Anion molecular recognition processes

Three aromatic carboxylic acids, benzoic add (Arl), phenylacetic acid (Ar2), and 4-methoxyphenylacetic acid were selected as guests to probe the depth of penetration in host 1, and, as well, two aliphatic carboxylic acid guests, cydo-hexylacetic acid (All), and l-adamantanecarboxyHc acid (A12), were also used to further study the importance of hydrophobic effects in the molecular recognition process with host 1. According to their plQ values, all of these carboxylic adds existed in the anionic form at pH 7 [4a, b]. The CICS values of the three guests, Arl, Ar2, and 4-methoxyphenylacetic acid, by host 1 are presented in a similar fashion as described above for the substituted aromatic carboxylic acids (Fig. 10.6). 

Some of the materials highlighted in this review offer novel redox-active cavities, which are candidates for studies on chemistry within cavities, especially processes which involve molecular recognition by donor-acceptor ii-Jt interactions, or by electron transfer mechanisms, e.g. coordination of a lone pair to a metal center, or formation of radical cation/radical anion pairs by charge transfer. The attachment of redox-active dendrimers to electrode surfaces (by chemical bonding, physical deposition, or screen printing) to form modified electrodes should provide interesting novel electron relay systems. 

The molecular recognition of anionic guest species by positively chaiged or neutral receptors is a relatively new area of research of growing interest in view of the key roles that these anions play in biochemical and chemical processes. For this reason, as part of the electrochemical studies, we decided to examine the use of the redox-active ferrocenyl dendrimers 3 and 4 that contain multiple N-H linkages capable of participating in H-bonding, as well as characteristic internal cavities,... 

Molecular recognition, binding and transport of different chemical species represents an aspect of supramolecular chemistry that has relevance to a number of areas that include biochemical processes, analytical techniques, recycling and environmental processes as vell as aspects of catalysis and medicine. Over the years, a large number of both efficient and selective receptors for cations, anions, salts and zwitterions based on different architectures and binding modes have been developed and studied [1-4],... 

With regard to molecular imprinting, a significant hindrance to the development of anion-recognition MIPs has been the fact that anionic species are very often incompatible with apolar media. The molecular imprinting process involves the formation of a pre-polymerisation complex between the template molecule and functional monomers. This is typically based upon H-bonding... 

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