posted on 2021-03-16, 18:15authored byJamie L. Manson, Samuel P. M. Curley, Robert C. Williams, David Walker, Paul A. Goddard, Andrew Ozarowski, Roger D. Johnson, Anuradha M. Vibhakar, Danielle Y. Villa, Melissa L. Rhodehouse, Serena M. Birnbaum, John Singleton
The [Zn1–xNix(HF2)(pyz)2]SbF6 (x = 0.2; pyz = pyrazine)
solid solution exhibits a zero-field
splitting (D) that is 22% larger [D = 16.2(2) K (11.3(2) cm–1)] than that observed
in the x = 1 material [D = 13.3(1)
K (9.2(1) cm–1)]. The substantial change in D is accomplished by an anisotropic lattice expansion in
the MN4 (M = Zn or Ni) plane, wherein the increased concentration
of isotropic Zn(II) ions induces a nonlinear variation in M-F and
M-N bond lengths. In this, we exploit the relative donor atom hardness,
where M-F and M-N form strong ionic and weak coordinate covalent bonds,
respectively, the latter being more sensitive to substitution of Ni
by the slightly larger Zn(II) ion. In this way, we are able to tune
the single-ion anisotropy of a magnetic lattice site by Zn-substitution
on nearby sites. This effect has possible applications in the field
of single-ion magnets and the design of other molecule-based magnetic
systems.