SCHEDULED MAINTENANCE
Synthesis, structure and magnetism of iron-(III) and
-(II) complexes of 1-thia-4,7-diazacyclononane and
N,N
′-dimethyl-1-thia-4,7-diazacyclononane
Abstract
The mononuclear complexes [Fe([9]aneN
2
S)Cl
3
] and
[Fe(Me
2
[9]aneN
2
S)Cl
3
]
([9]aneN
2
S = 1-thia-4,7-diazacyclononane,
Me
2
[9]aneN
2
S = N,N
′-dimethyl-1-thia-4,7-diazacyclononane) have been prepared by
addition of the cyclononane to an ethanolic solution of FeCl
3
.
µ-Oxo-bis(µ-acetato)diiron(III) complexes
[Fe
2
O(O
2
CMe)
2
([9]aneN
2
S)
2
][PF
6
]
2
and
[Fe
2
O(O
2
CMe)
2
(Me
2
[9]aneN
2
S)
2
][PF
6
]
2
have been synthesised by
addition of sodium acetate to suspensions of the mononuclear complexes and
isolated as the hexafluorophosphate salts. The iron(II) dimer
[Fe
2
(OH)(O
2
CMe)
2
(Me
2
[9]aneN
2
S)
2
]ClO
4
was prepared under anaerobic
conditions. The four iron(III) complexes were characterised by
crystal structural studies. On the bases of the isomer shift and quadrupole
splitting observed in the Mössbauer spectra of the dimers (4.2 K) the
iron-(III) and -(II) ions were determined to be in
the high-spin configuration. The magnetic susceptibility (300–4.2 K)
of
[Fe
2
O(O
2
CMe)
2
([9]aneN
2
S)
2
][PF
6
]
2
(ℋ = -2JS
1
·S
2
) indicated that the iron(III) sites were
antiferromagnetically coupled (J = -125
cm
-1
). In the case of the iron(II) dimer
J = -7.4 cm
-1
. The
differences observed in the redox behaviour of
[Fe
2
O(O
2
CMe)
2
([9]aneN
2
S)
2
][PF
6
]
2
and
[Fe
2
O(O
2
CMe)
2
(Me
2
[9]aneN
2
S)
2
][PF
6
]
2
are attributed to the
presence of the sterically demanding ligand methyl substituents.
Please wait while we load your content...
′-dimethyl-1-thia-4,7-diazacyclononane