John P. Mathias

Complexation of diquat and paraquat by macrocyclic polyethers incorporating two dibydroxynaphthalene residues

Abstract NMR Spectroscopy and FAB mass spectrometry demonstrate that the 38-crown-10 (1/5DN38C10) and 35-crown-9 (1/5DN35C9) ethers incorporating two 1,5-di-naphtho units form 1:1 complexes with the Paraquat [PQT] 2+ and Diquat [DQT] 2+ dications in solution. In the solid state, the [PQT.1/5DN38C10] 2+ complex is stabilised by face-to-face (π/π charge transfer) interactions between the naphtho and bipyridinium rings, whereas the free 1/5DN35C9 receptor features a classic edge-to-face (H δ+ /π electrostatic) interaction between its two naphtho rings.

The structure-directed synthesis of cyclacene and polyacene derivatives

The treble diastereoselectivities exhibited by Diels-Alder reactions which occur between diene and dienophilic components associated with bicyclic systems have been employed in the stepwise construction of compounds with molecular architectures that resemble cups and cages. These macropolycyclic compounds are potential synthetic precursors of novel hydrocarbons composed of (a,d)-fused and (a,c)-fused six-membered rings. The hydrocarbons themselves are of considerable importance in investigating the behaviour of x-electrons in highly-conjugated cyclic systems and in understanding the influence upon the aromaticity and antiaromaticity of benzenoid and fused benzenoid rings that are obliged to become bent.

Design and synthesis of hydrogen-bonded aggregates. Theory and computation applied to three systems based on the cyanuric acid-melamine lattice☆

Abstract The rational design of complex, self-assembling, non-covalent aggregates requires a workable understanding of association phenomena, a reliable rule-based mechanism to predict and compare the stabilities of potential target structures, and straightforward synthetic routes to the molecular components of the aggregates. Systems based on the cyanuric acid-melamine lattice satisfy many of these criteria. This paper reviews the design, synthesis, and characterization of three related aggregates, and summarizes initial results of two models: i) a computational model that predicts relative stabilities of aggregates; and ii) a theoretical model that assesses relative entropies of aggregation.