Cysteine-reactive polymers synthesized by atom transfer radical polymerization for conjugation to proteins

In this communication we report a strategy for the synthesis of semitelechelic polymers reactive to cysteines. An initiator modified with a pyridyl disulfide was prepared and used for the CuBr/2,2'-bipyridine-mediated atom transfer radical polymerization (ATRP) of 2-hydroxyethyl methacrylate. Polydispersity indices (M(w)/M(n)) of the polymers with different molecular weights were 1.25 or less. The pyridyl disulfide end group was preserved during the polymerization and allowed direct conjugation of the polymer to cysteine residues of bovine serum albumin. The described method provides a general way for the preparation of protein-polymer conjugates through a reversible disulfide bond without the need for postsynthesis modification of the polymers.     

Amphiphilic fluorous random copolymer self‐assembly for encapsulation of a fluorinated agrochemical

Amphiphilic self‐folding random copolymers exhibit different solution behaviors depending on the identity of the hydrophobic/hydrophilic units. Herein, it is demonstrated that changing the hydrophilic unit from poly(ethylene glycol) to the sugar trehalose causes increased discrepancy in the polarity difference with a fluorinated hydrophobic segment and changes the aggregation state of the polymer in water. The PEG‐fluorinated and trehalose/PEG‐fluorinated amphiphilic random copolymers were the most efficient at encapsulating a fluorinated agrochemical. The small‐molecule agrochemical exerts a strong influence on the self‐assembly of the polymers, demonstrating that fluorous interactions result in not only intramolecular self‐folding behavior but also intermolecular polymer association to form well‐defined nanoparticles. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 352–359     

Structural Modulation in Lanthanide Tetracyanoplatinates Incorporating Terpyridine: Synthesis and Structures of Four Distinct One-Dimensional Variants

Abstract  

The synthesis of four different lanthanide tetracyanoplatinates all incorporating 2,2′:6′,2″-terpyridine have been carried out in acetonitrile/water mixtures by reaction of an appropriate Ln³⁺ salt with 2,2′:6′,2″-terpyridine and potassium tetracyanoplatinate. The use of different Ln³⁺ salts as reactants results in the isolation of {La(tpy)(H₂O)₃}₂[Pt(CN)₄]₃·2CH₃CN·2H₂O (La-1) space group P[`1] P\bar{1} , a = 9.3862(15) ?, b = 12.186(1) ?, c = 13.493(1) ?, α = 88.082(7)°, β = 80.22(1)°, γ = 74.88(1)°, {Pr(tpy)(H<sub>2</sub>O)<sub>3</sub>}<sub>2</sub>[Pt(CN)<sub>4</sub>]<sub>3</sub>·2H<sub>2</sub>O (Pr-2) space group P[`1] P\bar{1} , a = 9.2458(15) ?, b = 10.8068(9) ?, c = 13.6178(14) ?, α = 84.554(8)°, β = 74.905(10)°, γ = 79.490(9)°, Ho(tpy)(H₂O)₂(NO₃)[Pt(CN)₄] · CH₃CN (Ho-3) space group P2₁/c, a = 12.867(1) ?, b = 15.1046(15) ?, c = 13.651(4) ?, β = 105.39(1)°, or Yb(tpy)(H₂O)₂(NO₃)[Pt(CN)₄]·0.5CH₃CN·1.5H₂O (Yb-4) space group Pbcn, a = 13.226(7) ?, b = 15.870(2) ?, c = 24.276(3) ? under quite similar reaction conditions. All four of these compounds have been isolated as single crystals and X-ray diffraction has been used to investigate their structural features. None of these compounds are isostructural with one another, but all contain one-dimensional, polymeric structures that contain tris chelation of the Ln³⁺ cations by terpyridine and bridging of the Ln³⁺ ions by tetracyanoplatinate. La-1 and Pr-2 contain both cis- and trans-bridging of Ln³⁺ cations by tetracyanoplatinate resulting in double chains with a ladder-type structure. Ho-3 and Yb-4 are similar in that they contain chelation of Ln³⁺ by both terpyridine and a nitrate anion and both structure types only contain cis-bridging by tetracyanoplatinate. All four structures contain Pt–Pt interactions in the form of dimeric units.