Pyrrolylquinoline-BF2 and BPh2 BODIPY-Type Analogues: Synthesis, Structural Analysis and Photophysical Properties

Two new pyrrolylquinoline-substituted heteroaromatic-containing compounds bearing a central boron bridge have been prepared by short, high-yielding sequence consisting of Suzuki-coupling 8-bromoquinoline and N-Boc 2-pyrroleboronic acid, thermolytic tert-butyloxycarbonyl deprotection, subsequent chelation (either using trifluoride or triphenylborane). Both derivatives display longer wavelength absorption maxima (λabsmax) than previously reported indolopyridine-BPh2 analogue, in agreement with the smaller HOMO-LUMO energy gap predicted DFT quantum chemical calculations. pyrrolylquinoline-boron chelates weak emission (quantum yields 0.3–0.9%) BPh2 complex displays very broad, long-wavelength (λemmax = 715 nm, MeCN), which may be due to dimer results large pseudo-Stokes’ shift (7753 cm−1) for this compound.