Bis(indenyl)titanium(IV) and zirconium(IV) complexes of monofunctional bidentate salicylidimines

Preparation, spectral characterization, electrochemistry, EXAFS, antibacterial and catalytic activity of new ruthenium (III) complexes containing ONS donor ligands with triphenylphosphine/arsine

“…47 Another medium intensity band, at 3300 cm −1 in the free ligands due to ν(OH), was absent in the complexes, indicating deprotonation of the Schiff bases prior to the coordination through the phenolic oxygen atom. 48 This is further supported by the increase in the absorption frequency of phenolic C-O band from 1263-1270 cm −1 in the free ligands to 1315-1340 cm −1 in the ruthenium complexes, indicating that the other coordination site of Schiff bases is phenolic oxygen in all the complexes. 35,48 The band of medium intensity at 792-817 cm −1 in the spectra of all the ligands may be assigned to the >C S stretching vibration.…”

“…48 This is further supported by the increase in the absorption frequency of phenolic C-O band from 1263-1270 cm −1 in the free ligands to 1315-1340 cm −1 in the ruthenium complexes, indicating that the other coordination site of Schiff bases is phenolic oxygen in all the complexes. 35,48 The band of medium intensity at 792-817 cm −1 in the spectra of all the ligands may be assigned to the >C S stretching vibration. This band disappeared in the complexes and a new band appears at 736-744 cm −1 .…”

Spectral, Magnetic, Electrochemical, Photochemical, DNA Binding and Cleavage, Catalytic and Biological Studies of 2, 2'-Bipyridyl Based d-f Hetero Binuclear Gd(III) and Cu(II) Complexes

“…Coordination of the ligand to the metal through the imine nitrogen and phenolic C-O-is expected to reduce the electron density in the imine nitrogen and lower ν(C=N) to 1619 cm -1 and phenolic (C-O-)1240 cm -1 that showed that Chem Sci Trans., 2013, 2(S1), S207-S219 S211 the imine nitrogen of the ligand is strongly coordinated to the metal center 12 . A medium intensity band, at 3330 cm -1 in the free ligand due to ν(OH) was absent in the complex, indicating deprotonation of the ligand prior to coordination 13 . For the complexes, bands at 430-466 cm -1 could be assigned to -(M-O) bond.…”

N-(2-Pyridyl)-5-chlorosalicylideneimine Schiff Base and its Tellurium(IV) Complexes: Synthesis, Characterization and In Vitro Biological Activities

“…The absence of a singlet in high frequency region (δ 13.460 ppm), which typically corresponds to phenolic hydrogen indicates that N-2-pyridyl-5-chlorosalicylideneimine binds tellurium by deprotonated phenolic oxygen. The singlet that appears at δ 9.392 ppm is ascribed to azomethine hydrogen, which is less shielded after coordination through azomethine nitrogen 38,41,50,51,70,78 and appear in the downfield region 10.254-10.271 δ ppm. The complex multiplets found in the spectrum of complexes in the δ 6.840-8.651 ppm region corresponds to coupled hydrogen atoms of aromatic rings.…”