A self-assembled octanuclear complex bearing the uncommon close-packed {Fe4Mn4(μ4-O)4(μ-O)4} molecular core

Article abstract of DOI:10.1039/c5dt02076j

A one-pot open-air reaction of manganese powder with iron(ii) chloride in DMF solution of the Schiff base (H₂L) formed in situ from salicylaldehyde and hydroxylamine hydrochloride yields the heterometallic complex [Fe₄(μ₄-O)₄Mn₄(L)₈(DMF)₄]·2DMF (1). Single crystal X-ray analysis shows that its molecular structure is based on the octanuclear core {Fe₄Mn₄(μ₄-O)₄(μ-O)₄} with a quite rare molecular structure type {M₈(μ₄-X)₄(μ-X)₄}, where the central cube-like iron motif is modified with four terminal manganese fragments, the whole core being presented as the {Fe₄(μ₄-O)₄} + 4{Mn(μ-O)} combination. Using the data from the Cambridge Structural Database (CSD), an analysis of the octanuclear structures with similar central {M₄(μ₄-X)₄} fragments was performed. The hierarchical order of molecular structure types with the general formula M₈X_n for such compounds was proposed and the topological features as well as the factors that influence the molecular type formation are discussed. Variable-temperature (1.8-300 K) magnetic susceptibility measurements reveal an antiferromagnetic coupling among the magnetic centres in 1.

Full text of DOI:10.1039/c5dt02076j

Dalton
Transactions
View Article Online
View Journal
PAPER
A self-assembled octanuclear complex bearing the
uncommon close-packed {Fe4Mn4(µ4-O)4(µ-O)4}
molecular core†
Cite this: DOI: 10.1039/c5dt02076j
Oksana V. Nesterova,a Eduard N. Chygorin,b Vladimir N. Kokozay,*b Irina V. Omelchenko,c
Oleg V. Shishkin,c Roman Bočad and Armando J. L. Pombeiro*a
A one-pot open-air reaction of manganese powder with iron(II) chloride in DMF solution of the Schiff
base (H2L) formed in situ from salicylaldehyde and hydroxylamine hydrochloride yields the heterometallic
complex [Fe4(µ4-O)4Mn4(L)8(DMF)4]·2DMF (1). Single crystal X-ray analysis shows that its molecular struc-
ture is based on the octanuclear core {Fe4Mn4(µ4-O)4(µ-O)4} with a quite rare molecular structure type
{M8(µ4-X)4(µ-X)4}, where the central cube-like iron motif is modified with four terminal manganese frag-
ments, the whole core being presented as the {Fe4(µ4-O)4} + 4{Mn(µ-O)} combination. Using the data
from the Cambridge Structural Database (CSD), an analysis of the octanuclear structures with similar
central {M4(µ4-X)4} fragments was performed. The hierarchical order of molecular structure types with
the general formula M8Xn for such compounds was proposed and the topological features as well as the
factors that influence the molecular type formation are discussed. Variable-temperature (1.8–300 K) mag-
netic susceptibility measurements reveal an antiferromagnetic coupling among the magnetic centres in 1.
Received 1st June 2015,
Accepted 16th July 2015
DOI: 10.1039/c5dt02076j
www.rsc.org/dalton
The majority of high nuclear complexes with close-packed
cores have been prepared via the spontaneous self-assembly of
Introduction
Sophisticated topologies and intriguing physico-chemical pro- metal ions and relatively simple ligands.1,4 This approach can
perties are the relevant factors which determine a continued lead to sophisticated coordination assemblies using non-labor-
interest in high nuclear coordination compounds. High sym- ious one-step protocol. However, in spite of the synthetic sim-
metry complexes possessing close-packed metal cores are plicity of such a method, it shows quite a low efficiency (yield
within the most interesting objects in this field.1 Moreover, by of successful syntheses within the range of screened con-
introducing few different metals into one molecule, it is poss- ditions) on account of considerable unpredictability. Although
ible not only to affect the complexity and structural diversity of a huge number of high nuclear complexes has already been
the resulting heterometallic assembly but also to influence its obtained, the exact structure and composition of the final
spin ground states, magnetic anisotropy, exchange interactions product are hardly or, most commonly, completely not predict-
and other magnetic properties.1c,2 Besides, a combination of able before their isolation. Furthermore, the synthesis of
different metal centres within one complex can lead to un- heterometallic high nuclear complexes by spontaneous self-
common physico-chemical properties.3 This provides a back- assembly is an even more complicated task, because the
ground for building novel structure–property correlations.
increasing number of initial reagents leads to a greater variety
of their possible combinations. Therefore, there is a need for
the study of synthesis–structure correlations in the self-assem-
bly of poly- and high-nuclear species, as well as for the estab-
lishment of clear and definite classifications of their
coordination cores.
In pursuit of our interest on the synthesis and investigation
of high nuclear coordination compounds, we have expanded
the classical spontaneous self-assembly approach and success-
fully applied the “direct synthesis of coordination compounds”
method for the preparation of novel complexes.4 The relevant
features of this strategy are simplicity and “straightforward”
formation of a complex high nuclear structure “directly” (upon
aCentro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa,
Avenida Rovisco Pais, 1049-001 Lisboa, Portugal.
E-mail: pombeiro@tecnico.ulisboa.pt
bDepartment of Inorganic Chemistry, Taras Shevchenko National University of Kyiv,
Volodymyrska str. 64/13, Kyiv 01601, Ukraine. E-mail: kokozay@univ.kiev.ua
cSTC “Institute for Single Crystals” National Academy of Sciences of Ukraine, 60,
Lenina Avenue, Kharkiv 61001, Ukraine
dDepartment of Chemistry, FPV, University of SS Cyril and Methodius, 91701
Trnava, Slovakia
†Electronic supplementary information (ESI) available: Selected bond lengths
and angles for the crystal structure of 1. CCDC 1049390. For ESI and crystallo-
graphic data in CIF or other electronic format see DOI: 10.1039/c5dt02076j
This journal is © The Royal Society of Chemistry 2015
Dalton Trans.

View Article Online
Paper
Dalton Transactions
one experimental stage) from metal powder(s). Using such con- tion of formation of 1 can be written as follows:
ditions we have already obtained a series of uncommon
4Mn0 þ 4FeIICl2 ꢀ 4H2O þ 8H2L ꢀ HCl þ 16Et3N þ 4O2 þ 6DMF
heterometallic high nuclear CuI2IFeI2II,5 Co2IIIFeI2II,6 Co4IIIFeI4II,6
! ½FeI4IIðμ4-OÞ4Mn4IIIðLÞ8ðDMFÞ4ꢁ ꢀ 2DMF þ 16Et3N ꢀ HCl
and Co4IIIFe2III 7 compounds with Schiff base aminoalcohol
þ 20H2O
ligands5–7 and determined the main factors responsible for
the molecular structure type formation. Furthermore, we have
shown that the synthesized complexes reveal an exceptionally
high catalytic activity in the oxidation of cyclohexane with
hydrogen peroxide under mild conditions, as well as an inter-
esting magnetic behaviour.5,7 In the current work, we have
investigated the interaction of manganese powder and iron(II)
chloride with an in situ formed Schiff base O,O,N-ligand that
afforded the novel octanuclear [Fe4(µ4-O)4Mn4(L)8(DMF)4]·
2DMF (1) coordination compound with an extremely rare type
of molecular core, now observed for the first time for a hetero-
metallic transition metal complex. The synthesis and magnetic
investigation of 1, as well as a discussion concerning its mole-
cular structure type formation and analysis of octanuclear
crystal structures having M8Xn cores with the general {M4(µ4-
X)4} fragment are also reported.
Single crystal X-ray analysis (see below) shows that the mole-
cular core of 1 {Fe4Mn4(µ4-O)4(µ-O)4} can be viewed as a central
cube-like iron motif {Fe4(µ4-O)4} supplemented with four
manganese fragments {Mn(µ-O)}. According to the Cambridge
Structural Database (CSD),9 cube-like {M4(µ4-X)4} (M = metal
atom, X = bridging atom) is the most widespread molecular
structure type for tetranuclear coordination compounds. Among
them there are a lot of complexes of iron with Schiff base
ligands.10 Therefore, one could assume that the formation of the
core of 1 starts from the assembling of the iron cube-like struc-
ture formed prior to the dissolution of the manganese powder:
4FeCl2 þ 4H2L þ 4DMF ! ½Fe4ðLÞ4ðDMFÞ4ꢁ þ 8HCl
Such reactions are known to proceed with high yield under
mild conditions with the Schiff bases formed from salicylalde-
hyde and simple aliphatic aminoalcohols, such as ethanol-
amine.10c However, the behaviour of H2L is known to be
considerably different due to the absence of the –CH2CH2OH
arm, which allows the formation of stable chelates. The known
products of the interaction of iron salts with H2L are tetra-
nuclear cores with a distorted geometry, where the oxime
group serves as a bridge (M–N–O–M):11
Results and discussion
Synthesis and spectroscopic analysis
The condensation of salicylaldehyde and hydroxylamine
hydrochloride in a basic (triethylamine) medium in DMF
afforded the in situ formation of the Schiff base H2L
(Scheme 1). The manganese powder and iron(II) chloride were
added to the solution of H2L in the same reaction vessel and
the reaction was brought to completion by heating and stirring
until the total dissolution of manganese was observed
(approximately 1 h). Dark-red microcrystals of 1 that showed
analytical data consistent with the Fe(III) : Mn(III) = 1 : 1 stoichi-
ometry were formed within six months after the addition of
iPrOH and Et2O into the resulting solution. Complex 1 was the
unique product obtained from the reaction mixture. Reactions
performed in DMSO or CH3CN (typical solvents for the direct
synthesis conditions4) did not afford any isolated product.
When CH3OH was employed as a solvent, a homometallic
compound of manganese was the only product. Single crystal
X-ray analysis disclosed its trinuclear structure with the
formula [Mn3OCl2(L3)(CH3OH)2(H2O)2]·H2O.8 The general reac-
4FeIICl2 þ 8H2L þ O2 ! ½Fe4IIIðLÞ4ðHLÞ4ꢁ þ 8HCl þ 2H2O
The tetranuclear compound with such a structure is a pre-
sumable intermediate in the formation of 1. It should be
noted that further growth of the nuclearity towards the octa-
nuclear iron core [Fe8(L)8], similar to that in 1, can be sup-
posed as an unfavourable process, which requires harsh
(solvothermal) or specific (microwave synthesis) conditions.12
Due to gradual oxidation of Mn0 powder, the equilibrium con-
centration of “free” manganese ions in the reaction mixture
should be quite low: MnII and MnIII ions are very labile and
easily participate in substitution coordination reactions. Thus,
all the manganese ions should readily react with excess of the
ligand and iron intermediate to form complex 1:
Mn0 þ H2L þ ½Fe4IIIðLÞ4ðHLÞ4ꢁ þ O2 ! 1
The IR spectrum of 1 in the 4000–400 cm−1 range shows a
very strong band at 1598 cm−1 which is assigned to ν(CvN) of
the Schiff base ligand. The strong peak at 1647 cm−1 and the
shoulder at 1668 cm−1 are attributed to ν(CvO) the vibrations
of coordinated and solvate molecules of DMF, respectively.
Crystal structures
The single crystal X-ray analysis reveals that 1 (Fig. 1) features
the octanuclear core {Fe4Mn4(µ4-O)4(µ-O)4}, belonging to the
{M8(µ4-X)4(µ-X)4} (M = metal atom, X = bridging atom) mole-
cular structure type (MST). This MST is obtained excluding all
Scheme 1
Dalton Trans.
This journal is © The Royal Society of Chemistry 2015

View Article Online
Dalton Transactions
Paper
each having a distorted octahedral environment with an O5N
donor set. In contrast to the iron(III) atoms, the coordination
spheres of the manganese(III) ones also involve the oxygen
atoms from coordinated DMF molecules. The Fe–O(N) bond
lengths range from 1.921(5) to 2.265(5) Å, while the Mn–O(N)
distances vary from 1.865(4) to 2.279(5) Å (Table S1†). The O
(N)–M–O(N)trans angles lie in the range of 149.15(18) to 162.1
(2)° for iron(III) and 165.4(2) to 176.4(2)° for manganese(III).
A huge variety of high nuclear coordination compounds
has been reported and their number continues to grow.13 In
this broad field of coordination chemistry, the comparison
and classification of the newly prepared compounds can be a
complicated task. Often, identical compounds from the topo-
logical point of view are drastically different from the chemical
one. An even more difficult task is to predetermine and predict
the final structure of the high nuclear assembly. The idea that
the majority of the crystal structures of high nuclear complexes
can be covered by the limited number of molecular structure
types, where the MST is seen as a set of topologically identical
MaXb combination (M = metal atom, X = bridging atom),4,14
can be not only helpful in the classification of such com-
pounds but also can result in an impressive progress in their
targeted synthesis. Bearing these ideas in mind, we continued
to investigate the properties of molecular structure types of
newly obtained high nuclear complexes and compared our
data with the statistical ones obtained from the CSD.
Fig. 1 Molecular structure of 1 in the ball-and-stick representation (a)
and the central part of 1 with atom numbering (b) where non-hydrogen
atoms are shown as 40% ellipsoids. The hydrogen atoms and carbon
atoms in (b) are omitted for clarity. Colour scheme: Fe, olive; Mn, violet;
O, red; N, blue; C, light grey.
non-bridging non-metal atoms of the coordination core of the
complex. The whole core {Fe4Mn4(µ4-O)4(µ-O)4} can be
described as a cube-like iron structure modified with four
terminal manganese fragments {Fe4(µ4-O)4}
(Fig. 2).
+ 4{Mn(µ-O)}
All Schiff bases H2L in the structure are doubly deproto-
nated and show tridentate coordination (N,O,O) in two
different modes (Scheme 2), thus being responsible both for
the molecular structure type formation and for the metal ion
charge compensation. Compound 1 contains two crystallo-
graphically independent iron(III) metal ions, Fe(1) and Fe(2),
and two independent manganese(III) atoms, Mn(3) and Mn(4),
The MST {M8(µ4-X)4(µ-X)4} observed in 1 is found to be
rather rare, according to the CSD. The CSD contains ca. 600
records of the octanuclear complexes and, among them, only 4
structures with the same MST as in 1 are found.15 Moreover,
compound 1 represents the first example of a heterometallic
transition metal complex possessing such a MST.
Trying to find a topological place of 1 in the group of octa-
nuclear compounds, we chose complexes similar to 1 with a
cube-like central fragment {M4(µ4-X)4} modified with terminal
metal-containing groups. Analysis of CSD data shows that only
57 hits of such a type are found. The carbonyl (M–C–O) and
the organometallic (M–C–C) compounds, as well as coordi-
nation polymers and polyoxometalates, were excluded accord-
ing to the search conditions. We succeeded in building a
hierarchical order of these complexes, which includes 4
different MSTs, distinguished from each other by the number
of µ-X bridging atoms (Fig. 3).
The first and simplest member of this row is the MST
{M8(µ4-X)4} (a), where four terminal metal atoms are co-
ordinated by each bridging atom of the cube fragment (Fig. 3).
This type of compound is the most abundant and includes
complexes of two categories – unsupported, where terminal
metal atoms do not have any additional coordination (20 hits
in CSD), and supported, where terminal metal atoms are con-
nected with metal atoms from the cube through the bridges
M–X–X⋯–M (22 hits, the search includes hits with 2, 3 and 4
bridging X atoms in the terminal fragments) (Fig. 4). In the
majority of the second type crystal structures, the supporting
bridges are carboxylate and pyrazole-containing ligands. The
presence of such additional bridges is essential for the com-
Fig. 2 The ball-and-stick (a) and polyhedral (b) representations of the
octanuclear {Fe4Mn4(µ4-O)4(µ-O)4} core in 1. Color scheme: Fe, olive;
Mn, violet; O, red.
Scheme 2
This journal is © The Royal Society of Chemistry 2015
Dalton Trans.

View Article Online
Paper
Dalton Transactions
Fig. 5 The polygonal representation of known (b1) and the suggested
(b2) structure configurations of the MST {M8(µ4-X)4(µ-X)4} (b) (see the
text).
Fig. 3 Hierarchical order of MSTs M8Xn for octanuclear complexes with
the similar cube-like central fragment {M4(µ4-X)4}, modified with term-
inal metal-containing groups and distribution of known complexes
according to CSD.
site faces of a cube-like central fragment. Such configurations
are observed in two bismuth complexes, in which crystal struc-
tures display dimeric units formed by two tetrametalated calix-
arenes.18 In the second type (c2), four terminal groups
sequentially coordinate to four neighbouring faces. This type
of geometrical configuration is reported for [(CaO)4·
4(THF)3CaI2],19
[MgTaO(OBu-n)5(n-BuOH)]4,20
[{FeCl-
(H2L)}4Fe4(μ4-O)4Cl4] (H4L
=
N[(CH2CH2NH2)(CH2CH2OH)-
(CH2CH2CH2OH)]21 and [V8O20(4,4′-tBubpy)4]22 octanuclear
complexes.
The MST {M8(µ4-X)4(µ3-X)2(µ-X)10} (d) (Fig. 3) is observed
only in three Ti4Ba4 crystal structures23–25 and it is the most
complex one since it is formed using 16 bridging atoms. A
determining role in the formation of such structures conceiva-
bly is the ability of Ti and Ba to show high coordination
numbers, supported by the small size of coordinated iso-
propanol ligands.
Fig. 4 Examples of complexes belonging to unsupported (exemplified
by [Me3SnOZnMe]4)16 and supported (exemplified by [Co4IICo4III(μ4-
O)4(μ-O2CPh)12(C2H5OH)4]·3C3H6O·C2H6O)17 types of the of MST
{M8(µ4-X)4} (a).
Looking at the hierarchical order of the octanuclear MSTs
a–d (Fig. 3), observed from the CSD, one may notice that brid-
ging atoms X are always added “four-by-four”: from the sim-
plest M8X4 (a) to the most complex M8X16 (d). Therefore, the
general formula of the MSTs of this series can be written as
M8X4n (n = 1–4). These MSTs possess the highest possible sym-
metry for each case, from cubic type a (Td) to monoclinic d (C2)
(Fig. 3). The elimination of even one X atom from the 4n com-
plete set of bridging X atoms (non-M8X4n MST) would result in
a lower symmetry, in general. No structures belonging to non-
M8X4n MSTs have been found in the CSD, although there are no
obvious geometrical or topological restrictions for their exist-
ence. These observations, as well as previous statistical studie-
s1e,4,7,14b on the CSD, point to the assumption that poly- and
high-nuclear species tend to form symmetrical cores (MSTs).
pounds of transition metals which allow a wide range of geo-
metries and coordination numbers, while the unsupported
{M8(µ4-X)4} type is common for complexes of p-metals.
The addition of four bridging atoms to MST {M8(µ4-X)4} (a)
(Fig. 3) affords the MST {M8(µ4-X)4(µ-X)4} (b), found in complex
15b
1 and in some reported O-bridged Mn8,15a,c Fe8
bridged Mn4Li4
and Se-
15d
clusters. It should be noted that all known
octanuclear compounds with this MST show the same geo-
metrical configuration (b1) (Fig. 5), although one of them
could reveal the existence of the other topology (b2), which has
no examples in the CSD yet. Obviously, the formation of com-
plexes with the same MST but with a different geometrical con-
figuration, at the least (b2), is also possible. One can suggest
that for the construction of such compounds, rigid and bulky
ligands could be used simultaneously, which are successfully
employed in the synthesis of complexes with MST (c) with a
similar type (c2) of structural configuration.
Magnetic properties
The next MST {M8(µ4-X)4(µ-X)8} (c) (Fig. 3) can be formed by
the addition of four more bridging atoms to the MST (b).
According to CSD, this MST includes examples of two pre-
dicted geometrical configuration (c1 and c2). The first type (c1)
contains two pairs of terminal groups fasted to the two oppo-
Four Fe(III) and four Mn(III) high-spin centres in the molecule
of 1 result in a limiting value of the dimensionless product
function
2
2
χT=C0ðHTÞ ¼ 4gFe sFeðsFe þ 1Þ=3 þ 4gMn sMnðsMn þ 1Þ=3 ð1Þ
Dalton Trans.
This journal is © The Royal Society of Chemistry 2015

View Article Online
Dalton Transactions
Paper
Conclusions
We have successfully applied the direct synthesis approach for
the preparation of the novel octanuclear FeIIIMnIII Schiff base
complex 1. Its crystal structure reveals the uncommon {M8(µ4-
X)4(µ-X)4} type of molecular core, the formation of which is
discussed and the analysis of octanuclear structures with the
similar central {M4(µ4-X)4} fragment is performed. It has been
demonstrated, by means of the search via the Cambridge
Structural Database, that the molecular structure type of 1
belongs to a family of M8X4n MSTs, (where n = 1–4), which
differ one from another by four bridging X atoms. The topolo-
gical study reveals the presence of one more possible mole-
cular structure type of this series (a topological isomer of the
MST of 1), which still has no examples in the CSD. The
obtained data lead to the assumption that the more symmetri-
cal coordination cores (MSTs) are favoured over the less sym-
metrical types, at least within the studied row of complexes.
This assumption is important in terms of developing a
concept of a predictable self-assembly synthesis of high-
nuclear complexes, especially those with close-packed mole-
cular cores. The magnetic investigations of 1 disclose an anti-
ferromagnetic coupling between the paramagnetic centres.
Fig. 6 Magnetic functions for 1. Left – product function, right – mag-
netization per formula unit, inset – molar magnetic susceptibility
(SI units, χ(SI) = χ(cgs emu) ( 4π × 10−6).
which amounts to 78.7 when sFe = 5/2, sMn = 2, and all g =
2.0 (C0 = NAμ0μB2/kB contains universal physical constants in
their usual meaning). On cooling, the product function gradu-
ally decreases from its room temperature value of χT/C0
=
128 to the value of 5.3 at T = 1.9 K (Fig. 6) and down to 2.0 K;
the molar magnetic susceptibility only increases showing no
maximum. This feature indicates a dominating antiferro-
magnetic coupling among the magnetic centres through a deli-
cate balance with several coupling constants that could reveal
that the state of the highest spin is not the highest in energy
and also the state with S = 0 may not be the lowest in energy.
The abnormal room-temperature value of the χT product may
arise due to several reasons: increased g-factors, high tempera-
ture-independent (para)magnetism, spin delocalization in the
d4d4d4d4d5d5d5d5 system, and a local Jahn–Teller effect on Mn
(III) centres. Also a non-isotropic exchange interaction (the
asymmetric and antisymmetric exchange) can be applied and
in such a case the spin is not a good quantum number any
longer.
Experimental section
General
General: All chemicals were of reagent grade and used as
received. All experiments were carried out in air. Infrared
spectra (4000 − 400 cm−1) were recorded on a BX-FT IR
“Perkin Elmer” instrument in KBr pellets.
Synthesis of [Fe4(µ4-O)4Mn4(L)8(DMF)4]·2DMF (1). Salicyl-
aldehyde (0.27 cm3, 2.5 mmol), hydroxylamine hydrochloride
(0.174 g, 2.5 mmol) and triethylamine (0.7 ml, 5 mmol) were
dissolved in DMF (25 cm3) in this order, forming a yellow solu-
tion which was magnetically stirred at 50–60 °C (10 min).
Then, manganese powder (0.069 g, 1.25 mmol) and
FeCl2·4H2O (0.249 g, 1.25 mmol) were added to the hot yellow
solution of the ligand and the system was magnetically stirred
until the total dissolution of manganese powder was observed
(1 h). A dark-red solution was obtained at the end of the reac-
tion. X-ray suitable microcrystals of 1 were formed within six
months after the addition of iPrOH and Et2O into the resulting
solution. Yield: 0.1 g, 16%. Anal. calc. for C74H82Fe4Mn4N14O26
(M = 2026.70): C, 43.86; H, 4.08; N, 9.68; Fe, 11.02; Mn,
10.84%. Found: C, 43.4; H, 4.0; N, 9.3; Fe, 11.8; Mn, 11.1%.
The molar magnetization per formula unit possesses the
saturation limit M1 = Mmol/NAµB = 4gFesFe + 4gMn Mn which
s
yields M1 = 36 for Smax = 18. The measured magnetization
adopts a value of only M1 = 2.5 at T = 2.0 K and B = 7 T. This
reduction is a fingerprint of the antiferromagnetic exchange,
eventually combined with the single-ion anisotropy. The Fe(III)
centres could be considered as isotropic (gFe ∼ 2.0, DFe ∼ 0),
while the Mn(III) ones are slightly anisotropic (gMn < 2.0,
|DMn| > 0).
The number of magnetic energy levels in complex 1 is N =
64 × 54 = 810 000; the number of spin states at zero magnetic
field with MS = 0 is Nzf = 71 346. The numbers of states for Smin
= 0 until Smax = 18 are 1650, 4735, 7221, 8844, 9500, 9250,
8290, 6890, 5326, 3829, 2555, 1576, 892, 458, 210, 84, 28, 7,
and 1. These numbers represent the dimensions of blocks for
which the eigenvalues need to be evaluated. The complication
arises from the fact that the Zeeman term mixes the states of
different spins. This complexity prevents a fitting of the mag-
netic data for 1 at present.
Crystallography
Crystal data for 1: C74H82Fe4Mn4N14O26, M = 2026.70, monocli-
nic, P2/c, a = 16.509(2) Å, b = 11.1843(17) Å, c = 27.176(4) Å, β =
122.487(10)°, V = 4232.6(10) Å3, Z = 2, dcalc = 1.590 g sm−1, μ =
1.326 mm−1, F(000) = 2072. 33 908 reflections (7469 indepen-
dent, Rint = 0.155) were collected on an “Xcalibur-3” diffracto-
meter
(MoKα
radiation,
CCD-detector,
graphite
monochromator, ω-scanning, 2θmax = 50°). The empirical
This journal is © The Royal Society of Chemistry 2015
Dalton Trans.

View Article Online
Paper
Dalton Transactions
absorption correction was provided with a multi-scan method
using spherical harmonics, implemented in the SCALE3
ABSPACK scaling algorithm of the CrysAlisPro program
package (Tmin = 0.970, Tmax = 1.000).26 The structure was
solved by direct methods and refined against F2 within the ani-
sotropic approximation for all non-hydrogen atoms using the
OLEX2 program package27 with SHELXS and SHELXL
modules.28 All H atoms were placed in idealized positions and
constrained to ride on their parent atoms with Uiso = nUeq (n =
1.5 for CH3 groups and n = 1.2 for other H atoms). During the
refinement, bonds in the solvent DMF molecule were con-
strained to have fixed values (1.25 Å for O1S–C1S, 1.35 Å for
C1S–N1S, and 1.45 Å for N1S–C2S and N1S–C3S) to be within
0.01 Å. Also, anisotropic thermal parameters of all non-hydro-
gen atoms in this molecule were restrained to be approxi-
mately equal within 0.02 Å2. The final refinement converged at
wR2 = 0.152 for all 7391 reflections (R1 = 0.071 for 3849 reflec-
tions with F > 4σ(F), S = 0.92). CCDC 1049390.
Y. H. Lan, W. Wernsdorfer, C. E. Anson, L. F. Chibotaru
and A. K. Powell, Angew. Chem., Int. Ed., 2010, 49, 7583–
7587; (d) S. K. Langley, L. Ungur, N. F. Chilton,
B. Moubaraki, L. F. Chibotaru and K. S. Murray, Chem. –
Eur. J., 2011, 17, 9209–9218; (e) J. A. Sheikh, S. Goswami
and S. Konar, Dalton Trans., 2014, 43, 14577–14585.
3 (a) L. John and P. Sobota, Acc. Chem. Res., 2014, 47, 470–481;
(b) G. A. Timco, E. J. L. McInnes and R. E. P. Winpenny,
Chem. Soc. Rev., 2013, 42, 1796–1806; (c) S. K. Mandal and
H. W. Roesky, Acc. Chem. Res., 2012, 45, 298–307.
4 D. S. Nesterov, O. V. Nesterova, V. N. Kokozay and
A. J. L. Pombeiro, Eur. J. Inorg. Chem., 2014, 4496–4517.
5 O. V. Nesterova, E. N. Chygorin, V. N. Kokozay, V. V. Bon,
I. V. Omelchenko, O. V. Shishkin, J. Titis, R. Boca,
A. J. L. Pombeiro and A. Ozarowski, Dalton Trans., 2013, 42,
16909–16919.
6 E. N. Chygorin, O. V. Nesterova, J. A. Rusanoya,
V. N. Kokozay, V. V. Bon, R. Boca and A. Ozarowski, Inorg.
Chem., 2012, 51, 386–396.
Magnetic measurements
7 D. S. Nesterov, E. N. Chygorin, V. N. Kokozay, V. V. Bon,
R. Boca, Y. N. Kozlov, L. S. Shul’pina, J. Jezierska,
A. Ozarowski, A. J. L. Pombeiro and G. B. Shul’pin, Inorg.
Chem., 2012, 51, 9110–9122.
8 Unpublished results.
9 CSD (version 5.34; May 2013): F. H. Allen, Acta Crystallogr.,
Sect. B: Struct. Sci., 2002, 58, 380.
The magnetic data were obtained with the SQUID apparatus
(MPMS-XL7, Quantum Design) using the RSO mode of detec-
tion. The susceptibility measured at B = 0.1 T has been cor-
rected for the underlying diamagnetism and converted to the
effective magnetic moment. The magnetization has been
measured at two temperatures: T = 2.0 and 4.6 K.
10 (a) J. M. Clemente-Juan, C. Mackiewicz, M. Verelst,
F. Dahan, A. Bousseksou, Y. Sanakis and J. P. Tuchagues,
Inorg. Chem., 2002, 41, 1478–1491; (b) H. Oshio,
N. Hoshino and T. Ito, J. Am. Chem. Soc., 2000, 122, 12602–
12603; (c) H. Oshio, N. Hoshino, T. Ito and M. Nakano,
J. Am. Chem. Soc., 2004, 126, 8805–8812.
11 (a) J. M. Thorpe, R. L. Beddoes, D. Collison, C. D. Garner,
M. Helliwell, J. M. Holmes and P. A. Tasker, Angew. Chem., Int.
Ed., 1999, 38, 1119–1121; (b) I. A. Gass, C. J. Milios, A. Collins,
F. J. White, L. Budd, S. Parsons, M. Murrie, S. P. Perlepes and
E. K. Brechin, Dalton Trans., 2008, 2043–2053.
Acknowledgements
This work has been partially supported by the Foundation for
Science and Technology (FCT), Portugal (project UID/QUI/
00100/2013, fellowship SFRH/BPD/63710/2009). Grant agencies
of Slovakia (VEGA 1/0522/14, APVV-14-0078 and APVV-14-0073)
are acknowledged for financial support.
12 I. A. Gass, C. J. Milios, A. G. Whittaker, F. P. Fabiani,
S. Parsons, M. Murrie, S. P. Perlepes and E. K. Brechin,
Inorg. Chem., 2006, 45, 5281–5283.
Notes and references
1 (a) G. E. Kostakis, S. P. Perlepes, V. A. Blatov,
D. M. Proserpio and A. K. Powell, Coord. Chem. Rev., 2012, 13 (a) E. M. Pineda, F. Tuna, Y. Z. Zheng, S. J. Teat,
256, 1246–1278; (b) Y. Z. Zheng, G. J. Zhou, Z. P. Zheng and
R. E. P. Winpenny, Chem. Soc. Rev., 2014, 43, 1462–1475;
(c) J. W. Sharples and D. Collison, Coord. Chem. Rev., 2014,
260, 1–20; (d) S. Schmidt, D. Prodius, G. Novitchi,
V. Mereacre, G. E. Kostakis and A. K. Powell, Chem.
Commun., 2012, 48, 9825–9827; (e) D. S. Nesterov,
J. Jezierska, O. V. Nesterova, A. J. L. Pombeiro and
A. Ozarowski, Chem. Commun., 2014, 50, 3431–3434.
R. E. P. Winpenny, J. Schnack and E. J. L. McInnes, Inorg.
Chem., 2014, 53, 3032–3038; (b) K. H. Zangana,
E. M. Pineda, E. J. L. McInnes, J. Schnack and
R. E. P. Winpenny, Chem. Commun., 2014, 50, 1438–1440;
(c) S. Mameri, A. M. Ako, F. Yesil, M. Hibert, Y. H. Lan,
C. E. Anson and A. K. Powell, Eur. J. Inorg. Chem., 2014,
4326–4334; (d) A. M. Ako, Y. H. Lan, O. Hampe,
E. Cremades, E. Ruiz, C. E. Anson and A. K. Powell, Chem.
Commun., 2014, 50, 5847–5850; (e) I. A. Kuhne,
N. Magnani, V. Mereacre, W. Wernsdorfer, C. E. Ansona
and A. K. Powell, Chem. Commun., 2014, 50, 1882–1885.
2 (a)
M.
Charalambous,
E.
E.
Moushi,
C. Papatriantafyllopoulou, W. Wernsdorfer, V. Nastopoulos,
G. Christou and A. J. Tasiopoulos, Chem. Commun., 2012,
48, 5410–5412; (b) V. Mereacre, Y. H. Lan, R. Clerac, 14 (a) V. G. Kessler, Chem. Commun., 2003, 1213–1222;
A. M. Ako, W. Wernsdorfer, G. Buth, C. E. Anson and
A. K. Powell, Inorg. Chem., 2011, 50, 12001–12009;
(c) J. Rinck, G. Novitchi, W. Van den Heuvel, L. Ungur,
(b) E. A. Buvaylo, O. V. Nesterova, V. N. Kokozay,
O. Y. Vassilyeva, B. W. Skelton, R. Boca and D. S. Nesterov,
Cryst. Growth Des., 2012, 12, 3200–3208.
Dalton Trans.
This journal is © The Royal Society of Chemistry 2015

View Article Online
Dalton Transactions
Paper
15 (a) S. Tanase, G. Aromi, E. Bouwman, H. Kooijman, 20 Z. A. Starikova, A. I. Yanovskii, D. E. Chebukov,
A. L. Spek and J. Reedijk, Chem. Commun., 2005, 3147–
3149; (b) I. A. Gass, C. J. Milios, A. G. Whittaker,
E. P. Turevskaya and N. Y. Turova, Zh. Neorg. Khim., 1998,
43, 1308–1318.
F. P. A. Fabbiani, S. Parsons, M. Murrie, S. P. Perlepes and 21 F. E. Hahn, C. Jocher and T. Lugger, Z. Naturforsch., B:
E. K. Brechin, Inorg. Chem., 2006, 45, 5281–5283; Chem. Sci., 2004, 59, 855–858.
(c) M. Viciano-Chumillas, G. de Ruiter, S. Tanase, 22 S. Kodama, N. Taya and Y. Ishii, Inorg. Chem., 2014, 53,
J. M. M. Smits, R. de Gelder, I. Mutikainen, U. Turpeinen, 2754–2756.
L. J. de Jongh and J. Reedijk, Dalton Trans., 2010, 39, 4991– 23 B. Gaskins, J. J. Lannutti, D. C. Finnen and A. A. Pinkerton,
4998; (d) C. B. Khadka, D. G. Macdonald, Y. H. Lan,
A. K. Powell, D. Fenske and J. F. Corrigan, Inorg. Chem.,
2010, 49, 7289–7297.
Acta Crystallogr., Sect. C: Cryst. Struct. Commun., 1994, 50,
1387–1390.
24 A. I. Yanovsky, M. I. Yanovskaya, V. K. Limar, V. G. Kessler,
N. Ya. Turova and Yu. T. Struchkov, J. Chem. Soc., Chem.
Commun., 1991, 1605.
16 M. Tsaroucha, Y. Aksu, E. Irran and M. Driess, Chem.
Mater., 2011, 23, 2428–2438.
17 A. E. Lapshin and O. V. Magdysyuk, Glass Phys. Chem., 25 A. I. Yanovsky, E. P. Turevskaya, M. I. Yanovskaya,
2011, 37, 196–205.
V. G. Kessler, N. Ya. Turova, A. P. Pisarevskii and
18 (a) L. H. Liu, L. N. Zakharov, A. L. Rheingold and
Yu. T. Struchkov, Russ. J. Inorg. Chem., 1995, 40, 355.
T. A. Hanna, Chem. Commun., 2004, 1472–1473; 26 CrysAlis PRO, Agilent Technologies, 2011.
(b) D. Mendoza-Espinosa, A. L. Rheingold and T. A. Hanna, 27 O. V. Dolomanov, L. J. Bourhis, R. J. Gildea, J. A. K. Howard
Dalton Trans., 2009, 5226–5238.
and H. Puschmann, J. Appl. Crystallogr., 2009, 42, 339–341.
19 S. Krieck, H. Gorls and M. Westerhausen, J. Organomet. 28 G. M. Sheldrick, Acta Crystallogr., Sect. A: Fundam. Crystal-
Chem., 2009, 694, 2204–2209.
logr., 2008, 64, 112–122.
This journal is © The Royal Society of Chemistry 2015
Dalton Trans.