Cyclic Hydrogen Bonding in Indole Carboxylic Acid Clusters

Monolayers of indole-2-carboxylic acid and indole-3-carboxylic acid on gold are studied using ultrahigh-vacuum scanning tunneling microscopy. Both molecules form symmetric, cyclic, hydrogen-bonded pentamers, a structure that is stabilized by the presence of a weak hydrogen-bond donor (NH or CH) adja...

Full description

Saved in:
Bibliographic Details
Published in:Journal of physical chemistry. C 2015-09, Vol.119 (36), p.21011-21017
Main Authors: Wasio, Natalie A, Quardokus, Rebecca C, Brown, Ryan D, Forrest, Ryan P, Lent, Craig S, Corcelli, Steven A, Christie, John A, Henderson, Kenneth W, Kandel, S. Alex
Format: Article
Language:English
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Monolayers of indole-2-carboxylic acid and indole-3-carboxylic acid on gold are studied using ultrahigh-vacuum scanning tunneling microscopy. Both molecules form symmetric, cyclic, hydrogen-bonded pentamers, a structure that is stabilized by the presence of a weak hydrogen-bond donor (NH or CH) adjacent to the carboxylic acid on the five-membered ring. In addition to pentamers, indole-2-carboxylic acid forms hexamers and catemer chains, while indole-3-carboxylic acid monolayers are generally disordered. Density functional theory calculations show that pentamers and hexamers have stability comparable to dimers or short catemers. The coexistence of all of these structures likely arises from the nonequilibrium conditions present in solution during pulse deposition of the monolayer.
ISSN:1932-7447
1932-7455
DOI:10.1021/acs.jpcc.5b06634