“…The cocrystallization of mesitylene in 4 and the presence of [MesCuMes] À (5 a) in 5 provides strong evidence that the migration of a bare Cu atom into an Sn 9 anion takes place through the release of a Mes À anion from mesitylcopper, which either migrates to another mesitylcopper to form 5 a or is subsequently protonated to give MesH.Zintl phases of the type A 4 E 9 and A 12 E 17 (A = K-Cs and E = Si-Pb), which contain exclusively nona-atomic [E 9 ] 4À or simultaneously [E 9 ] 4À and [E 4 ] 4À cluster anions, respectively, react in liquid ammonia, ethylenediamine (en), or N,N-dimethylformamide (dmf) with transition-metal complexes in two different manners: One possibility is that the clusters themselves act as sor p-bonded ligands. [1] In the case of nine-atomic cluster compounds, a large variety of different complexes of this type have been reported, such as [(h 4 -Si 9 )ZnPh] 3À , [2] [(h 4 -Ge 9 )CuPiPr 3 ] 3À , [3] [(h 4 -Sn 9 )Cr(CO) 3 ] 4À , [4] [(h 4 -Sn 9 )Ir(cod)] 3À (cod = cyclooctadiene), [5] [(h 4 -Pb 9 )M(CO) 3 ] 4À (M = Mo, W), [6] [(h 1 -Si 9 ) 2 {Ni(CO) 2 } 2 ] 8À , [7] [(h 4 -Ge 9 )Cu(h 1 -Ge 9 )] 7À , [3] [(Ge 9 )Au 3 (Ge 9 )] 5À , [8] [Au 3 Ge 45 ] 9À , [9] or [Ag(Sn 9 ÀSn 9 )] 5À , [10] whereas only a limited number of complexes of tetrahedral clusters, such as [(MesCu) 2 (h 3 -E 4 )] 4À (E = Si, Ge), [11,12] mixed clusters in [(MesCu) 2 -(Si 4Àx Ge x )] 4À (x = 2.2(1)) [13] and [(h 2 -Sn 4 )Zn(h 3 -Sn 4 )] 6À[14] , are known. Recently, neat E 4 clusters (E = Si, Sn) have been characterized by 29 Si and 119 Sn NMR spectroscopy [15] and isolated as solvates, for example, in the compounds A 4 Sn 4 ·(NH 3 ) 2 (A = Rb, Cs), Rb 4 Pb 4 ·(NH 3 ) 2 , [16] and Na 4 Sn 4 ·(NH 3 ) 13 , [17] which offer new access to subsequent reactions of these clusters in solution.The second variant is that these clusters incorporate a transition metal, leading to the formation of endohedral cluster subunits.…”