A series of new, all-aromatic, macrocyclic biaryls have been obtained by intramolecular, nickel-promoted coupling of bis(4-chlorobenzoylphenoxy)-terminated oligomers, and single-crystal X-ray analysis of one such macrocycle reveals extreme distortion of the biaryl unit; these highly strained materials undergo rapid ring-opening polymerisation in the presence of nucleophilic initiators to give high molecular weight polyetherketones.

High-temperature (330 °C) polycondensation of 4,4'-dihydroxydiphenyl sulfone with 4,4'bis(4-fluorobenzoyl)biphenyl, using diphenyl sulphone as solvent and sodium carbonate as base, leads to formation of an amorphous polymer (A) in which the monomer-derived subunits [-OArSOjAr-] ("S") and [OArCOArArCOAr-] ("K") essentially alternate along the polymer chain. In contrast, the polymer (B) formed on replacing part (ca. 10%) of the sodium carbonate by potassium carbonate is partially crystalline, and sequence analysis by 13C NMR indicates that the distribution of S and K units within a chain is now almost entirely random. The crystalline phase of polymer B is identified as [-OArCOArArCOAr-]", and a structure is proposed for this phase on the basis of X-ray fiber studies, single-crystal X-ray oligomer data, and molecular-modeling/diffraction-simulation techniques.

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The effect of modifying an η-alumina methyl chloride synthesis catalyst by doping with CsCl and KCl over the concentration range of 0.1–1.0 mmol g (cat) –1 is investigated by a combination of pyridine chemisorption coupled with infrared spectroscopy and mass-selective temperature-programmed desorption measurements. The loading of group 1 metal chloride is equivalent to a titrant that enables selective neutralization of Lewis acid sites present at the surface of the reference η-alumina catalyst. Specifically, a loading of 0.1 mmol g (cat) –1 is sufficient to neutralize the strong Lewis acid sites; a loading of 0.6 mmol g (cat) –1 is sufficient to neutralize the strong and medium-strong Lewis acid sites; a loading of 1.0 mmol g (cat) –1 neutralizes all of the strong and medium-strong Lewis acid sites and partially neutralizes the medium-weak Lewis acid site. These deductions connect with a catalyst design program to develop a methyl chloride synthesis catalyst that exhibits minimal formation of the byproduct dimethyl ether.

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Polymerizable macrocyclic biarylene−ether−ketones and biarylene−ether−sulfones are accessible from linear, bis(chloro)-terminated oligomers via nickel-catalyzed, intramolecular coupling under pseudo-high-dilution conditions. Single-crystal X-ray analyses of the resulting cyclo-oligomers reveal extremely distorted and highly strained geometries, with 4,4‘-biphenylene units showing deviations of up to 70° from linearity.

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