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1-Titanacyclobuta-2,3-diene - an elusive four-membered cyclic allene.

ABSTRACT: 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.

SUBMITTER: Reiß F

PROVIDER: S-EPMC6540905 | biostudies-literature | 2019 May

REPOSITORIES: biostudies-literature

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1-Titanacyclobuta-2,3-diene - an elusive four-membered cyclic allene.

Reiß Fabian F Reiß Melanie M Bresien Jonas J Spannenberg Anke A Jiao Haijun H Baumann Wolfgang W Arndt Perdita P Beweries Torsten T

Chemical science 20190423 20

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 aldehyde ...[more]

PMID: 31191888

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