Side-chain poly(phosphoramidate)s via acyclic diene metathesis polycondensation

Abstract

Poly(phosphoester)s (PPEs) are interesting degradable multi-functional polymers. Here, we present the first synthesis of poly(phosphoramidate)s (PPAs) via acyclic diene metathesis (ADMET) polycondensation with amidate linkages in side chains. In contrast to conventional polyamides, the P-N-bond in phosphoramidates is more labile than the corresponding esters. Unsaturated PPAs were compared with structural analogues of PPEs: two novel α,ω-dienes, i.e. bis-(undecen-10-yl)-n-butyl-phosphoramidate (1) and bis-(undecen-10-yl)-n-butyl-phosphate (2) have been polymerized by Grubbs-type catalysts to polymers with molecular weights up to ca. 20 000 g mol −1 . After hydrogenation polyethylene-like structures were obtained with the phosphoramidate or -ester representing a precisely placed defect. PPAs were compared to their PPE analogues with respect to their thermal behavior and stability by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), showing similar crystallization behavior for the saturated materials, but significant differences for unsaturated PPA vs. PPE. This synthesis of PPAs via ADMET polymerization offers an interesting approach to various PPAs. The hydrolytically labile pendant phosphoramidate further offers the possibility for the development of hydrolytically degradable materials or as processable intermediates for poly(phosphodiester)s which often show limited solubility. † Electronic supplementary information (ESI) available. See

Functional biodegradable polymers via ring-opening polymerization of monomers without protective groups

“…10 Contrary, polyphosphoramidates undergo hydrolysis in basic and acidic media. [11][12][13][14][15] While hydrolysis almost exclusively proceeds at the P-N bond under acidic and nearly neutral conditions, P-O, as well as P-N bond cleavage, occurs under basic conditions, still with a higher probability for P-N cleavage. 14 94% cleavage of mainchain polyphosphoramidates to diesters has been shown at pH 3.0 within 12.5 days.…”

Sterically‐Controlled Self‐Immolation in Phosphoramidate Linkers Triggered by Light

“…Phosphoramidates and other phosphate‐based constructs have become useful tools in chemical biology as probes for biochemical processes, such as membrane transport, protein phosphorylation and conjugation. [1a] In addition, these compounds can also be used as alternatives to phosphorothioate antisense oligonucleotides or as candidates for the development of smart materials, including biodegradable polymers, or sensors for medical applications such as diagnosis[1b], , and drug delivery…”

Crystallization of Poly(ethylene)s with Regular Phosphoester Defects Studied at the Air–Water Interface

“…This suggests that the LB film of Ethoxy-PPE possesses a similar chain packing as its bulk state. Melt grown and solvent cast crystals of Ethoxy-PPE also show a single Bragg reflection and the crystal structure was assigned to pseudo-hexagonal [ 42 , 71 , 72 ]. GI-WAXS pattern of Methyl-PPE- co -decadiene has also a single Bragg reflection at a similar q xy position of ~15.1 nm −1 as Ethoxy-PPE ( Figure S9 of supporting information).…”