Solid-state 115In NMR study of indium coordination complexes

Abstract

The feasibility of solid-state (115)In NMR studies is demonstrated by an examination of four different coordination complexes: indium(III) acetylacetonate, indium(III) tris(tropolonato), indium(III) triiodide bis(tris(4-methoxyphenyl)phosphine oxide) and indium(III) trichloride tris(2,4,6-trimethoxyphenyl)phosphine. The results provide information about the electric field gradients and magnetic shielding at the indium nuclei through the nuclear quadrupolar and chemical shift parameters, respectively. The C(Q) values in these four complexes range between 106.0 +/- 2.0 and 200.0 +/- 4.0 MHz, while the magnetic shielding anisotropies fall in the range from 85 +/- 15 to 550 +/- 60 ppm. Finally, this research demonstrates that solid-state (115)In NMR studies are facilitated by performing experiments at the highest possible magnetic-field strengths, and that NMR offers a promising tool for the characterization of indium compounds.