Unusual Magnetism of an Unsymmetrical Trinickel Chain Academic Article uri icon


  • An extended metal atom chain (EMAC) compound with an unsymmetrical trinickel core and the formula [Ni3(dpa)4-(CH 3CN)](PF6)2·2CH2Cl 2 (1·2CH2Cl2, dpa is the anion of 2,2′-dipyridylamine) has the central Ni atom in an essentially square-planar configuration. Besides having four equatorial nitrogen atoms, the two terminal metal centers have axial interactions that are notably different with one having a strongly bound acetonitrile molecule with a Ni(3)-N(3) distance of 2.108(5) Å while the other unit has a very weak interaction with an axial PF6 anion [Ni(1)-⋯F(1) separation of 2.690 Å]. In these outer units, the Ni(3) atom is pulled out of the idealized plane of the four equatorial nitrogen atoms by 0.239 Å, while in the one with an axial PF6 anion the metal atom is pulled from the plane of the equatorial nitrogen atoms by only 0.097 Å. In 1 there are two unpaired electrons and an S = 1 state prevails from ca. 25 to 300 K. This magnetic behavior differs considerably from that of symmetrical trinickel EMACs with two strongly pyramidal terminal nickel atoms. A discussion of the effect of various axial ligands on the geometry of the terminal nickel atoms is provided. © Wiley-VCH Verlag GmbH & Co. KGaA, 2008.

author list (cited authors)

  • Cotton, F. A., Murillo, C. A., Wang, Q., & Young, M. D.

citation count

  • 16

publication date

  • October 2008