Dramatic enhancement in pH sensitivity and signal intensity through ligand modification of a dicobalt PARACEST probe.


Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3113, USA. [Email]


The employment of an ancillary amine-substituted bisphosphonate ligand affords a dicobalt complex able to quantitate pH with a remarkably high sensitivity of 8.8(5) pH unit-1 at 37 °C through a ratiometric paramagnetic chemical exchange saturation transfer (PARACEST) approach, where the different pH dependences of amine and amide CEST peak intensities are utilized.