New Reagents for the Synthesis of Organic/Fluoroalkyl Copolymers DAVID A. VICIC

Transcription

1 New Reagents for the Synthesis of Organic/luoroalkyl Copolymers DAVID A. VICIC

2 Outline 1. Design approach for the preparation of co polymers consisting of a fluoroalkyl component and a nonfluorinated organic component. 2. History of α,ω perfluoroalkyl dinucleophiles. 3. Preparation of stable yet reactive perfluoroalkyl dizinc reagents. 4. Use of the reagents for (C 2 ) n transfer and the construction of fluoroalkyl containing rings.

3 Design of luoroalkyl Containing Co Polymers n perfluoroalkyl polymer 2 n 2 n m fluoroalkyl-containing co-polymer Cross coupling routes to fluoroalkylated co polymers are less developed.

4 Motivations for Cross Coupling Methodologies 1) A direct way to prepare non accumulating and more degradeable fluorochemicals and materials containing ~7 or less consecutive C 2 groups (seminal work by Maybury). 2) luoroalkyl chains can be directly attached to aryl groups. 3) Much progress in methodology in the past 5 years. u et al., JACS 2015, 137, 9523.

5 Selected Applications for Methodology Involving Perfluoroalkyl Dinucleophiles 1 + C 3 O HO OH + S C 3 O NaO 3 S SO 3 Na NaO 3 S O S O K 2 CO 3, solvent 170 o C SO 3 Na C 3 O O (C 2 ) 6 m C 3 2 O C 3 C 3 O n k The co polymer membrane 2 presented higher selectivity (ratio of proton conductivity to methanol permeability) than Nafion 117 as well as non fluorinated sulfonated poly(arylene ether sulfones). Yoon et al. Macromol. Res. 2010, 18, 352.

6 Other Possible Uses of Perfluoroalkyl Dinucleophiles fluorinated pourous organic polymers or metal organic frameworks organometallic transformations (C 2 ) n Nu (C 2 ) n Nu LM (C 2 ) n A D m C B

7 Example of an Organometallic Transformation Nu Nu M M fluoroalkyl metallacyclobutane perfluoroalkene metathesis chemistry? R A n polymers via ROMP R n D polymers via acyclic diene metathesis polymerization irst example of perfluoro olefin metathesis reaction by Takahira (Asahi Glass): J. Amer. Chem. Soc. 2015, 137, 7031.

8 Little is Known About Perfluorometallacyclobutanes OC OC CO O e O CO 1 75 o C 24 h OC OC CO e O CO [e(co) 4 ] o C 3 days O O OC OC CO e CO 2 Karel et al. Organometallics, 1990, Baker et al. JACS, 2013,

9 195 Pt NMR of Metallacyclobutanes in CD 2 Cl 2 Organometallics 2015, 34, 3474.

10 Known [Nu (C 2 ) 4 Nu] Species Denson, D. D.; Moore, G. J.; Tamborski, C. J. luorine Chem. 1975, 5, 475. McLoughlin, V. C. R.; Thrower, J. Tetrahedron 1969, 25, 5921.

11 Can a Better luoroalkyl Dinucleophile Be Prepared? Naumann et al. J. luorine Chem. 1984, 26, 435.

12 Preparation of (C 2 ) n Complexes of Zinc PCT/US2014/45673 Organometallics 2013,

13 Efficient (C 2 ) 4 Transfer Agents Organometallics 2013,

14 Effective (C 2 ) n Transfer Agents Organometallics 2013,

15 (C 2 ) 4 Reaction Competitive with Dicuprate ormation The dicuprate is inactive in coupling reactions. Cu Cu distance: (4) Å Organometallics 2013,

16 Additives Aid the (C 2 ) 4 Reactions o

17 Substrate Scope with C4 Derivative aryl diiodide + MeCN MeCN Zn Zn NCMe NCMe CuCl [Bu 4 N]Br DM, 100 o C arylc % 99 % x-ray x-ray 56 % N N Br MeO MeO 69 % 62 % x-ray 88 % 55 %

18 A More Practical Approach to Dizinc Reagents Complex mixtures were formed.

19 A More Practical Approach Diglyme solvent is key for isolation. Hydrodezincated products present in solution phase. J. luorine Chem. 2014, 168,

20 Stability of Dizinc Reagents at 23 C L L Br Zn Zn Br L L 1 2 Contrasts di Grignard reagents, which have half lives of ~2 hours at 50 C. 1 (red circles, 0.5 mmol) and 2 (black squares, 1 mmol) in 0.5 ml acetonitrile. J. luorine Chem. 1975, 5, 475. J. luorine Chem. 2014, 168,

21 Reactivity of the Dizinc Halide Reagents aryl diiodide + (diglyme)brzn CuCl ZnBr(diglyme) DM, 100 o C 3 h arylc 4 8 no [Bu 4 N]Br needed! N 84 % 81 % MeO MeO 65 % 62 % N N 40 % 50 % MeCN Ni MeCN 85 % (23 o C in MeCN) J. luorine Chem. 2014, 168,

22 Utility of the Dizinc Reagents t 4 decomposition to reduced species a problem J. luorine Chem. 2014, 167,

23 Chemistry of the (C 2 ) 6 Derivative 2 6 or or 2 6 Organometallics 2013,

24 Optimized for Catalysis L L Zn (C 2 ) 6 Zn (C 2 ) 6 L = MeCN 0.2 mmol L L Ph 0.2 mmol CuOAc (10 mol%) DMSO, 100 o C I Ph (C 2 ) 6 Ph 99%

25 uture work Co Polymerizations

26 Conclusions Diethyl zinc reacts with α, ω diiodoperfluoroalkanes to afford new stable yet reactive perfluoroalkyl dizinc reagents. The dizinc reagents can be used as (C 2 ) n transfer agents and the construction of fluoroalkyl containing rings. The dizinc reagents exhibit reactivity that is promising for the preparation of fluoroalkyl co polymers by cross coupling protocols.

27 Acknowledgements Collaborators Axel Klein (University of Cologne) Yulia Budnikova (Kazan, Russia) unding U.S. Department of Energy (DE G02 07ER15885) National Science oundation (CHE ) ACS luorine Division Moissan SUR

28