Two unprecedented
and stable metal–organic frameworks, {[Co
2
(H
2
O)
2
(L)(OH)]·2.5H
2
O·0.5DMF}
n
(
1
) and
{[Ni
2
(H
2
O)
2
(L)(OH)]·1.75H
2
O}
n
(
2
), have been
synthesized (H
3
L = 5-(5-carboxy-pyridin-3-yloxy)-isophthalic
acid, DMF =
N
,
N
-dimethylformamide).
Structural analysis shows that
1
and
2
are
heteronuclear isomorphous, possessing a three-dimensional (3D) (4,8)-connected
flu/fluorite topological framework formed through the interconnection
of tetranuclear butterfly {M
4
(COO)
6
(OH)
2
} clusters and the ligands. Although the frameworks of these
two compounds are similar, their magnetic properties are different.
Compound
1
exhibits an antiferromagnetic interaction
in the high-temperature region, while
2
shows a weak
ferromagnetic interaction in the whole-temperature region. Furthermore,
considering the presence of hydroxyl groups and water molecules in
the frameworks, we tested their proton conductivity. The efficient
proton transfer pathway in the framework endowed
1
and
2
with excellent proton conductivities of 9.07 × 10
–5
and 1.29 × 10
–4
S·cm
–1
at 363 K and 98% relative humidity (RH), respectively.