Synthesis and X-ray crystal structures of three new nickel(II) complexes of benzoylhydrazones: Catalytic applications in the synthesis of 2-arylbenzoxazoles
| Autor: | Necmi Dege, Bhumika Agrahari, Samaresh Layek, Akash Kumar, Devendra Deo Pathak |
|---|---|
| Přispěvatelé: | Ondokuz Mayıs Üniversitesi |
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Schiff base
010405 organic chemistry Ligand Crystal structure ONO pincer-type chemistry.chemical_element Nickel(II) complex Nuclear magnetic resonance spectroscopy 010402 general chemistry Homogeneous catalysis 01 natural sciences 0104 chemical sciences Pincer movement Catalysis 2-Arylbenzoxazole Inorganic Chemistry chemistry.chemical_compound Nickel Crystallography chemistry Materials Chemistry Physical and Theoretical Chemistry Methylene |
| DOI: | 10.1016/j.ica.2019.119222 |
| Popis: | WOS: 000505940600011 Three new complexes of nickel(II), having general formula [Ni(L-1)(PPh3)] (1), [Ni(L-1)(4-picoline)] (2), and [Ni (L-2)(4-picoline)] (3) were synthesized by the reaction of Ni(OAc)(2)center dot 4H(2)O with corresponding benzolyhydrazinederived Schiff base ligands i.e. [4-(diethylamino)-2-hydroxybenzylidene]-benzohydrazonic acid (H2L1) or [2-(hydroxynaphthalen-1-yl)methylene]-benzohydrazonic acid (H2L2) and PPh3/4-picoline as co-ligand in 1:1:1 ratio in methanol. All the three complexes were air-stable, isolated as reddish brown solids and characterized by Elemental analysis, FT-IR, H-1, C-13{H-1}, P-31{H-1} NMR spectroscopy and mass spectrometry. The structures of all three complexes were determined by single crystal X-ray diffraction studies which revealed the distorted square planar geometry of the complexes. In these complexes, three coordination sites were occupied by ONO pincer type Schiff base ligand and the fourth site was blocked by phosphorus (P) or nitrogen (N) atom of the co-ligand. The catalytic potential of all three complexes was explored in the synthesis of a series of 2-arylbenzoxazoles from aldehydes and 2-aminophenol, using low catalyst loading (0.5 mol%). Complex 1 was found to be the best catalyst among three complexes, for the synthesis of a series of 2-aryl benzoxazoles. The ease of synthesis, airstability and robustness of the catalyst, and good TONs are some of the key characteristics of the described catalytic system. IIT (ISM) senior research fellowship Authors are grateful to the CRF, IIT (ISM), Dhanbad; SAIF IISER Bhopal for the characterizations of the samples. Samaresh Layek, Bhumika Agrahari and Akash Kumar acknowledge the receipt of IIT (ISM) senior research fellowship. |
| Databáze: | OpenAIRE |
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