihedral angles of 55.72 (5), 13.36 (5) and 46.77 (4)° with the adjacent chloro-substituted benzene ring, the benzene ring and the 1,3-benzothia­zole ring system [maximum deviation = 0.012 (1) Å], respectively. An intra­molecular C—H⋯S(thienyl) hydrogen bond generates an S(6) ring motif in the mol­ecule. In the crystal, mol­ecules are linked by pairs of N—H⋯N hydrogen bonds into inversion dimers and the dimers are further connected by C—H⋯O hydrogen bonds into tapes running along [100]. Aromatic π–π stacking inter­actions are also observed [centroid-to-centroid distances = 3.6116 (6) and 3.7081 (6) Å].

N-[4-(4-Bromophenyl)thiazol-2-yl]-4-(piperidin-1-yl)butanamide

In the title compound, C18H22BrN3OS, the piperidine ring adopts a chair conformation. The mean plane of the thia­zole ring forms dihedral angles of 23.97 (10) and 75.82 (10)° with the mean planes of its adjacent benzene and piperidine rings, respectively. An intra­molecular N—H⋯N hydrogen bond generates an S(7) ring motif in the mol­ecule. In the crystal, no significant inter­moelcular hydrogen bonds are observed, but a weak π–π inter­action with a centroid–centroid distance of 3.8855 (13) Å occurs.

2-[N-(4-{4-[(2-Hydroxy-5-methoxybenzylidene)amino]benzyl}phenyl)carboximidoyl]-4-methoxyphenol

In the title Schiff base, C29H26N2O4, the complete molecule is generated by a crystallographic twofold axis and is V-shaped. The planes of the benzene rings of the central diphenyl­methane unit make a dihedral angle of 78.11 (4)° while adjacent benzene and 5-meth­oxy­salicyl­idene rings are twisted with respect to each other by a dihedral angle of 11.84 (8)°. The Schiff base is in the enol–imino form and an intra­molecular O—H⋯N hydrogen bond is observed.

Catena-Poly[[dinitratocopper(II)]-μ-4,4′′-bis(1H-benzimidazol-1-yl)-1,1′:4′,1′′-terphenyl

In the title one-dimensional coordination polymer, [Cu(NO3)2(C32H22N4)]n, the Cu2+ ion (site symmetry 2) is coordinated by two nitrate O atoms and two N atoms from two 4,4′-bis­(benzoimidazol-1-yl)terphenyl (L) ligands in a distorted cis-CuN2O2 square-planar coordination geometry. An alternative description of the metal coordination geometry, if long Cu—O contacts to the bonded nitrate anions are considered, is an extremely distorted cis-CuN2O4 octa­hedron. The complete L ligand is generated by crystallographic twofold symmetry and connects the metal ions into infinite chains propagating in [10]. The dihedral angle between the benzimidazole ring system and the adjacent benzene (B) ring is 51.12 (11)° and the dihedral angle between the B ring and the central ring is 19.45 (13)°.

N2,N2,N4,N4-Tetraethyl-6-{2-[(E)-1-(4-nitrophenyl)ethylidene]hydrazino}-1,3,5-triazine-2,4-diamine

The title compound, C19H28N8O2, was prepared by the reaction of N 2,N 2,N 4,N 4-tetra­ethyl-6-hydrazino-1,3,5-triazine-2,4-diamine and 1-(4-nitro­phen­yl)ethanone in ethanol at room temperature. The mol­ecular conformation is stabilized by intra­molecular C—H⋯N hydrogen-bonding inter­actions. There are also inter­molecular N—H⋯O hydrogen bonds, and C—H⋯π and π–π inter­actions, which help to stabilize the crystal structure. The centroid–centroid distance is 3.6172 (10) Å between adjacent benzene and 1,3,5-triazine rings.

Quinazoline-2,4(1H,3H)-dione

In the title compound, C8H6N2O2, inter­molecular N—H⋯O hydrogen bonds involving the amine and carbonyl groups create centrosymmetric dimers between adjacent nearly coplanar mol­ecules. These dimers are further connected by weak N—H⋯O hydrogen bonds, forming a two-dimensional network. Mol­ecules are packed in the crystal structure with adjacent benzene and pyrimidine rings approximately coplanar; the centroid–centroid separation is 3.863 Å and the dihedral angle between the mean planes is 0.64°, indicating the presence of weak inter­molecular face-to-face π–π stacking inter­actions.

Intramolecular and Intermolecular Rearrangements in Nanoconfined Polystyrene

Vacuum ultraviolet spectroscopy reveals an intramolecular rearrangement involving a change in “physical dimers” of adjacent pendant benzene rings of atactic polystyrene (aPS) from “oblique” to “head-to-tail” (ht) configuration in aPS films spin coated on fused quartz, as film thickness R goes below 4Rg (Rg = unperturbed polystyrene gyration radius ≈ 20.4 nm). Simultaneously, transverse layering of molecular “gyration spheres”, for film thickness R ≤ 4Rg, causes an increase in free energy (reduction in cohesion) that follows a (Rg/R)b dependence with b ≈ 3, a clear deviation from planar confinement. The variation of in-plane and out-of-plane cohesive energy over a film of a given thickness is explained by invoking a fixed-range, repulsive, modified Poschl-Teller intermolecular potential, with the strength of this potential decreasing with increase in R. Possible reduction of “dimer” dipole moment due to ht configuration is consistent with reduction of cohesion between aPS molecular gyration spheres.

Crystal structure of the supramolecular system of indole-2,3-dione 1-(2-oxopropyl)-3-ethylene ketal and its thiosemicarbazone

The crystal structure of a supramolecular system consisting of indole-2,3-dione 1-(2-oxopropyl)-3-ethylene ketal (I) and indole-2,3-dione 1-(2-oxopropyl)-3-ethylene ketal thiosemicarbazone (II) molecules that are linked together by hydrogen bonds is determined using X-ray diffraction. The crystal is monoclinic, and the unit cell parameters are as follows: a = 12.8360(3) A, b = 10.7330(3) A, c = 19.4610(3) A, β = 99.566(1)°, space group P21/c, and Z = 4 (C27H29N5O7S). In molecules I and II, the indole-2,3-dione 3-ethylene ketal fragments have a virtually identical structure. The pyrrole and dioxolane fragments are spiro-linked through the carbon atom with a dihedral angle close to 90°. The adjacent pyrrole and benzene rings are coplanar to within 4.4°. In molecule II, the oxygen atom of the dioxolane fragment and the terminal nitrogen atom of the thiosemicarbazide fragment are involved in the N-HiO intramolecular hydrogen bond [3.294(2) A]. The key role in the formation of the crystal structure is played by intermolecular hydrogen bonds of the N-H⋯dO, C-H⋯O, C-H⋯N, and N-H⋯S types.

Excimer Formation in Oligo[2,5-bis(hexadecyloxy)-1,4-phenylene]s Followed by Fluorescence Spectroscopy

Using the steady-state and time-resolved fluorescence spectroscopy, the behavior of "hairy-rod" oligo- and poly[2,5-bis(hexadecyloxy)-1,4-phenylene]s in tetrahydrofuran solutions was investigated. The materials were prepared by the Yamamoto coupling reaction using zinc as a reducing metal, the nickel(II)/triphenylphosphine complex as a catalyst, and 2,2'-bipyridine as a coligand. The appropriate oligomer fractions were separated by fractional precipitation and characterized by GPC and end group analysis. The fluorescence quantum yield of oligomers and polymers increased with their increasing conjugation length. The fluorescence emission spectra of polymers and longer oligomers exhibited one emission maximum at 390 nm with a single-exponential decay and fluorescence lifetimes (τ) around 1 ns. The substitution in positions 2 and 5 forces the adjacent backbone benzene units out of the plane, which results in twist angles 60-80°, and the bulky substituents exclude the cofacial sandwich-type configuration necessary for excimer formation. However, with shorter oligomers, another emission band at 460 nm appeared. Fluorescence decays at 460 nm were found to be double-exponential with longer excited-state lifetimes [e.g. τ1 = 6.9 ns (76%), τ2 = 2.4 ns (24%)]. With shorter oligomers (dimer, trimer), we assume a sandwich-type configuration with sufficiently close interchain distance and hence the excimer can form. Hydrophobic interactions of long aliphatic side chains in a polar medium play an important role in the excimer formation.

Localization of benzene in sodium-Y-zeolite by powder neutron diffraction

The structure of sodium-Y zeolite, Na/sub 56/Si/sub 136/O/sub 384/Al/sub 56/, containing chemisorbed deuterated benzene has been studied for two different benzene coverages at 4 K and room temperature by powder neutron diffraction. The space group is Fd3m. The sodium ions are distributed over three sites. At 4 K, the benzene molecules are localized on two distinct sites within the cavities of the zeolite. Benzene(1) is in the supercage with the center of the molecule on the cube diagonal at 32e (x,x,x). Benzene(2) is centered at 16d (1/2, 1/2, 1/2) in the window between adjacent supercages. At 4 K the average separation between adjacent benzene(1) sites decreases on increasing the benzene coverage, and Na(1) appears to migrate toward the center of the supercage. At room temperature, the benzene molecules are largely delocalized but are still confined to the supercages in the region of their positions at 4 K. 30 references, 7 figures, 5 tables.