The photochemical and photophysical properties of a-diimine Re(I) compounds have been recognized since the mid 1970's. In particular, these species possess exceptional photocatalytic ability to function as unique CO2 reduction catalysts without the requirement of additional complexes as photosensitizer or catalyst. However, the development of Re(I) chemistry has been restricted  by the limited structural and electronic variability of the common pseudo-octahedral fac-[ReX(CO)3L2] (L2 = a-diimine) products. We address this constraint by reporting the preparation and characterization of tridentate pincer ligand compounds possessing bis(imino)pyridine and terpyridine ligation, ?3-LRe (CO)2X  (L = 2,6-{ArN=CR}2(NC5H3), 2,2':6',2�-terpyridine; X = Cl -, Br -, OTf -). Single crystal X-ray analyses document the new coordination environment for Re(I) carbonyl chemistry where the metal center is supported by a planar, tridentate pincer ligand. The photophysical features of these compounds show significant elaboration in both number and intensity of the d-p* transitions observed in the UV-Vis spectra relative to the bidentate starting materials; these spectra were analyzed using time-dependent DFT computations. Electrochemical analysis indicated an increase in electrostatic stabilization of the reduced ligand in the tridentate conformation.

Expanding the coordination geometry and enhancing the photophysical features of Re(I) with redox non-innocent pincer ligands

247th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.