Details

Autor(en) / Beteiligte

• Zhu, Hai-Liang
• Zheng, Li-Min
• Fu, De-Gang
• Huang, Pei
• Bu, Wei-Ming
• Tang, Wen-Xia

Titel

Synthesis, structure and magnetic behavior of a di-μ-chloro-di-μ-imidazolato-tetracopper(II) complex with two dinucleating macrocycles

Ist Teil von

• Inorganica Chimica Acta, 1999-04, Vol.287 (1), p.52-60

Ort / Verlag

Elsevier B.V

Erscheinungsjahr

1999

Quelle

Elsevier Journal Backfiles on ScienceDirect (DFG Nationallizenzen)

Beschreibungen/Notizen

• The synthesis, crystal structure and magnetic behavior of the di-μ-chloro-di-μ-imidazolato-tetracopper(II) complex [L 2Cu 4(Im) 2Cl 2](ClO 4) 4(CH 3OH), where Im is imidazole and L is 3,6,9,17,20,23-hexaazatricyclo[23.3.1.1 11,13]triaconta-1(29),11(30),12,14,25(26),27-hexaene, have been studied. X-ray structure analysis shows that the compound crystallizes in monoclinic and space group P2(1)/ c, with a=13.716(3), b=11.165(2), c=27.340(6) Å, β=98.43(3)° and Z=2. The cation consists of two imidazolate bridged dicopper(II) centers encapsulated within two macrocycles, respectively, which are linked by a pair of chloride atoms. In each imidazolate bridged dicopper(II) center, both copper atoms are five-coordinated by four basal nitrogen atoms (three from the macrocycle and one from the imidazolate) and one axial chloride atom shared with another copper atom in the other imidazolate bridged dicopper(II) center in the molecule. pH-dependent ESR studies of the title complex in frozen 50% aqueous DMSO solution show that the bridged cation [LCu 2(Im)] 3+ exists as a major species in solution over the range 7.00≤pH≤11.5, and the μ-Im bridge is broken in the pH range of 7.00–5.20. The molar conductance of the title complex indicates that the μ-Cl bridge is almost entirely dissociated when dissolved in 1:1 DMSO aqueous solution. However, when Cl − ions were gradually added to the solution, a complex with a CuN 4Cl chromophore was successively formed. Magnetic measurement studies on the powder sample reveal that antiferromagnetic interactions are mediated through both μ-Im ( J 1=−26.78 cm −1) and μ-Cl ( J 2=−9.52 cm −1) bridges.