2-biphenylyl iodine

The synthesis and properties of heat-resistant polyazomethines containing 2,5-disubstituted oxadiazole fragments, being insulators convertible into semiconductors by doping with iodine, have been described. The radical copolymerization of alkenes with the fluorescent co-monomer 2-/-butyl-5-(4 -vinyl-4-biphenylyl)-l,3,4-oxadiazole has resulted in useful macromolecular scintillators. Anionic polymerization of 2-phenyl-l,3,4-oxadiazolin-5-one has produced a nylon-type product <1996CHEC-II(4)268>. 

Note that in this case a control of spin coupling via control of electron localization is attained. The straightforward control of electron localization was implemented via modification of the substituents at the center site (see Schemes 1-60 and 1-61). The mentioned anion diradicals were prepared by partial oxidation of relative polyanions with iodine (Rajca Rajca 1995). When the carbanion-stabilizing 4-biphenylyl, in the place of 4-tert-butylphe-nyl, was employed as a substituent at the center site, the negative charge was confined to the center site and the spin density to the terminal (nonadjacent) site. 

Biphenylyl Tellurium Triiodide14 To a stirred solution of 0.62 g (1.1 mmol) ofbis[2-biphenylyl] ditellurium in 11 ml of dry chloroform is added dropwise a solution of 0.84 g (3.3 mmol) of iodine in 35 ml of carbon tetrachloride. During this addition, fine dark-red needles of the triiodide precipitate. The mixture is filtered on standing overnight the filtrate deposits additional product m.p. 163-165°. 

Hexaaryldisilanes are thermally extremely stable. Hexakis(4-methylphenyl) and hexakis[biphenylyl(4)] disilanes do not react with oxygen, iodine or other reagents, even upon heating hexaarylethanes are attacked under the same conditions. In such cases, steric considerations may be decisive. 

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