Article (Accepted Version) http://sro.sussex.ac.uk Briffitt, Roseanne and Day, Iain (2015) Influence of structural isomerism and fluorine atom substitution on the self-association of naphthoic acid. Journal of Physical Chemistry B, 119 (22). pp. 6703-6710. ISSN 1520-6106 This version is available from Sussex Research Online: http://sro.sussex.ac.uk/54128/ This document is made available in accordance with publisher policies and may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the URL above for details on accessing the published version. Copyright and reuse:Sussex Research Online is a digital repository of the research output of the University.Copyright and all moral rights to the version of the paper presented here belong to the individual author(s) and/or other copyright owners. To the extent reasonable and practicable, the material made available in SRO has been checked for eligibility before being made available.Copies of full text items generally can be reproduced, displayed or performed and given to third parties in any format or medium for personal research or study, educational, or not-for-profit purposes without prior permission or charge, provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way. AbstractThe self-association of small aromatic systems driven by π-π stacking and hydrophobic interactions is well known. Understanding the nature of these interactions is important if they are to be used to control association. Here, we present results of an NMR study into the self-association of two isomers of naphthoic acid along with an investigation into the role of a fluorine substituent on that selfassociation. We interpret the results in terms of a simple isodesmic model of selfassociation and show that the addition of the fluorine atom appears to increase the stability of the aggregates by an order of magnitude (e.g. 1-naphothic acid vs 4-fluoro-1-naphthoic acid K eq = 0.05 increases to 0.35 M -1 ), a result which is supported by computational studies in the literature on the role of substituent effects on interaction energy. The use of fluorinated isomers to probe the assembly is also presented, with differing trends in fluorine-19 chemical shifts observed depending on the isomer substitution pattern.3