Preparation and Structural Properties of In-H Complexes.

The use of the tripodal ligands tris[(-butylureaylato)--ethyl]aminato ([Hbuea]) and the sulfonamide-based -[2,2',2"-nitrilotris(ethane-2,1-diyl)]tris(2,4,6-trimethylbenzene-sulfonamidato) ([MST]) has led to the synthesis of two structurally distinct In(III)-OH complexes. The first example of a five-coordinate indium(III) complex with a terminal hydroxide ligand, K[InHbuea(OH)], was prepared by addition of In(OAc) and water to a deprotonated solution of Hbuea. X-ray diffraction analysis, as well as FTIR and H NMR spectroscopic methods, provided evidence for the formation of a monomeric In(III)-OH complex. The complex contains an intramolecular hydrogen bonding (H-bonding) network involving the In(III)-OH unit and [Hbuea] ligand, which aided in isolation of the complex. Isotope labeling studies verified the source of the hydroxo ligand as water. Treatment of the [InMST] complex with a mixture of 15-crown-5 ether and NaOH led to isolation of the complex [15-crown-5⊃Na-(μ-OH)-InMST], whose solid-state structure was confirmed using X-ray diffraction methods. Nuclear magnetic resonance studies on this complex suggest it retains its heterobimetallic structure in solution.