Effect of Ligand Spacer on Metallosupramolecular Architectures: From a Dinuclear Copper(II) Double Helicate to a Tetranuclear Copper(II) Complex
✍ Scribed by Partha Halder; Priya Ranjan Banerjee; Ennio Zangrando; Tapan Kanti Paine
- Publisher
- John Wiley and Sons
- Year
- 2008
- Tongue
- English
- Weight
- 324 KB
- Volume
- 2008
- Category
- Article
- ISSN
- 1434-1948
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✦ Synopsis
Abstract
Two new bis(N,O‐bidentate) Schiff base ligands with asymmetric spacers between the donor sites have been synthesized. The asymmetric ligand H~2~L^1^ self‐assembles with copper(II) ions to give rise to a dinuclear copper(II) complex [Cu~2~L^1^~2~] (1), while a more flexible ligand H~2~L^2^, having an additional methylene group in the spacer, forms a tetranuclear copper(II) cluster [Cu~4~L^2^~4~] (2). Both complexes have been characterized by different analytical and spectroscopic techniques. Single‐crystal X‐ray diffraction study of 1 shows a dinuclear copper(II) double‐stranded helicate with the two heterotopic ligands oriented head‐to‐head (HH), with a separation of 7.687(3) Å between the distorted tetrahedral copper(II) centers. The bis(bidentate) ligand strands wrap around the copper centers with a similar relative orientation (HH) to give rise to a double‐helical structure. The intramolecular face‐to‐face π–π interaction stabilizes the double‐helical structure of the molecule. In the tetranuclear complex 2, the four copper(II) centers, separated by 7.288(2)–8.239(2) Å, define a slightly distorted tetrahedron.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)