Synthesis of cyano(selenone)gold(I) complexes and investigation of their scrambling reactions using 13C and 15N NMR spectroscopy

A number of new cyano(selenone)gold(I) complexes have been prepared and characterized by elemental analysis, IR and NMR methods for a series of selenones (imidazolidine-2-selenone and its derivatives or diazinane-2-selenone). It appears from the IR data two of the seven prepared complexes exist as nonionic complexes, [dropC=Se-Au-CN] while the remaining five exist as the ionic species, [Au(dropC=Se)(2)](+)[Au(CN)(2)](-) in the solid state. In solution, all complexes are observed to undergo ligand scrambling reactions exhibiting the equilibrium, 2 [dropC=Se-Au-CN]reversible arrow[(dropC-Se)(2)Au](+) + [Au(CN)(2)](-). Ligand scrambling reactions of the complexes have been studied in DMSO using C-13 and N-15 NMR spectroscopy. As a result of the scrambling reaction two sharp resonances are observed in all complexes for both the carbon and nitrogen of CN- in C-13 and N-15 NMR, respectively, corresponding to the two equilibrium components, [dropC=Se-Au-CN] and [Au(CN)(2)](-). Equilibrium constants (K-eq) were determined for the scrambling equilibria by integrating the CN- resonances in the C-13 NMR, recorded at 297 K. K-eq values obtained for cyano(selenone)gold(I) complexes are the highest of all the reported values, measured for other complexes. (C) 2002 Published by Elsevier Science Ltd.