Formation of the intermetalloid cluster [AgSn18]7− – the reactivity of coinage metal NHC compounds towards [Sn9]4−
In recent years the formation of intermetalloid clusters by reacting homoatomic tetrel cluster anions with transition metal complexes has become a promising synthetic route. Nevertheless a better understanding of the processes occurring in solution is necessary. Here we present a series of novel polyanionic coinage metal NHC Zintl clusters [NHCDippM(η4-Sn9)]3− (M: Cu, Ag, Au; Dipp: diisopropylphenyl) which are obtained at low temperatures from the reaction of K4Sn9 with NHCDippMCl (M: Cu–Au) in liquid ammonia. For M = Ag a larger intermetalloid AgI-bridged nonastannide dimer [(η4-Sn9)Ag(η1-Sn9)]7− is also formed. The stepwise formation of the intermetalloid cluster [AgSn18]7− is discussed and compared with that of previously reported intermetalloid stannides.