113816-19-6Relevant articles and documents
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.
Complex Formation between Bisparaphenylene-(3n+4)-crown-n Ethers and the Paraquat and Diquat Dications
Ashton, Peter R.,Slawin, Alexander M. Z.,Spencer, Neil,Stoddart, J. Fraser,Williams, David J.
, p. 1066 - 1069 (2007/10/02)
U.v. and n.m.r. spectroscopic investigations in solution have been employed to assess the ability of a series (n=7-12) of bisparaphenylene-(3n+4)-crown-n ethers to form stable 1:1 complexes with 2+ and 2+ dications; these mappings of molecular recognition are supported by fast atom bombardment mass spectrometry of the 1:1 complexes with both 2 and 2, and a single crystal X-ray structure analysis of 2.
