Synthesis, structures and magnetic properties of two iron(ii) tris(pyridyl)phosphine sulfide complexes

Article abstract of DOI:10.1016/j.mencom.2018.03.034

Two iron(ii) mononuclear metal complexes with tris(pyridyl)-phosphine sulfides and Fe(ClO₄)₂·6H₂O have been synthesized and characterized. Detailed structural analyses and magnetic susceptibility measurements confirm no spin transition from low-spin to the high-spin state between 2 and 300 K in these complexes.

Full text of DOI:10.1016/j.mencom.2018.03.034

Mendeleev
Communications
Mendeleev Commun., 2018, 28, 208–210
Synthesis, structures and magnetic properties of two
iron(ii) tris(pyridyl)phosphine sulfide complexes
Chunyang Zheng,*a,b Xuecheng Hu and Qin Tao
b
a
a
b
Hubei Collaborative Innovation Center for Rare Metal Chemistry, Hubei Key Laboratory of Pollutant
Analysis and Reuse Technology, Institute for Advanced Materials, Hubei Normal University,
4
35002 Huangshi, P. R. China. E-mail: zcy800204@163.com
Department of Chemistry, The School of Art and Science of Hubei Normal University, 435002 Huangshi,
P. R. China
DOI: 10.1016/j.mencom.2018.03.034
0.3
Two iron(ii) mononuclear metal complexes with tris(pyridyl)-
phosphine sulfides and Fe(ClO ) ·6H O have been synthesized
0.2
4
2
2
and characterized. Detailed structural analyses and magnetic
susceptibility measurements confirm no spin transition from
low-spin to the high-spin state between 2 and 300 K in these
complexes.
0
0
.1
.0
0
50
100 150 200 250 300
T/K
Pyridylphosphine ligands and their chalcogenide derivatives are
of considerable interest due to their fundamental importance and
prospective applications.1 Tris(2-pyridyl)phosphine exhibits rich
coordination capabilities owing to its unique structure, and a
large number of metal complexes with pyridylphosphine ligands are
molecular structures of complexes 1 and 2 were determined by
X-ray crystallography at 296 and 100 K, respectively(Figure 2).§
–
–3
Complexes 1 and 2 crystallize in the triclinic space group P1
with two DMF molecules in 1 and six MeCN molecules in 2.
ii
TppS or MeTppS acts as a tripodal ligand, and the Fe atom lies
4–12
reported;
however, the coordination chemistry of tris(2-pyridyl)-
on an inversion center and is octahedrally coordinated by the N
atoms of two tridentate ligands with an expected six-coordinate
geometry.
5
phosphine chalcogenides is poorly known.
Magnetic bistability induced by external stimuli (such as
temperature and light) attracts much attention. We recently
synthesized a cyano-bridged {Fe Co } grid and two mixed-
2
2
(a)
(b)
iii
2
ii
2
C(6)
C(3)
C(2)
C(1)
C(6)
C(3)
valence {Fe Fe } clusters, which exhibited reversible thermally
C(12)
C(9)
intramolecular charge transfer and spin crossover properties,
S(1)
N(2)
C(7)
C(11)
C(8)
C(2)
C(1)
1
3,14
C(4)
C(5)
respectively.
The fact that substituted tris(pyrazolyl)borate
C(7)
C(10)
C(11)
C(4)
C(5)
P(1)
C(8)
C(13)
C(10)
C(9)
C(12)
and tris(pyrazolyl)methane ligands induce a variety of electronic
spin-state behaviors in iron complexes15–17 led us to undertake
an extensive investigation into the iron(ii) complexes formed with
other tripodal ligands. Herein, we report the first iron(ii) mono-
nuclear complexes with tris(pyridyl)phosphine chalcogenides and
thoroughly characterize them by single-crystal X-ray diffraction
and magnetic susceptibility measurements.
P(1)
N(1)
N(2)
N(1)
C(13)
N(3)
C(14)
C(15)
N(3)
C(14)
C(15)
C(17)
C(17)
C(16)
C(18)
C(16)
C(18)
Two tris(pyridyl)phosphine ligands were synthesized by a
reaction of 2-bromopyridine or 2-bromo-4-methylpyridine with
Figure 1 Molecular structure of (a) MeTpp and (b) MeTppS.
Tris(4-methylpyridin-2-yl)phosphine sulfide (MeTppS): 1H NMR
(300 MHz, CDCl3) d: 8.60 (d, 3 H, J2 4.8 Hz), 8.12 (d, 3H, J 7.2 Hz),
red phosphorus in a superbasic KOH/DMSO(H O) suspension
2
at 120°C for 1 h to afford tris(2-pyridyl)phosphine (Tpp) or
tris(4-methylpyridin-2-yl)phosphine (MeTpp).1
0,18,19
These phos-
7.17 (d, 3H, J 4.8 Hz), 2.39 (s, 9H). 13C NMR (75.4 MHz, CDCl ) d:
3
2
1
[
1.2, 125.9 (d, JCP 3.1 Hz), 129.5 (d, JCP 24.9 Hz), 147.6 (d, JCP 10.4 Hz),
phines are easily oxidized by treatment with elemental sulfur in
49.3 (d, J 19.9 Hz), 154.8 (d, J 113.4 Hz). MS (ESI), m/z: 340.07
CP
CP
refluxing toluene to give corresponding phosphine chalcogenides
+
+
+
+
M+H] . MS (EI , 70 eV), m/z, (%): 339 (18) [M] , 306 (54) [M–S] ,
47 (41) [M–Py ] , 215 (100) [M–SPy ] , 92 (10) [PyMe] .
†
(
TppS and MeTppS).20 The identity of MeTpp or MeTppS was
Me +
Me +
+
2
also confirmed crystallographically (Figure 1).
‡
Synthesis of [Fe(TppS) ][ClO ] ·2DMF 1. Under an argon atmosphere,
2
4 2
The synthesis of complexes 1 and 2 was performed by a reaction
of two equivalents of TppS or MeTppS with Fe(ClO ) ·6H O,
a solution of Fe(ClO ) ·6H O (0.036 g, 0.1 mmol) and TppS (0.060 mg,
4
2
2
0.2 mmol) in DMF (4 ml) was stirred at room temperature for 2 h and left
under the diffusion of diethyl ether vapor slowly without disturbance.
Dark-red block crystals suitable for X-ray structure analysis were
obtained and isolated by filtration after about three days. Yield, 0.070 g.
Synthesis of [Fe(MeTppS) ][ClO ] ·6MeCN 2. Under an argon atmo-
4
2
2
‡
in DMF or MeCN under an N atmosphere in good yields. The
2
†
1
Tris(4-methylpyridin-2-yl)phosphine (MeTpp): H NMR (300 MHz,
CDCl ) d: 8.58 (t, 3H, J 9.6 and 4.8 Hz), 7.30 (d, 3H, J 9.6 Hz), 7.02
2
4 2
3
sphere, solution of Fe(ClO ) ·6H O (0.036 g, 0.1 mmol) and MeTppS
4 2 2
13
(d, 3H, J 4.8 Hz), 2.28 (s, 9H). C NMR (CDCl , 75.4 MHz) d: 21.1,
3
(0.068 mg, 0.2 mmol) in MeCN (5 ml) was stirred at room temperature
for 2 h and left it under the diffusion of diethyl ether vapor slowly without
disturbance. Dark-red block crystals suitable for X-ray structure analysis
were obtained and isolated by filtration after about five days.Yield, 0.065 g.
1
1
23.7, 130.1 (d, JCP 21 Hz), 146.9 (d, J 4.5 Hz), 150.1 (d, J 12 Hz),
CP CP
+
+
61.2 (d, J 3 Hz). MS (EI , 70 eV), m/z (%): 307 (6) [M] , 215 (100)
CP
Me +
Me
+
[
M–Py ] , 200 (10) [M–Py –Me] .
©
2018 Mendeleev Communications. Published by ELSEVIER B.V.
–
208 –
on behalf of the N. D. Zelinsky Institute of Organic Chemistry of the
Russian Academy of Sciences.

Mendeleev Commun., 2018, 28, 208–210
Table 1 Selected bond distances, angles and structural parameters.
0
0
.3
.2
2
1
Compound P=X/Å
MeTpp
C–P–C/deg
Fe–Naverage/Å SFea
100.06(7), 105.14(7),
9
6.19(7)
1.9506(16) 107.53(19), 105.8(2),
03.16(19)
.9507(16) 106.49(19), 104.17(19),
05.4(2)
102.62(18), 104.78(17),
.9283(14) 101.68(17)
.9268(12) 104.45(15), 101.43(15), 2.017(3)
02.74(15)
103.61(7), 102.80(7),
03.11(7)
SFe is the sum of the deviation from 90° of the 12 cis-angles of the FeN6
octahedron.
MeTppS
0.1
1
1
0
.0
1
0
50
100 150 200 250 300
1
T/K
1
1
2.009(3)
21.5
17.6
Figure 3 Temperature dependence of cMT plots for complexes (1) 1 and
(2) 2.
1
2
1.9348(6)
2.0150(14)
18.7
ii
1
state of the Fe ion in 1 and 2 is the LS state, which is in accordance
a
with the magnetic data (see below). The P=X bond lengths in the
Fe complexes (1.927 and 1.928 Å for 1 and 1.935 Å for 2) are
ii
shorter than those in the free MeTppS ligand (1.951 Å), whereas
the C–P–C angles of the complexes are 101.7–104.8°, comparable
to 103.2–107.5° in the free MeTppS ligand.
Magnetic susceptibility measurements in a 1000 Oe field
were performed in a temperature range of 2–300 K (Figure 3).
(a)
S(1)
(b)
S(1)
P(1)
P(1)
The c T values of 1 and 2 did not change as the temperature
M
N(1)
N(3)
N(2)
N(3)
N(1)
increased from 30 to 300 K to show a tendency to the LS state
stabilization, which is very similar to that observed for related
N(2)
Fe(1)
Fe(1)
ii
Fe complex systems chelating bis-tripodal ligands exhibiting no
N(3)
N(2)
N(1)
22,23
N(2)
temperature dependence (LS state) in the test temperature range.
N(1)
N(3)
3
–1
In addition, the c T values of 1 and 2 are 0.20 cm mol K at
M
3
0 K, indicating that about 5% of iron(ii) ions still remain in the
P(1)
S(1)
P(1)
S(1)
high-spin states, with the non-zero value being due to second
order Zeeman contributions from the t2g configuration possibly
augmented by some remnant HS form.
6
15–17,24
This is in accordance
with structure analysis (the coordination bond lengths in 1 and 2
are slightly longer than those of the {Fe[(TppO) ] } (1.982 Å)
2 2
Figure 2 Molecular structure of complexes (a) 1 and (b) 2. Anions, solvent
molecules and hydrogen atoms are omitted for clarity.
2
+
based on the tris(2-pyridyl)phosphine oxide ligand). The decrease
1
5–17,25,26
Note that the coordination bond lengths in 1 (av. 2.01 Å) and
of c T below 30 K is due to zero-field splitting.
In
M
ii
2
(av. 2.02 Å) (Table 1, Figure 2) are slightly longer than those
general, Fe complexes exist in either a high spin or a low spin
state depending on the nature of the ligand field on the metal
ions. We devote ourselves to select and change the ligands with
different electron-donating groups in order to get intermediate
ligand field, however spin transition from low-spin to the high-
spin state is not detected between 2 and 300 K in two complexes.
In summary, two mononuclear iron(ii) complexes with the
tris(2-pyridyl)phosphine sulfide ligands in a N,N',N''-tripodal mode
have been successfully synthesized. Although a spin transition
from low-spin to high-spin state was not detected at 2–300 K in
the two complexes, we believe that our results will have some
impact on the preparation of novel SCO molecular materials.
2
+
2+
of the {Fe[N(py) ] } (1.982 Å), {Fe[CH(py)3]2} (1.949 Å),
3
2
2
+
2+
{
Fe[MeC(py) ] } (1.973 Å) and {Fe[(TppO) ] } (1.982 Å)
based on a tris(2-pyridyl)phosphine oxide ligand.
3 2
2 2
1–23
2
In addition,
the S values are 21.5 and 17.6° for 1 or 18.7° for 2. Thus, the spin
§
Crystal data for MeTpp. C H N P, M = 307.32, monoclinic, space
18
18
3
group P2 /n, a = 11.1546(17), b = 12.1839(19) and c = 13.133(2) Å,
1
3
–3
b = 113.981(2)°, V = 1630.8(4) Å , Z = 4, d = 1.252 g cm , m(MoKa) =
0.753 mm , T = 296(2) K, 17449 reflections measured, 4940 independent
calc
–1
=
reflections (Rint = 0.0471), final R = 0.0694 [I > 2s(I)], wR = 0.1567,
1
2
GOF = 1.045.
Crystal data for MeTppS. C H N PS, M = 339.38, monoclinic, space
18
18
3
group P2 /n, a = 14.023(3), b = 8.4045(18) and c = 30.400(6) Å,
1
3
–3
This work was supported by the Educational Commission of
Hubei Province of China (project no. B2017141), the National
Undergraduate Training Program for Innovation and Entrepreneur-
ship (project no. 201613256001), the Open Fund of Hubei Key
Laboratory of Pollutant Analysis & Reuse Technology (project
no. PA160209) and the Key Fund of the School of Art and
Science of Hubei Normal University (project no. Ky201701).
b = 98.391(3)°, V = 3544.5(13) Å , Z = 8, d = 1.272 g cm , m(MoKa) =
calc
–1
=
0.275 mm , T = 296(2) K, 25914 reflections measured, 6193 independent
reflections (Rint = 0.0731), final R = 0.0834 [I > 2s(I)], wR = 0.1897,
1
2
GOF = 1.045.
Crystal data for 1. C H Cl N O P S Fe, M = 983.54, triclinic, space
35
38
2
8
10 2 2
–
group P1, a = 12.4325(14), b = 12.9046(14) and c = 14.5901(16) Å, a =
3
=
97.769(2)°, b = 105.062(2)°, g = 92.435(2)°, V = 2232.2(4) Å , Z = 2,
–3
–1
dcalc = 1.463 g cm , m(MoKa) = 0.684 mm , T = 296(2) K, 22066
reflections measured, 8686 independent reflections (Rint = 0.0594), final
R = 0.0719 [I > 2s(I)], wR = 0.2073, GOF = 1.077.
Online Supplementary Materials
1
2
Crystal data for 2. C H Cl N O P S Fe, M = 983.54, triclinic, space
Supplementary data associated with this article can be found
in the online version at doi: 10.1016/j.mencom.2018.03.034.
48
54
2
12
8 2 2
–
group P1, a = 11.2851(10), b = 11.5247(10) and c = 11.8662(11) Å, a =
3
=
88.1050(10)°, b = 80.6610(10)°, g = 64.3540(10)°, V = 1371.6(2) Å ,
–3
–1
Z = 1, dcalc = 1.428 cm , m(MoKa) = 0.569 mm , T = 100(2) K, 15996
reflections measured, 6551 independent reflections (Rint = 0.0333), final
R = 0.0373 [I > 2s(I)], wR = 0.1070, GOF = 1.052.
References
1 G. R. Newkome, Chem. Rev., 1993, 93, 2067.
1
2
CCDC 1568321, 1568322, 1568324 and 1568325 contain the supple-
mentary crystallographic data for this paper. These data can be obtained
free of charge from The Cambridge Crystallographic Data Centre via
http://www.ccdc.cam.ac.uk.
2 Z. Z. Zhang and H. Cheng, Coord. Chem. Rev., 1996, 147, 1.
3 P. Espinet and K. Soulantica, Coord. Chem. Rev., 1999, 193–195, 499.
4
L. F. Szczepura, L. M. Witham and K. J. Takeuchi, Coord. Chem. Rev.,
998, 174, 5.
1
–
209 –

Mendeleev Commun., 2018, 28, 208–210
5
6
A.V.Artem’ev, N. K. Gusarova,V.A. Shagun, S. F. Malysheva,V. I. Smirnov
T. N. Borodina and B. A. Trofimov, Polyhedron, 2015, 90, 1.
,
17 D. L. Reger, J. D. Elgin, M. D. Smith, F. Grandjean, L. Rebbouh and
G. J. Long, Eur. J. Inorg. Chem., 2004, 3345.
A. V. Artem’ev, N. K. Gusarova, S. F. Malysheva, O. N. Kazheva,
G. G. Alexandrov, O. A. Dyachenko and B. A. Trofimov, Mendeleev
Commun., 2012, 22, 294.
A. V. Artem’ev, N. K. Gusarova, A. O. Sutyrina, Yu. V. Gatilov and
B. A. Trofimov, Mendeleev Commun., 2016, 26, 314.
A. V. Artem’ev, N. K. Gusarova, S. F. Malysheva, N. A. Belogorlova,
O. N. Kazheva, G. G. Alexandrov, O. A. Dyachenko and B. A. Trofimov,
Mendeleev Commun., 2015, 25, 196.
18 V. A. Kuimov, S. F. Malysheva, N. K. Gusarova, T. I. Vakul’skaya,
S. S. Khutsishvili and B. A. Trofimov, Heteroat. Chem., 2011, 22, 198.
19 S. F. Malysheva, A. V. Artem’ev, N. A. Belogorlova, A. O. Korocheva,
N. K. Gusarova and B. A. Trofimov, Russ. J. Gen. Chem., 2012, 82,
1307 (Zh. Obshch. Khim., 2012, 82, 1210).
20 A. N. Kharat, A. Bakhod, T. Hajiashrafi and A. Abbasi, Phosphorus
Sulfur Silicon Relat. Elem., 2010, 185, 2341.
21 E. S. Kucharski, W. R. McWhinnie and A. H. White, Aust. J. Chem.,
1978, 31, 53.
7
8
9
N. K. Gusarova, P.A.Volkov, N. I. Ivanova, K. O. Khrapova,A.A. Telezhkin
,
A. I. Albanov and B. A. Trofimov, Mendeleev Commun., 2017, 27, 553.
22 A. Santoro, C. Sambiagio, P. C. McGowan and M. A. Halcrow, Dalton
Trans., 2015, 44, 1060.
23 P. A. Anderson, T. Astley, M. A. Hitchman, F. R. Keene, B. Moubaraki,
K. S. Murray, B. W. Skelton, E. R. T. Tiekink, H. Toftlund andA. H. White,
J. Chem. Soc., Dalton Trans., 2000, 20, 3505.
24 C. J. Schneider, B. Moubaraki, J. D. Cashion, D. R. Turner, B. A. Leita,
S. R. Batten and K. S. Murray, Dalton Trans., 2011, 40, 6939.
25 Y. H. Lee, K. Kato, E. Kubota, S. Kawata, and S. Hayami, Chem. Lett.,
2012, 41, 620.
26 R. Ishikawa, K. Matsumoto, K. Onishi, T. Kubo, A. Fuyuhiro, S. Hayami,
K. Inoue, S. Kaizaki and S. Kawata, Chem. Lett., 2009, 38, 620.
1
0 B. A. Trofimov, A. V. Artem’ev, S. F. Malysheva, N. K. Gusarova,
N. A. Belogorlova, A. O. Korocheva, Y. V. Gatilov and V. I. Mamatyuk,
Tetrahedron Lett., 2012, 53, 2424.
1 T. Gneuß, M. J. Leitl, L. H. Finger, N. Rau, H.Yersin and J. Sundermeyer,
Dalton Trans., 2015, 44, 8506.
2 A. Bakhoda, N. Safari, V. Amani, H. R. Khavasic and M. Gheidi,
Polyhedron, 2011, 30, 2950.
3 C. Zheng, J. Xu, Z. Yang, J. Tao and D. Li, Inorg. Chem., 2015, 54,
1
1
1
1
1
9
687.
4 C. Zheng, J. Xu, F. Wang, J. Tao and D. Li, Dalton Trans., 2016, 45,
7254.
1
5 D. L. Reger, J. R. Gardinier, W. R. Gemmill, M. D. Smith, A. M. Shahin,
G. J. Long, L. Rebbouh and F. Grandjean, J. Am. Chem. Soc., 2005,
1
27, 2303.
1
6 D. L. Reger, J. R. Gardinier, M. D. Smith, A. M. Shahin, G. J. Long,
L. Rebbouh and F. Grandjean, Inorg. Chem., 2005, 44, 1852.
Received: 11th August 2017; Com. 17/5332
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