Daran J.-C.Demirhan F.Yldrm O.Çetinkaya B.2019-10-272019-10-2720120108-27010108-2701https://doi.org/10.1107/S0108270112000601https://hdl.handle.net/11454/26705Owing to increasing inter-est in the use of N-heterocyclic carbenes (NHCs) based on imidazolidinium ions as ligands in the design of highly efficient transition-metal-based homogeneous catalysts, the characterizations of the 1-ferrocenylmethyl-3-(2,4,6-trimethyl-benzyl)imidazolidin-3-ium iodide salt, [Fe(C 5H 5)(C 19H 24N 2)]I, (I), and the palladium complex trans-bis-(3-benzyl-1-ferrocenylmethyl-1H- imidazolidin-2-yl-idene)diiodidopalladium(II), [Fe 2Pd(C 5H 5) 2(C 16H 17N 2) 2I 2], (II), are re-ported. Compound (I) has two iodide anions and two imidazolidinium cations within the asymmetric unit (Z' = 2). The two cations have distinctly different con-formations, with the ferrocene groups orientated exo and endo with respect to the N-heterocyclic carbene. Weak C-H donor hydrogen bonds to both the iodide anions and the ? system of the mesitylene group combine to form two-dimensional layers perpendicular to the crystallographic c direction. Only one of the formally charged imidazolidinium rings forms a near-linear hydrogen bond with an iodide anion. Complex (II) shows square-planar coordination around the Pd II metal, which is located on an inversion centre (Z' = 0.5). The ferrocene and benzyl substituents are in a trans-anti arrangement. The Pd-C bond distance between the N-heterocyclic carbene ligands and the metal atom is 2.036 (7) Å. A survey of related structures shows that the lengthening of the N-C bonds and the closure of the N-C-N angle seen here on metal complexation is typical of similar NHCs and their complexes. © 2012 International Union of Crystallography.en10.1107/S0108270112000601info:eu-repo/semantics/closedAccessArticle682m48m52N/A