Distibanes and Distibenes from Reduction of Sb(NONR )Cl by using MgI Reagents.

The bis(amidodimethyl)disiloxane antimony chlorides Sb(NONR )Cl (NONR =[O(SiMe2 NR)2 ]2- ; R=tBu, Ph, 2,6-Me2 C6 H3 =Dmp, 2,6-iPr2 C6 H3 =Dipp, 2,6-(CHPh2 )2 -4-tBuC6 H2 =tBu-Bhp) are reduced to SbII and SbI species by using MgI reagents, [Mg(BDIR' )]2 (BDI=[HC{C(Me)NR'}2 ]- ; R'=2,4,6-Me3 C6 H2 =Mes, Dipp). Stoichiometric reactions with Sb(NONR )Cl (R=tBu, Ph) form dimeric SbII stibanes [Sb(NONR )]2 , shown crystallographically to contain Sb-Sb single bonds. The analogous distibane with R=Dmp substituents has an exceptionally long Sb-Sb interaction and exhibits spectroscopic and reactivity properties consistent with radical character in solution. When R=Dipp, reductions with MgI reagents directly give distibenes [Sb(μ-NONDipp )Mg(BDIR' )(THF)n ]2 (R'=Mes, n=1; R'=Dipp, n=0). Crystallographic analysis shows a trans-substitution of the Sb=Sb double bond, with bridging NONDipp -ligands between the SbI and MgII centres. An attempt to access the NONPh -analogue using the same protocol afforded the polystibide cluster Sb8 [μ4 ,η2:2:2:2 -Mg(BDIMes )]4 , which co-crystallized with the ligand transfer product, [Mg(BDIMes )]2 (μ-NONPh ).