Synlett 2018; 29(19): 2503-2508
DOI: 10.1055/s-0037-1610219
cluster
© Georg Thieme Verlag Stuttgart · New York

pH-Driven Conformational Switching of Quinoxaline Cavitands in Polymer Matrices

M. Torelli
a   Department of Chemistry, Life Sciences and Environmental Sustainability and INSTM UdR Parma, University of Parma, Parco Area delle Scienze 17/A, 43124 Parma, Italy   Email: enrico.dalcanale@unipr.it
,
I. Domenichelli
a   Department of Chemistry, Life Sciences and Environmental Sustainability and INSTM UdR Parma, University of Parma, Parco Area delle Scienze 17/A, 43124 Parma, Italy   Email: enrico.dalcanale@unipr.it
,
A. Pedrini
a   Department of Chemistry, Life Sciences and Environmental Sustainability and INSTM UdR Parma, University of Parma, Parco Area delle Scienze 17/A, 43124 Parma, Italy   Email: enrico.dalcanale@unipr.it
,
F. Guagnini
a   Department of Chemistry, Life Sciences and Environmental Sustainability and INSTM UdR Parma, University of Parma, Parco Area delle Scienze 17/A, 43124 Parma, Italy   Email: enrico.dalcanale@unipr.it
,
R. Pinalli
a   Department of Chemistry, Life Sciences and Environmental Sustainability and INSTM UdR Parma, University of Parma, Parco Area delle Scienze 17/A, 43124 Parma, Italy   Email: enrico.dalcanale@unipr.it
,
F. Terenziani
a   Department of Chemistry, Life Sciences and Environmental Sustainability and INSTM UdR Parma, University of Parma, Parco Area delle Scienze 17/A, 43124 Parma, Italy   Email: enrico.dalcanale@unipr.it
,
F. Artoni
b  Department of Engineering & Architecture, University of Parma, Parco Area delle Scienze 181/A, 43124 Parma, Italy
,
R. Brighenti
b  Department of Engineering & Architecture, University of Parma, Parco Area delle Scienze 181/A, 43124 Parma, Italy
,
E. Dalcanale*
a   Department of Chemistry, Life Sciences and Environmental Sustainability and INSTM UdR Parma, University of Parma, Parco Area delle Scienze 17/A, 43124 Parma, Italy   Email: enrico.dalcanale@unipr.it
› Author Affiliations
This work is supported by the Hierarchical Self Assembly of Polymeric Soft Systems (SASSYPOL-ITN) Marie Skłodowska Curie network, funded through the European Union Seventh Framework Programme (FP7-PEOPLE-2013-ITN) under Grant Agreement No. 607602.
Further Information

Publication History

Received: 26 May 2018

Accepted after revision: 29 June 2018

Publication Date:
24 July 2018 (online)

Published as part of the Cluster Synthesis of Materials

Abstract

While pH-driven interconversion of tetraquinoxaline cavitands (QxCav) from vase to kite conformation has been extensively studied both in solution and at interfaces, cavitands behavior in solid matrices is still unexplored. Therefore, the synthesis of a new class of quinoxaline cavitand based copolymers is here reported; a soluble linear poly(butyl methacrylate) (PBMA) and an insoluble cross-linked polydimethylsiloxane (PDMS), ensuring a convenient incorporation of the switchable unit, were chosen as polymer matrices. Conformational studies, performed both in solution and at the solid state, confirmed the retention of vase → kite switching behavior when moving from monomeric units to polymeric structures.

Supporting Information

 
  • References and Notes

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  • 21 Preparation of PBMA-3 In a Schlenk tube, n-butyl methacrylate (0.242 mL, 1.52 mmol) was added to a solution of cavitand 3 (0.027 g, 0.015 mmol) in 2 mL of toluene. The mixture was degassed and heated at 70 °C, then AIBN (0.005 g) was added. The mixture was maintained at 70 °C for 12 h, then cooled at room temperature. The copolymer was recovered by precipitation in MeOH followed by trituration in the same solvent. Polymer PBMA-3 was obtained as a white solid (yield 48%) 1H NMR (400 MHz, CDCl3): δ = 8.67 (2 H, Ha), 8.25–8.08 (6 H, Hf + Hb), 7.82 (6 H, Hc + Hd), 7.54 (1 H, He), 7.44 (2 H, He), 7.25 (5 H, Hg + He), 5.57 (m, 4 H, CHCH2), 4.47 (4 H, Ar(C=O)OCH 2CH2), 4.0 (OCH 2,PBMACH2), 2.29 (8 H, CHCH 2), 2.1–1.7 (-CH 2,PBMA-C(C=O)CH3), 1.6 (-CH2-C(C=O)CH 3,PBMA + OCH2CH 2,PBMA), 1.4 (OCH2CH2CH 2,PBMA), 1.0–0.8 (CH2CH 3,PBMA) ppm (see Figure S9 in the Supporting Information).
  • 22 PDMS Samples Preparation RTV 615 base (3.0 g) and a THF cavitand solution were homogenized with a Vortex in a 15 mL Falcon tube. RTV 615 curing agent (0.3 g) was added, and the tube was extensively shacked with a Vortex. The homogenous mixture was degassed under vacuum and poured onto a PTFE plate. After a second degassing, the sample was cured in an oven at 60 °C for 16 h. Once cured the film was peeled away and cut into stripes for testing.
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