Synthesis and Characterization of Phosphorus Dendrimers Containing Long, Conjugated Branches

The synthesis of a new family of phosphorus dendrimers is described up to the fifth generation (96 end‐groups). The reaction is based on the nucleophilic substitution of P(S)Cl 2 end‐groups by 4‐hydroxy‐3‐methoxycinnamaldehyde, and by the condensation of CHO end‐groups with a dichlorophosphorhydrazide. The structure of the first generation has been determined by X‐ray diffraction. This structure shows that the OC 6 H 3 CH=CHCH=NNMeP(S) linkage is close to planarity, which indicates an extended conjugation of this linkage that leads to a semi‐rigid skeleton for these dendrimers. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)