Cover Story - Christmas Decorations?

The diagram on the front cover is not a design for a new type of Christmas decoration but a fascinating structure from Neil Champness, Nottingham University. Here is another view from the side.

During studies into the preparation of interpenetrated adamantoid lattices the remarkable complex {[Cu₂(MeCN)₂(L)₃](PF₆ ) ₂}_n, where L =1,4-bis-(4-pyridyl)butadiyne, was isolated. Characterisation by single crystal X-ray diffraction studies revealed a polycatenated undulating molecular ladder motif leading to the formation of fully-interwoven two-dimensional sheets. This was the first example of this structural type and it is formed due to the retention of an acetonitrile solvent molecule by each Cu(I) centre. This allows both the ladder structure to be formed, by blocking one of the Cu(I) coordination sites, and leads to the undulating nature of these ladders. Polycatenation is observed because the long bridging ligand results in a considerable space being left between the "rungs" of any given ladder, allowing the interpenetration of four other symmetry-related ladders. The diagrams on this page show the undulating structure from another view point, three shades distinguish the three ladders, and show the remarkable symmetry more clearly.

This structure has been published in:

A.J. Blake, N.R.Champness, A. Khlobystov, D.A. Lemenovskii, W-S. Li and M. Schr�der, Chem. Commun., (1997), 2027.

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