Towards a Molecular Anchor Chain. Synthesis and Catenations of Spiro Crown Ethers

Introduction of [2]Catenanes into Langmuir Films and Langmuir−Blodgett Multilayers. A Possible Strategy for Molecular Information Storage Materials

“…It has been demonstrated that, by utilizing the electrostatic interactions between the head groups of a phospholipid anion and the tetracationic [2]catenanes 1 4+ and 2 4+ , these complex charged species can be introduced into Langmuir films and subsequently into Langmuir−Blodgett multilayers in an ordered fashion. Thus, the combination of like−like (of the 3 - anions) and donor−acceptor (of the [2]catenane tetracations) interactions leads to the establishment of highly complex supramolecular architectures dictated by the order present in the molecular structures of the [2]catenanes. , The self-organization of Langmuir films and Langmuir−Blodgett multilayers, which incorporate self-assembled molecular entities with potentially controllable switching properties, constitutes one methodology for the construction, , by a bottom-up approach, materials in which information might be able to be stored in arrays of these individual molecular entities …”

“…The [2]catenanes 1 ·4PF 6 and 2 ·4PF 6 and the tetracationic cyclophane 4 ·4PF 6 were obtained as described previously. ,, The monosodium salt of dimyristoylphosphatidic acid (DMPA, 3 ·Na) was used as supplied by Sigma. CHCl 3 (50%), MeCN (25%), and MeOH (25%), used as a spreading solvent, were obtained from Baker Chemicals (HPLC grade).…”

“…A class of complexes and compounds, which rely upon these natural phenomenon for their construction, are the so-called pseudorotaxanes, rotaxanes, and catenanes , Also, by choosing appropriate recognition motifs in these (super)structures, they can show, in the solution state, mechanical switching properties. These molecular-level switches can be activated and driven by chemical, electrochemical, or photochemical stimuli.…”

The Story of the Little Blue Box: A Tribute to Siegfried Hünig

“…A diverse family of topologically distinct donor-acceptor MIMs comprised of CBPQT 4 + has been made (Figure 9) by employing either kinetic or thermodynamic approaches, including a) rotacatenanes, [137] with the illustrated example consisting [138] of a fused pillar [5]arene/naphtho [36]crown-10 macrobicyclic core and an imidazolium-based dumbbell, b) [3]pseudocatenanes or handcuff catenanes, [139] comprising πdonating macrocyclic polyethers fused to a central TTF core, c) side-chain poly [2]catenanes, [140] with the illustrated example consisting of polyurethane as the backbone, d) bis [2]catenanes, comprising two CBPQT 4 + rings fused to a flexible linker [141] or a central phenylene unit, [142] e) a cyclic bis [2]catenane, with two catenanes connected together by a covalent linker, [143] f) a side-chain poly [2]rotaxane with polyacrylate as the backbone, [144] g) tripodal [4]rotaxanes, reminiscent of G1 dendrimers, [116,145] h) branched catenanes possessing a combination of linear and radial links, [99,146] i) a [3]catenane, which comprises a fused triple-torus polyether catenated by two CBPQT 4 + rings, [147] j) a pseudo [1]catenane, where the interlocked polyether macrocycle is fused to a phenylene unit in CBPQT 4 + , [148] k) [1]rotaxanes, [149] in which the rods that thread through CBPQT 4 + are fused to the encircling rings, l) a molecular figure-of-eight, in which the rod is anchored to opposite ends of an encircling ring, [150] and m) oligorotaxanes [151] in which CBPQT 4 + rings thread onto polyether-bridged DN oligomers, causing the thread to fold into an extended stack of alternating π-donors and πacceptors. Many other donor-acceptor MIMs, such as pretzelanes, [152] polyrotaxanes, [153] and poly [2]catenanes [154] are not dis...…”