Hetero and homo α,ω‐chain‐end functionalized polyphosphazenes

Abstract

The control of chain‐ends is fundamental in modern macromolecular chemistry for directed one‐to‐one bioconjugation and the synthesis of advanced architectures such as block copolymers or bottlebrush polymers and the preparation of advanced soft materials. Polyphosphazenes are of growing importance as elastomers, biodegradable materials and in biomedical drug delivery due to their synthetic versatility. While controlled polymerization methods have been known for some time, controlling both chain‐ends with high fidelity has proven difficult. We demonstrate a robust synthetic route to hetero and homo α,ω‐chain‐end functionalized polyphosphazenes via end‐capping with easily accessible, functionalized triphenylphosphine‐based phosphoranimines. A versatile thiol‐ene “click”‐reaction approach then allows for subsequent conversion of the end‐capped polymers with various functional groups. Finally, we demonstrate the utility of this system to prepare gels based on homo α,ω‐chain‐end functionalized polyphosphazenes. This development will enhance their progress in various applications, particularly in soft materials and as degradable polymers.

Degradable Bottlebrush Polypeptides and the Impact of their Architecture on Cell Uptake, Pharmacokinetics, and Biodistribution In Vivo

“…The controlled polymerization of Cl 3 PNSiMe 3 initiated by 4‐(diphenylphosphino)styrene was conducted in a ratio M:I of 75:1, giving the macromolecular intermediate poly(dichloro)phosphazene with a chain‐length of ( N BB ) 73 repeat units according to 1 H‐NMR spectroscopy. [ 45,48 ] Subsequent substitution with mono‐BOC protected 2,2′‐(ethylendioxy)‐bisethylamine resulted in a PPz bearing two pendant amine groups per repeat unit (Figure S1, Supporting Information), which could then be readily converted to a BF 4 ammonium salt in the macroinitiator P1 ( Figure ) with a conversion of >95%, as confirmed by NMR spectroscopy (Figures S2–S4, Supporting Information). [ 49 ]…”

Inorganic Bottlebrush and Comb Polymers as a Platform for Supersoft, Solvent-Free Elastomers

“…Moreover, a second series of bottlebrush polymers based on a PDMS backbone with both PNF and PDMS as the side chains was prepared, denoted PDMS BB -PNF SC -PDMS SC -1−2 (see Figure 2a). To achieve this, styrene-capped [NPCl 2 ] n was synthesized according to our previous reports, using diphenylphosphinostyrene instead of PPh 3 Cl 2 as the initiator, 28,29 and functionalized with a 1:1 ratio of trifluoroethanol (TFE) and 2,2,3,3,4,4,5,5-octafluor-1-pentanol (OFP). Again, the conversion from monomer to polymer was tracked by 31 P NMR spectroscopy.…”

“…The poly­(fluoroalkoxy)­phosphazene was synthesized according to adapted literature procedures at room temperature in the glovebox under an argon atmosphere. , To this end 4-(diphenylphosphino) styrene (100.0 mg, 0.35 mmol, 1 equiv) and hexachloroethane (90.3 mg, 0.38 mmol, 1.1 equiv) were dissolved separately in about 0.5 mL of dichloromethane, mixed, and reacted overnight. Subsequently, the monomer Cl 3 PNSi­(CH 3 ) 3 (1.9468 g, 8.67 mmol, 25 equiv) was dissolved in about 2 mL of DCM, added to the reaction solution, and stirred for an additional 24 h. The resulting poly­(dichloro)­phosphazene was further reacted in a macromolecular substitution reaction without purification.…”

Superfluorinated, Highly Water-Soluble Polyphosphazenes as Potential 19F Magnetic Resonance Imaging (MRI) Contrast Agents

“…PPz P1 was synthesized in an argon-filled glove box according to an adapted literature procedure [26,27]. Briefly, 4-(diphenylphosphino)styrene (30.0 mg, 0.104 mmol, 1 eq.)…”

“…They are of high interest in the field of biomedicine, with potential applications such as stent coatings, drug and protein delivery systems, and vaccine adjuvants [24,25]. The controlled synthesis of these polymers, primarily through living cationic polymerization methods, allows for the creation of polymers with precisely controlled length and a narrow range of characteristics (referred to as Ð) [26,27]. Subsequently, various modification reactions can be employed after polymerization to fine-tune the functionality, degradability, and overall architecture of PPz.…”