Abstract
Using a (2-pyridyl)ethylamine-appended carboxylate ligand a new cluster [CuII7(L)4(μ3-OH) 2(H2O)2(DMF)2][ClO4] 4·4H2O (1) [L(2-): N-{CH2CH 2(2-pyridyl)}(CH2CH2CO2) 2] is synthesized, as a result of 'coordination-driven self-assembly'. The structure of 1 is unique and consists of a centrosymmetric carboxylato- and hydroxo-bridged heptanuclear copper(ii) cation, with body-centred anti-prismatic topology. The four crystallographically independent copper(ii) centres differ markedly in their coordination geometry. In addition to establishing cluster authenticity, the structural analysis of 1 discloses two notable features. The existence of {CuII3(μ 3-OH)}5+ core and H-bonded metal-coordinated carboxylate and water unit, with water acting as a proton donor. Both of these features have biological implications. Magnetic measurements reveal that in this unprecedented cluster the net magnetic-exchange is antiferromagnetic. The different types of magnetic-exchange coupling constants (J values) considered for magnetic data analysis appear to adopt a variety of values depending on the specific geometric parameters associated with two interacting copper(ii) centres. Notably, for 1 a good agreement between the J values obtained from DFT calculations at the B3LYP level of theory and from the experimental data is achieved.
Original language | English |
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Pages (from-to) | 10055-10062 |
Number of pages | 8 |
Journal | Dalton Transactions |
Volume | 40 |
Issue number | 39 |
DOIs | |
State | Published - 21 Oct 2011 |
Externally published | Yes |