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Phosphorus‐Stabilized Titanium Carbene Complexes: Synthesis, Reactivity and DFT Studies
Author(s) -
Lafage Mathieu,
Heuclin Hadrien,
Le Goff XavierFrédéric,
SaffonMerceron Nathalie,
Mézailles Nicolas
Publication year - 2014
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201403708
Subject(s) - carbene , reactivity (psychology) , geminal , chemistry , nucleophile , electrophile , titanium , medicinal chemistry , yield (engineering) , transition metal carbene complex , isocyanate , organic chemistry , catalysis , materials science , medicine , alternative medicine , pathology , metallurgy , polyurethane
Abstract The synthesis of two novel titanium carbene complexes from the bis(thiophosphinoyl)methanediide geminal dianion 1 (SCS 2− ) is described. Dianion 1 reacts cleanly with 0.5 equivalents of [TiCl 4 (thf) 2 ] to afford the bis‐carbene complex [(SCS) 2 Ti] ( 2 ) in 86 % yield. The mono‐carbene complex [(SCS)TiCl 2 (thf)] ( 3 ) can also be obtained by using an excess of [TiCl 4 (thf) 2 ]. The structures of 2 and 3 are confirmed by X‐ray crystallography. A strong nucleophilic reactivity towards various electrophiles (ketones and aldehydes) is observed. The reaction of 3 with N , N ′‐dicyclohexylcarbodiimide (DCC) and phenyl isocyanate leads to the formation of two novel diphosphinoketenimines 8 a and 8 b . The bis‐titanium guanidinate complex 9 is trapped as the by‐product of the reaction with DCC. The X‐ray crystal structures of 8 a and 9 are presented. The mechanism of the reaction between complex 3 and DCC is rationalized by DFT studies.