Cyanide coordinated

Mohamed, A.A., Abdou, H.E. and Fackler, J.P. Jr (2006) Mercury(ll) cyanide coordination polymer with dinuclear gold (1) amidinate. Structure of the 2-D [Au2(2,6-Me2-formamidinate)2]-2Hg (CN)2 2THF complex. Inorganic Chemistry, 45, 11-12. 

Metal complexes of several zinc, cadmium and mercury salts with 2-, 3- and 4-cyanopyridine have been reported.495 In none of the complexes was cyanide coordination observed. Zinc halides react with 3- and 4-cyanopyridine, but not with 2-cyanopyridine, to give 1 2 complexes which are assigned a monomeric tetrahedral structure on the basis of IR evidence. The cadmium halides also form 1 2 complexes with all the cyanopyridines, except cadmium chloride, which reacts with 2-cyanopyridine to give a 1 1 complex. The former contain... 

Effect of Water. The reduction rate increased as the concentration of water was decreased. For example, removing water ( 50 mM) to levels where it is not observed by NMR increased the reduction rate almost three fold. Cyanide coordinated to ferric porphyrins acts as a hydrogen-bond acceptor towards water (23). Such an interaction would make the coordinated cyanide more difficult to oxidize (24) and hence would decrease the reaction rate. 

Thermodynamics of metal-cyanide coordination. I. pK, AH°, and AS° values as a function of temperature for hydrocyanic acid dissociation in aqueous solution, Inorg. Chem., 1, (1962), 828-831. Cited on page 435. 

Likewise, differences in reaction driving forces do not explain such a difference in rates. Interestingly, it was found that the rate of intramolecular electron transfer in Pa-NiR was accelerated four orders of magnitude by cyanide coordination to the oxidized heme-dj (104) it was suggested that, in the absence of cyanide, a coordination change takes place upon reduction of this heme. 

As an extension of their work on gas-phase decomposition of cyanides coordinated to transition metal ions, Schwarz and co workers studied similar reactions of isocyanides 33... 

The first step in the reduction of bis[histidinato]cobalt(III) by hexacyano-ruthenium(II) is in fact a substitution process, attack of the cobalt(III) at cyanide coordinated to the ruthenium. 

Xia J, Zhang Z-J, Shi W et al (2010) Copper(I) cyanide coordination polymers constructed from bis(pyrazole-l-yl)alkane ligands observation of the odd-even dependence in the structures. Cryst Growth Des 10 2323-2330... 

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