134881-76-8Relevant articles and documents
Disabling Molecular Recognition through Reversible Mechanical Stoppering
Soto, Miguel A.,Maclachlan, Mark J.
, p. 1744 - 1748 (2019)
Mechanical stoppering of a guest molecule prevents its self-assembly with a macrocycle unit, so that both species coexist in a medium but do not recognize each other. The application of a chemical or physical stimulus reverses mechanical stoppering and su
Biscatenanes and a Bisrotaxane-Model Compounds for Polymers with Mechanically Interlocked Components
Ashton, Peter R.,Huff, Juergen,Menzer, Stephen,Parsons, Ian W.,Preece, Jon A.,et al.
, p. 31 - 44 (2007/10/03)
The self-assembly of three biscatenanes and a bisrotaxane, by two complementary strategies, is reported.A synthetic route to derivatives of bis-para-phenylenecrown-10 (BPP34C10) and 1,5-naphtho-para-phenylene-crown-10 (1/5NPP36C10) containing a fused five-membered ring with a secondary amine function is described.These intermediate N-allylimido macrocyclic polyethers undergo template-directed reactions with 1,1'-bis-4,4'-bipyridinium bis-(hexafluorophosphate) and 1,4-bis(bromo-methyl)benzene to produce catenanes containing an N-allyl functionality.The allylimido macrocyclic polyethers have also beeen reduced and deprotected to afford macrocycles possessing a free NH group, which are then linked through a 4,4'-biphenyldicarbonyl spacer to produce bis(crown ether)s, in which each crown ether moiety has two recognition sites.These ditopic BPP34C10 and 1/5NPP36C10 derivatives are capable of sustaining self-assembly reactions at both recognition sites to yield biscatenanes.The self-assembly of a complementary biscatenane, in which two tetracationic cyclophanes are linked together with a flexible hexyl chain, has also been achieved by treating 1,1'-bis-4,4'-bipyridinum bis-(hexafluorophosphate) with a compound containing two linked 1,4-bis(bromomethyl)benzene units in the presence of BPP34C10.Replacing BPP34C10 with a dumbbell-shaped compound containing a linear polyether unit intercepted by a naphthalene residue and terminated by two bulky adamantoyl groups has led to the self-assembly of a bisrotaxane.The X-ray crystal structures of one of the catenanes and its associated crown ether component are reported, together with solution state dynamic 1H NMR spectroscopic studies, showing that there is substantial degree of order characterizing the molecular structure of the catenanes. - Keywords: catenanes, polycatenanes, polyrotaxanes, rotaxanes, self-assembly.
Molecular meccano. 2. Self-assembly of [n]catenanes
Amabilino, David B.,Ashton, Peter R.,Brown, Christopher L.,Córdova, Emilio,Godínez, Luis A.,Goodnow, Timothy T.,Kaifer, Angel E.,Newton, Simon P.,Pietraszkiewicz, Marek,Philp, Douglas,Raymo, Fran?isco M.,Reder, Anatoli S.,Rutland, Marcus T.,Slawin, Alexandra M. Z.,Spencer, Neil,Stoddart, J. Fraser,Williams, David J.
, p. 1271 - 1293 (2007/10/02)
The mutual molecular recognition between different structural components in large rings has led to the template-directed synthesis of a wide range of catenanes composed of from two to five interlocked rings. The molecular self-assembly processes rely upon the recognition between (i) π-electron rich and π-electron deficient aromatic units and (ii) hydrogen bond donors and acceptors, in the different components. In order to increase our knowledge of the factors involved in such molecular self-assembly processes, a homologous series of [2]catenanes has been constructed using macrocyclic polyethers of the bis(p-phenylene)-(3n+4)-crown-n (n = 9-14) type as templates for the formation of the tetracationic cyclophane, cyclobis(paraquat-p-phenylene). Increasing the size of the tetracationic cyclophane to cyclobis(paraquat-4,4′-bitolyl) allows the simultaneous entrapment of two hydroquinone ring-containing macrocyclic polyethers affording a series of [3]catenanes, and one [4]catenane incorporating a cyclic dimer of the expanded cyclophane and three bis(p-phenylene)-34-crown-10 components. By analogy, increasing the number of hydroquinone rings in the macrocyclic polyether permits the self-assembly of more than one tetracationic cyclophane around the templates present in the macrocyclic polyether. In this context, the template-directed synthesis of two [3]catenanes, incorporating two cyclobis(paraquat-p-phenylene) components and either (i) tris(p-phenylene)-51-crown-15 or (ii) tetrakis(p-phenylene)-68-crown-20, has been achieved and is reported. A combination of these two approaches has led to the successful self-assembly, in two steps, of a linear [4]catenane, together with a small amount of a [5]catenane. The creation of these intricate molecular compounds lends support to the contention that self-assembly is a viable paradigm for the construction of nanometer-scale molecular architectures incorporating a selection of simple components.
