Synthesis and crystallographic characterization of a ‘palladadehydrobenzo[19]annulene’

The trans-palladium bis(σ-acetylide) complex (Et3P)2Pd(C30H12) (2) was synthesized from hexane 4 in 77% yield via a simple three-step process. The X-ray crystal structure of 2 shows a strained and warped annulenic core upon insertion of the organometallic fragment. UV–vis data of the molecule suggest limited electronic delocalization throughout the metallacycle.