Syntheses, structure, and magnetic properties of extended structured Cr(II) pentacyanopropenide compounds

Journal article, 2008

The reaction between [Cr-II(NCMe)(4)][BF4](2) and the different cations of [C-3(CN)(5)](-), i.e. [PPN](+) [PPN = bis(triphenylphosphoranylidene)ammonium] and [NMe4](+) in different solvents led to two different tri-solvated structures possessing Cr-II[C-3(CN)(5)](2): Cr-II [C-3(CN)(5)](2).2MeCN.H2O (1) and Cr-II[C-3(CN)(5)](2).(THF) 2THF (2). 2 possesses layers of mu-1, 1'-[C-3(CN)(5)](-) while 1 contain a three- and six-connected 3D pyrite network structure with mu(3)-1,1',3-[C-3(CN)(5)](-) trigonal nodes. Both compounds possess a tetragonally elongated distorted Cr(II) site. Magnetic susceptibility measurements between 5 and 300 K reveal significant antiferromagnetic interactions for both 1 and 2, with theta = -26 and -23 K, respectively, from a fit to the Curie-Weiss law. Upon a comparison to related and similarly structured materials the coupling increases as Cr-II > Fe-II > Mn-II. (C) 2008 Elsevier B.V. All rights reserved.