2015, Godemann, Christian, Dura, Laura, Hollmann, Dirk, Grabow, Kathleen, Bentrup, Ursula, Jiao, Haijun, Schulz, Axel, Brückner, Angelika, Beweries, Torsten

Irradiation of a substituted ansa-titanocene(IV) dihydroxido complex with visible light induces Ti–O bond dissociation. In contrast to previous studies on structurally similar unbridged complexes, no side reactions are observed and formation of the Ti(III) species is highly selective. The formation of OH radicals was proved using a biradicaloid species.

2019, Reiß, Fabian, Reiß, Melanie, Bresien, Jonas, Spannenberg, Anke, Jiao, Haijun, Baumann, Wolfgang, Arndt, Perdita, Beweries, Torsten

The synthesis of an unusual 1-metalla-2,3-cyclobutadiene complex [rac-(ebthi)Ti(Me3SiC3SiMe3)] (rac-ebthi = rac-1,2-ethylene-1,1′-bis(η5-tetrahydroindenyl)), a formal metallacyclic analogue of a non-existent four-membered 1,2-cyclobutadiene, is described. By variation of the cyclopentadienyl ligand of the titanocene precursor it was possible to stabilise this highly exotic compound which selectively reacts with ketones and aldehydes to yield enynes by oxygen transfer to titanium. Analysis of the bonding and electronic structure of the metallacycle shows that the complex is best described as an unusual antiferromagnetically coupled biradicaloid system, possessing a formal Ti(iii) centre coordinated with a monoanionic radical ligand. © 2019 The Royal Society of Chemistry.