Homometallic Dinuclear Cu(II) and Zn(II) Complexes Derived from Salophen-type Ligand: Synthesis, Characterization and Anticancer Screening

Introduction: A series of salophen-type Cu(II) and Zn(II) dinuclear metal complexes of a Schiff base derived from o-phenylenediamine were successfully synthesized, characterized and screened for their anticancer activity. Methods and Results: All compounds were characterized physicochemical and spectral techniques namely elemental analysis (C, H, N), magnetic susceptibility (MSB), molar conductivity, thermal gravimetric analysis (TGA), infrared (IR) and nuclear magnetic resonance (NMR) spectroscopy. The shifting of C=N, C-O phenolic and C-O methoxy peaks and the appearance of new peaks assignable to M-N and M-O in IR spectra of the complexes indicated the coordination of azomethine N, phenolic O and methoxy O donor atoms with metal centers. The disappearance of the hydroxyl peak in 1H NMR spectra of the Zn(II) complex supported the involvement of phenolic O upon formation of the metal complex. The Cu(II) complex was paramagnetic with magnetic moment values of 1.97, close to the theoretical spin only magnetic moment, μso, for Cu(II). The compounds were screened for anticancer activity against human colon cancer cells (HCT116). The Cu(II) complex revealed the highest activity with IC50 value of 21.17 ± 0.76 μM. Conclusion: The ligand coordinated as a hexadentate ligand through O and N donor atoms of phenolic, methoxy and azomethine groups. From anticancer screening, it was observed that Cu2(OVanOPD) complex exhibited the highest activity followed by OVanOPD ligand and Zn2(OVanOPD) complex

6,6′-Dimeth­oxy-2,2′-[(E,E′)-(4-chloro-m-phenyl­ene)bis­(nitrilo­methyl­idyne)]diphenol

The title compound, C22H19ClN2O4, has the appearance of a warped butterfly. One 2-hydr­oxy-3-methoxy­benzyl­idene­amino fragment is planar [with a maximum deviation of 0.056 (3) Å] and forms a dihedral angle of 9.85 (9)° with the central benzene ring. The other fragment is not planar; however, the methoxy­phenol group is planar [with the maximum deviation of 0.033 (2) Å] and makes a dihedral angle of 41.7 (3)° with the central benzene ring. The mol­ecule is stabilized by intra­molecular O—H⋯N hydrogen bonding. The crystal structure is stabilized by weak inter­molecular C—H⋯O hydrogen bonding and C—H⋯π inter­actions

Multidentate azomethine series: complexation and bioactivity studies / Prof Dr Hadariah Bahron, Dr Karimah Kassim and Sharifah Rohaiza Syed Omar

Three Schiff bases namely L1: MPD(ovan)₂, L2: triMe-MPD(ovan)₂ and L3: Cl-MPD(ovan)₂ are obtained from the condensation reaction between derivatives of m-phenylenediamine (MPD) with o-vanillin. Complexation with Co(II), Cu(II) and Zn(II) afford novel dinuclear complexes of dimeric nature. Their structures are elucidated using various physicochemical techniques. The Schiff bases are indicated to act as tetradentate ligands in which both oxygen and nitrogen atoms serve as coordination sites for the metal ions. Antibacterial investigations revealed that the complexes are better bactericides than the parent ligands. The IC50 values against liver cells of the complexes are much lower than those of the parent ligands

Bis{2-[(E)-(4-fluoro­benz­yl)imino­meth­yl]-6-meth­oxy­phenolato-κ2 N,O 1}nickel(II)

In the title compound, [Ni(C15H13FNO2)2], the NiII atom is tetra­coordinated by two N atoms and two O atoms from two 2-[(4-fluoro­benz­yl)imino­meth­yl]-6-meth­oxy­phenolate ligands in a square-planar geometry. The two N atoms and two O atoms around the NiII atom are trans to each other, as the NiII atom lies on an inversion centre. In the fluoro­phenyl group, five C atoms and an F atom are disordered over two sets of positions of equal occupancy. In the crystal, the complex mol­ecules are linked via inter­molecular C—H⋯F hydrogen bonds, forming chains along [001]

2-[(E)-(2,4-Dihy­droxy­benzyl­idene)aza­nium­yl]-3-phenyl­propano­ate

The title compound, C16H15NO4, exists as a zwitterion in the solid state, with the carb­oxy­lic acid group being deprotonated and the imine N atom being protonated. The mol­ecule adopts an E configuration about the C=N double bond. The dihedral angle between the benzene rings is 46.34 (4)°. An intra­molecular N—H⋯O hydrogen bond generates an S(6) ring motif. In the crystal, adjacent mol­ecules are connected by inter­molecular O—H⋯O and C—H⋯O hydrogen bonds, forming supra­molecular ribbons along the a axis

(E)-2-[1-(3-Amino-4-chloro­phenyl­imino)eth­yl]-4-bromo­phenol

The title Schiff base compound, C14H12BrClN2O, exists in an E configuration with respect to the central C=N double bond. The amino group adopts a pyramidal configuration. The dihedral angle between the two benzene rings is 76.88 (10)° and an intra­molecular O—H⋯N hydrogen bond forms a six-membered ring, generating an S(6) ring motif. In the crystal structure, mol­ecules are linked into chains along [010] via N—H⋯O hydrogen bonds. The presence of π–π inter­actions [centroid–centroid distance = 3.6244 (12) Å] further stabilizes the crystal structure

Crystal structure of bis{2-[(E)-(4-methoxylbenzyl)- iminomethyl]phenolato-j2N,O1}nickel(II)

The asymmetric unit of the title compound, [Ni(C15H14NO2)2], comprises an NiII cation, lying on an inversion centre, and a Schiff base anion that acts as a bidentate ligand. The NiII cation is in a square-planar coordination environment binding to the imine N and phenolate O atoms of the two Schiff base ligands. The N- and O-donor atoms of the two ligands are mutually trans, with Ni—N and Ni—O bond lengths of 1.9191 (11) and 1.8407 (9) A ° , respectively. The plane of the methoxybenzene ring makes a dihedral angle of 84.92 (6)� with that of the phenolate ring. In the crystal, molecules are linked into screw chains by weak C—H� � �O hydrogen bonds. Additional C—H� � �O hydrogen bonds, together with C—H� � �� contacts, arrange the molecules into sheets parallel to the ac plane

6,6′-Dimeth­oxy-2,2′-[(E,E′)-(2,4,6-trimethyl-1,3-phenyl­ene)bis­(nitrilo­methanylyl­idene)]diphenol chloro­form monosolvate

In the title compound, C25H26N2O4·CHCl3, the aromatic rings of the imino­methyl-6-meth­oxy­phenol fragments make dihedral angles of 58.33 (6) and 87.74 (6)° with the central benzene ring. The mol­ecular conformation is stabilized by intra­molecular O—H⋯N hydrogen bonds. In the crystal, an inter­molecular C—H⋯O hydrogen bond involving the chloro­form solvent mol­ecule is observed. The crystal packing is further stabilized by π–π stacking inter­actions [centroid–centroid distances = 3.739 (3)–3.776 (3) Å] between the benzene rings of centrosymmetrically related mol­ecules

Synthesis, characterization and biological activity of NitrogenOxygen-Sulfur (NOS) transition metal complexes derived from novel s-2,4-dichlorobenzyldithiocarbazate with 5-fluoroisatin / Mohd Abdul Fatah Abdul Manan ... [et al.]

A novel Schiff base containing nitrogen-oxygen-sulfur (NOS) donor atoms formed from the condensation reaction of S-2,4dichlorobenzyldithiocarbazate (S-2.4BDTC) with 5-fluroisatin has been synthesized. Complexes of cobalt(ll), nickel(ll), copper(ll), zinc(ll) and cadmium(ll) with this Schiff base have been prepared and characterized using elemental analysis and various physico-chemical techniques. In the cobalt(ll) andnickel(II) complexes the SchifJbase behaves as a uninegatively charged tridentate nitrogen-oxygen-sulfur (NOS) chelating ligand, bonding through the azomethine nitrogen, thiolate sulfur and carbonylic oxygen of the isatin moiety. However. in the copper(ll), zinc(II) and cadmium(II) complexes the Schiff base behaves as a nitrogen-sulfur (NS) bidentate chelating ligand, bonding through the azomethine nitrogen and thiolate sulfur. The Schiff base and the metal complexes were evaluated with respect to antimicrobial activity, which was performed in reallion to two selected pathogenic microbials (Bacillus subtilis and Pseudomonas aeruginosa). It was observed that only the zinc Schiffbase complex exhibited strong activity against the Bacillus subtilis bacteria with an inhibition zone of 25 mm