(8-Amino)quinoline and (4-Amino)phenanthridine Complexes of Re(CO) 3 Halides.

In this report, we present a study on the synthesis, structure, and electronics of a series of (8-amino)quinoline and (4-amino)phenanthridine complexes of Re(CO) ₃ X, where X = Cl and Br. In all cases, the (amino)heterocycles bind as bidentate ligands, with surprisingly symmetric modes of binding based on Re-N bond lengths. Between the complexes of (8-amino)quinolines and (4-amino)phenanthridines studied in this report, we do not observe much structural variation, and remarkably similar UV-visible absorption spectra. Expansion of the π-system in the (4-amino)phenanthridine complexes does result in an increase in the intensity of the lowest energy transitions (λ _max ), which computational modeling suggests are more purely MLCT in character compared with the mixed π-π*/MLCT character of these transitions in the smaller (8-amino)quinoline-supported complexes. DFT and TDDFT modeling further showed that consideration of spin-orbit coupling (SOC) is essential; omitting SOC misses the π-π* contributions to λ _max and is unable to accurately model the observed electronic absorption spectra.
Competing Interests: Conflicts of interest There are no conflicts to declare. Declaration of interests The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.