Using ligand exchange reactions to control the coordination environment of Pt(II) acetylide complexes: applications to conjugated metallacyclynes

Ligand exchange of cis-bis(diphenylphosphino)ethylene (dppee) with trans-(Ph3P)(2)Pt(Cequivalent toCR)(2) easily generates the cis-complexes (dppee)Pt(Cequivalent toCR)(2) in 64-95% yield. This transformation is used to convert pyridine-containing macrocycle 7 to its cis-analogue 8 and the macrocyclic bipyridine analogue 10 to the unique macrocyclic ligand 11. X-ray structural characterization of trans-complexes 5a and 5b and cis-complexes 6a and 6b are reported, as is the structure of the strained macrocycle 8. (C) 2003 Elsevier B.V. All rights reserved.