| Autor: |
Stamatatos, Theocharis C., Vlahopoulou, Gina, Raptopoulou, Catherine P., Psycharis, Vassilis, Escuer, Albert, Christou, George, Perlepes, Spyros P. |
| Předmět: |
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| Zdroj: |
European Journal of Inorganic Chemistry; Jul2012, Vol. 2012 Issue 20, p3121-3131, 11p |
| Abstrakt: |
The use of α-benzoin oxime (bzoxH2) in copper(II) benzoate chemistry, in the absence or presence of ancillary azido ligands, is reported. The reaction of Cu(O2CPh)2 ·2H2O with one equivalent of bzoxH2 in N, N-dimethylformamide (DMF) affords the decanuclear complex [Cu10(bzox)10(DMF)4] ( 1) in good yield. Dissolution of 1 in CH2Cl2 leads to the subsequent isolation of the solvent-free complex [Cu10(bzox)10] ( 2) in moderate yields. Complexes 1 and 2 are isostructural and possess a loop or single-strand molecular wheel topology. The bzox2- dianions behave as η1:η1:η2:μ3 ligands, which give rise to an overall [Cu10(μ-ONR)10(μ-OR′)10] core. Both 1 and 2 stack to form nanotubular columns with beautiful supramolecular architectures. The reaction of Cu(O2CPh)2 ·2H2O with bzoxH2 and NaN3 in a 1:1:1 molar ratio in MeOH gives the bzoxH2-free complex [Cu(N3)(O2CPh)(MeOH)] n ( 3), which is a 1D chain. The CuII atoms in 3 are linked by a single, end-on N3- group, a syn, syn-η1:η1:μ PhCO2- ion, and an oxygen atom from the bridging MeOH ligand. The 1D chains are hydrogen bonded into 2D sheets through Nazide ···H(OMeOH) interactions. Variable-temperature, solid-state direct-current magnetic studies were carried out on 1- 3. The data for 1 and 2 indicate very strong antiferromagnetic exchange interactions and a S = 0 ground state, which is expected for even-membered loop arrays of CuII atoms. In contrast, 3 exhibits ferromagnetic exchange interactions; the data were fitted to the appropriate equation derived from the Hamiltonian H = - JΣ( Si · Si+1), which includes a zJ′ interchain interaction term. The best-fit parameters were J = +49.6(4) cm-1, g = 2.067(3), and zJ′ = 2.3(1) K. The combined results demonstrate the ligating flexibility of both the bzoxH2 and azido groups and their usefulness in the synthesis of polynuclear CuII clusters and coordination polymers. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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