Sunlight-induced dehydrogenation rearrangement of the dititanium complex [Ti(eta(5)-C5HMe4)(mu-eta(1) : eta(5)-C5Me4)](2)

0538224 - ÚFCH JH 2022 RIV CH eng J - Journal Article
Gyepes, Robert - Pinkas, Jiří - Kubišta, Jiří - Mach, Karel - Horáček, Michal
Sunlight-induced dehydrogenation rearrangement of the dititanium complex [Ti(eta(5)-C5HMe4)(mu-eta(1) : eta(5)-C5Me4)](2).
Journal of Organometallic Chemistry. Roč. 934, FEB 2021 (2021), č. článku 121663. ISSN 0022-328X. E-ISSN 1872-8561
Institutional support: RVO:61388955
Keywords : Fulvalene * Photolysis * Rearrangement * Solid-state structures * Titanium
OECD category: Physical chemistry
Impact factor: 2.345, year: 2021
Method of publishing: Limited access

Sunlight photolysis of the triplet state (S = 1) dititanium compound 1 induced its rearrangement to diamagnetic 2, which was a molecule containing two hydrogens less. The cage structure of 2 was determined by single crystal X-ray diffraction and was corroborated fully by 1H and 13C NMR spectra that identified three simple bridging moieties — a hydrogen atom, a methine carbon and a methylene carbon. Its extremely short Ti−Ti distance 2.7537(7) Å causes a strong distortion of the bridging fulvalene ligand, which becomes η5- bonded to one Ti(IV) and connected by two σ-bonds from nearest carbon atoms of its other ring to the other Ti(IV) of 2. Other photolytical byproducts in very minor amounts were also isolated, which differed from 2 by the absence of one bridging moiety: compound 4 lacked the methine group and compound 5 had no bridging hydrogen. In the latter cases, the Ti−Ti distance fell in the range 3.2077(8) – 3.5543(12) Å and the fulvalene ligand was coordinated in the common µ-η5: η5-mode to both titanium atoms. The octamethylfulvalene ligands in 4 and 5 had their ring planes rotated mutually by about 40° in order to relieve the steric hindrance between their methyl groups. The thermally robust µ-oxo complex 3 obtained from reacting 2 with water showed a very similar structure.
Permanent Link: http://hdl.handle.net/11104/0316048