A series of rhodium complexes of the form [Rh(L)(2)NBD]BF4 where L represents a phosphine ligand and [Rh(L-L)NBD]BF4 where (L-L) represents a diphosphine ligand and NBD = norbornadiene have been prepared. The complexes have been incorporated into Nation by ion-exchange and the supported catalysts thus obtained have been compared with their homogeneous precursors for their activity as catalysts for the hydroformylation of hex-1-ene. The overall yield and the ratio of normal heptanal to branched products are reduced in all cases by introduction of the catalyst into Nation. The modification of Nation to produce a polymeric phosphine and its use as a ligand for hydroformylation using rhodium is also described. (C) 2002 Elsevier Science B.V. All rights reserved.