Chelate bis(imino)pyridine cobalt complexes: synthesis, reduction, and evidence for the generation of ethene polymerization catalysts by Li+ cation activation.

Treatment of the bis(iminobenzyl)pyridine chelate Schiff-base ligand 8 (ligPh) with FeCl2 or CoCl2 yielded the corresponding (ligPh)MCl2 complexes 9 (Fe) and 10 (Co). The reaction of 10 with methyllithium or "butadiene-magnesium" resulted in reduction to give the corresponding (ligPh)Co(I)Cl product 11. Similarly, the bis(aryliminoethyl)pyridine ligand (ligMe) was reacted with CoCl2 to yield (ligMe)CoCl2 (12).

Synthesis and explosive decomposition of organometallic dehydro[18]annulenes: an access to carbon nanostructures.

The synthesis of eight new cyclobutadiene or ferrocene-fused organometallic dehydroannulenes is reported. Cadiot-type coupling of a 1-bromoethynyl-2-silylethynylbenzene derivative to an organometallic diyne (1,2-diethynyl-3,4-bis(trimethylsilyl)cyclobutadiene(cyclopentadienyl )cobalt or 1,2-diethynylferrocene) is followed by deprotection and Cu(OAc)(2)-promoted ring closure. Five of the organometallic dehydroannulenes were structurally characterized.

Chiroptical properties of poly(p-phenyleneethynylene) copolymers in thin films: large g-values.

A series of chirally substituted poly (p-phenyleneethynylene) copolymers was prepared by alkyne metathesis of mixtures of two different 2,5-dialkyl-1,4-dipropynylbenzenes. One of the monomers was the chiral bis-2,5-(S)-3,7-dimethyloctyl-1,4-dipropynylbenzene, and the second one was an achiral dipropynyl monomer. If the content of chiral monomer is 25-50 mol %, unusually large chiroptical effects, that is, optical dissymmetries, result in absorption (g = -0.