Complexes of semicarbazones and thiosemicarbazones with nickel(II)

Spectroscopic characterization of some metal complexes derived from 4-acetylpyridine nicotinoylhydrazone

“…spectra of Zn II and Cu II complexes show that (4-APNH) behaves as mononegative bidentate ligand coordinating through carbonyl oxygen in the enol form and azomethine nitrogen ( Figure 5). This behavior is supported by the following evidences: ( [16,17].…”

Synthesis and characterization studies of new five member ring metal chelates derived from benzion phenoxyacetyl hydrazone(H2BPAH)

“…This mode of complexation is supported by the following evidences. (i) t(C‚N) shifts to a lower wavenumber, (ii) the disappearance of d(OH), (iii) t(C-O) (Lal et al, 2001) alcoholic shifts to a lower wavenumber indicating the probable participation of the oxygen in coordination, (iv) t(C‚O) appears in the same position at 1692 cm À1 as observed in the free ligand, suggesting that the carbonyl oxygen (C‚O) does not take part in coordination and (v) the appearance of new bands at 508 and 473 cm À1 assigned to t(Pd-O) (Speca et al, 1974) and t(Pd-N) (Beecroft et al, 1974), respectively.…”

“…In Compound alcoholic also shifts to a lower wavenumber and (iv) the appearance of new bands at 512-513 and 449-471 cm À1 regions assigned to t(M-O) (Speca et al, 1974) and t(M-N) (Beecroft et al, 1974), respectively.…”

“…The IR spectrum of [Cd(H 2 BPAH)Cl 2 ] shows that H 2 BPAH behaves as a neutral bidentate ligand, coordinating through the carbonyl oxygen (C‚O) and azomethine (C‚N) nitrogen forming a five membered ring including the cadmium atom. This mode of chelation (structure II) is supported by the following evidences: (i) both t(C‚O) and t(C‚N) shift to a lower wavenumber, (ii) The stretching vibration of the (OH) group appears as a strong band in the high frequency regions at 3632 cm À1 indicating the non-involvement of the OH group in bonding (Abu El-Reash et al, 1988); and (iii) the appearance of new bands in the low frequency region at 544 and 514 cm À1 assigned to t(Cd-O) (Speca et al, 1974) and t(Cd-N) (Beecroft et al, 1974), respectively. The IR spectrum data of [Pd(HBPAH) 2 ] show that H 2 BPAH behaves as a mononegative bidentate ligand which coordinates via the azomethine nitrogen (C‚N) and the oxygen atom of the deprotanted alcoholic forming a five membered ring including the palladium atom as shown in structure III.…”

SYNTHESIS, SPECTRAL AND BIOLOGICAL STUDIES OF Mn(II), Co(II) AND Cu(II) COMPLEXES OF [2-CHLORO-5-(2,4-DIHYDROXYPHENYL AZO)PHENYL] PHENYLMETHANONE.

“…The strong absorption band shown by the ligand RABP at 1460 cm -1 corresponds to ѵ N=N suffers a shift to higher wave number may taken as an evidence for the participation of -N=N group in coordination (Gaber, M., et al, 2008). This is supported by the appearance of new band in the region of 423-467 cm -1 assignable to ν M-N (Beecroft, B., et al, 1974). The considerable shift shown by strong ν C=O band at 1619 cm -1 of RABP to lower value in complexes is a clear evidence for the participation of >C=O in coordination (Radhakrishnan, P.K., et al, 1984).…”