{"id":469,"date":"2020-10-06T10:06:39","date_gmt":"2020-10-06T09:06:39","guid":{"rendered":"http:\/\/lclac.chimie.unistra.fr\/?page_id=469"},"modified":"2020-10-06T10:28:36","modified_gmt":"2020-10-06T09:28:36","slug":"redox-active-organic-materials","status":"publish","type":"page","link":"https:\/\/clic.chimie.unistra.fr\/?page_id=469","title":{"rendered":"Redox-active organic materials"},"content":{"rendered":"

In the past two decade, many electroactive structures developed in the group used porphyrin as their redox addressable sub-unit. For example, the co-facial bis-porphyrin(Ni) species (PacMan bis-porphyrins) shown in Figure 5 could be opened and closed by electrochemistry due to the use of a crown-ether derivative of calix[4]arene as a spacer.1<\/sup> Synthetic difficulties and the opportunity for a nice collaboration with C. Bucher prompted synthetic efforts targeting scaffolds in which the porphyrin is replaced by a viologen unit.2<\/sup><\/span><\/p>\n

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Fig. 5.<\/strong> An electro-addressable PacMan bis-Ni porphyrin (left), and an electrochemically switchable scaffold built with viologen derivatives (right). \u00a0<\/em><\/span><\/p>\n

More recently, switchable structures, such as the series of cyclophanes in Figure 6, that can be redox triggered have been designed using a viologen subunit as the electroactive part.3<\/sup><\/span><\/p>\n

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Fig. 6.<\/strong> X-ray structures of flex-boxes (flexible blue-boxes) three cyclophanes of viologen that show different flexibilities and different rates of \u03c0-dimer formation in spectroelectrochemistry.4<\/sup><\/em><\/span><\/p>\n

Engaging in the field of viologens has also been the opportunity to develop or revisit the synthesis of several bipyridines. Among these, the preparation of a previously reported viologen tetraester derivative has been improved. EPR and electrochemical studies have shown that the compound in Figure 7 forms extremely stable radical species.5<\/sup><\/span><\/p>\n

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Fig. 7.<\/strong> Structure of a viologen tetraester derivative 12+<\/sup> (left) and 1+<\/sup>.<\/sup> stability vs MV+<\/sup>.<\/sup> in various conditions(right).<\/em><\/span><\/p>\n

    \n
  1. Electrochemically Triggered Open and Closed Pacman Bis-metalloporphyrins J. Am. Chem. Soc.<\/em> (2006), 128, 3488-3489<\/a>; Unsymmetrical Calix[4]arene Bisporphyrin Pacman
    \nOrg. Lett.<\/em> (2007), 9, 785-788;<\/a>     \u201cEvidence for Dual Pathway in Through-Space Singlet Energy Transfers inFlexible Cofacial Bisporphyrin Dyads\u201d, Chem. Eur. J.<\/em>, 2009, 15, 524-535.<\/a><\/li>\n
  2. Hydrogen-Bond Controlled \u03c0-Dimerization in Viologen-Appended Calixarenes: Revealing a Subtle Balance of Weak Interactions Org. Lett.<\/em> (2015), 17, 4058-4061.<\/a><\/li>\n
  3. Viologen cyclophanes: redox controlled host-guest interactions Chem. Comm.<\/em> (2015), 51, 15772-15775.<\/a><\/li>\n
  4. Flexible Viologen Cyclophanes: Odd\/Even Effects on Intramolecular Interactions ChemPhysChem<\/em> (2017), 18, 796-803<\/a>; Pairing-up viologen cations and dications: a microscopic investigation of van der Waals interactions Phys. Chem. Chem. Phys.<\/em> (2018), 20, 27878-27884.<\/a><\/li>\n
  5. A Highly Stable Organic Radical Cation Org. Lett.<\/em> (2018), 20, 8004-8008.<\/a><\/li>\n<\/ol>\n","protected":false},"excerpt":{"rendered":"

    In the past two decade, many electroactive structures developed in the group used porphyrin as their redox addressable sub-unit. For example, the co-facial bis-porphyrin(Ni) species (PacMan bis-porphyrins) shown in Figure… Read More<\/a><\/span><\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-469","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/clic.chimie.unistra.fr\/index.php?rest_route=\/wp\/v2\/pages\/469","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/clic.chimie.unistra.fr\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/clic.chimie.unistra.fr\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/clic.chimie.unistra.fr\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/clic.chimie.unistra.fr\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=469"}],"version-history":[{"count":3,"href":"https:\/\/clic.chimie.unistra.fr\/index.php?rest_route=\/wp\/v2\/pages\/469\/revisions"}],"predecessor-version":[{"id":487,"href":"https:\/\/clic.chimie.unistra.fr\/index.php?rest_route=\/wp\/v2\/pages\/469\/revisions\/487"}],"wp:attachment":[{"href":"https:\/\/clic.chimie.unistra.fr\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=469"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}