Dinuclear complexes with a μ-cyano ligand. part IX. synthesis,characterization and magnetic studies of several derivatives of [Cr(CN)6]3− and [Cr(NO)(CN)5]3−

Summary Twelve dinuclear complexes, each with a bridging cyano group, of formulaecis-M[(aa)₂FCr-NC-Cr(CN)₅] andcis- M[(aa)₂FCr-NC-CrNO(CN)₄] (aa=ethylenediamine or 1,3-diaminopropane; M=K⁺, Na⁺ or NH₄⁺) have been prepared by solid state heating of the corresponding doubly complexed saltstrans-M[CrF(H₂O)(aa)₂][Cr(CN)₆] andtrans-M [CrF(H₂O)(aa)₂][CrNO(CN)₅]. All have been characterized by chemical analysis, electronic and i.r. spectra and conductivity measurements.Magnetic susceptibilities down to liquid helium temperature have been determined forcis-K[(en)₂FCr-NC-Cr(CN)₅],cis-K[(tn)₂FCr-NC-Cr(CN)₅] andcis-K[(en)₂FCr-NC-CrNO-(CN)₄]. Slight antiferromagnetic interactions have been found in the first two compounds (J=–1.4 and –1.2 cm^–1, respectively). Thecis-K[(en)₂FCr-NC-CrNO(CN)₄] compound behaves as a Curie paramagnet and a structural model is proposed to explain this fact.