Cr(III), Fe(III) and Co(III) complexes of tetradentate (ONNO) Schiff base ligands: Synthesis, characterization, properties and biological activity

Synthesis, Characterization and Biological Studies of New Mn(II), Ni(II), Co(II), Cu(II) and Zn(II) of 2-(benzothiazol-2-yl)-N'-(2,5-dihydroxybenzylidene)acetohydrazide

“…It bonded to metal ions through the azomethine (C=N) and deprotonated phenolic groups as in complex (14). This mode of bonding was suggested by the following evidence: (i) the disappearance of the band for the phenolic OH, indicating the subsequent deprotonation of the phenolic proton prior to coordination, 24 (ii) the shift of υ(C=N) to lower frequency (16 cm ) together with its weak appearance, which indicates the coordination of the azomethine nitrogen, 19,20 (iii) the band due to υ(C=O) group retained its intensity and place, (iv) the occurrence of the υ(N-N) band at higher wave number, (v) the band due to phenolic C-O stretching vibration is upward shifted due to oxygen-metal coordination, 21 (vi) the simultaneous appearance of new bands at 551 and 647 cm -1 due to the υ(M-N) and υ(M-O) vibrations, respectively.…”

“…Itbonded to metal ions through the enolic carbonyl (C-O), azomethine (C=N) and phenolic groups as in complexes (4), (5), (6), (7) and (8). this mode of bonding was suggested by the following evidence: (i) the band due to the phenolic OH group is weakened and shifted to lower wave number by 10 -15 cm ) together with its weak appearance, which indicates the coordination of the azomethine nitrogen, 19,20 (iii) the disappearance of the band due to the carbonyl and the amine groups with the appearance of a new band due to the new υ(C=N) found at higher wave number, (iv) the occurrence of the υ(N-N) band at higher wave number, (v) the band due to phenolic C-O stretching vibrations are upward shifted due to O-metal coordination, 21 (vi) the simultaneous appearance of new bands in the 540 -590 and 608 -655 cm -1 regions due to the υ(M-N) and υ(M-O) vibrations, respectively.…”

Synthesis, Characterization and Biological Studies of Homobimetallic Schiff Base Cu(II) and Ni(II) Complexes

“…Schiff base ligands with donors N, O, S etc., have structural similarities with natural biological systems and imports and rasemination reaction in biological systems due to presence of imine (-N=CH-) group 3 . Schiff bases are important intermediate for the synthesis of bioactive compounds [4][5][6] .…”

Convenient and mild synthesis and characterisation of some new Schiff bases

“…These compounds also find many important catalytic applications, ranging from asymmetric epoxidation [16], Lewis acid assisted organic transformations [17], solid phase extraction of metal ions [18] to various types of polymerization [19][20][21][22] as well as their application for the preparation of ion selective electrodes [23][24][25][26][27]. Recently, Ayla Balaban Gunduzalp and co-worker have been prepared and characterized complexes of tetra dentate Schiff base ligands [28].…”