Template synthesis of 1-(8'-amino-α-naphthyl)-4-(8'-amino-α-naphthylamine)-1-azabuta-1,3-diene, a tetraaza half-cyclised ligand, and characterisation of its copper(II) complexes

Nita Lewis, D. A. Tocher, G. K. Patra, J. P. Naskar, D. Datta

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Abstract

Reaction of 1,1,3,3-tetramethoxypropane with 1,8-diaminonaphthalene in presence of a nickel(II) template in aqueous medium generates the free acyclic ligand 1-(8'-amino-α-naphthyl)-4-(8'-amino-α-naphthylamine)-1-azabuta-1,3-diene (LH; H: dissociable proton) as a 1.5 hydrate. The ligand undergoes acid dissociation in non-aqueous solvents which is reflected in its 13C NMR spectrum in deuteriated dimethyl sulphoxide (DMSO). Its pK(a) value determined in DMSO from conductivity data is 5.18. With copper(II) perchlorate, LH forms air sensitive complexes of type CuL(ClO4).3H2O and CuL(ClO4).DMF (DMF: dimethylformamide). In both the complexes, the perchlorate anion is weakly bound to the metal as revealed by their conductivity in DMF suggesting a CuN4O2+ chromophore. Their EPR spectra in DMF-toluene glass at 77 K are almost identical and have rhombic features (<g3>, 2.40; <g2>, 2.08; <g1>, 2.01; <A3>, 137x10-4 cm-1; <A2>, 18x10-4 cm-1) indicating that the coordination sphere around the copper ion is of distorted square-pyramidal type. ZINDO calculations show that the CuL+ fragment has a butterfly like shape with the naphthalene fragments spanning like two wings and the metal in the N4 plane. In cyclic voltammetric experiments in DMF at a platinum electrode, the complexes show a quasi-reversible two-electron ligand oxidation with an E(1/2) of 0.12 V vs saturated calomel electrode (SCE) and an irreversible metal oxidation process at a low potential (< 0.5 V vs SCE).

Original languageEnglish
Pages (from-to)400-406
Number of pages7
JournalIndian Journal of Chemistry - Section A Inorganic, Physical, Theoretical and Analytical Chemistry
Volume39
Issue number4
StatePublished - Jan 1 2000
Externally publishedYes

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1-Naphthylamine
dienes
Copper
templates
Metals
perchlorates
Ligands
Dimethyl Sulfoxide
copper
ligands
Electrodes
electrodes
synthesis
fragments
metals
Dimethylformamide
Oxidation
conductivity
oxidation
Toluene

ASJC Scopus subject areas

  • Chemistry(all)

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@article{559ea75915d74bdfbaf3345cd4d31383,
title = "Template synthesis of 1-(8'-amino-α-naphthyl)-4-(8'-amino-α-naphthylamine)-1-azabuta-1,3-diene, a tetraaza half-cyclised ligand, and characterisation of its copper(II) complexes",
abstract = "Reaction of 1,1,3,3-tetramethoxypropane with 1,8-diaminonaphthalene in presence of a nickel(II) template in aqueous medium generates the free acyclic ligand 1-(8'-amino-α-naphthyl)-4-(8'-amino-α-naphthylamine)-1-azabuta-1,3-diene (LH; H: dissociable proton) as a 1.5 hydrate. The ligand undergoes acid dissociation in non-aqueous solvents which is reflected in its 13C NMR spectrum in deuteriated dimethyl sulphoxide (DMSO). Its pK(a) value determined in DMSO from conductivity data is 5.18. With copper(II) perchlorate, LH forms air sensitive complexes of type CuL(ClO4).3H2O and CuL(ClO4).DMF (DMF: dimethylformamide). In both the complexes, the perchlorate anion is weakly bound to the metal as revealed by their conductivity in DMF suggesting a CuN4O2+ chromophore. Their EPR spectra in DMF-toluene glass at 77 K are almost identical and have rhombic features (3>, 2.40; 2>, 2.08; 1>, 2.01; <A3>, 137x10-4 cm-1; <A2>, 18x10-4 cm-1) indicating that the coordination sphere around the copper ion is of distorted square-pyramidal type. ZINDO calculations show that the CuL+ fragment has a butterfly like shape with the naphthalene fragments spanning like two wings and the metal in the N4 plane. In cyclic voltammetric experiments in DMF at a platinum electrode, the complexes show a quasi-reversible two-electron ligand oxidation with an E(1/2) of 0.12 V vs saturated calomel electrode (SCE) and an irreversible metal oxidation process at a low potential (< 0.5 V vs SCE).",
author = "Nita Lewis and Tocher, {D. A.} and Patra, {G. K.} and Naskar, {J. P.} and D. Datta",
year = "2000",
month = "1",
day = "1",
language = "English",
volume = "39",
pages = "400--406",
journal = "Indian Journal of Chemistry - Section A Inorganic, Physical, Theoretical and Analytical Chemistry",
issn = "0376-4710",
publisher = "Scientific Publishers of India",
number = "4",

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TY - JOUR

T1 - Template synthesis of 1-(8'-amino-α-naphthyl)-4-(8'-amino-α-naphthylamine)-1-azabuta-1,3-diene, a tetraaza half-cyclised ligand, and characterisation of its copper(II) complexes

AU - Lewis, Nita

AU - Tocher, D. A.

AU - Patra, G. K.

AU - Naskar, J. P.

AU - Datta, D.

PY - 2000/1/1

Y1 - 2000/1/1

N2 - Reaction of 1,1,3,3-tetramethoxypropane with 1,8-diaminonaphthalene in presence of a nickel(II) template in aqueous medium generates the free acyclic ligand 1-(8'-amino-α-naphthyl)-4-(8'-amino-α-naphthylamine)-1-azabuta-1,3-diene (LH; H: dissociable proton) as a 1.5 hydrate. The ligand undergoes acid dissociation in non-aqueous solvents which is reflected in its 13C NMR spectrum in deuteriated dimethyl sulphoxide (DMSO). Its pK(a) value determined in DMSO from conductivity data is 5.18. With copper(II) perchlorate, LH forms air sensitive complexes of type CuL(ClO4).3H2O and CuL(ClO4).DMF (DMF: dimethylformamide). In both the complexes, the perchlorate anion is weakly bound to the metal as revealed by their conductivity in DMF suggesting a CuN4O2+ chromophore. Their EPR spectra in DMF-toluene glass at 77 K are almost identical and have rhombic features (3>, 2.40; 2>, 2.08; 1>, 2.01; <A3>, 137x10-4 cm-1; <A2>, 18x10-4 cm-1) indicating that the coordination sphere around the copper ion is of distorted square-pyramidal type. ZINDO calculations show that the CuL+ fragment has a butterfly like shape with the naphthalene fragments spanning like two wings and the metal in the N4 plane. In cyclic voltammetric experiments in DMF at a platinum electrode, the complexes show a quasi-reversible two-electron ligand oxidation with an E(1/2) of 0.12 V vs saturated calomel electrode (SCE) and an irreversible metal oxidation process at a low potential (< 0.5 V vs SCE).

AB - Reaction of 1,1,3,3-tetramethoxypropane with 1,8-diaminonaphthalene in presence of a nickel(II) template in aqueous medium generates the free acyclic ligand 1-(8'-amino-α-naphthyl)-4-(8'-amino-α-naphthylamine)-1-azabuta-1,3-diene (LH; H: dissociable proton) as a 1.5 hydrate. The ligand undergoes acid dissociation in non-aqueous solvents which is reflected in its 13C NMR spectrum in deuteriated dimethyl sulphoxide (DMSO). Its pK(a) value determined in DMSO from conductivity data is 5.18. With copper(II) perchlorate, LH forms air sensitive complexes of type CuL(ClO4).3H2O and CuL(ClO4).DMF (DMF: dimethylformamide). In both the complexes, the perchlorate anion is weakly bound to the metal as revealed by their conductivity in DMF suggesting a CuN4O2+ chromophore. Their EPR spectra in DMF-toluene glass at 77 K are almost identical and have rhombic features (3>, 2.40; 2>, 2.08; 1>, 2.01; <A3>, 137x10-4 cm-1; <A2>, 18x10-4 cm-1) indicating that the coordination sphere around the copper ion is of distorted square-pyramidal type. ZINDO calculations show that the CuL+ fragment has a butterfly like shape with the naphthalene fragments spanning like two wings and the metal in the N4 plane. In cyclic voltammetric experiments in DMF at a platinum electrode, the complexes show a quasi-reversible two-electron ligand oxidation with an E(1/2) of 0.12 V vs saturated calomel electrode (SCE) and an irreversible metal oxidation process at a low potential (< 0.5 V vs SCE).

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