The indan derived diphosphine, cis-1,3-(diphenylphosphino)indan (anphos) is synthesised by the addition of Ph2P(BH3)Li to cis-1,3-dibromoindan followed by deprotection with diethylamine. Anphos readily forms the bicyclic chelates [RhCl(CO)(anphos)], [PtCl2(anphos)], [PtCl(Me)(anphos)] and [FeCl2(anphos)]. The crystal structures of [FeCl2(anphos)] and the monoxide complex, [RhCl(CO)(anphosO)] have been determined. Reaction of the diphosphine with [Rh(acac)(CO)(2)] under moderate hydroformylation conditions catalysed the formation of 1- heptanal and branched aldehydes from 1-hexene in a ratio of 1.5:1. (C) 2004 Elsevier B.V. All rights reserved.