Hyperconjugative Aromaticity-Based Circularly Polarized Luminescence Enhancement in Polyaurated Heterocycles

Hyperconjugative aromaticity (HA) frequently appears in metalla-aromatics, but its effect on photophysical properties remains unexplored to date. Herein, we reveal two different HA scenarios in nearly isostructural triaurated indolium and benzofuranylium compounds. The biased HAs show a discernible effect on the spatial arrangement of metal atoms and thus tailor metal parentage in frontier orbitals and the HOMO–LUMO energy gap. Theoretical calculations and structural analyses demonstrate that HA not only influences the degree of electron delocalization over the trimetalated aromatic rings but also affects π-coordination of Au(I) and intercluster aurophilic interaction. Consequently, the triaurated benzofuranylium complex shows better photoluminescence performance (quantum yield up to 49.7%) over the indolium analogue. Furthermore, four pairs of axially chiral bibenzofuran-centered trinuclear and hexanuclear gold clusters were purposefully synthesized to correlate their HA-involved structures with the chiroptical response. The triaurated benzofuranylium complexes exhibit strong circular dichroism (CD) response in solution but CPL silence even in solid film. In contrast, the hexa-aurated homologues display strong CD and intense CPL signals in both aggregated state and solid film (luminescence anisotropy factor glum up to 10–3). Their amplified chiroptical response is finally ascribed to the dominant intermolecular exciton couplings of large assemblies formed through the HA-tailored aggregation of hexanuclear compounds

Additional file 1 of Microbiota-derived tryptophan metabolites indole-3-lactic acid is associated with intestinal ischemia/reperfusion injury via positive regulation of YAP and Nrf2

Aditional file 1: Table S1. Primer sequences

Additional file 2 of Microbiota-derived tryptophan metabolites indole-3-lactic acid is associated with intestinal ischemia/reperfusion injury via positive regulation of YAP and Nrf2

Additional file 2: Figure S1. ILA promoted ISCs proliferation. (A) Ki67 mRNA levels in intestinal tissues (n = 4–5/group). (B) Lgr5 mRNA levels in intestinal tissues (n = 4–5/group). (C) Ascl2 mRNA levels in intestinal tissues (n = 4–5/group). Results are presented as mean ± SEM. * p < 0.05, ** p < 0.01