Terminal Phenyl Ring Research Articles

A new polymorph of N-(2-{N'-[(1E)-2-hy-droxy-benzyl-idene]hydrazinecarbon-yl}phen-yl)benzamide.

The title compound, C21H17N3O3, is a new polymorph of an already published structure [Shashidhar et al. (2006 ▶). Acta Cryst. E62, o4473–o4475]. The previously reported structure crystallizes in the monoclinic space group C2/c, whereas the structure reported here is in the tetra­gonal space group I41/a. The bond lengths and angles are similar in both structures. The mol­ecule adopts an extended conformation via intra­molecular N—H⋯O and O—H⋯N hydrogen bonds; the terminal phenyl ring and the hy­droxy­lphenyl ring are twisted with respect to the central benzene ring by 44.43 (7) and 21.99 (8)°, respectively. In the crystal, mol­ecules are linked by N—H⋯O hydrogen bonds, weak C—H⋯O hydrogen bonds and weak C—H⋯π inter­actions into a three-dimensional supra­molecular network.

Synthesis, and Properties of 1-[2-methyl-5-(1,3-difluorophenyl)-3-thienyl]-2-[2-methyl-5-(4-methoxylphenyl)-3-thienyl]perfluorocyclopentene

A new unsymmetrical photochromic diarylethene 1-[2-methyl-5-(1,3-difluorophenyl)-3-thienyl]-2-[2-methyl-5-(4-methoxylphenyl)-3-thienyl] perfluorocyclopentene has been synthesized,which a methoxyl group was substituted at the para-positions of the terminal phenyl ring. The photochromism of this compound was investigated, the results showed that this compound exhibited reversible photochromism, inducing cyclization and cycloreversion reactions upon alternating irradiation with UV and visible light both in solution and in a PMMA film. When irradiated 297 nm UV light, in hexane solution the maximum absorption was observed at 289 nm and 588 nm in opening-ring form and in close-ring form, respectively.

N-(6-Chloro-1-methyl-1H-imidazo[4,5-c]pyridin-4-yl)benzene-sulfonamide.

The asymmetric unit of the title compound, C13H11ClN4O2S, contains two mol­ecules (A and B), in which the dihedral angles between the 1H-imidazo[4,5-c]pyridine system and terminal phenyl ring are 80.83 (10) and 62.34 (1)°. In the crystal, A–B dimers are linked by pairs of N—H⋯N hydrogen bonds, which generate R 2 2(10) loops. The dimers are linked by C—H⋯O and C—H⋯Cl inter­actions, generating a three-dimensional network. Aromatic π–π stacking inter­actions [shortest centroid–centroid distance = 3.5211 (12) Å] are also observed.

N (1),N (4)-Diphenyl-3,6-bis-(phenyl-imino)-cyclo-hexa-1,4-diene-1,4-di-amine.

In the title compound, C30H24N4, the central benzo­quinonedi­imine moiety is approximately planar, with a maximum deviation of 0.044 (14) Å. The four terminal phenyl rings are twisted by 44.95 (11), 54.90 (10), 44.98 (10) and 50.68 (11)° with respect to the mean plane the benzo­quinonedi­imine unit. In the crystal, mol­ecules are linked by weak C—H⋯π inter­actions into supra­molecular chains running along the b-axis direction.

(E)-Benz-yl(4-{[1-(prop-2-en-1-yl)-1H-1,2,3-triazol-4-yl]meth-oxy}benzyl-idene)amine.

The triazole ring of the title compound, C20H20N4O, is normal to the central benzene ring, making a dihedral angle of 90.0 (3)°, and forms a dihedral angle of 69.2 (3)° with the terminal phenyl ring. The dihedral angle between the phenyl and benzene rings is 88.2 (3)°. The atoms of the terminal propenyl group are disordered over two sets of sites, with a site-occupancy ratio of 0.663 (13):0.337 (13). In the crystal, C—H⋯N contacts lead to the formation of a layer structure extending parallel to (011). Two weak C—H⋯π inter­actions are also observed.

1-(6-Chloro-1-methyl-1H-imidazo[4,5-c]pyridin-4-yl)-3-(2-chloro-phen-yl)urea.

In the title compound, C14H11Cl2N5O, the plane of the 1H-imidazo[4,5-c]pyridine ring system [r.m.s. deviation = 0.087 (19) Å] makes a dihedral angle of 4.87 (10)° with the terminal phenyl ring. An intra­molecular N—H⋯N hydrogen bond stabilizes the mol­ecular conformation. In the crystal, N—H⋯O hydrogen bonds link the mol­ecules into inversion dimers. These dimers are connected by π–π inter­actions between imidazole rings [shortest centroid–centroid distance = 3.4443 (14) Å].

7-Nitro-2-phenyl-imidazo[2,1-b][1,3]benzo-thia-zole.

In the title mol­ecule, C15H9N3O2S, the central imidazo[2,1-b][1,3]benzo­thia­zole heterotricyclic unit is essentially planar (r.m.s. deviation = 0.021 Å). The terminal phenyl ring and nitro group are twisted by 9.06 (1) and 11.02 (4)°, respectively, from the mean plane of the heterotricycle. In the crystal, mol­ecules are linked by π–π stacking inter­actions into columns along [100]; the inter­planar distance between neighboring imidazo[2,1-b][1,3]benzo­thia­zole planes within the columns is 3.370 (2) Å. Furthermore, the columns interact with each other by secondary S⋯O [2.9922 (10) and 3.1988 (11) Å] inter­actions, forming a three-dimensional framework.

5-[(1-Benzyl-1H-1,2,3-triazol-4-yl)methyl]-5H-dibenzo[b,f]azepine

In the title compound, C24H20N4, the azepine ring adopts a boat conformation. The dihedral angle between the benzene rings fused to the azepine ring is 49.40 (9)°. The triazole ring makes a dihedral angle of 77.88 (9)° with the terminal phenyl ring. In the crystal, mol­ecules are linked via C—H⋯π inter­actions and a parallel slipped π–π inter­action [centroid–centroid distance = 3.7324 (9), normal distance = 3.4060 (6) and slippage = 1.526 Å], forming a three-dimensional network.

Synthesis and Application of Photochromic Materials in Holographic Recording of a Asymmetrical Diarylethene

A novel unsymmetrical diarylethene derivative containing thiophene moieties, in which a methoxy group was substituted at the para-positions of the terminal phenyl ring, was synthesized. Its photochromic properties were investigated in detail, the results indicated that the diarylethene 1o changed the color from colorless to blue, which the absorption maxima were observed at 611 and 627 nm in hexane and PMMA film when irradiation with 297 nm UV light. Additionally, the open-ring isomer of the diarylethene 1o exhibited relatively strong fluorescence at 305 nm in hexane when excited at 322 nm and the fluorescence intensity progressively decreased accompany with the photocyclization occurs. Finally, using this diarylethene as recording medium, polarization optical recording was carried out successfully.

N′-(3-Sulfanylidene-3,4-dihydroquinoxalin-2-yl)benzohydrazide dimethylformamide monosolvate

The 2-sulfanyl­idene-3,4-di­hydro­quinoxalin-2-yl ring system of the title solvate, C15H12N4OS·C3H7NO, is essentially planar, the maximum deviation from the mean plane being 0.024 (2) Å for the thione C atom. The mean plane through the fused-ring system is almost perpendicular to the terminal phenyl ring, as indicated by the dihedral angle of 70.05 (8)°. In the crystal, the main and solvent mol­ecules are linked by N—H⋯O hydrogen bonds, forming a layer parallel to (010).

2,2-Diphenyl-N-{[2-(trifluoromethyl)phenyl]carbamothioyl}acetamide

The title mol­ecule, C22H17F3N2OS, adopts a trans–cis conformation with respect to the positions of the carbonyl and tri­fluoro­methyl­benzene groups against the thio­carbonyl group across the C—N bonds. The mol­ecular structure is stabilized by an intra­molecular N—H⋯O hydrogen bond with an S(6) ring motif. The tri­fluoro­methyl-substituted benzene ring forms dihedral angles of 66.05 (9) and 47.19 (9)° with the terminal phenyl rings and is twisted from the O=C—N—(C=S)—N carbonyl­thio­urea plane [maximum deviation = 0.0535 (12) Å], making a dihedral angle of 63.59 (8)°. In the crystal, N—H⋯O and C—H⋯F hydrogen bonds link the mol­ecules into a layer parallel to the bc plane. A C—H⋯π inter­action is also observed.

Theoretical study on electronic structures and optical properties of blue phosphorescent Iridium(III) complexes with C∧N and N∧N ligands

We report a quantum-chemical study on the electronic structures and optical properties of two series of heteroleptic iridium(III) complexes [(dfb-pz)2Ir(N∧N+sub)], [dfb-pz=2,4-difluorobenzyl-N-pyrazole, sub indicates substituent group, N∧N+sub=tphppz=4-tert-butyl-2-(5-phenyl-[1,2,4]triazol-3-yl)-pyridine (1a), tmppz=4-tert-butyl-2-(5-methyl-[1,2,4]triazol-3-yl)-pyridine (1b), fphppz=4-fluoro-phenyl-5-(2-pyridyl)pyrazole (1c), and fmphppz=4-trifluoromehtyl-phenyl-5-(2-pyridyl)pyrazole (1d)]; with [(C∧N+sub)2Ir(fppz)], [C∧N=b-pz=benzyl-N-pyrazole, fppz=3-trifluoromethyl-5-(2-pyridyl)pyrazole, C∧N+sub=dfb-pz=2,4-difluorobenzyl-N-pyrazole (2a), tfmfb-pz=2-trifluoromethyl-5-fluorobenzyl-N-pyrazole (2b), phb-pz=3-phenyl-benzyl-N-pyrazole (2c), and dfphb-pz=3-phenyl-2,4-difluorobenzyl-N-pyrazole (2d)]. The calculated results shed light on the reasons of the remarkably manipulated excited-state and electroluminescent properties through substitution effect. The phenyl ring on main ligands can enhance the π-conjugation of the main ligands moiety and increase the metal-ligand bond strength for 2c and 2d, then enhancing the transition strength. From 1c, 1d, 2c, and 2d, it can also be seen that substituents on the terminal phenyl ring have a slight effect on the excited energy because the distance between the substituents and the ancillary (or main) ligand is interrupted by the phenyl moiety. The calculated absorption and luminescence properties of the four complexes 1a, 1b, 2a, and 2b are compared with the available experimental data and a good agreement is obtained. Furthermore, the assumed complex 1c, 2c, and 2d possess better charge transfer abilities and more balanced charge transfer rates. The designed complexes 2c and 2d are potential candidates for blue phosphorescent materials.

4,7-Diphenyl-1,10-phenanthroline methanol hemisolvate

The asymmetric unit of the title compound, C24H16N2·0.5CH3OH, is comprised of two independent bathophenanthroline mol­ecules (systematic name: 4,7-diphenyl-1,10-phenanthroline) and one methanol mol­ecule. The bathophenanthroline mol­ecules are not planar as there is a considerable rotation of all terminal phenyl rings with respect to the central phenanthroline units [dihedral angles in the range 52.21 (12)–62.14 (10)°]. In addition, a non-negligible torsion is apparent in one of the phenanthroline units: the angle between the mean planes of the two pyridine rings is 14.84 (13)°. The methanol solvent mol­ecule is linked to both N atoms of a bathophenanthroline mol­ecule through a bifurcated O—H⋯(N,N) hydrogen bond.

Material Properties with Syntheses and Properties of a Novel Unsymmetrical Photochromic Diarylethene

A novel unsymmetrical diarylethene derivative bearing thiophene moieties, in which a methyl group was substituted at the ortho-positions of the terminal phenyl ring, was synthesized. At the same time, its photochromic properties and fluorescence switch were investigated in detail. The results showed that this compound exhibited reversible photochromism, undergoing reversible cyclization and cycloreversion reactions upon alternating irradiation with UV and visible light both in solution and in PMMA film,and its absorption maxima were observed at 556 nm in hexane and at 560 nm in PMMA amorphous film, respectively, upon irradiation with 297 nm UV light. The fluorescence intensity of diarylethene decreased dramatically along with the photochromism from open-ring isomer to closed-ring isomer upon irradiation with 297 nm UV light in PMMA.

Influence of an Atom in EGaIn/Ga2O3 Tunneling Junctions Comprising Self-Assembled Monolayers

We compared the electrical properties of self-assembled monolayers (SAMs) formed on template-stripped Au from two homologous series of five different oligo(phenylene)s bearing alkane thiol tails. The terminal phenyl ring is substituted by a 4-pyridyl ring in one series, thus the two differ only by the substitution of C–H for N. We formed tunneling junctions using the liquid metal eutectic Ga–In (EGaIn) as a nondamaging, conformal top contact that is insensitive to functional groups and measured the current-density, J, tunneling decay constants, β, and transition voltages, Vtrans. Conductance measurements alone did not sufficiently differentiate the two series of molecules. The length dependences of the two series of SAMs produced values of β of 0.44 and 0.42 Å–1 for pyridyl- and phenyl-terminated SAMs, respectively, which lie between the expected values for alkanethiolates and oligo(phenylene)s. The values of Vtrans were ∼0.3 V larger for the phenyl-terminated SAMs than for the pyridyl-terminated SAMs. A comparison of the values of J to highest occupied molecular orbital (HOMO) levels determined by density functional theory (DFT) calculations revealed an odd–even effect for the phenyl-terminated SAMs but not the pyridyl-terminated SAMs. Plots of Vtrans versus the measured shift in work function, measured with a Kelvin probe, reveal a roughly linear trend. Plots of the difference between HOMO and Fermi energies reveal a strong linear trend with two distinct series that clearly differentiate the two series of SAMs, even between SAMs with nearly identical HOMO levels, but only when the dipole-induced shift in vacuum level is considered. The influence of the electronic properties of the SAMs is clearly evident in the conductance data and highlights the importance of molecular dipoles in tunneling junctions comprising SAMs. Taken together, the data show that tunneling junctions incorporating EGaIn as a top contact are sensitive enough to differentiate SAMs that differ by the substitution of a single atom.

5-{4′-[(5-Benzyl-2H-tetrazol-2-yl)methyl]biphenyl-2-yl}-1H-tetrazole monohydrate

In the title compound, C22H18N8·H2O, the dihedral angle between the tetra­zole rings is 69.58 (1)° while the terminal phenyl ring makes dihedral angles of 26.98 (8) and 39.75 (8)° with the other benzene rings. The rings of the biphenyl unit subtend a dihedral angle of 55.23 (8)°. In the crystal, the solvent water mol­ecule is linked to the main mol­ecule via an N—H⋯O hydrogen bond. In addition, C—H⋯N and O—H⋯N hydrogen bonds link the components into chains along [010]. The crystal structure also features C—H⋯π and π–π inter­actions, with centroid–centroid distances of 3.6556 (9) and 3.826 (1) Å.

2-[(5'-Chloro-1,1':3',1''-terphenyl-4'-yl)imino]-acenaphthylen-1(2H)-one.

The title compound, C30H18ClNO, is a product of the condensation reaction of acenaphthyl­ene-1,2-dione and 5′-chloro-1,1′:3′,1′′-terphenyl-4′-amine. The acenaphthyl­ene fragment and two terminal phenyl rings are rotated relative to the central benzene ring by 72.2 (3), 43.2 (3) and 41.2 (3)°, respectively. This mol­ecular conformation is supported by weak C—H⋯π inter­actions. In the crystal, mol­ecules form centrosymmetric dimers by the stacking inter­actions between two neighboring acenaphthyl­ene fragments, with an inter­planar distance of 3.365 (3) Å. The dimers are bound to each other by weak C—H⋯N and C—H⋯π inter­actions, forming a three-dimensional framework.

Design and synthesis of l- and d-phenylalanine derived rhodanines with novel C5-arylidenes as inhibitors of HCV NS5B polymerase

Hepatitis C virus (HCV) NS5B polymerase is a key target for anti-HCV therapeutics development. Herein, we report the synthesis and in vitro evaluation of anti-NS5B polymerase activity of a molecular hybrid of our previously reported lead compounds 1 (IC50=7.7μM) and 2 (IC50=10.6μM) as represented by hybrid compound 27 (IC50=6.7μM). We have explored the optimal substituents on the terminal phenyl ring of the 3-phenoxybenzylidene moiety in 27, by generating a set of six analogs. This resulted in the identification of compound 34 with an IC50 of 2.6μM. To probe the role of stereochemistry towards the observed biological activity, we synthesized and evaluated the d-isomers 41 (IC50=19.3μM) and 45 (IC50=5.4μM) as enantiomers of the l-isomers 27 and 34, respectively. The binding site of compounds 32 and 34 was mapped to palm pocket-I (PP-I) of NS5B. The docking models of 34 and 45 within the PP-I of NS5B were investigated to envisage the molecular mechanism of inhibition.

3-Bromo-7-meth-oxy-2-phenyl-imidazo[2,1-b][1,3]benzothia-zole.

In the title mol­ecule, C16H11BrN2OS, the central imidazo[2,1-b][1,3]benzothia­zole tricycle is essentially planar (r.m.s. deviation = 0.021 Å). The terminal phenyl ring is twisted at 36.18 (5)° from the mean plane of the tricycle. In the crystal, pairs of eak C—H⋯O hydrogen bonds link mol­ecules into centrosymmetric dimers, which are further packed into stacks along the a axis.

(2E)-1-(2,4-Dimethylquinolin-3-yl)-3-phenylprop-2-en-1-one

Two independent mol­ecules comprise the asymmetric unit of the title compound, C20H17NO, which differ in the orientation of the terminal phenyl ring with respect to the quinoline ring [the dihedral angles are 75.72 (11) and 84.53 (12)° for the two mol­ecules]. The conformation about each of the ethyl­ene bonds [1.329 (3) and 1.318 (3) Å] is E. The crystal structure features a combination of C—H⋯N, C—H⋯π and π–π contacts [inter-centroid between the phenyl ring and the quinoline benzene ring is 3.6024 (19) Å], generating a three-dimensional network.