Chemistry Reference
In-Depth Information
clusters have opposite signs, their mutual compensation contributions smoothes the functional features on
the curve of the temperature dependence
χ
χ
µ
eff
, which hinders the extraction of exchange param-
eters from magnetochemical experiments. A typical example of this situation is the magnetic properties of
the chain polymer heterospin complex [Cu(hfac)
2
]
7
(L
61
or
T, or
)
µ
2
(Scheme 13.28). Its experimental
eff
(T) curve
µ
eff
decreases from 6.15 to 5
has few distinguishing features. The
.
68
µ
B
when the temperature changes
from 2 to 14 K; then it slightly increases to 5
.
84
µ
B
at
∼
50 K and changes little if at all thereafter (from
at 300 K.
253
5.84 to 5
µ
eff
(T), it is impossible to sug-
gest a justified scheme of exchange interactions in metal-nitroxide chains. A quantum chemical study,
.
88
µ
B
)
Based on this low-informative dependence
Cu(hfac)
2
O
N
N
O
O
Cu(hfac)
2
N
N
N
Cu(hfac)
2
O
O
N
O
Cu(hfac)
2
N
N
N
N
O
O
O
Cu(hfac)
2
O
N
N
N
O
N
N
O
Cu(hfac)
2
Cu(hfac)
2
[Cu(hfac)
2
]
7
(L
61
)
2
L
61
Cu(3)
J
2
J
1
Cu(1)
NN
Cu(2)
J
3
...
Py
NN
Py
NN
J
4
Cu(2)
NN
J
5
Cu(4)
J
1
J
2
J
4
Cu(3)
Py
NN
J
3
Cu(1)
Scheme 13.28
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