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The Missing Link in Ni(II)‐Ln(III) System: Design and Synthesis of a Dinuclear [Ni 2 ] and Three Pentanuclear [Ni 3 Ln 2 ] (Ln=La, Ce, Eu) Complexes of a Schiff Base Ligand
Author(s) -
Saha Sudeshna,
Sarkar Arijit,
Das Suman,
Panda Tarun K.,
Harms Klaus,
Nayek Hari Pada
Publication year - 2017
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201701146
Subject(s) - isostructural , heteronuclear molecule , ligand (biochemistry) , crystallography , chemistry , lanthanide , nickel , schiff base , crystal structure , metal ions in aqueous solution , metal , stereochemistry , ion , nuclear magnetic resonance spectroscopy , organic chemistry , biochemistry , receptor
A new Schiff base ligand N‐(2‐hydroxyphenyl‐3‐methoxy‐salicylideneamine)‐5‐nitrophenol ( H 2 L ) has been synthesized by the reaction of o ‐vanillin with 2‐amino‐4‐nitrophenol. The ligand H 2 L has been employed to prepare homo‐ and heteronuclear metal complexes. For example, a dinuclear Ni(II) complex, [Ni 2 (L) 2 (H 2 O) 3 ]⋅2DMF⋅3H 2 O ( 1 ) and a new family of three pentanuclear heterometallic [Ni 3 Ln 2 L 6 (H 2 O) 4 (DMF) 2 ]⋅4DMF (Ln=La ( 2 ), Ce ( 3 ) and Eu ( 4 ) were prepared by the reaction of it with nickel nitrate hexahydrate and hydrated lanthanide nitrates. The solid state structures of ligand ( H 2 L ) and complexes 1–4 were determined by single crystal X‐ray diffraction analyses. Single crystal X‐ray diffraction and NMR data reveal that the ligand H 2 L exist as a keto‐enamine form in the solid state. Structure of complex 1 indicates formation of a dinuclear Ni(II) complex. Complexes 2–4 are isostructural and exhibits a butterfly‐like structure containing two Ln(III) ions and three Ni(II) ions. The Ni(II) and Ln(III) are bridged by phenoxo and aqua ligands resulting a pentanuclear chain with alternating Ni(II) and Ln(III) ions. Different coordination modes of ligand ( H 2 L) have been explored. To the best of our knowledge, such pentanuclear complexes containing Ni−Ln and Schiff base ligand are hitherto unknown. The thermal stability and optical properties of all complexes are also investigated.