The scope for the immobilization of homogeneous catalysts in supported ionic liquids was explored. Here, a solution of cationic transition metal complexes in the ionic liquid 1-ethyl-3-methylimidazolium trifluoromethanesulfonate was supported on diatomic earth. The catalysts were then tested in the direct addition of 4-isopropylaniline to phenylacetylene (hydroamination). Supported Rh(I), Pd(II) and Zn(II) complexes combined a higher intrinsic catalytic activity relative to the corresponding homogeneous catalysts with a high selectivity. (C) 2004 Elsevier B.V. All rights reserved.