Abstract
The use of the tripodal ligands tris[(N'-tert-butylureaylato)-N-ethyl]aminato ([H(3)buea](3-)) and the sulfonamide-based N,N',N"-[2,2',2"-nitrilotris(ethane-2,1-diyl)]tris(2,4,6-trimethylbenzene-sulfonamidato) ([MST](3-)) 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[In(III)H(3)buea(OH)], was prepared by addition of In(OAc)(3) and water to a deprotonated solution of H(6)buea. X-ray diffraction analysis, as well as FTIR and (1)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 [H(3)buea](3-) ligand, which aided in isolation of the complex. Isotope labeling studies verified the source of the hydroxo ligand as water. Treatment of the [In(III)MST] complex with a mixture of 15-crown-5 ether and NaOH led to isolation of the complex [15-crown-5⊃Na(I)-(μ-OH)-In(III)MST], 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.