Reactivity of a Neutral Yttrium(III) Trimethyl Complex toward Brønsted and Lewis Acids.

The present study corroborates that the neutral tridentate N-ligand 1,4,7-trimethyl-triazacyclononane (Me 3 TACN) qualifies as a versatile platform to study selective ligand exchange with rare-earth-metal alkyl complexes, herein [(Me 3 TACN)YMe 3 ]. Treatment with Brønsted-acidic bis(dimethylsilyl)amine, HN(SiHMe 2 ) 2 , gave selectively the mono-exchanged heteroleptic complex [(Me 3 TACN)YMe 2 {N(SiHMe 2 ) 2 }]. Depending on the molecular ratio employed, the reaction of [(Me 3 TACN)YMe 3 ] with AlMe 3 resulted in the isolation/crystallization of [(Me 3 TACN)YMe 2 (AlMe 4 )] [1 : 1] or ion-separated [(Me 3 TACN)YMe(AlMe 4 )][AlMe 4 ] [1 : 2] and [(Me 3 TACN)YMe(AlMe 4 )][Al 2 Me 7 ] [1 : 3]. Analogous reactions with the heavier group 13 methyls GaMe 3 and InMe 3 generated mixed methyl/tetramethylgallato complex [(Me 3 TACN)YMe 2 (GaMe 4 )] and ion-separated [{(Me 3 TACN)YMe 2 } 2 {μ-Me}][InMe 4 ]. Finally, dimethylalane, HAlMe 2 , converted [(Me 3 TACN)YMe 3 ] into heteroaluminate [(Me 3 TACN)Y(HAlMe 3 ) 3 ], representing an AlMe 3 -supported, molecular yttrium trihydride complex. All compounds were investigated by single crystal X-ray diffraction (SC-XRD), homo- and heteronuclear ( 13 C, 27 Al, 89 Y, 115 In) NMR as well as IR spectroscopies and elemental analyses.