Hexaarylbenzene Research Articles

Synthesis of three-dimensionally arranged bis-biphenol ligand on hexaaryl benzene scaffold and its application for cross-pinacol coupling reaction

The three-dimensionally arranged bis-biphenol ligand on a hexaaryl benzene scaffold for a dinuclear complex was synthesized by the Diels–Alder addition–decarbonylation reaction as a key step. Its preliminary studies on the titanium-induced cross-pinacol coupling reaction were performed based on step-by-step activation of two different aldehydes.

Synthesis of new aryl and hetaryl dibromides and diiodides, the monomers for preparation of polyarylene ethynylenes

Dibromides and diiodides with quinoxaline, phenylimidazole, and hexa- or pentaphenylarylene fragments were synthesized from dihalotolans obtained from chloral. Oligoarylene ethynylenes were synthesized by the reaction of the monomers with equimolar amounts of diethynyl aromatic compounds in the presence of the PdII complex. Oligomers with imidazole and hexa(penta)arylbenzene cycles are soluble in amide organic solvents and their reduced viscosities do not exceed 0.09 dL g−1.

The fluxional behaviour of hexaphenylbenzene chromium tricarbonyl: A variable-temperature 13C NMR spectroscopic study

The 125 MHz 13C NMR spectrum of (C 6Ph 6)Cr(CO) 3 reveals that the metal is π-bonded to a peripheral ring. At −80°C this chromium-bonded phenyl exhibits slowed rotation on the NMR time-scale and is effectively orthogonal to the central ring. The fluxional process is shown to involve rotation of the Cr(CO) 3-complexed phenyl ring; the activation energy barrier is ≈ 12.2 kcal mol −1, a value much lower than those previously reported for non-complexed hexa-aryl benzenes bearing ortho or meta methyl or methoxy substituents.