Chemistry Reference
In-Depth Information
H
H
O
CF
3
F
3
C
N
O
O
C
Cu
O
O
F
3
C
CF
3
N
N
C
O
L
5
Cu(hfac)
2
L
5
(H
2
O)
N
O
Scheme 13.5
O
CF
3
N
CF
3
O
O
O
O
H
Rh
Rh
OH
O
O
O
O
F
3
C
CF
3
N
O
Rh
2
(O
2
CCF
3
)
4
(L
4
)
2
Scheme 13.6
mononitroxides, namely: the tetranuclear [Cu(hfac)
2
]
4
(L
6
)
2
complex
61
; various types of the trinuclear
[Cu(hfac)
2
]
3
(L
n
10
62-69
; and binuclear [Ni
2
en
4
L
11
](ClO
4
)
3
70
and hexanuclear
Hg
6
(C
6
F
4
)
6
L
12
complexes.
71
For copper(II) complexes, the formation of closed multinuclear molecules
is promoted by the anomalously high stereochemical nonrigidity of the bishexafluoroacetyl acetonate
molecule, which is capable of performing the function of “caps,” preventing chain propagation. If the
reaction of L
6
is performed with Mn(hfac)
2
instead of Cu(hfac)
2
, the terminal metal ions have coordination
number 6, which leads to the formation of heterospin compounds
)
2
complex,
n
=
7
−
[Mn(hfac)
2
]
3
(L
6
,inwhich(inthe
solid state) the binuclear cyclic fragments are joined into chains via Mn(hfac)
2
terminal matrices.
72
The same is also possible for complexes with biradical molecules. Scheme 13.8 shows examples of
these heterospin complexes, namely, the binuclear [Mn(hfac)
2
]
2
L
13
,
73
{
)
2
}
tetranuclear [Cu(hfac)
2
]
4
L
14
,
74
hep-
tanuclear [Cu(hfac)
2
]
7
(L
15
76,77
complexes.
Cis
-coordination of nitroxides can favour the formation of multinuclear macrocycles, for example, the
36-membered ring in [Mn(hfac)
2
L
12
]
6
and the 42-membered ring in [Cu(hfac)
2
L
16
]
6
, respectively,
78,79
)
2
,
75
Hg[(L
15
)
−
]
2
}
and hexanuclear [Cu(hfac)
2
]
4
{
or
80-82
(Scheme 13.9). These heterospin
complexes have a large spin even with metal - nitroxide antiferromagnetic exchange but are not liable to
[Ni(L
17
spheroid structures such as the structures in
{
)
2
]
3
[Fe(CN)
6
]
2
}
Search WWH ::
Custom Search