Helquat-Induced Chiroselective Aggregation of Au NPs

Au nanoparticles (NPs) are functionalized with chiral (R) or (S) binaphthol phenylboronic acid ligands, (la) or (1b) The (R)- or (S)-binaphthol phenylboronic acid ligands form donor-acceptor complexes with the chiral dicationic helicene, helquat (P)-HQ(2+) or (M)-HQ(2+), (2a) or (2b). The association constants between (1a)/(2a) and (1a)/ (2b) correspond to (7.0 +/- 0.5 ) x 10(5) M-1 and (2.5 +/- 0.3) x 10(5) M-1 respectively, whereas the association constants between (1b)/(2b) and (1b)/(2a) correspond to (4.0 +/- 0.5) X 10(5) M-1 and (1.8 +/- 0.3) x 10(5) M-1, respectively. Chiroselective aggregation of chiral binaphthol phenylboronic acid-capped Au NPs triggered by the chiral helquats, is demonstrated.