Rh(I) and Pd(II) complexes of methoxy functionalized heterocyclic carbene: Synthesis and characterization

A new methoxy functionalized 2‐(trichloromethyl)‐1,3‐diarylimidazolidin (6) was synthesized as the precursor for N‐heterocyclic carbene complexes of Pd(II) and Rh(I) by the condensation of N,N'‐bis(2,4‐dimethoxyphenyl)‐1,2‐diaminoethane with chloral. The structures of all compounds have been elucidated by a combination of multinuclear NMR spectroscopy, elemental analysis and in one instance, by single crystal X‐ray diffraction. Compound 8, C₂₇H₃₄N₂O₄ClRh, crystallizes in the triclinic space group P‐1 with cell dimensions a = 9.7642(12)Å, b = 11.1914(11)Å, c = 13.0102(14)Å, α = 104.034(9)°, β = 106.658(9)°, γ = 99.658(9)° with Z = 2. The molecular structure of 8 shows the geometry around the Rh metal to be a slightly distorted square planar. The crystal structure shows the formation of centrosymmetric dimers via intermolecular C‐H...Cl hydrogen bonds. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)