Chemistry Reference
In-Depth Information
{
}
(a
fragment) is isolated from the honeycomb motif, and a scheme of the formation of a hexanuclear
metallocycle is shown. In these compounds, the anions lie in the interlayer space. The coordination units
of the
MnL
3
{
MnL
3
}
fragments have a
mer
arrangement of the donor atoms. The
-
{
MnL
3
}
and
-
{
MnL
3
}
enantiomer units alternate in sequence in the polymer layers. The authors noted that the
and
combinations were favorable for the formation of layered structures, while
and
could lead to
frameworks.
119
The highest temperature at which spontaneous magnetization was recorded was
∼
40 K.
A layered polymer structure is inherent in the Ni(L
26
)
2
bischelate with a deprotonated enaminoketone
derivative of 3-imidazoline nitroxide.
120
This complex exists in two polymorphic modifications which differ
in the position of the coordinated oxygen atoms of the
N-
•
O groups (
trans
positions in the
>
α
modification
and
cis
in the
-NiL
2
, whose magnetic properties are determined by
the competition of the two major channels of exchange interactions (antiferromagnetic (J
β
modification, Scheme 13.13). For
β
115 cm
−
1
∼−
)
R
1
=CF
3,
R
2
=H (L
26
);
R
1
=COOCH
3,
R
2
=H (L
27
);
R
1
=COOC
2
H
5,
R
2
=H (L
28
);
R
1
=CF
3,
R
2
=Cl (L
29
);
R
1
=CF
3,
R
2
=Br (L
30
); R
1
=CF
3,
R
2
=CN (L
31
);
R
2
R
1
N
O
O
N
M
/2
M=Co,Ni,Cu
O
O
N
N
N
O
N
O
M
N
O
N
O
M
O
N
O
M
O
N
N
O
N
O
N
O
N
O
N
N
O
N
O
O
M
N
N
O
N
O
M
O
N
N
O
M
O
N
O
O
N
N
N
O
trans
-ML
2
O
O
O
O
M
M
N
N
N
N
N
N
N
N
O
O
O
O
O
O
O
O
O
O
M
M
M
N
N
N
N
N
N
N
N
N
N
N
N
O
O
O
O
O
O
O
O
O
O
M
M
N
N
N
N
cis
-ML
2
N
N
N
N
O
O
O
O
Scheme 13.13
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