Nanostructured Block-Random Copolymers with Tunable Magnetic Properties

Zha, Yongping; Thaker, Hitesh D.; Maddikeri, Raghavendra R.; Gido, Samuel P.; Tuominen, Mark; Tew, Gregory N.

doi:10.1021/ja305249b

Cited by 64 publications

(43 citation statements)

References 50 publications

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“…Peaks at 6.58, 6.10, and 5.93 ppm were assigned to protons from the Cp rings (protons "a, b, and c"). 13 C and 19 F NMR spectra ( Figure S10), high-resolution mass spectrum (Figure S11), and organic (C/H/N) elemental analysis results were consistent with the assigned structure.…”

Section: ■ Results and Discussionsupporting

confidence: 67%

“…The η 4 /η 5 -Rh(I) structure was preserved after the click reaction, as shown by the proton signals from the Cp rings (protons "a, b, and c") around 5.3, 5.1, and 3.6 ppm. Furthermore, 13 C NMR ( Figure S7) and organic elemental analysis also confirmed the structure of monomer M1. Meanwhile, the isotope pattern in the high-resolution mass spectrum matched well with the rhodium element ( Figure S8).…”

Section: ■ Results and Discussionmentioning

confidence: 60%

“…1 H NMR (CDCl 3 , 400 MHz, δ, ppm): 7.08 (s, 1H, triazole H), 6.10−6.15 (m, 2H), 5.25 (s, 5H), 5.16 (s, 2H), 4.40−4.50 (m, 4H, CH 2 CH 2 O), 4.19 (t, J = 0.6 Hz, 1H), 3.63 (s, 2H), 2.96 (m, 2H), 2.20 (br, 1H), 1.86 (br, 1H), 1.40 (m, 3H). 13 Synthesis of Polymer P1. Grubbs third-generation catalyst (3.75 mg, 5.16 × 10 −3 mmol) was dissolved in 0.5 mL of dichloromethane, and then monomer M1 (120 mg, 0.258 mmol) in 1.5 mL of dichloromethane was added quickly.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

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Syntheses of Monosubstituted Rhodocenium Derivatives, Monomers, and Polymers

et al. 2015

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We report the first chemoselective, high yield synthesis of monosubstituted rhodocenium through a "η 5 → η 4 → η 5 " strategy detailing sequential nucleophilic addition and endohydride abstraction. Monosubstituted rhodocenium derivatives are then used as versatile synthons for the preparation of the first-ever vinyl monomers that allow controlled polymerizations including ROMP and RAFT, leading to rhodocenium-containing metallopolymers. Exploratory ion-exchange and self-assembly of this new class of polyelectrolytes cultivates the potential of side-chain rhodocenium-containing polymers. ■ INTRODUCTIONMetallopolymers combine inorganic metal centers with catalytic, magnetic, and electronic properties and organic polymeric frameworks with desirable mechanical and processing properties. 1−4 Among them, metallocenes are the most important foci, as the field has been particularly inspired by the seminal work on the preparation of ferrocene-based polymers by the Manners group in the early 1990s. 5,6 There are two major states of a metallocene: neutral metallocene and cationic metallocenium. Neutral metallocenes, predominantly 18-e ferrocene and ruthenocene, are widely explored. 7−15 In comparison, cationic metalloceniums are disproportionally biased, 16−22 mostly due to either their chemical instability (for 17-e metalloceniums) or synthetic challenges (for 18-e metalloceniums). As a matter of fact, cationic metalloceniums are fundamentally different from neutral metallocenes, as they are ionic, and can be hydrophilic or hydrophobic depending on their counterions. 1 Thus, integration of metalloceniums into polymeric frameworks would constitute a class of polyelectrolytes that are ubiquitous for a variety of applications ranging from traditional electrolyte chemistry to biomedical applications to membranes, to name just a few. 21,23−25 After the struggle in early years, cationic 18-e metalloceniumcontaining polymers have gained momentum over the past few years. 18−20,22 Recent efforts have overcome many key hurdles to make 18-e cobaltocenium-containing materials not just a curiosity. Synthetic methodologies on cobaltocenium-containing main-chain 19,20 and side-chain 26,27 polymers as well as dendrimers 28,29 have been established. Many of these materials have exhibited unprecedented properties such as peptide nuclear delivery, DNA complexation, and antimicrobial bioconjugates. 21,23,25 Compared with cobaltocenium, the isoelectronic 18-e rhodocenium is a nearly unexplored cationic metallocenium. 30−35 To the best of our knowledge, there are almost no reports on either Rh-or rhodocenium-containing polymers, 36,37 except that the Astruc group recently prepared rhodocenium-containing polymers and dendrimers via ionic interactions between parent substrates and unsubstituted rhodocenium. 31 However, the major dilemma is the lack of a synthetic platform for the preparation of rhodocenium derivatives (both mono-and disubstituted), monomers, and polymers. 30,33 Thus, potential electrolyte chemistry and utilities of rhodocenium ...

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Section: ■ Results and Discussionsupporting

confidence: 67%

Section: ■ Results and Discussionmentioning

confidence: 60%

Section: ■ Experimental Sectionmentioning

confidence: 99%

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Syntheses of Monosubstituted Rhodocenium Derivatives, Monomers, and Polymers

et al. 2015

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“…Macromolecules containing metals are attracting a great interest due to their multiple materials properties . Recent research has focused on block copolymers, and in particular on diblock copolymers containing metal‐containing groups such as ferrocenyl (Fc) or cobalticenium in their side chains . These copolymers were synthesized using various polymerization methods and showed materials properties of polyelectrolytes, micelles, and magnetic materials.…”

Section: Introductionmentioning

confidence: 99%

“…Ring‐opening metathesis polymerization (ROMP) has been used for the synthesis of metallocene‐containing polymers since the early 1990s, first by Schrock's and Wrighton's groups and then by others . Recently, the ROMP synthesis of block copolymers containing either Fc or cobalticenium in the side chain has been reported using the third‐generation Grubbs metathesis catalyst 4 . This ruthenium ROMP catalyst is very active, because it shows a much faster initiation (by at least three orders of magnitude) than Grubbs' first and second‐generation catalysts .…”

Section: Introductionmentioning

confidence: 99%