A novel tetranuclear iodoargentate(I) ion, [Ag 4I 8] 4−, with a cubane-type core

Abstract

A novel tetranuclear iodoargentate(I) anion, [Ag 4I 8] 4−, with a cubane-type Ag 4I 4 core has been isolated as the tetrapropylammonium salt and characterised by means of crystal structure determination. There are two crystallographically independent anions, each of which is situated around a two-fold axis. One of the terminal iodide ligands in one such [Ag 4I 8] 4− anion is disordered, as are two of the tetrapropylammonium cations. The ordered terminal AgI bonds range from 2.748(2) to 2.765(2) Å and the bridging AgI from 2.897(2) to 2.932(3) Å, all four silver(I) centres exhibiting distorted tetrahedral coordination geometry. The compound crystallises in the monoclinic space group C2, with a=26.836(6), b=12.535(4), c=24.509(6) Å, β=118.54(2)°, V=7243(4) Å 3, at −120 °C, and Z=4. Full-matrix least-squares refinement yielded a final R=0.042 ( R w=0.045) for 333 parameters and 3784 observed reflections.