Preparation of new bio-based chitosan/Fe2O3/NiFe2O4 as an efficient removal of methyl green from aqueous solution.

Modified chitosan with various functional groups has high potential as an efficient adsorbent in removing water pollution. In this study, new magnetic adsorbent, bio-based chitosan/Fe2O3/NiFe2O4, was successfully prepared by green chemistry route involving mixing of chitosan as core moiety and Fe2O3/NiFe2O4 nanocomposite, and slow evaporation of solvent. Synthesized chitosan/Fe2O3/NiFe2O4 was characterized by FT-IR, TGA, XRD, VSM and FE-SEM. The FT-IR and XRD results confirmed that the successful preparation of chitosan/Fe2O3/NiFe2O4. Uniform dispersion of Fe2O3/NiFe2O4 nanoparticles with low aggregation was confirmed by FE-SEM. The as-prepared magnetic chitosan/Fe2O3/NiFe2O4 was developed as solid phase adsorbent to remove methyl green (MG) dye from aqueous solutions. Several important parameters such as contact time, pH, temperature and adsorbent dosage were investigated systematically. The high and fast MG dye removal (≈ 80%) occurs after 30 min. The optimal conditions for MG removal was recorded at pH = 8, contact time of 60 min, adsorbent dosage of 0.2 g and 25 °C and displayed a high MG dye removal percentage of 96.51% and adsorption capacity of 77.22 mg/g.

New chitosan Schiff base and its nanocomposite: Removal of methyl green from aqueous solution and its antibacterial activities.

New chitosan Schiff base (CS-NB) and its CS-NB-NiFe nanocomposite have been prepared and characterized by FTIR spectroscopy, XRD, SEM and DSC. FT-IR spectra and XRD patterns revealed the preparation of chitosan Schiff base CS-NB and its CS-NB-NiFe nanocomposite. DSC demonstrated the endo and exothermic correspondence the evaporation of solvent and decomposition of pyranose ring, respectively. Antibacterial activities was evaluated for the as-prepared compounds against two Gram-positive (Staphylococcus aureus and Bacillus cereus) and two Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria and the results shows that the antibacterial activities of the compounds are found to be stronger than that of chitosan. The order of antibacterial effect according to inhibitory zone around is as follows: S. aureus > E. coli > B. cereus > P. aeruginosa. In addition, the removal of methyl green (MG) dye using CS-NB and its CS-NB-NiFe nanocomposite were analyzed and results showed that the compounds can be effectively used to remove of MG from aqueous solution. Results show that the percentage removal of MG by nanocomposite is higher than Schiff base.

Synthesis of new chitosan Schiff base and its Fe2O3 nanocomposite: Evaluation of methyl orange removal and antibacterial activity.

New chitosan Schiff base (3EtO-4OH/Chit) and its 3EtO-4OH/Chit/Fe2O3 nanocomposite were synthesized and characterized by FTIR, 1H NMR, XRD, TGA, DSC and SEM. The result confirmed the preparation of 3EtO-4OH/Chit and its 3EtO-4OH/Chit/Fe2O3 nanocomposite. The efficiency of the prepared catalysts was studied for the methyl orange (MO) removal from aqueous solution. The effect of adsorbent dose and contact time on the removal of dye has been studied. Their antibacterial activities were considered against two Gram positive (S. aureus and B. cereus) and two Gram negative (E. coli and P. aeruginosa) bacteria and the results showed that the activity of the 3EtO-4OH/Chit/Fe2O3 is excellent and is more than chitosan and 3EtO-4OH/Chit. Thermogravimetry studies shows that the weight loss stages and the residual value at 600 °C are different for the two compounds. DSC curve of the title compounds 3EtO-4OH/Chit and 3EtO-4OH/Chit/Fe2O3 is different from each other. The reason for this difference could be due to the presence of iron oxide nanoparticles in 3EtO-4OH/Chit/Fe2O3.

Isolation, spectroscopic characterization, X-ray, theoretical studies as well as in vitro cytotoxicity of Samarcandin.

Samarcandin 1, a natural sesquiterpene-coumarin, was isolated as well as elucidated from F. assa-foetida which has significant effect in Iranian traditional medicine because of its medicinal attitudes. The crystal structure of samarcandin was determined by single-crystal X-ray structure analysis. It is orthorhombic, with unit cell parameters a=10.8204 (5)Å, b=12.9894 (7)Å, c=15.2467 (9)Å, V=2142.9 (2)Å(3), space group P212121 and four symmetry equivalent molecules in the unit cell. Samarcandin was isolated in order to study for its theoretical studies as well as its cellular toxicity as anti-cancer drug against two cancerous cells. In comparison with controls, our microscopic and MTT assay data showed that samarcandin suppresses cancer cell proliferation in a dose-dependent manner with IC50=11µM and 13 for AGS and WEHI-164 cell lines, respectively. Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) of the structure was computed by three functional methods and 6-311++G(∗∗) standard basis set. The optimized molecular geometry and theoretical analysis agree closely to that obtained from the single crystal X-ray crystallography. To sum up, the good correlations between experimental and theoretical studies by UV, NMR, and IR spectra were found.

Crystal structure, spectroscopic and theoretical studies on two Schiff base compounds of 2,6-dichlorobenzylidene-2,4-dichloroaniline and 2,4-dichlorobenzylidene-2,4-dichloroaniline.

The crystal structures of two Schiff base compounds, 2,6-dichlorobenzylidene-2,4-dichloroaniline (1) and 2,4-dichlorobenzylidene-2,4-dichloroaniline (2) have been determined from single-crystal X-ray diffraction and characterized by FT-IR and (1)H NMR spectroscopy. The electronic structures of compounds 1 and 2 in the gas phase were computed by the density functional theory (DFT) method. The obtained theoretical results were supported by the crystallographic data. In addition, theoretical configurations of the title compounds were relaxed and studied in terms of the combined analysis of HOMO-LUMO energy gap, total density of states (DOS), molecular electrostatic potential (MEP), NMR spectra and harmonic vibrational frequencies.

4-[(E)-(4-Eth-oxy-phen-yl)imino-meth-yl]phenol.

In the title compound, C(15)H(15)NO(2), the dihedral angle between the benzene rings is 52.04 (5)° and the mol-ecule has an E conformation about the central C=N bond. In the crystal, mol-ecules are connected by O-H⋯N hydrogen bonds, forming zigzag chains along the b axis. The crystal packing also features weak C-H⋯O inter-actions.

[N,N'-Bis(2,3,4-trimeth-oxy-benzyl-idene)-ethane-1,2-diamine-κ(2)N,N']dibromido-mercury(II).

In the title compound, [HgBr(2)(C(22)H(28)N(2)O(6))], the Hg(II) ion is bonded to two Br(-) ions and two N atoms of the chelating Schiff base ligand in a distorted tetra-hedral geometry. The Schiff base ligand adopts an E,E conformation. The dihedral angle between the planes of the two halves of the central N,N'-dimethyl-ethylenediamine part of the ligand is 2.3 (11)°. The crystal studied was twinned by pseudomerohedry [twin law (0-10/-100/00-1)]; the contribution of the minor twin component refined to 0.208 (3).

2-[(4-Meth-oxy-2-nitro-phen-yl)imino-meth-yl]phenol.

The crystal structure of the title compound, C(14)H(12)N(2)O(4), contains four crystallographically independent mol-ecules in the asymmetric unit. All the mol-ecules have similar conformations; the dihedral angles between the aromatic rings are 33.1 (1), 33.76 (9), 31.41 (9) and 32.56 (10)°. Intra-molecular O-H⋯N hydrogen bonds form S(6) ring motifs in each molecule. In the crystal, there are two pairs of pseudo-inversion-related mol-ecules. Along the c axis, mol-ecules are stacked with π-π inter-actions between the 2-hy-droxy-phenyl and 4-meth-oxy-2-nitro-phenyl rings [centroid-centroid distances = 3.5441 (12)-3.7698 (12) Å].

(E)-4-[(4-Bromo-phen-yl)imino-meth-yl]-2-meth-oxy-phenol.

In the crystal structure of the title compound, C(14)H(12)BrNO(2), the dihedral angle between the rings is 37.87 (10)° and the mol-ecule has an E conformation about the central C=N bond. In the crystal, mol-ecules are connected by inter-molecular O-H⋯N hydrogen bonds into zigzag chains running parallel to the b axis. The packing also features C-H⋯O inter-actions.

[4-Bromo-N-(pyridin-2-yl-methyl-idene)aniline-κ(2)N,N']iodido(triphenyl-phosphane-κP)copper(I).

In the title compound, [CuI(C(12)H(9)BrN(2))(C(18)H(15)P)], the Cu(I) ion is bonded to one I atom, one triphenyl-phosphane P atom and two N atoms of the diimine ligand in a distorted tetra-hedral geometry. The Schiff base acts as a chelating ligand and coordinates to the Cu(I) atom via two N atoms. In the diimine ligand, the dihedral angle between the pyridine and bromo-phenyl rings is 19.2 (2)°. In the crystal, mol-ecules are connected by π-π stacking inter-actions between inversion-related pyridine rings [centroid-centroid distance = 3.404 (3) Å].

[N,N'-Bis(2,6-dichloro-benzyl-idene)propane-1,3-diamine-κ(2)N,N']dibromidozinc.

In the title compound, [ZnBr(2)(C(17)H(14)Cl(4)N(2))], the Zn(II) ion is bonded to two bromide ions and two N atoms of the diimine ligand and displays a moderately distorted tetra-hedral coordination geometry. The Schiff base ligand acts as a chelating ligand and coordinates to the Zn(II) atom via two N atoms.

2-(3,4-Dimeth-oxy-phen-yl)-1H-benzimidazole.

In title compound, C(15)H(14)N(2)O(2), the dihedral angle between the 3,4-dimeth-oxy-phenyl group and the benzimidazole system is 26.47 (6)°. In the crystal, neighbouring mol-ecules are linked by N-H⋯N hydrogen bonds into C(4) chains propagating along the c-axis direction. The crystal structure also features weak C-H⋯O inter-actions.

(E)-2-Cyano-3-(2,3-dimeth-oxy-phen-yl)acrylic acid.

The asymmetric unit of the title compound, C(12)H(11)NO(4), contains two mol-ecules. In the crystal, neighbouring mol-ecules are linked together by O-H⋯O hydrogen bonds into dimers. The dimers are arranged into columns parallel to the a axis, meditated by π-π inter-actions [centroid-centroid distances = 3.856 (3) and 3.857 (3) Å]. The crystal structure is further stabilized by weak inter-molecular C-H⋯O inter-actions. The crystal studied was a non-merohedral twin with a ratio of the twin components of 0.657 (11):0.343 (11).

Evidence for side-chain π-delocalization in a planar substituted benzene: an experimental and theoretical charge density study on 2,5-dimethoxybenzaldehyde thiosemicarbazone.

The charge density in 2,5-dimethoxybenzaldehyde thiosemicarbazone (1) has been studied experimentally using Mo-K(α) X-ray diffraction at 100 K, and by theory using DFT calculations at the B3LYP/6-311++G(2d,2p) level. The quantum theory of atoms in molecules (QTAIM) was used to investigate the extent of π-delocalization in the thioamide side-chain, which is virtually coplanar with the benzene ring. The experimental and theoretical ellipticity profiles along the bond paths were in excellent agreement, and showed that some of the formal single bonds in the side-chain have significant π-bond character. This view was supported by the magnitudes of the topological bond orders and by the delocalization indices δ(Ω(A), Ω(B)). An orbital decomposition of δ(Ω(A), Ω(B)) demonstrated that there was significant π-character in all the interchain non-H chemical bonds. On the other hand, the source function referenced at the interchain bond critical points could not provide any evidence for π-delocalization, showing instead only limited σ-delocalization between nearest neighbors. Overall, the topological evidence and the atomic graphs of the oxygen atoms did not provide convincing evidence for π-delocalization involving the methoxy substituents.

Synthesis and Characterization of Two Diimine Schiff Bases Derived from 2,4-Dimethoxybenzaldehyde: The Crystal Structure of N,N'-Bis(2,4-dimethoxy-benzylidene)-1,2-diaminoethane.

Two diimine Schiff bases derived from 2,4-dimethoxybenzaldehyde; N,N'-bis(2,4-dimethoxybenzylidene)-1,2-diaminoethane (1) and N,N'-bis(2,4-dimethoxybenzylidene)-1,4-diaminobutane (2), were prepared and characterized by elemental analyses, FT-IR and 1H NMR spectroscopy. The crystal structure of 1 has been determined by single crystal X-ray diffraction. Its molecule adopts an E configuration with respect to the C=N bond and is located on a center of inversion with one half-molecule in the asymmetric unit.

(E)-4-Bromo-N-(2,3,4-trimeth-oxy-benzyl-idene)aniline.

The title Schiff base compound, C(16)H(16)BrNO(3), adopts an E configuration with respect to the C=N bond. The dihedral angle between the two aromatic rings is 64.02 (6)°.

(E)-4-Bromo-N-(2,3-dimeth-oxy-benzyl-idene)aniline.

The title Schiff base compound, C(15)H(14)BrNO(2), was prepared by the condensation of 2,3-dimeth-oxy-benzaldehyde with 4-bromo-aniline. It adopts an E configuration with respect to the C=N bond. The dihedral angle between the two aromatic rings is 56.79 (8)°. Weak C-H⋯O and C--H⋯π bonds can be found in the crystal structure.

(E)-N-(2,4-Dimeth-oxy-benzyl-idene)-4-ethoxyaniline.

In the title compound, C(17)H(19)NO(3), the mol-ecule has an E configuration with respect to the C=N bond and the dihedral angle between the aromatic rings is 56.07 (5)°. In the crystal, inversion dimers linked by pairs of C-H⋯O hydrogen bonds occur. The dimers are linked by weak C-H⋯π inter-actions, forming a three-dimensional network.

4-Bromo-N-(3,4,5-trimethoxy-benzyl-idene)aniline.

The title compound, C(16)H(16)BrNO(3), adopts an E configuration with respect to the imine C=N bond. The two benzene rings are twisted with respect to each other at an angle of 38.3 (1)°. In the crystal structure, mol-ecules are connected by weak bifurcated C-H⋯(O, O) hydrogen bonds, forming a helical chain along the b axis.

catena-Poly[[[N,N'-bis-(3-methoxy-benzyl-idene)ethyl-enediamine]copper(I)]-µ-thio-cyanato-κN:S].

In the cyrstal structure of the title compound, [Cu(NCS)(C(18)H(20)N(2)O(2))](n), the Cu(I) atom is coordinated in a distorted tetra-hedral geometry by two imino N atoms from a bidentate chelating Schiff base ligand, and one N and one S atoms from two thio-cyanate anions. The thio-cyanate anion bridges the Cu(I) atoms, forming a zigzag chain along [101]. The Schiff base ligand adopts an E,E configuration and the dihedral angle between the terminal benzene rings is 53.68 (8)°.