Metal complexes with unsymmetrical tetradentate ketoenamines derived from β-diketones or ethoxymethylene-β-dicarbonyl compounds and 1-amino-4-methyl-3-azahept-4-ene-6-one

Novel Unsymmetrical Tetradentate Schiff Base Complexes of Cobalt (II) and Palladium (II) with N2O2 Donor Sets

“…Comparing 1 H NMR spectra, which are taken in the same condition, the chemical shift of NH 2 in HA 1 is less than for that of HA 2 . The result also shows that the reactivity toward salicylaldehyde generally follows the decrease in NH 2 proton acidity HA 2 > HA 1 . This increase follows as the increase in electron-withdrawing properties of the aromatic ring, which decrease the electron-density at the site of electrophilic attack, thus inhibiting the condensation.…”

“…The reaction of salicylaldehyde with the precursors HA 1 and HA 2 were monitored by 1 H NMR spectrometry. Comparing 1 H NMR spectra, which are taken in the same condition, the chemical shift of NH 2 in HA 1 is less than for that of HA 2 .…”

“…This increase follows as the increase in electron-withdrawing properties of the aromatic ring, which decrease the electron-density at the site of electrophilic attack, thus inhibiting the condensation. The H 2 A 3 , H 2 A 4 ligands were isolated as yellow-orange solids and characterised by IR, 1 H NMR, and elemental analysis C, H, N. The ligands were then used without further purification to prepare the metal complexes.…”

“…5b The infrared spectra of the complexes have no bands between 3100 and 4000 cm -1 , indicating the absence of enamine protons and water. 1 The absorption Fig. 1 Half-units HA 1 and HA 2 ; H 2 A 3 and H 2 A 4 ligands.…”

Palladium(II) 9,10-phenanthrenequinone N-substituted thiosemicarbazone/semicarbazone complexes as efficient catalysts for N-arylation of imidazole

“…The appearance of bands below 470 nm suggests a square planar geometry around palladium(II) in the complexes [20,21]. Bands in the ultraviolet region at 250-334 nm have been assigned to intra ligand transitions.…”