Abstract
Complex (
1) [Co(H
2O)
4(pyrazine)](NO
3)
2
·
2H
2O forms a one-dimensional coordination polymer along the crystallographic
b-axis. Hydrogen-bonding between chains forms a two-dimensional network in the
ac-plane. The solvent effect on the electronic spectra of pyrazine and pyrazine cobalt complex
1 has been investigated. The magnetic susceptibility of
1 versus temperature data showed a strong antiferromagnetic coupling between Co ions.
The synthesis, structure and magnetic properties of the cobalt(II) complex (
1) [Co(H
2O)
4(pyz)](NO
3)
2
·
2H
2O is reported. The compound crystallizes in the triclinic system, space group
P
1
¯
, with cell constants:
a
=
7.0328(15) Å,
b
=
7.1255(16) Å,
c
=
8.4198(19) Å,
α
=
107.226(4)°,
β
=
114.242(4)°,
γ
=
90.487(4)°,
Z
=
1 and
V
=
363.35(14) Å
3. The structure of
1 consists of elongated octahedral CoO
4N
2 chromophores with bridging pyrazine ligands forming a one-dimensional coordination polymer along the crystallographic
b-axis. The nitrate ions hydrogen-bond to the water ligands (L) and guest water (G), and form
H
2
O
(
L
)
⋯
H
2
O
(
G
)
⋯
NO
3
-
⋯
H
2
O
(
G
)
⋯
H
2
O
(
L
)
chains which flank either side of the coordination polymer chains. Hydrogen-bonding is extended to neighboring chains forming a two-dimensional network. The solvent effect on the electronic spectra of pyrazine and pyrazine cobalt complex
1 has been investigated. The magnetic susceptibility of complex
1 versus temperature data showed a strong antiferromagnetic coupling between Co ions. The best fitting parameters were obtained for
J
1/
k
B
=
−26.4 K,
J
2/
k
B
=
−2.2 K and
g
=
2.3.