To create lowb and-gap,f luorescent, and elastic organic crystal emitters,w ef ocused on an extended pconjugated system based on:a )aplanar conformation,b) arigid structure,and c) controlled intermolecular interactions. Herein, we report on two fluorescent and highly flexible organic crystals (1 and 2)whichcould bend under an applied stress.T he bent crystals rapidly recover their straight shape upon release of the stress.C rystal 1 with at etrafluoropyridyl terminal unit and al ower band-gap energy (orange emission, l em = 573 nm, F F = 0.50), showed no bending mechanofluorochromism and had superior performance as an optical waveguide with reddish orange emission. The waveguide performance of the crystal did not decrease under bending stress.F or crystal 2 with ap entafluorophenyl terminal unit (green emission, l em = 500 nm, F F = 0.38), the original waveguide performance decreased under an applied bending stress; however,this crystal showed aunique bending mechanofluorochromism.

Bulky bis(phenolate) complexes of titanium alcoholates were found to initiate living polymerization of -caprolactone, affording a polyester with a narrow molecular weight distribution. By changing the initial monomer-to-initiator mole ratio, the molecular weight of the polymer was controlled over a wide range. 1 H NMR studies on the produced polymer showed the presence of an alkoxy group originating from the initiator at the polymer terminal, indicating that the polymerization takes place at the titanium alcoholate bond of the initiator. Use of titanium complexes prepared with nonbridged hindered phenols or a less bulky bisphenol resulted in a poorly controlled chain growth or no polymerization.

A dipalladium complex with a double-decker structure catalyzes ethylene-acrylate copolymerization to produce the branched polymer containing the acrylate units in the polymer chain, not at the branch terminus. The cooperation of the two palladium centers, which are fixed in a rigid framework of the macrocyclic ligand, is proposed to have a significant dinuclear effect on the copolymerization.