Synthesis, characterization and redox properties of a new vic-dioxime and its transition metal complexes

Multinuclear Cu(II) Schiff Base Complex as Efficient Catalyst for the Chemical Coupling of CO2 and Epoxides: Synthesis, X-ray Structural Characterization and Catalytic Activity

“…p * and n ? p * of C=N chromophore or changetransfer transition arising from p electron interactions between the metal and ligand which involves either a metal-to-ligand or ligand-to-metal electron transfer and d-d transitions [35][36][37]. The electronic spectra of the free ligands in CHCl 3 showed strong absorption bands in the ultraviolet region (264-368 nm) that could be attributed respectively to the p ?…”

Novel vic-dioxime ligands and their poly-metal complexes bearing 1,8-diamino-3,6-dioxaoctane: synthesis, characterization, spectroscopy and electrochemistry

“…This large peak separation (DE = 0.83 V) between the reduction and its re-oxidation wave is probably due to the coupled chemistry following the electrode reaction. The reduction wave is assigned to metal-based character since the reduction based on the Co(II)/Co(I) process, in vicdioxime complexes, are usually observed at more positive values compared to that of ligand-based [24,43,[44][45][46][47]. The anodic peak observed at E pc = -0.20 V indicates that the six-coordination of the cobalt complex [Co(L 3 SL 3 )(H 2 O)] n changes into the four-coordination by loosing its axial ligands following the reduction process (Co(II)/Co(I)).…”

Synthesis, Spectroscopic, and Biological Studies of Chromium(III), Manganese(II), Iron(III), Cobalt(II), Nickel(II), Copper(II), Ruthenium(III), and Zirconyl(II) Complexes of N1,N2-Bis(3-((3-hydroxynaphthalen-2-yl)methylene-amino)propyl)phthalamide

“…Neutral hexadentate ligand, coordinating through all OH, C=N and NH groups as in case of complexes 10-12, the mode of coordination was suggested by the following evidence: i) the bands of C=N, OH and NH groups were shifted to lower wave number with decreasing their intensities, indicating that, all C=N, OH and NH groups were involved in the coordination, 19,25,[28][29][30] iii) the band of both C-O groups were shifted to higher wave number, indicating that, all hydroxyl groups were involved in the coordination 28 iv) the bands of both carbonyl groups were observed as single band at its original place in the ligand indicating that, they are not involved in coordination, 18,26,27 iv) the simultaneous appearance of new bands in the 650-670 and vibrations, respectively. 31,32 All complexes except complex 5, show band in the 375-413 region, assignable to υ(M-Cl).…”

“…Also, the spectrum shows bands at 1656 and 1620 and 1586 cm which were assigned to υ(C=O), υ(C=N) and (C=C) Ar respectively. 26,27 The spectra of solid complexes are compared with those of the ligand in order to know the mode of bonding. The spectra showed that the ligand behaved either as: Neutral tridentate ligand, coordinating through OH, C=N, and NH of one arm of the ligand as in case of complexes 2-5, the mode of coordination was suggested by the following evidence: i) the bands due toone OH, C=N, and NH were shifted to lower wave number with decreasing their intensities, while the other ones found almost at their original place, indicating that, only one of each pair were involved in the coordination, 19,25,[28][29][30] ii) one band of the two C-O bands was shifted to a higher wave number while the other is found almost at its original place, indicating that, only one phenolic oxygen was involved in the coordination, 28 iii) the band of both carbonyl groups found as one band almost at its original place in the ligand indicating that they are not involved in the coordination, 18,26,27 iv) the simultaneous appearance of new bands in the 656-690 and 560-570 cm -1 regions are due to the υ(M-N) and υ(M-O) vibrations, 31,32 respectively.…”

“…26,27 The spectra of solid complexes are compared with those of the ligand in order to know the mode of bonding. The spectra showed that the ligand behaved either as: Neutral tridentate ligand, coordinating through OH, C=N, and NH of one arm of the ligand as in case of complexes 2-5, the mode of coordination was suggested by the following evidence: i) the bands due toone OH, C=N, and NH were shifted to lower wave number with decreasing their intensities, while the other ones found almost at their original place, indicating that, only one of each pair were involved in the coordination, 19,25,[28][29][30] ii) one band of the two C-O bands was shifted to a higher wave number while the other is found almost at its original place, indicating that, only one phenolic oxygen was involved in the coordination, 28 iii) the band of both carbonyl groups found as one band almost at its original place in the ligand indicating that they are not involved in the coordination, 18,26,27 iv) the simultaneous appearance of new bands in the 656-690 and 560-570 cm -1 regions are due to the υ(M-N) and υ(M-O) vibrations, 31,32 respectively. Bibasichexadentate ligand, coordinating through all O -, C=N and NH groups as in case of complexes 6-9 and 13, the mode of coordination was suggested by the following evidence: i) the disappearance of the band of the two OH groups, 28 ii) the bands of C=N and NH groups were shifted to lower wave number with decreasing their intensities, indicating that, all C=N and NH groups were involved in the coordination, 19,25,29,30 iii) the band of two C-O groups were shifted to higher wave number, indicating that, both phenolic oxygen atoms were involved in the coordination 28 iv) the bands of both carbonyl groups were observed as single band at its original place in the ligand indicating that, they are not involved in the coordination, 18,26,27 iv) the simultaneous appearance of new bands in the 650-690 and 550-590 cm -1 regions are due to the υ(M-N) and υ(M-O) vibrations, respectively.…”