Synthesis, characterization and magnetic studies on mono-, di-, and tri-nuclear Cu(ii ) complexes of a new versatile diazine ligand
| Autor: | Laurence K. Thompson, Melanie Pilkington, Jeremy M. Rawson, Emma L. Gavey, Muhammad U. Anwar, Ahmed Al-Harrasi |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Diazine
chemistry.chemical_classification 010405 organic chemistry Ligand Stereochemistry Hydrazone 010402 general chemistry Oxime 01 natural sciences Medicinal chemistry 0104 chemical sciences Coordination complex Inorganic Chemistry Bipyridine chemistry.chemical_compound Deprotonation chemistry Moiety |
| Zdroj: | Dalton Transactions. 46:2105-2113 |
| ISSN: | 1477-9234 1477-9226 |
| DOI: | 10.1039/c6dt04794g |
| Popis: | The synthesis and coordination chemistry of a new open-chain diazine ligand (L4H2) containing bipyridine, oxime and hydrazone functionalities is reported. Reaction of L4H2 with CuCl2·2H2O affords the mononuclear complex [Cu(L4H2)Cl2] (1) in which the ligand acts as a neutral tridentate N,N',N'' donor, whereas treatment with a large excess of CuCl2·2H2O affords the dinuclear complex [Cu2(L4H)Cl3(CH3OH)(H2O)] (2) in which the ligand is singly-deprotonated at the diazine, offering N,N',N'' and N,N' donor sets to two Cu(ii) ions. Reaction with Cu(NO3)2·3H2O yields the trinuclear complex, [Cu3(L4H)2(CH3OH)4(NO3)4] (3) in which the ligand is again singly deprotonated, but now presents a tetradentate N,N',N'',N'''-donor set to the first Cu(ii) and behaves as an N,O-chelate to a second Cu(ii), with a conformational change from cis to trans at the diazine moiety. When the latter reaction is repeated in the presence of a mild base, a second trinuclear complex is isolated, [Cu3(L4)2(CH3CH2OH)](NO3)2 (4) in which both the diazine and oxime functionalities of the ligand are deprotonated which subsequently bridges all three Cu(ii) ions, acting as an N,N',N'' donor to the first Cu(ii), a N,N' donor to a second Cu(ii) (similar to 2) and as a terminal O-donor to a third Cu(ii) ion. The Cu(ii) ions are linked mutually cis via the two-atom diazine bridge in the case of 2 and 4 and trans in the case of 3. Magnetic studies reveal the presence of weak ferromagnetic interactions in 2 (g = 2.2, J/k = +12.8 K) and strong antiferromagnetic interactions in both 3 and 4 (g = 2.093 J/k = -140 K and g = 2.24 J/k = -300 K respectively). |
| Databáze: | OpenAIRE |
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