Phosphorus‐Stabilized Titanium Carbene Complexes: Synthesis, Reactivity and DFT Studies

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.