Solvothermal synthesis, a new preparative route to mononuclear lanthanide complexes with in situ built N4O2 hexadendate Schiff base. Synthesis and crystal structure of N,N′-bis[(2-salicylideneamino)ethyl]ethane-1,2-diamine nitrato[O,O]Erbium(III) hydrate

Synthesis and characterization of a series of transition metal complexes with a new symmetrical polyoxaaza macroacyclic Schiff base ligand: X-ray crystal structure of cobalt(II) and nickel(II) complexes and their antibacterial properties

A new symmetrical [N4O2] hexadentate Schiff base ligand, (E)-N-(pyridin-2-ylmethylene)-2-(3-(2-((E)-pyridin-2-lmethyleneamino)phenoxy)naphthalen-2-yloxy)benzenamine, abbreviated to L, and its complexes of Ni(II), Cu(II), Zn(II), Co(II), Cd(II) and Mn(II) have been synthesized in the presence of metal ions. The complexes were structurally characterized by elemental analyses, IR, UV-Vis, NMR and molar conductivity. The crystal structures of two complexes, [NiL(ONO2)2]·2H2O and [CoLCl2]CH3OH·0.5H2O, have been determined by a single crystal X-ray diffraction study. In these complexes, the ligand is coordinated in a neutral form via pyridine and azomethine nitrogen atoms. The metal ions complete their six coordination with two coordinated nitrate or chloride ions, forming a distorted octahedral geometry. The synthesized compounds have antibacterial activity against the three Gram-positive bacteria: Enterococcus faecalis, Bacillus cereus and Staphylococcus epid and also against the three Gram-negative bacteria: Citrobacter freundii, Enterobacter aerogenes and Salmonella typhi. The activity data show that the complexes are more potent antibacterials than the parent Schiff base.

FT-IR, FT-Raman and computational study of (E)-N-carbamimidoyl-4-((4-methoxybenzylidene)amino)benzenesulfonamide

The FT-IR and FT-Raman spectra of (E)-N-carbamimidoyl-4-((4-methoxybenzylidene)amino)benzenesulfonamide were recorded and analyzed. Geometry and harmonic vibrational wavenumbers were calculated theoretically using Gaussian 03 set of quantum chemistry codes. Calculations were performed at the Hartree-Fock (HF) and density functional theory (DFT) levels of theory. The calculated wavenumbers (B3LYP) agree well with the observed wavenumbers. Potential energy distribution is done using GAR2PED program. The red shift of the N-H stretching bands in the infrared spectrum from the computed wavenumber indicates the weakening of the N-H bond. The calculated first hyperpolarizability is comparable with the reported value of similar derivative and may be an attractive object for further studies of nonlinear optics. The variations in the CN bond lengths of the title molecule suggest an extended π-electron delocalization over the sulfaguanidine moiety which is responsible for the nonlinearity of the molecule. The geometrical parameters of the title compound are in agreement with that of reported similar derivatives.

Vibrational spectroscopic and quantum chemical calculations of (E)-N-Carbamimidoyl-4-((naphthalen-1-yl-methylene)amino)benzene sulfonamide

FT-IR and FT-Raman spectra of (E)-N-Carbamimidoyl-4-((naphthalen-1-yl-methylene)amino)benzene sulfonamide were recorded and analyzed. The vibrational wavenumbers were computing at various levels of theory. The data obtained from theoretical calculations are used to assign vibrational bands obtained experimentally. The results indicate that B3LYP method is able to provide satisfactory results for predicting vibrational frequencies and structural parameters. The calculated first hyperpolarizability is comparable with reported values of similar derivatives and is an attractive object for future studies of non-linear optics. The geometrical parameters of the title compound are in agreement with that of similar derivatives.

FT-IR, FT-Raman and quantum chemical calculations of (E)-N-carbamimidoyl-4-((3,4-dimethoxybenzylidene) amino) benzenesulfonamide

FT-IR and FT-Raman spectra of (E)-N-carbamimidoyl-4-((3,4-dimethoxybenzylidene) amino) benzenesulfonamide were recorded and analyzed. The vibrational wavenumbers were computed using HF/6-31G*, B3PW91/6-31G* and B3LYP/6-31G* basis. The data obtained from vibrational wavenumber calculations are used to assign vibrational bands obtained experimentally. The results indicate that the B3LYP method is able to provide satisfactory results for predicting vibrational frequencies and structural parameters. The calculated first hyperpolarizability is comparable with the reported values of similar derivatives and is an attractive object for future studies of non-linear optics. The geometrical parameters of the title compound are in agreement with that of similar derivatives.

FT-IR, FT-Raman spectroscopy and computational study of (E)-4-((anthracen-9-ylmethylene)amino)-N-carbamimidoylbenzene sulfonamide

The infrared and Raman spectra of (E)-4-((anthracen-9-ylmethylene)amino)-N-carbamimidoylbenzene sulfonamide have been recorded and analysed. Geometry and harmonic vibrational wavenumbers were calculated theoretically using Gaussian03 set of quantum chemistry codes. The data obtained from vibrational wavenumber calculations are used to assign vibrational bands found in infrared and Raman spectra of the studied molecule. The red-shift of the NH stretching band in the infrared spectrum from the computed wavenumber indicates the weakening of the NH bond. The NH stretching band has split into a doublet in the IR spectrum owing to the Davydov coupling between neighbouring units. The geometrical parameters of the title compound are in agreement with the reported similar derivatives. The calculated first hyperpolarizability is comparable with the reported value of similar structures and may be an attractive object for further studies on non-linear optics. The important thermodynamical parameters are also reported.

A series of transition and non-transition metal complexes from a N₄O₂ hexadentate Schiff base ligand: Synthesis, spectroscopic characterization and efficient antimicrobial activities

Some transition and non-transition metal complexes of the hexadentate N₄O₂ donor Schiff base ligand 1,8-N-bis(3-carboxy)disalicylidene-3,6-diazaoctane-1,8-diamine, abbreviated to H₄fsatrien, have been synthesized. All the 14 metal complexes have been fully characterized with the help of elemental analyses, molecular weights, molar conductance values, magnetic moments and spectroscopic (UV-Vis, IR, NMR, ESR) data. The analytical data helped to elucidate the structures of the metal complexes. The Schiff base, H₄fsatrien, is found to act as a dibasic hexadentate ligand using N₂N₂O₂ donor set of atoms (leaving the COOH group uncoordinated) leading to an octahedral geometry for the complexes around all the metal ions except VO²(+) and UO₂²(+). However, surprisingly the same ligand functions as a neutral hexadentate and neutral tetradentate one towards UO₂²(+) and VO²(+), respectively. In case of divalent metal complexes they have the general formula [M(H₂fsatrien)] (where M stands for Cu, Co, Hg and Zn); for trivalent metal complexes it is [M(H₂fsatrien)]X·nH₂O (where M stands for Cr, Mn, Fe, Co and X stands for CH₃COO, Cl, NO₃, ClO₄) and for the complexes of VO²(+) and UO₂²(+), [M(H₄fsatrien)]Y (where M=VO and Y=SO₄); M=UO₂ and Y=2 NO₃). The Schiff base ligand and most of the complexes have been screened in vitro to judge their antibacterial (Escherichia coli and Staphylococcus aureus) and antifungal (Aspergillus niger and Pencillium chrysogenum) activities.

Tris[2-(2-pyridylimino-meth-yl)phenol-ato(0.67-)]europium(III) nitrate

The title compound, [Eu(C₁₂H_9.33N₂O)₃]NO₃, was obtained by the reaction of Eu(NO₃)·3H₂O and the Schiff base ligand 2-(2-pyridylimino­meth­yl)phenol. The Eu atom is located on a threefold rotation axis and is nine-coordinated by three tridentate Schiff base ligands in a distorted tricapped trigonal-prismatic geometry. The O atom at the phenol hydr­oxy group is partially deprotonated and the H atoms are modelled with one-third occupancy according to the space group R. Offset face-to-face π–π [centroid–centroid distance = 3.886 (3) Å] and edge-to-face C—H⋯π inter­actions are found between adjacent mol­ecules. An intra­molecular O—H⋯N hydrogen bond is also present.