Synthesis, crystal structure and magnetic properties of a dinuclear and a trinuclear Ni(II) complexes derived from tetradentate ONNO donor Mannich base ligands
| Autor: | Avijit Das, Kisholoy Bhattacharya, Sanjib Giri, Ashutosh Ghosh |
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| Rok vydání: | 2017 |
| Předmět: |
010405 organic chemistry
Stereochemistry Ligand Protonation Mannich base Crystal structure 010402 general chemistry 01 natural sciences Magnetic susceptibility Square pyramidal molecular geometry 0104 chemical sciences Inorganic Chemistry chemistry.chemical_compound Crystallography chemistry Octahedron Octahedral molecular geometry Materials Chemistry Physical and Theoretical Chemistry |
| Zdroj: | Polyhedron. 134:295-301 |
| ISSN: | 0277-5387 |
| DOI: | 10.1016/j.poly.2017.06.022 |
| Popis: | Two complexes, [Ni 2 (HL 1 ) 2 (NCS) 2 ]·CH 2 Cl 2 ( 1 ) and [Ni 3 (L 2 ) 2 (NCS) 2 (H 2 O) 2 ]·CH 3 CN ( 2 ) have been synthesized using two different tetradentate ONNO donor Mannich base ligands N,N ′-bis(3,5-dimethyl-2-hydroxybenzyl)- N,N ′-dimethylethylenediamine(H 2 L 1 ) and N,N ′-bis(3-methoxy-5-methyl-2-hydroxybenzyl)- N,N ′-dimethylethylenediamine(H 2 L 2 ), respectively. Compound 1 is μ 1,1 isothiocyanato bridged dinuclear compound whereas compound 2 is phenoxido bridged trinuclear compound with SCN − as a terminal ligand. In compound 1 one of the two phenoxido oxygen atoms from each ligand remains protonated and hence makes the compound electrically neutral. X-ray-crystallography reveals that the two Ni(II) centres in compound 1 are in a distorted octahedral geometry and N atom of each of the two SCN − groups bridge the two metal centres. On the other hand, compound 2 possesses a centrosymmetric trinuclear structure where two distorted square pyramidal terminal Ni(II) centres are connected to a central octahedral Ni(II) via phenoxido bridge. Here SCN − ligand occupies the axial positions of the terminal Ni(II) centres by coordinating through N atom. Variable temperature magnetic susceptibility measurements of solid samples reveal that the Ni(II) paramagnetic centres in both 1 and 2 are antiferromagnetically coupled with J values of −30.66 cm −1 and −5.92 cm −1 for 1 and 2 , respectively. These values are in accordance with the magneto structural correlations of previously reported isothiocyanato bridged dinuclear and phenoxido bridged trinuclear Ni(II) compounds. |
| Databáze: | OpenAIRE |
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