Complexes Containing at Least Two Classical Functionalities

Because of their great capacity of water-solubility, a large proportion of the research has been directed toward the sulfonated phosphines. Nevertheless, it is obvious that other hydrophilic functionalities can be introduced on phosphines. Adapting the kind and the number of hydrophilic groups, it is thus possible to have a better control of the water-solubility of the complex thus formed by this way. 

As an introduction, it is of interest to report the special influence of the position of a functionality, taking as an example the phosphonation of 1-phosphanorbornadiene 1 [4]. This molecule has shown very good properties as a ligand for transition-metal catalyzed hydrogenation [5] and hydroformylation [6] of alkenes. 

Aqueous-Phase OrganometaUic Catalysis, Second Edition 

Copyright 2004 WILEY-VCH Verlag GmbH Co. KGaA, Weinheim 

Generally, polydentate phosphines are synthesized by sequential introduction of phosphine units into a precursor [9]. Nevertheless, Whitesides and co-workers proposed a synthetic route by which diphosphine 4 is obtained in situ, as shown in Eq. (1) [10-12], 

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