The development of photometric sensors for boronic acids

Boronic acids bind certain 1,2- and 1,3-diols with high affinity through re versible formation of boronate esters. They have been utilized as the recog nition moiety for artificial receptors, particularly receptors for carbohyd rates that have cis-diol moieties. Therefore, sensors for boronic acids cou ld serve as universal reporters for monitoring boronate formation. This pap er reports the design and synthesis of a series of photometric chemosensors for phenylboronic acid using diethanolamine as the recognition moiety. Die thanolamine, which binds strongly to boronic acids, has been linked to thre e different types of optical reporters. A photoinduced electron transfer sy stem based on the anthracene fluorophore has been used to create sensors th at show up to a fivefold increase in fluorescent intensity in the presence of millimolar concentrations of phenylboronic acid. Sensor designs based on the restriction of free rotation of extended pi systems and on the perturb ed electronic proper-ties of azo dyes are also included. This work demonstr ates that sensors based on several different designs can be used for the de tection of boronic acids. (C) 2001 Academic Press.