The preparation and some properties of complexes of 3-and 4-cyanopytiine with the Fe(CN)g-and Co(CN):-groups are described. Visible, IR and NMR spectra indicate a coordination through the pytiine nitrogen.
Introductbn
In this work we describe and discuss the structural properties of complexes of 3cyanopyridine (3cyp~j and 4cyanopyridine (4cypy) with the Fe(CN)s and Co(CN)i-moieties.
To our knowledge, only references reporting the kinetic behaviour in solution for some of these complexes are found in the literature [1, 21. No suggestions have been made about the bonding behaviour of the bifunctional cyanopyridines in these compounds. It is therefore most interesting to determine at which of the two potential sites of coordination of cyanopyridines does the bonding to the metal center occur. Note added in proof. The nitrite-bonded unstable 3-cypy and 4cypy complexes have been recently detected in aqueous solutions and proved to change rapidly into the stable pyridine-bonded isomers. (A. P. Szecsy, S. S. Miller and A. Haim, private communication). In what follows, the solid salts Nas[Fe(CN)s(3-CYPY)~ l 5H20, Na3 [Fe(CN)s@cypy)l l 10, K2 [Co(CN),(3cypy)] l l .5H20 and K2 [Co(CN)s-(4cypy)] l 1.5H20 will be referred to as Fe-3cypy, Fe&ypy, Co3cypy and Co4cypy, respectively.