Cyanide‐Bridged Oligonuclear Complexes Containing Ni‐CN‐Cu and Pt‐CN‐Cu Linkages

The central building blocks Ni(CN) 4 2− and Pt(CN) 4 2− can be combined with one, two or four Cu II L units (L = tren, Me 6 tren, tpa) to form di‐, tri‐ and pentanuclear complexes with Ni‐CN‐Cu and Pt‐CN‐Cu linkages. Structure determinations of these and the side product [(tren)Cu−CN−Cu(tren)] (ClO 4 ) 2 reveal mostly linear M‐C‐N‐Cu arrays and cis ‐, trans ‐ and star‐like arrangements of the CN‐Cu units around the central Ni or Pt ions. The $\tilde {\nu}$ (CN) IR data for the bridging cyanides show a characteristic hypsochromic effect compared to the data for the free M(CN) 4 2− complexes. The absorption bands in the visible spectra of the oligonuclear complexes are shifted to shorter wavelengths than those of the free LCu II ‐X complexes. The Cu II /Cu I redox steps in the cyclic voltammograms allow the conclusion that there is electronic communication between the external CuL units when they are arranged in a trans ‐orientation at Pt II , but not Ni II , centers. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)