Substituted Benzene Rings Research Articles

{4,4′,6,6′-Tetraiodo-2,2′-[2,2-dimethylpropane-1,3-diylbis(nitrilomethanylylidene)]diphenolato}copper(II)

In the title compound, [Cu(C19H16I4N2O2)], the CuII atom and the substituted C atom of the diamine segment lie on a crystallographic twofold rotation axis. The geometry around the CuII atom is distorted square-planar, which is supported by the N2O2 donor atoms of the coordinated Schiff base. The dihedral angle between the symmetry-related substituted benzene rings is 29.40 (19)°. In the crystal, a short I⋯I [3.8766 (6) Å] contact is present and links neighbouring mol­ecules into chains propagating along the a axis.

(Z)-1,3-Bis(4-chlorophenyl)-2-(1H-1,2,4-triazol-1-yl)prop-2-en-1-one

In the title mol­ecule, C17H11Cl2N3O, the C=C bond connecting the triazole and 4-chloro­phenyl groups adopts a Z geometry. The dihedral angles formed by the triazole ring and the 4-chloro substituted benzene rings are 67.3 (1) and 59.1 (1)°. The dihedral angle between the two benzene rings is 73.5 (1)°.

(E)-3-[(2-Hydroxy-3-methoxybenzylidene)amino]benzoic acid

In the title compound, C15H13NO4, the dihedral angle between the substituted benzene rings is 9.9 (8)°. Part of the mol­ecule (the salicylaldimine segment) is disordered over two sets of sites, with a refined site-occupancy ratio of 0.550 (14):0.450 (14). Intra­molecular O—H⋯N hydrogen bonds form S(6) ring motifs. In the crystal, pairs of O—H⋯O hydrogen bonds link mol­ecules into centrosymmetric dimers with R 2 2(8) ring motifs. The crystal packing also features C—H⋯π inter­actions.

{4,4′,6,6′-Tetrabromo-2,2′-[(2,2-dimethylpropane-1,3-diyl)bis(nitrilomethanylylidene)]diphenolato}copper(II)

In the title compound, [Cu(C19H16Br4N2O2)], the CuII ion and the substituted C atom of the diamine fragment lie on a crystallographic twofold rotation axis. The geometry around the CuII ion is distorted square-planar, which is defined by the N2O2 donor atoms of the coordinated Schiff base ligand. The dihedral angle between the symmetry-related substituted benzene rings is 25.33 (14)°. The crystal structure is stabilized by an inter­molecular π–π inter­action [centroid–centroid distance = 3.8891 (18) Å].

4-Bromo-2-methoxy-6-(1-phenyl-1H-benzimidazol-2-yl)phenol

The title compound, C20H15BrN2O2, crystallized with three independent molecules in the asymmetric unit. Intramolecular O—H⋯N hydrogen bonds induce coplanarity of the substituted benzene ring and the benzimidazole ring, with mean deviations from the planes of 0.0931 (10), 0.0448 (10) and 0.0083 (11) Å in the three mol­ecules.

ChemInform Abstract: Construction of Substituted Benzene Rings by Palladium‐Catalyzed Direct Cross‐Coupling of Olefins: A Rapid Synthetic Route to 1,4‐Naphthoquinone and Its Derivatives.

Ring the changes: the direct cross-coupling of electron-deficient 1,4-benzoquinone or its derivatives with electron-rich alkyl vinyl ethers proceeds in a tandem manner to produce substituted benzene rings with good selectivity and in good to excellent yields. The reaction has the potential for the rapid synthesis of diverse substituted benzene rings as it is not limited by substituent effects.

(E)-N-(1-Benzothiophen-3-ylmethylidene)-2,6-dimethylaniline

In the title compound, C17H15NS, the benzothio­phene residue and the substituted benzene ring are oriented at a dihedral angle of 61.99 (7)°. An inter­molecular C—H⋯π inter­action contributes to the stability of the crystal structure.

{4,4′,6,6′-Tetrachloro-2,2′-[2,2-dimethylpropane-1,3-diylbis(nitrilomethanylylidene)]}nickel(II)

In the title compound, [Ni(C19H16Cl4N2O2)], the NiII ion is in a distorted square-planar environment coordinated by two N atoms and two O atoms of the tetra­dentate ligand. The dihedral angle between the benzene rings is 24.8 (2)°. In the crystal, mol­ecules are linked into chains along the b axis by weak C—H⋯O and C—H⋯Cl inter­actions. An inter­molecular Cl⋯Cl [3.4564 (19) Å] inter­action is present which is shorter than the sum of the van der Waals radii of Cl atoms (3.50 Å).

{4,4′,6,6′-Tetrachloro-2,2′-[2,2-dimethylpropane-1,3-diylbis(nitrilomethanylylidene)]}copper(II)

In the title Schiff base complex, [Cu(C19H16Cl4N2O2)], the geometry around the CuII atom is distorted square-planar defined by the N2O2 donor atoms of the coordinated ligand. The dihedral angle between the substituted benzene rings is 29.95 (16)°. In the crystal, mol­ecules are linked along the b axis, forming individual dimers through C—H⋯O inter­actions. The crystal structure is further stabilized by inter­molecular π–π inter­actions [centroid–centroid distance = 3.6131 (17) Å].

(E)-3-[(2-Methyl-4-nitrophenyl)iminomethyl]-1-benzothiophene

In the title conpound, C16H12N2O2S, the 1-benzothio­phene residue and the substituted benzene ring are oriented at a dihedral angle of 53.36 (6)°. The mol­ecular conformation features a short C—H⋯N contact. There are no significant inter­molecular contacts.

Binding energy of H2to MOF-5: A Model Study

Using models simulating the environment of two distinct adsorption sites of <TEX>$H_2$</TEX> in metal-organic framework-5 (MOF-5), binding energies of <TEX>$H_2$</TEX> to MOF-5 were evaluated at the MP2 and CCSD(T) level. For organic linker section modeled as dilithium 1,4-benzenedicarboxylate (<TEX>$C_6H_4(COO)_2Li_2$</TEX>), the MP2 and CCSD(T) basis set limit binding energies are estimated to be 5.1 and 4.4 kJ/mol, respectively. For metal oxide cluster section modeled as <TEX>$Zn_4O(CO_2H)_6$</TEX>, while the MP2 basis set limit binding energy estimate amounts to 5.4 kJ/mol, CCSD(T) correction to the MP2 results is shown to be insignificant with basis sets of small size. Substitution of benzene ring with pyrazine ring in the model for the organic linker section in MOF-5 is shown to decrease the <TEX>$H_2$</TEX> binding energy noticeably at both the MP2 and CCSD(T) level, in contrast to the previous study based on DFT calculation results which manifested substantial increase of <TEX>$H_2$</TEX> binding energies upon substitution of benzene ring with pyrazine ring in the similar model.

(Z)-Ethyl 2-(2,4-dimethylbenzylidene)-7-methyl-3-oxo-5-phenyl-3,5-dihydro-2H-thiazolo[3,2-a]pyrimidine-6-carboxylate

In the title compound, C25H24N2O3S, the dihedral angles between the thia­zole ring and the phenyl and substituted benzene rings are 84.91 (11) and 11.58 (10)°, respectively. The dihydro­pyrimidine ring adopts a flattened boat conformation. The olefinic double bond is in a Z configuration.

N,N′-Bis(2,6-diethylphenyl)acenaphthylene-1,2-diimine

The title compound, C32H32N2, has crystallographic twofold rotation symmetry, with two C atoms lying on the rotation axis. The dihedral angle between the substituted benzene ring and the naphthalene ring system is 79.8 (1)°. The crystal structure is stabilized by C—H⋯N inter­actions, which form a chain motif along the b-axis direction.

(E)-1-(5-Bromo-thio-phen-2-yl)-3-(3,4,5-trimeth-oxy-phen-yl)prop-2-en-1-one.

In the title compound, C16H15BrO4S, the dihedral angle between the thio­phene and benzene rings is 13.08 (16)°. The C atoms of the meta meth­oxy groups of the substituted benzene ring lie close to the plane of the ring [displacements = 0.049 (5) and −0.022 (4) Å], whereas the para-C atom is significantly displaced [−1.052 (4) Å]. In the crystal, mol­ecules are linked by weak C—H⋯O hydrogen bonds, forming C(11) chains propagating in [100].

Thermal behavior of furosemide

Data from theoretical, thermal, and spectroscopic methods were compared in order to map a possible mechanism for the thermal decomposition of furosemide, a diuretic compound, in solid state. TG/DTG curves suggested a two-stage decomposition process. The first product of decomposition is water (m/z = 18), released due to a dimerization resulting in the formation of an amide. Then carbon dioxide (m/z = 44), nitroxide (m/z = 30), and 2-methyl-furanyl ion (m/z = 81) are released in the second stage. The chlorine substituted benzene ring, due to the double bond conjugated system, being the last fraction to decompose. Theoretical calculations presented are in agreement with experimental results.

N′-(4-Methoxybenzylidene)-4-methylbenzohydrazide

The title compound, C16H16N2O2, is the product of the reaction of 4-meth­oxy­benzaldehyde and 4-methyl­benzo­hydrazide. The dihedral angle between the substituted benzene rings is 17.6 (3)° and the meth­oxy C atom is almost coplanar with its attached ring [deviation = 0.019 (4) Å]. In the crystal, mol­ecules are linked by N—H⋯O hydrogen bonds, forming C(4) chains propagating along the b-axis direction.

N′-(2-Hydroxybenzylidene)-3-methylbenzohydrazide

The title compound, C15H14N2O2, is the product of the reaction of 2-hy­droxy­benzaldehyde and 3-methyl­benzo­hydrazide. The dihedral angle between the substituted benzene rings is 19.5 (3)° and an intra­molecular O—H⋯N hydrogen bond generates an S(6) ring motif. In the crystal, mol­ecules are linked by N—H⋯O hydrogen bonds to generate C(4) chains propagating in [001] and C—H⋯O inter­actions to the same O-atom acceptor reinforce the chains.

(Z)-Methyl 2-[(2-ethoxy-6-formylphenoxy)methyl]-3-(4-ethylphenyl)acrylate

The title compound, C22H24O5, consists of two substituted benzene rings linked by an ethyl acrylate group. The dihedral angle between the two benzene rings is 58.39 (7)°. The crystal packing is governed by two C—H⋯O inter­actions, one of which forms centrosymmetric dimers with a graph-set descriptor of R 2 2(18).

Ethyl (Z)-2-(2-fluorobenzylidene)-7-methyl-3-oxo-5-phenyl-3,5-dihydro-2H-thiazolo[3,2-a]pyrimidine-6-carboxylate

The title compound, C23H19FN2O3S, a fused-pyrimidine derivative, displays dihedral angles between the thia­zole ring and the benzene ring and substituted benzene ring of 7.10 (14) and 3.48 (12)°, respectively. The dihydro­pyrimidine ring adopts a flattened boat conformation. The olefinic double bond is in a Z configuration.

Simultaneous interactions of pyridine with substituted benzene ring and H–F in X-ben⊥pyr···H–F complexes: a cooperative study

The cooperative effects between T-shape stacking and hydrogen bond interactions in X-ben⊥pyr···H–F complexes were investigated in this work. The results indicate that the electron-withdrawing/donating substituents decrease/increase the magnitude of the binding energies compared to the unsubstituted X-ben⊥pyr···H–F (X = H) complex. The cooperative effects have been studied while using the atoms in molecules (AIM) and natural bond orbital (NBO) methods, allowing us to evaluate the interplay between T-shape stacking and hydrogen bond interactions. There are good relationships among binding energies, Hammett constants, geometrical parameters, and the results of AIM and NBO analysis in X-ben⊥pyr···H–F complexes.