Dehydrogenation of hydrocarbons with metal-carbon multiple bonds and trapping of a titanium(II) intermediate.

Reacting (PNP)Ti=CH^tBu(CH₂^tBu) with 2,2'-bipyridine (bipy) in cyclohexane or heptane results in dehydrogenation, cleanly producing cyclohexene and 1-heptene, respectively, and a Ti^II intermediate that is trapped by bipy to produce [(PNP)Ti^III(CH₂^tBu)(bipy^·-)] (1). This titanium(II) intermediate reduces the bipy ligand upon coordination to form a Ti^III center, where the unpaired electron is antiferromagnetically coupled to the electron of the reduced [bipy^·-] π-radical moiety, giving an overall diamagnetic species. Complex 1 has been characterized by NMR and UV-vis spectroscopies as well as single crystal X-ray diffraction studies. [ABSTRACT FROM AUTHOR]