Living metathesis polymerization of [o- (trifluoromethyl)phenyl] acetylene, a phenylacetylene with an electron-withdrawing group, has been achieved by using molybdenum-based three-component catalysts. Thus polymerization by MoOCWt-BuiSn-EtOH (1:1:0.5 mole ratio) catalyst in toluene at 30 °C produced a polymer having a narrow molecular weight distribution; MjMa = 1.06. Upon three consecutive additions of fresh monomer feeds to completely polymerized systems, the M" of the polymer increased in direct proportion to monomer conversion, while the MjM" remained < 1.1. The initiator efficiency was ca. 0.10. The M0CI5n-ButSn-EtOH (1:1:0.5) catalyst also induced living polymerization, though the MJMn (ca. 1.20) was somewhat larger. Effects of catalyst components and polymerization conditions have been studied.
A series of mono-, bis-, and trissubstituted pyridinium and pyrylium dyes have been synthesized by the condensation of methylpyridinium and methylpyrylium salts with aldehydes or nitroso compound. Large bathochromic shifts were observed in the following order, both in substituted azomethine pyridinium and pyrylium dyes, mono < bis < tris. The magnitude of the shift appeared in the order of multiple bonds, –CH=CH– < –CH=CH–CH=CH– < –CH=N–.
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