Dario Pasini Department of Organic Chemistry University of Pavia, Italy 13 th International IUPAC Conference on Polymers and Organic Chemistry 8 th July 2009 Cyclopolymerization as a Tool for the Synthesis of Functional Macromolecular Materials

Outline Cyclopolymers obtained from difunctional acrylic monomers Cyclopolymers obtained from difunctional styrenic monomers Previous work and introduction

Mathias, L. J. Trends Polym. Sci. 1996, 10, Acar, A. E. et al. Macromolecules 2008, 41, Difunctional monomers (usually for crosslinking) Efficient Cyclization and Propagation Linear, Soluble Polymers Difunctional monomers (with differing reactivity) Cyclization, Alternation and Propagation Stereochemical control, Steric positioning, Material properties (T g, etc.) Fréchet J. M. J, et al. Chem. Mater. 2001, 13,

2.7 Å Recent Examples 4.6 Å Holmes, A. B. et al. Chem. Commun. 2000, Prata, J. V. et al. React. Funct. Polym. 2006, 66, Endo, T. et al. J. Am. Chem. Soc. 2008, 130, membered rings formed Control achieved using RAFT

Cyclopolymers obtained from difunctional acrylic monomers Cyclopolymers obtained from difunctional styrenic monomers Previous work and introduction

Inserting Recognition Elements Quaternary centers holding crown ethers orthogonally to the growing chain 61% 80%

Gel Permeation 2% AIBN in THF M n = M w = DP = 21 2% AIBN in Toluene M n = M w = DP = 50 1% AIBN in THF M n = 5900 M w = DP = 14 2% AIBN in THF M n = 4800 M w = DP = 12

Acqueous Solution of Picrate Salt (10 -2 M) Organic Solution (CHCl 3 ) with carrier (10 -3 M) Distilled H 2 O (Receiving Phase) Transport through a Liquid Membrane Absorbance of receiving Phase (380 nm) measured by UV/Vis vs time With no carrier, no transport occurring

Selectivity- Monomer vs Polymer Polymer Monomer Transport Rate (  mol/h) NaKCs Cagnoni, E.; Pasini, D.; Galbiati, A.; Ricci, M.; Righetti, P. P. Macromolecules 2003, 36, Blazquez, E. ; Mustarelli, P.; Pasini, D.; Righetti, P. P.; Tomasi, C. J. Mater Chem. 2004, 14,

Novel D-  -A Chromophores LA = Lewis acid cation (e.g. Ln 3+ ) D. Pasini, P. P. Righetti, V. Rossi Org. Lett. 2002, 4, G. Garlaschelli I. Messina, D. Pasini, P. P. Righetti Eur. J. Org. Chem. 2002, D. Pasini, P. P. Righetti, M. Zema Org. Biomol. Chem. 2004, 2, Lewis Acid O O OMe OMe N O O MeO MeO N 1 1. LA D--AD--A D-  -A. LA + Eu(OTf) 3 In MeCN  (nm) A

Supramolecular Chromophore-Supporting Polymers n=1 n=2 n=3 A B Lanthanide ion Complexation D--AD--A C Eu 3+ D--AD--A A OO O O OO O O O O n n Ar R R m D--AD--A (nm) A Double Chromophores

1 H NMR Characterization 357  (ppm) 1 a b c d e         ’,  ’      Differences between feed and observed ratios (70/30 to 65/35 and 50/50 to 30/70) AIBN (3%) PhCH 3 (0.025 M) AIBN (3%) PhCH 3 (0.25 M) AIBN (3%) PhCH 3 (0.025 M) a b c d e DP=13 DP=58 DP=17-35

Eu 3+ Binding  (nm) 7.5  (x10 -3 )  (x10 -3 )  (nm) Log K a [Eu(OTf) 3, MeCN] = 3.0 max complex = 480 nm  max complex = 7200 Log K a [Eu(OTf) 3, MeCN] = 2.1 max complex = 480 nm  max complex = 3400 Copolymers have intermediate values C. Coluccini, P. Metrangolo, M. Parachini, D. Pasini, G. Resnati, P. Righetti, J. Polym. Sci. A 2008, 46,

Cyclopolymers obtained from difunctional acrylic monomers Cyclopolymers obtained from difunctional styrenic monomers Previous work and introduction

Styrenic Systems Crosslinking 53-65% a) R = Me R’ = Me b) R = Ph R’ = H 40-50%70-80% More flexible Efficient Cyclopolymerization

Styrenic systems Cyclopolymerization works efficiently in diluted conditions [M]/ [%AIBN] MnMn MwMw PDIDPYield% 0.01/4----No polymer 0.02/ (MeOH) 0.04/ (MeOH) 0.13/ (MeOH) S. Edizer, B. Veronesi, O. Karahan, V. Aviyente, I. Değirmenci, A. Galbiati, D. Pasini, Macromolecules 2009, 42, protected deprotected Deprotected polymer crosslinks thermally by the loss of H 2 O at 100°C Polar groups (amphiphilic character)

Inefficient cyclization Large extent of crosslinking Introduce steric hindrance M n = 8800 M w = PD = 2.9 Yield (prec.) =24% All soluble material M n = 6300 M w = PD = 1.9 Yield (prec.) =64%

Controlled Polymerization M:RAFT:AIBNTimePDIMnMn MwMw M n (calcd) Conversion 100:3:1.522 h % -22 h precipitated 100:6:322 h % -22 h precipitated Conversion (%) MnMn RAFT RAFT = Gives worse results

Towards Alternating Systems Ester cleavage = =

Acknowledgments Claudio CornaggiaDr. Arvind Sharma Barbara VeronesiEnrique Blazquez Federica SpiaggiaEmanuela Cagnoni Seda EdizerMarco Parachini Luigi Garlaschelli- Pierpaolo Righetti Alessandro Galbiati (NPT) University of Pavia MIUR PRIN 2004 Fondazione CARIPLO 2007 Regione Lombardia Group website:

Conclusions and Outlook Cyclopolymers obtained from difunctional acrylic monomers Cyclopolymers obtained from difunctional styrenic monomers Why Cyclopolymers? Previous work and applications

Easy Organic Functionalization Knoevenagel ReactionBingel reaction Double Alkylation Access to a Variety of Intermediates

Fitting the Values. A 1:1 Model R 2 = 0,99 Log K a = 3.8±0.1 + Eu(OTf) 3 in MeCN All spectroscopic titrations are fitted with a 1:1 model.

Initiator Good resolution (down to 170 nm) Carbon-rich functionality for Etch Resistance Acid-Labile Protecting Group Polar Functionality for Development Wettability 70% yield M n =5,800 PDI=2.0 A = 0.23 /  PAG: 8% wt Etch: 1.22 vs APEX-E (50 Cl 2 / 150 HBr) Pasini, D.; Low, E.; Fréchet, J. M. J. Adv. Mater. 2000, 12, Imaging of a symmetrical cyclopolymer

Transport in the Solid State (Li + ) No Tg observed (up to 100°C) Blends of Polymer and PEO (1:1) doped with LiTFSI does not show the expected orders of magnitude increase in conductivity in the solid state M n = 6300 M w = DP = 15 With Li + Blazquez, E. ; Mustarelli, P.; Pasini, D.; Righetti, P. P.; Tomasi, C. J. Mater Chem. 2004, 14, At 100°C