G. Rombaut et al., Structural and photomagnetic studies of two compounds in the system Cu2+/Mo(CN)(8)(4-): From trinuclear molecule to infinite network, INORG CHEM, 40(6), 2001, pp. 1151-1159
The syntheses and structural and physical characterization of the compounds
[Cu(bipy)(2)](2)[Mo(CN)(8)]. 5H2O . CH3OH (1) with bipy = 2,2'-bipyridine
and M-2(II)[Mo-IV(CN)(8)]. xH(2)O (2 with M = Cu, x = 7.5; 3 with M = Mn, x
= 9.5) are presented. 1 crystallizes in the triclinic space group P (1) ov
er bar (a = 11.3006(4) Angstrom, b = 12.0886(5) Angstrom, c = 22.9589(9) An
gstrom, alpha = 81.799(2)0, beta = 79.787(2)degrees gamma = 62.873(2)degree
s, Z = 2). The structure of 1 consists of neutral trinuclear molecules in w
hich a central [Mo(CN)(8)](4-) anion is linked to two [Cu(bipy)(2)](2+) cat
ions through two cyanide bridges. 2 crystallizes poorly, and hence, structu
ral information has been obtained from the wide-angle X-ray scattering (WAX
S) technique, by comparison with 3 and Fe(II)2(H2O)(4)[Mo-IV(CN)(8)]. 4H(2)
O whose X-ray structure has been previously solved. 2, 3, and Fe(II)2(H2O)(
4)[Mo-IV(CN)(8)]. 4H(2)O form extended networks with all the cyano groups a
cting as bridges. The magnetic properties have shown that 1 and 2 behave as
paramagnets. Under irradiation with light, they exhibit important modifica
tions of their magnetic properties, with the appearance at low temperature
of magnetic interactions. For 1 the modifications are irreversible, whereas
they are reversible for 2 after cycling in temperature. These photomagneti
c effects are thought to be caused by the conversion of Mo-IV (diamagnetic)
to Mov(paramagnetic) through a photooxidation mechanism for 1 and a photoi
nduced electron transfer in 2. These results have been correlated with the
structural features.