[(1,2,5,6-η)-Cyclo-octa-1,5-diene](1-ethyl-4-isobutyl-1,2,4-triazol-5-yl-idene)(tri-phenyl-phosphane)rhodium(I) tetra-fluorido-borate.

A new, cationic N -heterocyclic carbene Rh I complex with a tetra-fluorido-borate counter-anion, [Rh(C 8 H 12 )(C 8 H 15 N 3 )(C 18 H 15 P)]BF 4 , has been synthesized and structurally characterized. There are two independent ion pairs in the asymmetric unit. Each complex cation exhibits a distorted square-planar conformation around the Rh I atom. Bond lengths and bond angles are as expected for an Rh-NHC complex. There are several close, non-standard C-H⋯F hydrogen-bonding inter-actions between the ions. One of the tetra-fluorido-borate anions shows statistical disorder of the F atoms.