Crystal Structure of Rhodium(II) Formamidinate Dimer with an Axial Acetonitrile Molecule

Abstract

The title compound, dinuclear rhodium(II) complex with di-N,N′-p-tolylformamidinate ion (form^-) and acetonitrile [Rh₂(form)₄(CH₃CN)]·2H₂O, was isolated from the CH₂Cl₂-CH₃CN solution containing equimolar amounts of [Rh₂(form)₄] and 1,4-dicyanobenzene (1,4-dcb), and the crystal structure was determined by the single-crystal X-ray diffraction method at 293 K. It crystallizes in the tetragonal space group P4/ncc with a = 16.275(3)Å, c = 23.955(6)Å, V = 6345(2)ų, D_x = 1.231 g/cm³, and Z = 4. The R1 and wR2 values are 0.0437 and 0.1402, respectively, for 3250 reflections. The crystal consists of tetrakisformamidinato-bridged rhodium(II) dimers with a Rh-Rh distance of 2.4750(10)Å, CH₃CN molecules axially coordinating to the rhodim(II) dimer with a Rh-N distance of 2.119(7)Å, and crystal waters. The crystal does not include 1,4-dcb, showing that 1,4-dcb did not work to link the rhodium(II) dimer.