Synthesis, characterization and structural study of new vanadium complexes with phenolic oxime ligands

Preparation of Cu(II), Ni(II), Ti(IV), VO(IV), and Zn(II) Metal Complexes Derived from Novel vic‐Dioxime and Investigation of Their Antioxidant and Antibacterial Activities

“…It was observed that infrared spectra of metal complexes (2 -6) of this free vic-dioxime ligand (1) were compared, some peaks belonging to the dioxime ligand disappeared, while some vibrational peaks shifted to low or high frequency after complexation. The azomethine (C=N) vibrational bands after its bonding to metal centers, which firstly located at 1613 cm À 1 in the free vicdioxime ligand (1), then shifted to between 1601-1604 cm À 1 in metal complexes (2 -6) and were consistent with N 4 -chelate coordination. As a result of the coordination of nitrogen with the metal atom, it is expected to reduce the electron density on the azomethine connection, thus causing a shift in the C=N oxime group.…”

“…Electronic spectra were obtained in ethanol and chloroform solvent in a Perkin-Elmer model Lamda 25 UV spectrometer in the 200-1100 nm range using a quartz tube with a path length of 1 cm at room temperature. 1 H and 13 C-NMR spectra were recorded in (D 6 )DMSO on Agilent Technologies and a Bruker Avance III ( 1 H: 400 MHz, and 13 C: 100 MHz). Elemental analysis (C, H, N) was performed using a thermos scientific CHNS/O FlashSmart Instruments elemental analyzer at ambient temperature.…”

“…1 B 1g transitions from the nitrogen donor center of vic-dioxime ligands to metal(II) centers. [28,29] In the visible region, one can appear a very weak intensity band around 539 nm for nickel complex (3) attributed to the d-d and 1 A 1g ! 1 B 1g transitions, which are compatible with the Ni(II) complex (3) having square-planar geometry.…”

“…The oxo-vanadium (IV) is coordinated to the oxime nitrogen atoms, forming a planar base with a V=O bond in an apical position. [1] The tetrahedral nature of the metal complexes ( 4) and ( 6) is based on the disappearance of the (OÀ H…O) band in the 1 H-NMR spectrum, which can be explained by the fact that these signals are very weak or a very broad, possibly due to hydrogen bridges. Another powerful piece of evidence, the chemical shifts related to imine (CH=N) proton are detected at 8.42 ppm as a singlet for vicdioxime ligand (1) was significantly different field shift (8.29 -10.99 ppm) compared to the metal complexes which confirm the metal complexes formation via imine nitrogen coordination to metal centers.…”

“…Nowadays, the coordination chemistry of vic-dioximes is interesting due to stable, easy to prepare, highly colored complexes with a large structural diversity, very efficient and versatile biological properties, and thus numerous transition metal complexes of these ligands have been investigated in detail. [1,2] The chemistry of vic-dioximes and their numerous transition metal complexes are being used as coordination compounds, and also there are lots of usage areas, such as analytical, [3] biological systems, [4,5] and medicinal chemistry. [2] Many researchers have studied vicdioximes which have an important role in the complexes especially 1, 2-dioximes in coordination chemistry.…”