Phosphorus-containing dendrimers: Another type of phosphorus polymers, and their properties

Dendrimers are a very special type of polymers, which are obtained by the association of branched monomers, but in a stepwise manner and not by polymerization reactions. The structure of dendrimers resembles that of trees, with branches emanating from a central core. The most widely used type of phosphorus-containing dendrimers, i.e. dendrimers having a phosphorus atom at each branching point, are poly(phosphorhydrazone) (PPH) dendrimers. The main advantages of PPH dendrimers are their easy characterization by ³¹P NMR, their easy functionalization, thanks to their highly reactive terminal functions (P(S)Cl₂ and Ar-CHO), and even their specific difunctionalization. These advantages allow an easy customized preparation of suitable candidates for a wide panel of (potential) applications. The synthesis, characterization, and functionalization of PPH dendrimers are the topic of this review, with emphasis on their properties. These dendrimers have been used as catalysts (homogeneous, organometallic, organic, enantioselective catalysis, recycling, etc.), for elaboration or modification of (nano)materials (biosensors, chemical sensors, nanotubes, microcapsules, trapping of pollutants, OLED), and as drugs by themselves or as drug carriers and deliverers in vitro and in vivo (against cancers, against infectious diseases such as tuberculosis or HIV, against neurodegenerative diseases such as prions, Alzheimer, Parkinson, and against inflammatory diseases such as rheumatoid arthritis, neuro-inflammations, Uveitis, and psoriasis).