Donor-acceptor interactions between cyclic trinuclear pyridinate gold(i)-complexes and electron-poor guests: nature and energetics of guest-binding and templating on graphite.

ABSTRACT: Donor-acceptor-type interactions between ?-electron systems are of high relevance in the design of chemical sensors. Due to their electron-rich nature, cyclic trinuclear complexes (CTCs) of gold(i) are ideal receptor sites for electron-deficient aromatic analytes. Scanning tunneling microscopy provided insight into the structures of two-dimensional crystals of pyridinate gold CTCs that form on a graphite template at the solid/liquid interface. One polymorph thereof - in turn - templated the on-top co-adsorption of ?-acidic pyrazolate CTCs as electron-poor guests up to a certain threshold. From NMR titration experiments, we quantified free energies of -6.1 to -7.5 kcal mol^-1 for the binding between pyridinate gold(i) CTCs and ?-acidic pyrazolate CTCs. Quantum chemical calculations revealed that these interactions are largely dominated by London dispersion. These results give a more detailed insight into a rational design of sensitive CNT- or graphene-based sensors for ?-acidic analytes, such as electron-deficient aromatics.

SUBMITTER: Hahn R 

PROVIDER: S-EPMC5934696 | biostudies-literature | 2018 Apr

REPOSITORIES: biostudies-literature