title: Theoretical studies on the magnetic switching controlled by stacking patterns of bis(maleonitriledithiolato) nickelate(III) dimers.
abstract: Magnetic switchable maleonitriledithiolate (mnt) complexes were studied by density functional theory. The calculations were performed for anion dimers of [RBzPyR'][Ni(mnt)(2)] (RBzPyR' = derivatives of benzylpyridinium) to elucidate magnetostructural correlations and the nature of the weak intermolecular chemical bonding. The calculated results showed that the spin delocalization, favored by the eclipsed stacking and the shorter interlayer distance, was responsible for the diamagnetic character of [1-benzyl-4-aminopyridinium][Ni(mnt)(2)] at low temperature. The weak antiferromagnetic and ferromagnetic interactions were also reproduced for [1-benzyl-4-aminopyridinium][Ni(mnt)(2)] and [1-(4'-fluorobenzyl)pyridinium][Ni(mnt)(2)] at high temperature, respectively. The natural bond orbital analysis suggested that the cooperative effect of the weak intermolecular bondings may be the intrinsic driving force resulting in the switchable property, which is essentially similar to those in organic radicals exhibiting magnetic bistability. Further investigations with varying interlayer distance d, the extent of slippage (slipping distance r and deviation angle alpha), and rotational angle theta suggested that the extent of slippage played an important role in magnetic interactions. Therefore, the abrupt modulation of the extent of slippage in the [Ni(mnt)(2)](-) complexes by external perturbations provided new possibilities for the design of molecular magnetic switching devices.
authors.affiliation: Coordination Chemistry Institute, State Key Laboratory of Coordination Chemistry, and Institute of Theoretical and Computational Chemistry, Key Laboratory of Mesoscopic Chemistry of MOE, Nanjing University, Nanjing 210093, P. R. China.
authors.forename: Zhaoping
authors.initials: Z
authors.lastname: Ni
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Ren
authors.forename: Jing
authors.initials: J
authors.lastname: Ma
authors.forename: Jingli
authors.initials: J
authors.lastname: Xie
authors.forename: Chunlin
authors.initials: C
authors.lastname: Ni
authors.forename: Zhida
authors.initials: Z
authors.lastname: Chen
authors.forename: Qingjin
authors.initials: Q
authors.lastname: Meng
mesh_terms: D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000737:chemistry* / Q000494:pharmacology; D003198:Computer Simulation; D018360:Crystallography, X-Ray; D019281:Dimerization; D008280:Magnetics; D008956:Models, Chemical; D008958:Models, Molecular; D008962:Models, Theoretical; D015394:Molecular Structure; D009532:Nickel / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D011725:Pyridines / Q000737:chemistry* / Q000494:pharmacology; D013438:Sulfhydryl Compounds / Q000737:chemistry*
chemical_list: D019086:Bridged Bicyclo Compounds, Heterocyclic; D009942:Organometallic Compounds; D011725:Pyridines; D013438:Sulfhydryl Compounds; C507196:bis(maleonitriledithiolato) nickelate(III); C507197:deschloroepibatidine; C459462:maleinitriledithiolate; D009532:Nickel