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

Twelve dinuclear complexes, each with a bridging cyano group, of formulae cis-M[(aa)2FCr-NC-Cr(CN)5] and cis- 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 salts trans-M[CrF(H2O)(aa)2][Cr(CN)6] and trans-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 for cis-K[(en)2FCr-NC-Cr(CN)5], cis-K[(tn)2FCr-NC-Cr(CN)5] and cis-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). The cis-K[(en)2FCr-NC-CrNO(CN)4] compound behaves as a Curie paramagnet and a structural model is proposed to explain this fact. © 1984 Verlag Chemie GmbH.