More Like this

1. Metals in polymers: hybridization enables new functions

   https://doi.org/10.1039/d0tc03810e  

   Wei, Zichao ; Duan, Hanyi ; Weng, Gengsheng ; He, Jie ( November 2020 , Journal of Materials Chemistry C)

   null (Ed.)

   Adding metals into synthetic polymers is of broad interest to design multifunctional materials, particularly harnessing unique properties and functionalities not found in pure organic polymers. Other than simple emergence of the two, such hybridization often enables synergies to amplify the existing properties and/or create new properties not existing in either component. In this review, we highlight recent examples of metal/polymer hybrids based on either well-defined or ill-defined metal–ligand (M–L) coordination to design multifunctional materials. This review describes how in the hybridization of metal ions and polymers they complement each other synergistically in terms of their optical, mechanical and catalytic functionalities. Synthetic polymers once bound to metals enable stimuli-responsive properties of the metals and control over the luminescence of the metals in response to a change in the environment. As the second coordination sphere, synthetic polymers also enhance the reactivity of metal sites as a means to design bioinspired artificial enzymes. Additionally, the impact of the M–L coordination on the dynamic properties of polymers is summarized in the context of self-healable and tough materials built on the reversible network of interchangeable M–L coordination. 

   more » « less
2. Synthesis of terpyridine-containing polycarbonates with post polymerization providing water-soluble and micellar polymers and their metal complexes

   https://doi.org/10.1039/d0py00850h  

   Bhat, Gulzar A. ; Rashad, Ahmed Z. ; Darensbourg, Donald J. ( July 2020 , Polymer Chemistry)

   null (Ed.)

   Carbon dioxide based polymers synthesized from the metal-catalyzed copolymeriation of epoxides and CO 2 containing the terpyridine ligand as an end group are reported. The strategy used was to carry out the polymerization in the presence of a carboxylic acid derivative of terpyridine, 4′-(4-carboxyphenyl)-2,2′:6′,2′′-terpyridine (HL), as a chain transfer agent. The epoxide monomer possessing a vinyl substituent, allyl glycidyl ether (AGE), was copolymerized with CO 2 employing a (salen)Co( iii ) catalyst to afford a polycarbonate which upon the addition of mercaptoacetic acid across the double bond, followed by deprotonation, yielded a water soluble polymer. In a similar manner, the sequential formation of a diblock terpolymer produced from propylene oxide, AGE, and CO 2 provided a amphiphilic polycarbonate which self-assembled upon addition to water to form micelle nanostructures. The molecular weights of these CO 2 -derived polycarbonates were shown to be easily controlled by the quantity of chain transfer agent used. These polymeric ligands were demonstrated to provide a modular design for synthesizing a wide variety of metal complexes as illustrated herein for zinc and platinum derivatives. 

   more » « less
3. Molecular chains of coordinated dimolybdenum isonicotinate paddlewheel clusters

   https://doi.org/10.1039/C9RA03572A  

   Li, Minyuan M. ; Claire, F. James ; Solomos, Marina A. ; Tenney, Stephanie M. ; Ivanov, Sergei A. ; Siegler, Maxime A. ; Kempa, Thomas J. ( May 2019 , RSC Advances)

   A growing focus on the use of coordination polymers for active device applications motivates the search for candidate materials with integrated and optimized charge transport modes. We show herein the synthesis of a linear coordination polymer comprised of Mo 2 (INA) 4 (INA = isonicotinate) metal–organic clusters. Single-crystal X-ray structure determination shows that this cluster crystallizes into one-dimensional molecular chains, whose INA-linked Mo 2 cores engage in alternate axial and equatorial binding motifs along the chain axis. Electron paramagnetic resonance spectra, absorption spectra, and density functional theory calculations show that the aforementioned linear coordination environment significantly modifies the electronic structure of the clusters. This work expands the synthetic foundation for assembly of coordination polymers with tailorable dimensionalities and charge transport properties. 

   more » « less
4. Ligand effect in the synthesis of hyperbranched polymers via copper‐catalyzed azide‐alkyne cycloaddition polymerization (CuAACP)

   https://doi.org/10.1002/pola.29194  

   Gan, Weiping ; Cao, Xiaosong ; Shi, Yi ; Zou, Lei ; Gao, Haifeng ( September 2018 , Journal of Polymer Science Part A: Polymer Chemistry)

   Copper‐catalyzed azide‐alkyne cycloaddition polymerization (CuAACP) of AB₂monomers demonstrated a chain‐growth mechanism without any external ligand because of the complexation ofin situformed triazole groups with Cu catalysts. In this study, we explored the use of various ligands that affected the polymerization kinetics to tune the polymers’ molecular weights and the degree of branching (DB). Eight ligands were studied, including polyethylene glycol monomethyl ether (PEG₃₅₀,M_n= 350), tris(benzyltriazolylmethyl)amine (TBTA), 2,6‐bis(1‐undecyl‐1H‐benzo[d]imidazol‐2‐yl)pyridine (Py(DBim)₂), 2,2′‐bipyridyl (bpy), 4,4′‐di‐n‐nonyl‐2,2′‐bipyridine (dNbpy),N,N,N′,N″,N″‐pentamethyldiethylenetriamine (PMDETA),N,N,N′,N″,N″‐penta(n‐butyl)diethylenetriamine (PBuDETA), andN,N,N′,N″,N″‐pentabenzyldiethylenetriamine (PBnDETA). All ligands except PEG₃₅₀exhibited stronger coordination with Cu(I) than the polytriazole polymer, which freed the Cu catalyst from polymers and resulted in dominant step‐growth polymerization with simultaneous chain‐growth feature. Meanwhile, the use of PEG₃₅₀ligand retained the confined Cu in the polymer, demonstrating a chain‐growth mechanism, but lower polymer molecular weights as compared with the no‐external‐ligand polymerization. Results indicated that aliphatic substituent groups on ligands had little effect on the molecular weights and DB of the polymers, but rigid aromatic substituent groups decreased both values. By varying the ligand species and amounts, hyperbranched polymers with DB value ranging from 0.53 ([TBTA]₀/[Cu]₀= 5) to 0.98 ([PMDETA]₀/[Cu]₀= 2) have been achieved. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem.2018,56, 2238–2244

    

   more » « less
5. N-Heterocyclic carbene-ended polymers as surface ligands of plasmonic metal nanoparticles

   https://doi.org/10.1039/c9tc04776j  

   Thanneeru, Srinivas ; Ayers, Kaitlynn M. ; Anuganti, Murali ; Zhang, Lei ; Kumar, Challa V. ; Ung, Gaël ; He, Jie ( February 2020 , Journal of Materials Chemistry C)

   A facile methodology to prepare N-heterocyclic carbene (NHC)-terminated polymers as surface ligands to functionalize gold nanoparticles (AuNPs) is reported. Our method highlights a mild, aerobic synthesis of NHC-functionalized polymers and a simple ligand exchange approach towards surface modification of AuNPs prepared in aqueous solution. Two methods, including end-group functionalization of halogen-ended polymers from a conventional atom transfer radical polymerization (ATRP) and post-polymerization functionalization of imidazole-containing polymers using imidazole-containing ATRP initiator, have been investigated to prepare imidazolium-ended polymers. Using a one-step, oxygen and moisture tolerant procedure, the polymer–NHC–Cu( i ) species can be synthesized from imidazolium-ended polymers and readily bind to citrate-capped AuNPs likely through transmetalation, yielding robust polymer-stabilized AuNPs. Our synthetic method significantly simplifies the preparation and use of polymer–NHC ligands for surface functionalization of metal NPs. Our methodology is general and potentially applicable to any polymers prepared by ATRP to functionalize metal NPs via NHC–metal coordination; therefore, it will likely broaden the applications of polymer–NHC ligands for metal nanoparticles in the fields of catalysis and nanomedicine. 

   more » « less