om010449g_si_002.pdf (544.08 kB)
Doubly Cyclometalated Pyridazines: Contrasting Behavior with Palladium and Platinum
journal contribution
posted on 2001-09-11, 00:00 authored by Jonathan W. Slater, Donocadh P. Lydon, Nathaniel W. Alcock, Jonathan P. RourkeThe cyclometalation of 3,6-diphenylpyridazines with palladium and platinum has been
studied. When palladium acetate is used as the metal source, two sequential cyclometalations
are observed, with the first cyclometalation deactivating the system toward a second
cyclometalation. Both monocyclopalladated and dicyclopalladated species have been isolated
and characterized as their acetylacetonate derivatives. When potassium tetrachloroplatinate
is used as the metal source, only double cycloplatination is observed: the first cycloplatination
activates the system toward a second cycloplatination through a combination of nitrogen
coordination and a chloride bridging two platinums. A doubly cycloplatinated compound
has been isolated as its triphenylphosphine derivative, which has been fully characterized:
the single-crystal X-ray structure shows that the two platinums are bridged by a chloride.