Heteroarylazo derivatives of cyclohexane-1,3-dione and their metal complexes

The coupling of diazotized 2-aminothiazole and 2-aminobenzo-thiazole with cyclohexane-1,3-dione yielded a new type of tridentate ligand systems (HL). Analytical, IR, 1H NMR, 13C NMR and mass spectral data indicate the existence of the compounds in the intramolecularly hydrogen bonded azo-enol tautomeric form. Monobasic tridentate coordination of the compounds in their [CuL(OAc)] and [ML2] complexes [M = Ni(II) and Zn(II)] has been established on the basis of analytical and spectral data. The Zn(II) chelates are diamagnetic while Cu(II) and Ni(II) complexes showed normal paramagnetic moment

1-Naphthylazo derivatives of some 1,3-dicarbonyl compounds and their Cu(II), Ni(II) and Zn(II) complexes

The coupling of diazotized 1-aminonaphthalene with 1,3-dicarbonyl compounds (acetylacetone, methylacetoacetate and acetoacetanilide) yielded a new series of bidentate ligand systems (HL). Analytical, IR, 1H-NMR and mass spectral data indicate that the compounds exist in the intramolecularly hydrogen bonded keto-hydrazone form. With Ni(II), Cu(II) and Zn(II), these potential monobasic bidentate ligands formed [ML2] type complexes. The IR, 1H-NMR and mass spectral data of the complexes are consistent with the replacement of the chelated hydrazone proton of the ligand by a metal ion, thus leading to a stable six-membered chelate ring involving the hydrazone nitrogen and the hydrogen bonded carbonyl oxygen. The Ni(II) and Zn(II) chelates are diamagnetic, while the Cu(II) complexes are paramagnetic. In the metal complexes of the naphthylazo derivatives of acetylacetone and methylacetoacetate, the acetyl carbonyl is involved in coordination, whereas in the chelates of the naphthylazo derivative of acetoacetanilide, the anilide carbonyl is bonded with the metal ion

Metal complexes of Schiff bases derived from dicinnamoylmethane and aliphatic diamines

(Received 26 July, revised 10 December 2007)Two new Schiff bases containing olefinic linkages have been synthesized by condensing aliphatic diamines with dicinnamoylmethane under specified conditions. The existence of these compounds predominantly in the intramolecularly hydrogen bonded keto-enamine form was well demonstrated by their IR, 1H-NMR and mass spectral data. Dibasic tetradentate N2O2 coordination of the compounds in their [ML] complexes (M = Ni(II), Cu(II) and Zn(II)) was established on the basis of analytical and spectral data

Unsaturated b-ketoesters and their Ni(II), Cu(II) and Zn(II) complexes

A new series of b-ketoesters in which the keto group is attached to the olefinic linkage were synthesized by the reaction of methyl acetoacetate and aromatic aldehydes under specified conditions. The existence of these compounds predominantly in the intramolecularly hydrogen bonded enol form was well demonstrated from their IR, 1H-NMR and mass spectral data. Details on the formation of their [ML2] complexes with Ni(II), Cu(II) and Zn(II) and the nature of the bonding are discussed on the basis of analytical and spectral data

Original scientific paper

Abstract: The coupling of diazotized 1-aminonaphthalene with 1,3-dicarbonyl compounds (acetylacetone, methylacetoacetate and acetoacetanilide) yielded a new series of bidentate ligand systems (HL). Analytical, IR, 1 H-NMR and mass spectral data indicate that the compounds exist in the intramolecularly hydrogen bonded keto-hydrazone form. With Ni(II), Cu(II) and Zn(II), these potential monobasic bidentate ligands formed [ML 2] type complexes. The IR, 1 H--NMR and mass spectral data of the complexes are consistent with the replacement of the chelated hydrazone proton of the ligand by a metal ion, thus leading to a stable six-membered chelate ring involving the hydrazone nitrogen and the hydrogen bonded carbonyl oxygen. The Ni(II) and Zn(II) chelates are diamagnetic, while the Cu(II) complexes are paramagnetic. In the metal complexes of the naphthylazo derivatives of acetylacetone and methylacetoacetate, the acetyl carbonyl is involved in coordination, whereas in the chelates of the naphthylazo derivative of acetoacetanilide, the anilide carbonyl is bonded with the metal ion

Original scientific paper Metal complexes of Schiff’s bases derived from 3-(arylazo)-2,4-

Abstract: Phenylazo- and thiazolylazo-2,4-pentanediones on reaction with 2-aminophenol and 2-aminothiophenol yielded a new series of polydentate Schiff’s base ligands. The structure and tautomeric nature of these compounds and their metal complexes were established on the basis of their IR, 1 H-NMR and mass spectral data. The spectral and analytical data revealed the condensation of both carbonyl groups of 3-(2-thiazolylazo)-2,4-pentanedione with 2-aminophenol to form an N 2O 2 tetradentate ligand