Chemistry of Rh-N,S heterocyclic carbene complexes

• Z-class boratrane has been synthesized from Rh-N,S-heterocyclic carbene complex.
• A η1-vinyl complex resulted from chloroboratrane and ethynylmagnesium bromide.
• The vinyl complex possesses a unique five membered metallaheterocycle.

Chloro-rhodaboratrane [(Cp*Rh)(L2)BCl] 4 has been synthesized from rhodium N,S-heterocyclic carbene complex [(Cp*Rh)(L2)(1-benzothiazol-2-ylidene)], 1, (L = C7H4NS2) and borane reagent BHCl2.SMe2. The RhB bond in 4 is buttressed between two benzothiazolyl units in [3.3.0] fashion. The presence of BCl bond allowed us to explore the chemistry of boratrane 4 at the boron centre. The reaction of ethynylmagnesium bromide with 4 yielded η1-vinyl complex [Cp*RhBr(C2H2)L] 5, containing a five membered metallaheterocycle. In an objective to abstract the chloride, alike borylene synthesis from haloboryl, we performed the reaction of 4 with NaBArF4 that resulted the thiolato bridged bimetallic compound [Cp*Rh(μ-L)3RhCp*][BArF4] 6 (ArF: C6H3(CF3)2-3,5).

Rh-N,S-heterocyclic carbene complex, [(Cp*Rh)(L2)(1-benzothiazol-2-ylidene)] has been utilized for the synthesis of chloroboratrane which generated η1-vinyl complex [Cp*RhBr(C2H2)L] on reaction with ethynylmagnesium bromide.Figure optionsDownload as PowerPoint slide