Synthesis of Cyclopenta-HBCs and their Regioselective Chlorination During Oxidative Cyclodehydrogenation.

Hexa-peri-hexabenzocoronenes with a bay-fused five-membered ring are synthesized from fluorenyl precursors. The key oxidative cyclodehydrogenation step is accompanied by regioselective chlorination that is enhanced by methylation at the cyclopenta-ring or increased reaction concentration. The CpHBC products undergo mild electrophilic aromatic bromination, without catalyst, to afford adducts suitable for π-extension by cross-coupling.

Dramatic Alteration of ILCT Lifetimes Using Ancillary Ligands in [Re(L)(CO)(phen-TPA)] Complexes: An Integrated Spectroscopic and Theoretical Study.

The ground and excited state photophysical properties of a series of fac-[Re(L)(CO)(α-diimine)] complexes, where L = Br, Cl, 4-dimethylaminopyridine (dmap) and pyridine (py) have been extensively studied utilizing numerous electronic and vibrational spectroscopic techniques in conjunction with a suite of quantum chemical methods. The α-diimine ligand consists of 1,10-phenanthroline with the highly electron donating triphenylamine (TPA) appended in the 5 position. This gives rise to intraligand charge transfer (ILCT) states lying lower in energy than the conventional metal-to-ligand charge transfer (MLCT) state, the energies of which are red and blue-shifted, respectively, as the ancillary ligand, L becomes more electron withdrawing.