Synthesis and Reduction of Super-Bulky Bis(anilido)acridanide Aluminium Complexes.

Super-bulky bis(anilido)acridanide pro-ligands (NNNAr)H3 (NNNAr = 4,5-bis(anilido)-2,7,9,9-tetramethylacridanide, anilido = NAr, Ar = DCHP, 2,6-dicyclohexylphenyl; TCHP, 2,4,6-tricyclohexylphenyl) have been prepared in high yields. The reaction of (NNNTCHP)H3 with trimethylaluminium affords bimetallic complex [Al2Me3(NNNTCHP)] which reacts with iodine to form the corresponding monometallic complex [Al(NNNTCHP)(I)2]. The reduction of [Al(NNNTCHP)(I)2] with sodium and potassium containing reducing agents was explored. From potassium reductions, only complexes K[Al(NNNTCHP)(I)] (from K/KI) and [Al(NNNTCHP)(TMEDA)] (from KC8/TMEDA, TMEDA = N,N,N',N'-tetramethyl ethylenediamine) could be isolated. In contrast, aluminium(III) hydride [Na(C6H6)][Al(NNNTCHP)(H)] was formed from reduction of [Al(NNNTCHP)(I)2] in benzene with excess sodium metal (mirror). This complex is unstable and readily decomposes in the presence of ethers, such as 2.2.2-cryptand, to give the aluminium(III) complex [Al(NNNTCHP)(2.2.2-cryptand)].