[NH4]2Mn3(H2O)4[Mo(CN)7]2.4H2O: tuning dimensionality and ferrimagnetic ordering temperature by cation substitution.
[NH(4)](2)Mn(3)(H(2)O)(4)[Mo(CN)(7)](2).4H(2)O (1) has been synthesized by slow diffusion of aqueous solutions containing K(4)[Mo(CN)(7)].2H(2)O, [Mn(H(2)O)(6)](NO(3))(2), and (NH(4))NO(3). Compound 1 crystallizes in the monoclinic C2/c space group. The basic motif of the three-dimensional structure consists of a Mo1-Mn1 gridlike sheet parallel to the bc plane. Two of these sheets are connected through CN-Mn2-NC linkages to form a bilayer reminiscent of the K(2)Mn(3)(H(2)O)(6)[Mo(CN)(7)](2).6H(2)O (2) two-dimensional structure. In 1, [NH(4)](+) cations allow these bilayers to be connected through direct Mo1-CN-Mn1 bridges to form a three-dimensional network, whereas in 2, they are isolated by (H(2)O)K(+) cations. As shown by the magnetic measurements, this increase of dimensionality by counterion substitution induces an enhancement of the ferrimagnetic critical temperature from 39 K in 2 to 53 K in 1.
Le Goff
Xavier F
XF
Centre de Recherche Paul Pascal (CRPP), UPR CNRS 8641, 115 avenue du Dr. A. Schweitzer, 33600 Pessac, France.
Willemin
Stéphanie
S
Coulon
Claude
C
Larionova
Joulia
J
Donnadieu
Bruno
B
Clérac
Rodolphe
R