Construction of an ortho-phenol polymer

Synthesis and study of an ortho-phenol polymer, a highly functionalized polyphenylene, have been conducted. A dibromo ortho-biphenol monomer was synthesized and its homocoupling in the presence of Ni(1,5-cyclooctadiene)2 followed by hydrolysis led to the formation of an ortho-phenol polymer. This polymer was soluble in common organic solvents. It was characterized by gel permeation chromatography, UV–vis, IR, 1H and 13C NMR spectroscopic methods. The use of this polymer in the Lewis acid-catalyzed reaction of phenylacetylene with benzaldehyde in the presence of diethylzinc was studied. It was found that the polymer when treated with 1/4 equiv. (relative to the phenol unit of the polymer) of Ti(OiPr)4 generated a much more active Lewis acid catalyst than when treated with excess Ti(OiPr)4. This indicates that different types of catalytic sites in the polymer have been produced under these conditions.