Sn^IV and Zr^IV Compounds of a <i>C</i>₃-Symmetric Ligand with Amine [ONN] and [ONNO] Coordination Sites

Abstract

This contribution describes the synthesis and structural characterization of a triaminoguanidinium ( TAG )-based ligand [H 6 ( OMe ) 3 L imin ]BF 4 ( 1 ) containing imine bonds ( L imin ) and its reduction with a dimethylamino borane complex to the corresponding amine compound ( L amin )[H 9 ( OMe ) 3 L amin ]OTs ( 2 ). In solution, both ligands are C 3 -symmetric but crystal structures show the great influence of the reduction on the molecular structure. We show that the planar imine ligand is converted to a highly flexible compound which has nine potential coordination sites, three phenoxy and six amine donors, for binding metal ions. First solid state structures of 1:1 (metal:ligand) coordination compounds with Sn IV and Zr IV are presented. Sn IV exhibits an octahedral coordination sphere and is bound in a facial [ONN] coordination pocket. Zr IV is pentagonal bipyramidal coordinated and the ligand stabilizes this with its’ [ONNO] binding sites.