Cationic Indium Alkyl Complexes Incorporating Aminotroponiminate Ligands

The synthesis and structures of indium complexes incorporating the bidentate monoanionic ligand N, N ‘ -diisopropylaminotroponiminate ( i Pr 2 -ATI) are described. The reaction of InCl 3 with Li[ i Pr 2 -ATI] yields ( i Pr 2 -ATI)InCl 2 ( 3 ), which is converted to ( i Pr 2 -ATI)InMe 2 ( 4 ) by reaction with MeLi; 4 is also formed by the reaction of InMe 3 with ( i Pr 2 -ATI)H. The reaction of 4 with [Ph 3 C][B(C 6 F 5 ) 4 ] at 23 °C yields the diimine complex [{1,2-(N i Pr) 2 -5-CPh 3 -cyclohepta-3,6-diene}InMe 2 ][B(C 6 F 5 ) 4 ] ( 5 ) via addition of Ph 3 C + to the C5 carbon of 4 . Thermolysis of 5 (75 °C) yields [( i Pr 2 -ATI)InMe][B(C 6 F 5 ) 4 ] ( 6 ) and Ph 3 CMe. 6 was isolated as the chlorobenzene solvate 6 ·PhCl. An X-ray diffraction study shows that there are two independent cations in the asymmetric unit of 6 ·PhCl. One cation (In(1)) is ion-paired with two B(C 6 F 5 ) 4 - anions, while the second cation is complexed with two PhCl molecules and is disordered between two equally occupied positions (In(2) and In(3)). Dative In−ClPh bonding and PhCl/ATI π-stacking interactions contribute to the PhCl coordination in 6 ·PhCl. The reaction of 4 with B(C 6 F 5 ) 3 yields [( i Pr 2 -ATI)InMe][MeB(C 6 F 5 ) 3 ] ( 7 ), which decomposes slowly at 23 °C by C 6 F 5 - transfer reactions. The reaction of 4 with [HNMe 2 Ph][B(C 6 F 5 ) 4 ] yields the labile amine adduct [( i Pr 2 -ATI)In(Me)(NMe 2 Ph)][B(C 6 F 5 ) 4 ] ( 10 ).