SCHEDULED MAINTENANCE
Structurally diverse manganese(III) complexes of tetradentate
N2O2 Schiff-base ligands with ancillary
carboxylate donors
Abstract
A number of manganese(III) complexes of tetradentate
N
2
O
2
Schiff-base ligands have been prepared with
various additional carboxylate anions. Five of these compounds have been
crystallographically characterised revealing that a remarkable array of
structural chemistry is available. A polymeric species is observed for
[{Mn(saltn)(O
2
CEt)}
n
] 1,
whereas a monomeric species is found in
[Mn(saltn)(O
2
CBu
t
)] 2
[H
2
saltn = N,N′-bis
(salicylidene)trimethylenediamine]. The anti-anti
bridging of the manganese centres in 1 is in contrast to that in
[{Mn(bsaltn)(O
2
CCH
2
Ph)}
2n
] 3 (H
2
bsaltn = 5-bromo derivative of
H
2
saltn), which exhibits rare syn-anti
bridging; 3 also contains a dimeric repeat unit due to an alternate
180° twist in the polymeric chain necessitated by steric
constraints. In contrast, the complexes containing the dianion of
N,N′-bis(3-methoxysalicylidene)ethane-1,2-
diamine (H
2
msalen) appear to be isostructural,
[{Mn(msalen)(O
2
CEt)}
2
]·EtOH 4 and
[{Mn(msalen)(O
2
CBu
n
)}
2
] 5
being structurally characterised as essentially identical
phenoxy-bridged dimers. An insoluble material of stoichiometry
Mn
4
(O
2
CR)
3
(saltn)
3
(H
2
O)
n
(n = 0–3) was
isolated from all reactions involving the saltn ligand; attempts to
characterise these compounds by X-ray diffraction have been
unsuccessful. However, the previously characterised
manganese(IV) dimer
[{Mn(saltn)O}
2
]·2dmf 6
(dmf = dimethylformamide) and the monomeric species
[Mn(saltn)(O
2
CEt)] 7 were isolated in attempts to crystallise
these materials.
Please wait while we load your content...
