Contrasting a series of bidentate amido phosphine oxide, sulfide, or selenide ligands and complexes of dimethyl aluminum and indium.

A series of EP(V)-imine phosphine-imine ligands (Dipp-NC(CH 3 )-(CH 2 )-PE(Ph 2 )) (Dipp = 2,6-diisopropylphenyl, E = O, S, Se) and corresponding dimethyl aluminum and indium complexes were prepared and characterized using multi-nuclear NMR spectroscopy and SC-XRD. Solution-state 1 H and 31 P NMR spectroscopy indicate a mixture of isomers in solution (C 6 D 6 , CDCl 3 , and CD 3 CN). Solid state structures of both the imine and ( E )-enamine isomers of the oxygen-based ligand have been observed. These three ligands (L) were then deprotonated with M(CH 3 ) 3 (M = Al or In), with methane loss forming a 6-membered ring via bidentate chelation ((κ 2 -L)M(CH 3 ) 2 ). The indium/oxide complex also crystallized as a 12-membered ring.