Crystal Structures and Spin-Crossover Behavior of Iron(II) Complexes with Chiral and Racemic Ligands

Article abstract of DOI:10.1002/ejic.201601232

Chiral iron(II) complexes, [Fe{(R)-L}₂(NCS)₂] (1) and [Fe{(S)-L}₂(NCS)₂] (2), and racemic complex [Fe(rac)-L)₂(NCS)₂] (3) {L = α-methyl-N-(2-pyridinylmethylene)cyclohexanemethanamine} were synthesized. Their structures and magnetic properties were investigated by X-ray crystallography, magnetic susceptibility measurements, and M?ssbauer spectroscopy. Complexes 1 and 2 crystallize in the trigonal system with space group P3₁21 and P3₂21, respectively. All complexes exhibit spin-crossover (SCO) behavior and light induced excited spin state trapping (LIESST) effects at 532 nm. Complexes 1 and 2 show similar gradual SCO behavior, and complex 3 shows more gradual SCO, which seems to be a result of the different crystal packing, as complex 3 is the symmetric isomer but 1 and 2 are asymmetric.

Full text of DOI:10.1002/ejic.201601232

A Journal of
Accepted Article
Title: Crystal Structures and Spin-Crossover Behavior of Iron(II)
Complexes with Chiral and Racemic Ligands
Authors: Yusuke Sekimoto, Mohammad Razaul Karim, Naoto Saigo,
Ryo Ohtani, Masaaki Nakamura, and Shinya Hayami
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content of this Accepted Article.
To be cited as: Eur. J. Inorg. Chem. 10.1002/ejic.201601232
Link to VoR: http://dx.doi.org/10.1002/ejic.201601232

10.1002/ejic.201601232
European Journal of Inorganic Chemistry
FULL PAPER
Crystal Structures and Spin-Crossover Behavior of Iron(II)
Complexes with Chiral and Racemic Ligands
Yusuke Sekimoto,[a] Mohammad Razaul Karim,[a,b] Naoto Saigo,[a] Ryo Ohtani,[a] Masaaki Nakamura,[a]
Shinya Hayami*[a,c]
Abstract: Chiral and racemic iron(II) complexes, [Fe((R)-L)2(NCS)2]
(1), [Fe((S)-L)2(NCS)2] (2) and [Fe(R,S)-L)2(NCS)2] (3) (L = α-methyl-
respectively.5 Its cooperativity was triggered by numerous
intermolecular interactions including hydrogen-bonding and van
der Waals forces throughout neighboring molecules. Optically
active complexes, either - and -isomer, much drew attention
to magnetic properties. Boinnard et al. have suggested from the
different average bond length of racemic-[FeII(5-NO2-sal-
N(1,4,7,10))] complex that the iron(II) of -isomer was low-spin
but the iron(II) of the -isomer was high-spin.6 In the
intermediate phase of its two step spin transition phenomenon,
half of the molecules are associated with both S = 0 (Λ
enantiomer) and S = 2 (Δ enantiomer) states. Homochiral SCO
complexes generated by spontaneous resolution have been also
reported.7 For the effect of Δ/Λ configuration on SCO behavior,
optically active and racemic metal complexes, [Fe((R)-
L)2(NCS)2] (1), [Fe((S)-L)2(NCS)2] (2) and [Fe((rac)-L)2(NCS)2]
N-(2-pyridinylmethylene)-cyclohexanemethanamine)
were
synthesized. Their structures and the magnetic properties were
investigated by the X-ray analysis, the magnetic susceptibility and
Mössbauer spectra measurements. Complexes
1 and 2 were
crystallized in trigonal system with space groups P3121 and P3221,
respectively. All complexes exhibited spin-crossover (SCO)
behaviors and light induced exited spin state trapping (LIESST)
effects at 532 nm. Complexes 1 and 2 showed similar gradual SCO
behavior and complex 3 more gradual SCO, which seems to be
different crystal molecular packing, since complex 3 is the symmetric
isomer, and 1 and 2 are asymmetric.
(3)
(L
=
α-Methyl-N-(2-pyridinylmethylene)-
cyclohexanemethanamine), were prepared8, respectively and
characterized by powder XRD, X-ray crystallography, and
Mössbauer spectra.
Introduction
In recent years, chiral magnetic systems are increasingly
attracting attention in the prospects of magneto-optical devices,
chiral magnetism, and chiral catalysis.1 Enantiopure magnetic
materials based on the interactions between pendant chiral
groups and macrocyclic metal complexes have been reported.2
The expected magnetic property in terms of SCO phenomenon
involves external perturbations (e.g., temperature, pressure,
magnetic field or light) from induced transition between low spin
(LS) and high spin (HS) states in the solid phase of the first
Results and Discussion
The crystal data and structural details are summarized in
Table S1.9,10 ORTEP drawings for 1 and 2 are shown in figure 1.
The complex 2 was crystallized in the chiral space group P3221.
The molecular symmetry of the complexes could not affirm due
to the chirality of ligands and complexes and the general
features of the structures as previous report.11 Each iron atom is
octahedrally coordinated with four nitrogen atoms of two chiral
bidentate ligands and two thiocyanato ions arranged by cis
configurarion. The bond lengths of Fe-N at 278 K match with
typical values for HS iron(II) species. The two Fe-N(pyridine)
distances, Fe-N(1) and Fe-N(2), are 2.188(4) and 2.195(4) Å,
respectively. The Fe-N(imine) distances (Fe-N(3) = 2.292(4) and
Fe-N(4) = 2.240(7) Å) are longer than Fe-N(pyridine). The Fe-
N(CS) distances (Fe-N(5) = 2.129(6) and Fe-N(6) = 2.072(9) Å)
are shorter than other Fe-N(pyridine and imine). The steric
hindrance was reflected in N-Fe-N angles. The N-Fe-N bond
angles between adjacent and opposite nitrogen atoms are within
the range of 74.6(2)˚ to 99.01(17)˚ and 166.2(2)˚ to 167.1(2)˚,
respectively (Table S1). The less differences in bond lengths
and angles of complex 2 imply more regulated octahedral
geometry as compared with analogues, [Fe(PM-BiA)2(NCS)2]
(PM is N-2-pyridylmethylene and BiA is 4-aminobiphenyl).12 All
molecules of 2 consist of Λ-enantiomer in the single crystal and
are consistent with Flack parameter. Optically active Δ or Λ
complex can be introduced by the chiralirty or steric hinderance
transition metal complexes with 3dn (n
= 4-7) electronic
configurations.3 Iron(II) SCO complexes, [Fe(L)2(NCX)2] (L =
bidentate or tetradendtate ligand; X = S or Se), have been
extensively studied as the SCO behaviors are affected
according to their stereoisomerism (cis/trans or mer/fac) of the
coordinated polydentate and NCX ligands. Interestingly, only cis
isomer between cis- and trans-[FeII(triaryltriazole)(NCS)
complexes showed SCO behavior.4 Matouzenko et al. have
reported the abrupt SCO behavior in [Fe(DPEA)(NCS)2] (DPEA
=
(2-aminoethyl)bis(2-pyridyl-methyl)-amine)),
where
the
tetradentate ligand (DPEA) and NCS- are in mer and cis position,
[a]
Department of Chemistry, GSST, Kumamoto University,
2-39-1, Kurokami, Chuo-ku, Kumamoto860-8555, Japan
E-mail:hayami@sci.kumamoto-u.ac.jp
[b]
[c]
Department of Chemistry, School of Physical Sciences, Shahjalal
University of Science & Technology, Sylhet-3114, Bangladesh
Institute of Pulsed Power Science (IPPS), Kumamoto University,
2-39-1, Kurokami, Chuo-ku, Kumamoto860-8555, Japan
E-mail: hayami@sci.kumamoto-u.ac.jp
Supporting information for this article is given via a link at the end of the
document.((Please delete this text if not appropriate))
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10.1002/ejic.201601232
European Journal of Inorganic Chemistry
FULL PAPER
of the coordinating ligands.11 Supposed that two cyclohexyl
groups are orientated parallel to another ligands for proper
intermolecular packing in the single crystals. Any H-bonding or
π-π interaction was not found in the crystal structure. Van der
Waals interaction was also formed between 2 in this crystal
packing. Structure 1 is almost same as 2 except different
absolute configuration. The single crystal 3 was analyzed by X-
ray crystallography but the cyclohexyl moiety were highly
disordered and the R value was not improved. The powder X-ray
diffraction (PXRD) pattern of 3 is well matched by the simulated
one from the single crystal (Figure. S1).
Despite the XRD data for 2 at 110 K, the R value (= 11.43)
was not improved but we estimated all Fe-N distances. There
are two units in the crystal packing of 2 at 110 K and the all Fe-N
bonds are shown in Table S2. The average bond lengths of Fe-
N are almost same in each unit, one is 2.121(6) and the other
2.132(2) Å. Therefore, HS and LS states do not coexist in the
crystals, which suggest the HS-LS stabilization in the packing at
low temperature does not come from a mixture of HS and LS
states but a mixture of HS and LS domains in microstructural
scale. Compared the XRD data for 2 between HS and LS state,
most of Fe-N bonds were decreased when HS state was
transformed to LS state. The Fe-N distances of 2 range from
2.072(9) to 2.292(4) Å in the HS state and from 2.05(1) to
2.20(1) Å in LS state. Compared with the case of Marchivie and
coworkers,12 these decline are not enough to exhibit abrupt SCO
behavior. Furthermore, one of Fe-N(NCS) bonds at 110 K is
2.12(1) Å and longer than 2.072(9) Å at 278 K, which explain
why 1 and 2 exhibit gradual and incomplete spin crossover
behavior.
Figure 1. Single crystal structures of 1 and 2 at 298 and 278 K, respectively.
Hydrogen atoms are omitted for clarity; thermal ellipsoids are at the 50%
probability level.
The magnetic properties of 1, 2 and 3 were measured in the
temperature range of 5 to 400 K (Figure 2), whereas Mössbauer
spectra were obtained at 80 and 295 K (Figure S3, S5, S6, S8
and Table S3-S5). The magnetic susceptibilities are shown in
Figure 2 after removing the solvents by annealing under vacuum
condition. The χMT values of 2 with 2.82 cm3 K mol-1 above 310
K resembles with HS iron(II) complexes. On cooling mode, the
χMT value was gradually decreased, exhibiting incomplete SCO
behaviour (T1/2=230 K). The χMT value at 80 K with 1.62 cm3 K
mol-1 implies 58 % of HS fraction. Since the decrease of χMT
value below 30 K corresponds to zero-field splitting, this is not
two-step SCO behavior. The plateau behavior is caused by the
mixture of HS and LS domains.
The Mössbauer spectra match with the magnetic behavior.
The Mössbauer spectrum of 2 at 295 K consists of one doublet
as the main peak (Figure S5). The isomer shift (I.S.) of the
doublet and the quadruple splitting (Q.S.) as 0.99 and 2.34 mms-,
respectively, are typical appearance for the HS state of iron(II).1
Two kinds of doublet including wide (I.S. = 1.16 mms-1, Q.S. =
3.10 mms-1) and narrow (I.S. = 0.49 mms-1, Q.S. = 0.56 mms-1)
doublet at 80 K are assigned to the HS and LS state of iron(II)
species, respectively. The ratio of HS species (estimated form
area ratio) in 2 was 41 %. 2 exhibited the LIESST effect, as well
(Figure S4). Irradiation with laser (532 nm) at 5 K afforded the
increasement in χMT value from 0.92 to 1.38 cm3 K mol-1, which
is implicative for the trapping of metastable HS state. When the
light was switched off, χMT value increased to 1.87 cm3 K mol-1
at 40 K on warming mode. The χMT value within 40 to 70 K
Figure 2. Temperature dependence of magnetic susceptibilities (χmT) for the
single crystals of 1 (△), 2 (△) and 3 (△).
Being enantiomeric pair 1 and 2 possess almost similar crystal
structures (except the configurations of the coordinated ligands
and complexes), the magnetic behavior of 1 is similar to 2. The
χMT value of the compound 1 at higher than 310 K was ca. 2.94
cm3 K mol-1 and 1.68 cm3 K mol-1 at 80 K (Figure S2). The χMT
value at 80 K corresponds to 57 % of HS fraction and T1/2 is 230
K. The Mössbauer spectra of the compound 2 showed one
doublet (I.S. = 1.00 mms-1, Q.S. = 2.31 mms-1) at 295 K, the
wide doublet (I.S. = 1.16 mms-1, Q.S. = 3.09 mms-1) at 80 K and
narrow doublet (I.S. = 0.48 mms-1, Q.S. = 0.54 mms-1) at 80 K.
And the HS fraction was 45 % (Figure S3 and Table S3). For the
compound 1, the LIESST effect was observed as well as the
compound 2, of which TLIESST was 60 K.
range was decreased by HS → LS thermal relaxation (TLIESST
=
60 K), and recovered to the original one above 70 K.
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10.1002/ejic.201601232
European Journal of Inorganic Chemistry
FULL PAPER
The powdered compound 3 exhibited different magnetic
behavior comparing the compounds 1 and 2. The spin state at
400 K was expected to nearly HS state with the χMT value of
2.99 cm3 K mol-1. On cooling, the χMT value showed more
noticeable decrease (T1/2 = 214 K) than that of the compounds 1
and 2. The χMT vs. T curve became plateau at 30 to 80 K and
the χMT value was 0.90 cm3 K mol-1, which corresponds to 30 %
of HS fraction. The Mössbauer parameters indicated that iron(II)
at 295 K was nearly HS state (I.S. = 1.01 mms-1, Q.S. = 2.39
mms-1), and the one at 80 K coexisted in HS (I.S. = 1.07 mms-1,
Q.S. = 3.00 mms-1) and LS state (I.S. = 0.43 mms-1, Q.S. = 0.57
mms-1). The ratio of the HS fraction was 23 % at 80 K. The
noticeable spin conversion at low temperature was detected by
Mössbauer spectrum and magnetic susceptibilities for powdered
sample of the compound 3, which also exhibited the LIESST
effect. The χMT value was increased from 0.44 cm3 K mol-1 to
0.74 cm3 K mol-1 by laser irradiation at 5 K and showed
maximum value (1.15 cm3 K mol-1) at 40 K as 11% of LS → HS
spin conversion. The thermal relaxation was back to the original
state at above 70 K (TLIESST = 60 K). By comparison these values
with the ones of solvent-free complexes, the dissimilarity
between 2 (or 1) and 3 is not derived from the solvent nature.
From spin crossover behavior between single crystal and
powder sample of the compound 3, the χMT value of single
crystals was ca. 2.70 cm3 K mol-1 at above 310 K and 1.40 cm3 K
mol-1 at 80 K (Figure 2). These values are close to the
compounds 1 and 2 rather than powder sample of 3. The HS
fraction at 80 K was estimated 53 % from χMT value. The T1/2 for
single crystal of 3 (193 K), however, was different from the ones
for compounds 1 and 2 (230 K). The Mössbauer spectrum for
single crystal of the compound 3 at 295 K showed only one
doublet (I.S. = 0.99 mms-1, Q.S. = 2.38 mms-1), which is
assigned to HS species of iron(II) as well as other samples
(Figure S6 and Table S4). Its spectrum at 80 K reflects magnetic
susceptibility data and consists of the wide doublet (I.S. = 1.11
mms-1, Q.S. = 3.12 mms-1) and narrow doublet (I.S. = 0.43 mms-
1, Q.S. = 0.58 mms-1). The HS fraction at 80 K obtained from
area ratio was 45 %.
Mössbauer fitting parameters for mixture of 1 and 2 at 80 K
are summerized in Table 1. Since the preparative condition of
each sample such as stirring time or amount of solvent was not
the same, percentage of HS and LS fraction in the complex is
not expected to follow the R:S ratio of the ligand. However, the
addition of one enantiomer to a homogeneous racemic mixture
(50:50 for R:S) may promote more spin conversion and this
effect is mainly likely because of the crystal defects. The SC
behavior is influenced by the preparative procedure or additional
post-preparative treatment such as ball-milling or crushing in a
mortar.13 These effects are mainly caused by crystal defects.
However, such crystal defects increases residual HS fraction
and/or results in less steep spin transition curve. The powder
samples are regarded having more crystal defects than single
crystal. However, HS → LS spin conversion is promoted at low
temperature in the powder sample of 3 (Figure S6, S8, Table S4
and S5). To the best of our knowledge, such example has not
been reported so far. In case of pure single crystal, i.e. HS:LS =
50:50, of compound 3 at low temperature, it should be stabilized
Figure 3. Temperature dependence of magnetic susceptibilities (χmT) for the
powder samples of 1 (△), 2 (△) and 3 (△)
by···-HS-LS-HS-LS-··· assembly as the reported phenomenon
for 2 step SCO behaviour of [Fe(2-pic)3]Cl2·EtOH (2-pic = 2-
picoline or 2-aminomethylpyridine) or dinuclear complexes.14
We assume (the data sequence in Table 2 also imply) that even
in
stabilization at low temperature through the spin conversion to
LS species is possible by mixing and enantiomer,
1
and 2, establishment of ···-HS-LS-HS-LS-··· type
R
S
respectively. Such effect was observed by adding 10% of the
opponent enantiomer. Therefore, single crystals of 1, 2 and 3
are stabilized as ···-HS-LS-HS-LS-··· formation at low
temperature. Depending on the extent of chirality, the crystal
structures affect cooperativity, which results in the difference in
T1/2 value.
A packing preference for ···-HS-LS-HS-LS-···
stabilization seems that such patterning is naturally favoured to
afflict the anisotropy of molecules caused by chirality and
distortion. Array of chiral molecules in the crystals might render
stabilizing factors such as dipole-dipole interactions then the···-
HS-LS-HS-LS-··· type formation recover the loss in stabilization.
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10.1002/ejic.201601232
European Journal of Inorganic Chemistry
FULL PAPER
Table 1. Mössbauer fitting parameters for mixture of 1 and 2 at 80 K.
[Fe((R)-L)2(NCS)2] (1), [Fe((S)-L)2(NCS)2] (2), and [Fe ((rac)-L)2(NCS)2]
(3): FeCl2·4H2O (0.20 g, 1.0 mmol), was dissolved in methanol (5 mL) in
the presence of a small amount of ascorbic acid to prevent oxidation of
iron(II). KSCN (0.19 g, 1.0 mmol) in methanol (5 mL) was added and the
mixture stirred for 15 minutes. The solution was separated from white
precipitate of potassium chloride by filtration and added dropwise to the
ligand, L (2 mmol) with stirring in deoxygenated methanol (20 mL). The
color of solution turned to violet and the precipitate was formed
immediately. The solid was filtered, washed with a small amount of cold
methanol and dried under vacuum. Yield: 0.39 g (62.9%). Element. Anal.
Calcd. for C31H44Fe1N6O1S2: C, 58.84; H, 6.97; N, 13.20. Found: C,
58.72; H, 6.74; N, 13.34 %. IR: νmax/cm-1; 2925, 2852 (νCH), 2076, 2063
(νCN) (KBr). The single crystal was obtained from diffusion of diethylether
into a chloroform solution of each complex. 1 and 2 were prepared by
using either (R)-L or (S)-L, respectively. 3 was prepared by using 1:1
mixture of of (R)-L and (S)-L.
Physical measurement: The structure of the compounds 1 and 2 were
determined at 298 K and 278K, respectively. The crystals mounted on a
glass capillary. All the measurements were made on a Rigaku/MSC
Mercury CCD diffractometer with graphite monochromated Mo-Kα (λ=
0.71070 Å) radiation. The data were collected at 298±2 K and 278±2 K,
respectively. The maximum 2θ value is 55.0º. A total of 1240 oscillation
images were collected. Data were collected and processed using the
Crystalclear program (Rigaku). The linear absorption coefficients, μ, for
Mo-Kα radiation were 5.55 cm-1, 5.57 cm-1, respectively. The data were
corrected for Lorentz and polarization effects. The structure was solved
by direct method (SIR-92) and expanded using Fourier techniques. The
non-hydrogen atoms were refined anisotropically. Hydrogen atoms were
included for structure analysis but not refined. The final cycle of full-
matrix least-squares refinement was based on all reflections.
Computations were carried out on a SGI O2 computer using teXsan
crystallographic software package. The magnetic susceptibilities χ(T)
were measured between 5 K and 400 K with a superconducting quantum
interference device magnetometer (Quantum Design MPMS-5S) in an
external field of 0.5 T. LIESST experiment was done with using an Ar+
laser (λ = 532 nm, continuous wave) as a light source. The Mössbauer
spectrometer, with a 57Co/Rh source, was driven in the transmission
mode.
Conclusions
[Fe((R)-L)2(NCS)2] (1), [Fe((S)-L)2(NCS)2] (2), and [Fe((rac)-
L)2(NCS)2] (3) were prepared by using chiral/racemic ligands as
the starting materials. 1 and 2 existed in Δ and Λ enantiomer,
respectively. All complexes exhibited SCO behavior. The SCO
behaviors for 1 and 2 showed no differences in their magnetic
property but 3 was different from the one of 1 and 2. The T1/2
value for 3 at 230 K and for 1 and 2 at 204 K displayed such
variation. The racemic complex which was prepared by 50:50
ratio of each enantiomeric ligand existed as major contribution
of HS state. But an increased chirality (prepared from higher
ratio of either R or S) resulted in an increasing contribution of the
LS state.
Keywords: Iron(II) compound • Chirality • Stereochemistry •
Spin crossover • Mössbauer spectra
[1]
[2]
a) M. Mito, K. Iriguchi, H. Deguchi, J. Kishine, K. Kikuchi, H. Ohsumi, Y.
Yoshida and K. Inoue, Phys. Rev. B, 2009, 79, 012406/1-012406/4. b)
C. Train, R. Gheorghe, V. Krstic, L. M. Chamoreau, N. S. Ovanesyan,
G. L Rikken, M. Gruselle, M. Verdaguer, Nat. Mater, 2008, 7, 729-734.
c) J.-M. Lehn, Supramolecular chemistry, Concept and Perspectives,
Wiley-VCH, Weinheim, 1995.
a) S. Yamamura, Y. Sugawara, K. Suzuki, T. Sugawara, J. Am. Chem.
Soc., 2010, 132, 4528-4529. b) M. Kurmoo, A. W. Graham, P. Day, S. J.
Coles, M. B. Hursthouse, J. L. caufield, J. Singleton, F. L. Pratt, W.
Hayes, L. Ducasse, P. Guionneau, J. Amer. Chem. Soc., 1995,117,
12209-12217. c) H.-R. Wen, C.-F. Wang, Y. Song, J.-L. Zuo, X.-Z. You,
Inorg. Chem., 2005, 44, 9039-9045. d) J. H. Han, M. J. Cha, B. G. Kim,
S. K. Kim, K. S. Min, Inorg. Chem. Commun., 2008, 11, 745-748.
a) J. Olguín, S. Brooker, Coord. Chem. Rev., 2011, 255, 203-240. b) Y.
Garcia, F. Robert, A. D. Naik, G. Y. Zhou, B. Tinant, K. Robeyns, S.
Michotte, L. Piraux, J. Am. Chem. Soc., 2011, 133, 15850-15853. c) X.-
Y. Wang, C. Avendaño, K.R. Dunbar, Chem. Soc. Rev., 2011, 40,
Experimental Section
(R,S)-N-(1-cyclohexylethyl)-1-(pyridin-2-yl)methanimine
(R)-,
(S)-,
and
(R,S)-N-(1-cyclohexylethyl)-1-(pyridin-2-
yl)methanimine (L): (R)-, (S)-, or (R,S)-Cyclohexylethylamine (0.25 g,
2.0 mmol) and pyridine-2-carboxyaldehyde (0.21 g, 2.0 mmol) were
stirred in methanol (20 mL) for 3 h. Removal of solvent under reduced
pressure gave yellow oil. The product was of high purity and used next
steps without further purification. H NMR (400MHz) in CDCl3 :  0.8-2.0
(m), 3.44 (s, 1H), 3.12 (m, 1H), 7.28 (t, 1H), 7.70 (t, 1H), 8.04 (d, 1H),
[3]
[4]
1
3213-3238.
D. Zhu, Y. Xu, Z. Yu, Z. Guo, H. Sang, T. Liu, X. You, Chem. Mater.
2002, 14, 838-843.
8.61 (d, 1H).
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10.1002/ejic.201601232
European Journal of Inorganic Chemistry
FULL PAPER
[5]
G. S. Matouzenko, A. Bousseksou, S. Lecocq, P. J. van
Koningsbruggen, M. Perrin, O. Kahn, A. Collet, Inorg. Chem., 1997, 36,
2975-2981.
R = 0.0656 for all data with a linear absorption coefficient Mo-Kα
radiation = 5.55 cm-1. CCDC 1508831.
[10] X-ray crystallographic data for 2 (C30H40FeN6S2) at 278 K: FW= 604.65,
trigonal, space group P3221, a (or b) = 16.7528(7) Å, c = 22.8703(9) Å,
V = 5558.75 Å3, Z = 6, Dcalcd = 1.084 g cm-3, Flack parameter = 0.00(2),
R = 0.0848 for all data with a linear absorption coefficient Mo-Kα
radiation = 5.57 cm-1. CCDC 1508832.
[6]
[7]
D. Boinnard, A. Bousseksou, A. Dworkin, J.-M. Savariault, F. Varret, J.-
P. Tuchagues, Inorg. Chem., 1994, 33, 271-281.
Y. Sunatsuki, Y. Ikuta, N. Matsumoto, H. Ohta, M. Kojima, S. Iijima,
S.Hayami, Y. Maeda, S. Kaizaki, F. Dahan, J. P. Tuchagues, Angew.
Chem. Int. Ed., 2003, 42, 1614-1618.
[11]
E. Coronado, F. Palacio, J. Veciana, Angew. Chem. Int. Ed., 2003, 42,
[8]
[9]
a) X.-L. Tong, T.-L. Hu, J.-P Zhao, Y.-K Wang, H. Zhang, X.-stH. Bu,
Chem. Commun., 2010, 46, 8543-8545. b) A.-K. Klehe, V. Laukhin, P.
A. Goddard, J. A. Symington, J. Aghassi, J. Singleton, E. Coronado, J.
R. Galan-Mascaros, C. J. Gomez-Garcia, C. Gumez-Garcia, Synth.
Met., 2003, 133, 549-551.
2570-2572.
[12] a) M. Marchivie, P. Guionneau, J.-F. Létard, D. Chasseau, Acta Cryst.
B, 2003, 59, 479-486. b) P. Guionneau, Dalton Trans., 2014, 43, 382-
393.
[13] a) E. W. Müller, H. Spiering, P. Gütlich, Chem. Phys. Lett. 1982, 93,
567-571. b) E. W. Müller, H. Spiering, P. Gütlich, Inorg. Chem. 1984,
23, 119-120.
X-ray crystallographic data for 1 (C30H40FeN6S2) at 298 K: FW= 604.65,
trigonal, space group P3121, a (or b) = 16.6877(4) Å, c = 22.8415(5) Å,
V = 5508.69 Å3, Z = 6, Dcalcd = 1.094 g cm-3, Flack parameter = 0.00(3),
[14] P. Gütlich, Y. Garcia, T. Woike, Coord. Chem. Rev., 2001, 219-221,
839-879
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10.1002/ejic.201601232
European Journal of Inorganic Chemistry
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Key Topic*
Chiral [Fe((R)-L)2(NCS)2] and [Fe((S)-
L)2(NCS)2] (2) and racemic [Fe((rac)-
L)2(NCS)2] complexes, where (L = N-
(1-cyclohexylethyl)-1-(pyridin-2-
Chiral Spin-Crossover
Yusuke Sekimoto, Mohammad Razaul
Karim, Naoto Saigo, Ryo Ohtani,
Masaaki Nakamura, Shinya Hayami*
yl)methanimine)
exhibited
spin-
crossover (SCO) behaviors and light
induced exited spin state trapping
effects
Author(s), Corresponding Author(s)*
Page No. – Page No.
Title
Crystal Structures and Spin-Crossover
Behavior of Iron(II) Complexes with Chiral
and Racemic Ligands
* Chiral ligand, Spin crossover
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