Synthesis, structure, electronic properties and thermal behavior of butadiynyl substituted phenylCr(CO)3-complexes

Butadiynyl-substituted h-benzeneCr(CO)3 complexes 3 are very efficiently prepared by a copper catalyzed coupling of the phenylacetylene complex 1 and bromo alkynes 2. The transmission of electronic effects through the butadiynyl bridge operates by resonance mechanisms as established by correlations between Hammett’s sp, sR and sP parameters. Most interestingly, however, is an unusual thermal behavior that leads to intractable paramagnetic polymers of unknown structure. According to thermal analyses (thermal gravimetrical analysis, differential scanning calorimetry) the complexes 3 react in a thermal solid-state reaction under CO extrusion to give amorphous cross-linked polymers. # 2003 Elsevier B.V. All rights reserved.