Crystal structures and magnetic properties of Ni-bisdithiolene complexes with decamethylmetallocenium cations

Three new compounds of formula (Cp2∗Co)[Ni(dmit)2](1), (Cp2∗Mn)[Ni(dmid)2]·(CH3)2CO (2), and (Cp2∗Mn)2[Ni(dmid)2]2·C6H5CN (3) have been synthesised, and structurally and magnetically characterised (dmit2− = 1,3-dithiol-2-thione-4,5-dithiolato; dmid2− = 1,3-dithiol-2-one-4,5-dithiolato). Their structural features and magnetic behaviours are compared with those of (Cp2∗Mn)[Ni(dmit)2] and (Cp2∗Mn)[Ni(dmid)2]·CH3CN. The result of this is that the interactions between the Ni(dmit)2 units in 1 are of ferromagnetic-type, as suggested previously for (Cp2∗Mn)[Ni(dmit)2]. The change from acetonitrile to acetone when going from (Cp2∗Mn)[Ni(dmid)2]·CH3CN to 2 results in stronger ferromagnetic intermolecular interactions. This better cooperativity is due to a significant increase of the number of contacts between the various moieties within the (Cp2∗Mn)[Ni(dmid)2]·solvent. On the contrary, the inclusion of larger solvents such as benzonitrile in this type of complexes results in a totally different structural arrangement, which leads to an antiferromagnetic behaviour for 3.

Graphical abstractThree new compounds (Cp2∗Co)[Ni(dmit)2],(Cp2∗Mn)[Ni(dmid)2]·(CH3)2CO, and (Cp2∗Mn)2[Ni(dmid)2]2·C6H5CN were synthesised, structurally and magnetically characterised. The interactions between the Ni(dmit)2 units in (Cp2∗Co)[Ni(dmit)2] are of ferromagnetic-type. (Cp2∗Mn)[Ni(dmid)2]·(CH3)2CO exhibits stronger ferromagnetic intermolecular interactions than (Cp2∗Mn)[Ni(dmid)2]·CH3CN, thanks to a significant increase of number of contacts between the various moieties within (Cp2∗Mn)[Ni(dmid)2]·solvent. On the opposite, insertion of benzonitrile in this type of complex results in a different structural arrangement, and to an antiferromagnetic behaviour for (Cp2∗Mn)2[Ni(dmid)2]2·C6H5CN.Figure optionsDownload full-size imageDownload as PowerPoint slide