Biswas, Chaitali ; Drew, Michael G. B. ; Ruiz, Eliseo ; Estrader, Marta ; Diaz, Carmen ; Ghosh, Ashutosh (2010) Synthesis, crystal structure and magnetic properties of three unprecedented tri-nuclear and one very rare tetra-nuclear copper (II) Schiff-base complexes supported by mixed azido/phenoxo/nitrato or acetato bridges Dalton Transactions, 39 (32). pp. 7474-7484. ISSN 1477-9226
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Official URL: http://pubs.rsc.org/en/content/articlelanding/2010...
Related URL: http://dx.doi.org/10.1039/C0DT00331J
Abstract
Three novel mixed bridged trinuclear and one tetranuclear copper(II) complexes of tridentate NNO donor Schiff base ligands [Cu3(L1)2(μ1,1-N3)2(CH3OH)2(BF4)2] (1), [Cu3(L1)2(μ1,1-N3)2(μ-NO3-1κO:2κO′)2] (2), [Cu3(L2)2(μ1,1-N3)2(μ-NO3-1κO:2κO′)2] (3) and [Cu4(L3)2(μ1,1-N3)4(μ-CH3COO-1κO:2κO′)2] (4) have been synthesized by reaction of the respective tridentate ligands (L1 = 2-[1-(2-dimethylamino-ethylimino)-ethyl]-phenol, L2 = 2-[1-(2-diethylamino-ethylimino)-ethyl]-phenol, L3 = 2-[1-(2-dimethylamino-ethylimino)-methyl]-phenol) with the corresponding copper (II) salts in the presence of NaN3. The complexes are characterized by single-crystal X-ray diffraction analyses and variable-temperature magnetic measurements. Complex 1 is composed of two terminal [Cu(L1)(μ1,1-N3)] units connected by a central [Cu(BF4)2] unit through nitrogen atoms of end-on azido ligands and a phenoxo oxygen atom of the tridentate ligand. The structures of 2 and 3 are very similar; the only difference is that the central unit is [Cu(NO3)2] and the nitrate group forms an additional μ-NO3-1κO:2κO′ bridge between the terminal and central copper atoms. In complex 4, the central unit is a di-μ1,1-N3 bridged dicopper entity, [Cu2(μ1,1-N3)2(CH3COO)2] that connects two terminal [Cu(L3)(μ1,1-N3)] units through end-on azido, phenoxo oxygen and μ-CH3COO-1κO:2κO′ triple bridges to result in a tetranuclear unit. Analyses of variable-temperature magnetic susceptibility data indicates that there is a global weak antiferromagnetic interaction between the copper (II) ions in complexes 1–3, with the exchange parameter J of −9.86, −11.6 and −19.98 cm−1 for 1–3, respectively. In complex 4 theoretical calculations show the presence of an antiferromagnetic coupling in the triple bridging ligands (acetato, phenoxo and azido) while the interaction through the double end-on azido bridging ligand is strongly ferromagnetic.
| Item Type: | Article |
|---|---|
| Source: | Copyright of this article belongs to Royal Society of Chemistry. |
| ID Code: | 108332 |
| Deposited On: | 13 Oct 2017 12:56 |
| Last Modified: | 13 Oct 2017 12:56 |
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