A number of phosphine selenide ligands and their gold(I) complexes of gener
al formula R3P=Se-Au-X (where X is Cl-, Br- and CN- and R=phenyl, cyclohexy
l and tolyl) were prepared. The complexes were characterized by elemental a
nalysis, IR and P-31 NMR spectroscopic methods. In the IR spectra of all co
mplexes a decrease in frequency of P=Se bond upon coordination was observed
, indicating a decrease in P=Se bond order. P-31 NMR showed that the electr
onegativity of the substituents is the most important factor determining th
e P-31 NMR chemical shift. It was observed that phosphorus resonance is mor
e downfield in alkyl substituted phosphine selenides, as compared to the ar
yl substituted ones. Ligand disproportionation in the complex Cy3P=SeAuCN i
n solution to form [Au(CN)(2)](-) and [(Cy3P=Se)(2)Au](+) was investigated
by C-13 and N-15 NMR spectroscopy.