Neutral and cationic alkyl and alkynyl complexes of lanthanum : Synthesis, stability, and cis-selective linear alkyne dimerization

Neutral triazacyclononane−amide lanthanum dialkyl and dialkynyl complexes were synthesized and structurally characterized. A cationic triazacyclononane−amide lanthanum monoalkyl species was generated and found to be highly active (tof > 100 h-1) in the rare cis-selective catalytic linear dimerization of phenylacetylene.