A DOTAM-based paraCEST agent favoring TSAP geometry for enhanced amide proton chemical shift dispersion and temperature sensitivity


R. H. E. Hudson, Department of Chemistry, The University of Western Ontario, London, Ontario, Canada N6A 5B7.

E-mail: robert.hudson@uwo.ca


The Tm3+ chelate of DOTAM [1,4,7,10-tetrakis(carbamoylmethyl)-1,4,7,10-tetraazacyclododecane] possessing sterically demanding t-butyl amide substitution favors TSAP geometry. This chelate displayed a paraCEST signal associated with the highly shifted amide proton signal at approximately −100 ppm that was beyond the frequency of macromolecule magnetization transfer. This signal also displayed high temperature dependence (0.57 ppm °C−1) in the range of 35–42 °C and at neutral pH. Copyright © 2013 John Wiley & Sons, Ltd.