N‐Heterocyclic Carbene and Cyclic (Alkyl)(amino)carbene Adducts of Antimony(III)

A systematic study on Lewis-acid/base adducts of N-heterocyclic carbenes (NHCs) and the cyclic (alkyl)(amino)carbene cAACMe (1-(2,6-di-iso-propylphenyl)-3,3,5,5-tetramethyl-pyrrolidin-2-ylidene) with antimony(III) chlorides general formula SbCl2R (R=Cl, Ph, Mes) is presented. The reaction NHCs Me2ImMe (1,3,4,5-tetra-methyl-imidazolin-2-ylidene), iPr2ImMe (1,3-di-isopropyl-4,5-dimethyl-imidazolin-2-ylidene), Mes2Im, Dipp2Im (R2Im=1,3-di-organyl-imidazolin-2-ylidene; Mes=2,4,6-trimethylphenyl, Dipp=2,6-di-isopropylphenyl) compounds (R=Cl (1), Ph (2) Mes (3)) yields NHC ⋅ (4), (5) (6); NHC=Me2ImMe (a), (b), (c) Mes2Im (d)) (4 e) (5 e)). Thermal treatment (Dipp2Im) SbCl2Ar (Ar=Ph c) (6 c)) in benzene leads to isomerization backbone coordinated aNHC-adduct aDipp2Im (Ar=Mes (7) (8)) (“a” denotes “abnormal” coordination mode NHC) high yields. One chloride substituents at antimony 7 can be abstracted by GaCl3 or Ag[BF4] obtain imidazolium salts [aDipp2Im SbClMes][BF4] (9) SbClMes][GaCl4] (10).