Synthesis, crystal structure, and magnetic property of a rarely seen μ1,1-OMe-bridged dimeric manganese(III) complex derived from 2-[1-(2-methylaminoethylimino)ethyl]phenol

Article abstract of DOI:10.1016/j.inoche.2012.01.034

A novel μ_1,1-OMe-bridged dimeric manganese(III) complex with the tridentate Schiff base ligand 2-[1-(2-methylaminoethylimino)ethyl]phenolate has been prepared and structurally characterized. The magnetic property of the complex shows the presen

Full text of DOI:10.1016/j.inoche.2012.01.034

Inorganic Chemistry Communications 19 (2012) 47–50
Contents lists available at SciVerse ScienceDirect
Inorganic Chemistry Communications
journal homepage: www.elsevier.com/locate/inoche
Synthesis, crystal structure, and magnetic property of a rarely seen
μ -OMe-bridged dimeric manganese(III) complex derived from
1,1
2
-[1-(2-methylaminoethylimino)ethyl]phenol
a,
b
a
a
a
a
Zhong-Lu You ⁎, Tao Liu , Na Zhang , Mei Zhang , Dong-Mei Xian , Hai-Hua Li
a
Department of Chemistry and Chemical Engineering, Liaoning Normal University, Dalian 116029, PR China
State Key Laboratory of Fine Chemistry, Dalian University of Technology, Dalian 116012, PR China
b
a r t i c l e i n f o
a b s t r a c t
Article history:
A novel μ1,1-OMe-bridged dimeric manganese(III) complex with the tridentate Schiff base ligand 2-[1-(2-
methylaminoethylimino)ethyl]phenolate has been prepared and structurally characterized. The magnetic
property of the complex shows the presence of ferromagnetic interaction mediated by double methoxy
bridges.
Received 1 January 2012
Accepted 28 January 2012
Available online 8 February 2012
©
2012 Elsevier B.V. All rights reserved.
Keywords:
Schiff base
Manganese complex
Crystal structure
Magnetic property
Considerable attention has been focused on the polynuclear man-
ganese complexes due to their wide applications in magnetic [1–4]
and catalytic fields [5–7]. The preferred way to construct polynuclear
crystallography [21] reveals that the complex is a similar μ1,1-OMe-
bridged centrosymmetric and dimeric compound. The inversion cen-
ter is located at the midpoint of the two Mn atoms. The Mn···Mn
distance is 3.236(1) Å. The Schiff base serves as a tridentate ligand
to form five- and six-membered chelate rings with Mn atom in the
complex. The coordination geometry around the metal center in the
complex can be best described as a distorted octahedron, with the
three donor atoms of the Schiff base ligand and one methoxy O
atom defining the equatorial plane, and with the symmetry-related
methoxy O atom and one thiocyanate N atom occupying the two
axial positions. The Mn atom in the complex lies 0.168(2) Å from
the least-squares plane defined by the equatorial donor atoms, in
the direction of the axial thiocyanate ligand.
–
–
complexes is the use of suitable bridging groups, such as N
3
, NCS ,
–
N(CN)
2
, dicarboxylate, 4,4′-bipy, etc. [8–10]. The methanol is a com-
mon used solvent for the preparation of complexes. In addition, the
methanol can also acts as coligand in the self-assembly of complexes
[11–13], however, the μ1,1-OMe-bridged complexes with transition
metal atoms are very rare. The mere examples of μ1,1-OMe-bridged
dinuclear manganese(III) complexes show interesting magnetic
properties [14,15]. Schiff bases bearing two or three donor atoms
are a kind of versatile ligands in the construction of polymeric struc-
tures of complexes [16,17]. During the search of literature, only one
μ
1,1-OMe-bridged manganese(III) complex with Schiff base ligand
was reported [18]. In this paper, a new μ1,1-OMe-bridged dimeric
manganese(III) complex, [Mn (μ1,1-OMe) (NCS) ], where L is the
deprotonated form of 2-[1-(2-methylaminoethylimino)ethyl]phenol
HL; Scheme 1), was prepared and structurally characterized. The
The four equatorial coordinate bond distances in the complex are
shorter than the two axial bonds, which are caused by the Jahn–Teller
effects. The bond distances and bond angles in the complex are typi-
cal, and are comparable to those observed in other similar mangane-
se(III) complexes with Schiff bases [22,23].
2
L
2
2
2
(
magnetic property of the complex was studied.
In the crystal structure of the complex, there forms four intermo-
lecular N–H···O hydrogen bonds in each dimer. The dimeric manga-
nese(III) complex molecules are stacked via weak π···π interactions
along the a axis with no other obvious short contacts, as shown in
Fig. 2.
The Schiff base ligand HL was prepared by the reaction of 2-
acetylphenol with N-methylethane-1,2-diamine in methanol [19].
The complex was readily prepared by the reaction of the Schiff base
ligand, ammonium thiocyanate, and manganese chloride in methanol
[
20]. The molecular structure of the complex is shown in Fig. 1. X-ray
In the i.r. spectra of the complex, the middle band centered at
−
1
3
135 cm
absorption band at 1620 cm
intense band indicative of the thiocyanate ligands is located at
is assigned to the vibration of the N–H groups. The strong
−
1
is assigned to the C=N groups. The
−
1
−1
2
044 cm . The weak bands in the region 300–600 cm
for the
⁎
Corresponding author.
E-mail address: youzhonglu@yahoo.com.cn (Z.-L. You).
complex may be assigned to the Mn–O and Mn–N vibrations.
1387-7003/$ – see front matter © 2012 Elsevier B.V. All rights reserved.
doi:10.1016/j.inoche.2012.01.034

48
Z.-L. You et al. / Inorganic Chemistry Communications 19 (2012) 47–50
3
−1
which gave a Curie constant of 6.97 cm mol
K and a Weiss
temperature of 10.9 K. The positive Weiss temperature confirms the
dominant intra-chain ferromagnetic interactions bridged via oxygen
atoms.
In summary, the present paper reports the synthesis, crystal struc-
ture, thermal stability and magnetic property of a novel μ1,1-OMe-
bridged centrosymmetric and dimeric manganese(III) complex with
tridentate Schiff base 2-[1-(2-methylaminoethylimino)ethyl]phenol.
The methanol solvates act as interesting bridging groups for the
self-assembly of the complex. The thermal stability of the complex
was studied, which agreed well with the component of the complex.
The magnetic property of the complex shows the presence of ferro-
magnetic interaction mediated by double methoxy bridges.
Scheme 1. The Schiff base HL.
Differential thermal (DT) and thermal gravimetric analyses (TGA)
were conducted to examine the stability of the complex (Fig. 3). The
first step started at about 168 °C and was completed at about 218 °C,
corresponding to the loss of the methoxy ligands. The observed
weight loss of 9.2% is equal to the calculated value. The second step,
from 259 °C to 479 °C, corresponds to the loss of the thiocyanate li-
gands. The observed weight loss of 17.7% is close to the calculated
value (17.3%). The third step, from 480 °C to 771 °C, corresponds to
the loss of the Schiff base ligands. The observed weight loss of 49.0%
is close to the calculated value (49.6%), and the formation of the
Acknowledgements
This work was financially supported by the Natural Science Foun-
dation of China (Project No. 20901036), and by the Distinguished
Young Scholars Program of Higher Education of Liaoning Province
(Grant No. LJQ2011114).
2 3
final product (Mn O ). The total weight loss of 77.8% is close to the
calculated value (76.1%).
The temperature dependence of the χT product and inverse
magnetic susceptibility (1/χ) for the complex at 1000 Oe in the
temperature range 2–300 K is shown in Fig. 4. The χT value of
Appendix A. Supplementary material
3
−1
7
.3 cm mol
K at 300 K, corresponding to the two isolated Mn(II)
of S=5/2 with significant orbital contribution. Upon cooling, the χT
Crystallographic data for the structural analysis has been deposited
with the Cambridge Crystallographic Data Centre (CCDC – 855110).
Copy of this information can be obtained free of charge from The Direc-
tor, CCDC, 12 Union Road, Cambridge CB2 1EZ, UK (fax: +44 1223 336
033; e-mail: deposit@ccdc.cam.ac.uk or www: http://www.ccdc.cam.
ac.uk).
3
−1
values gradually increased to a sharp maximum of 12.3 cm mol
K
around 9.8 K, and then dropped rapidly. This behavior of the complex
indicates predominant ferromagnetic interaction within the dinuc-
lear, and intercluster antiferromagnetic interactions. The magnetic
susceptibility data above 70 K were fitted by the Curie–Weiss law,
Fig. 1. A perspective view of the molecular structure of the complex with the atom labeling scheme. The thermal ellipsoids are drawn at the 30% probability level. Atoms labelled
with the suffix A or unlabelled are at the symmetry position 2 – x, – y, – z. Selected bond lengths (Å) and bond angles (°): Mn1-O1 1.865(2), Mn1-O2 1.882(2), Mn1-O2A 2.279(2),
Mn1-N1 2.017(3), Mn1-N2 2.069(3), Mn1-N3 2.200(3); O1-Mn1-O2 91.0(1), O1-Mn1-N1 91.1(1), O2-Mn1-N1 167.1(1), O1-Mn1-N2 171.6(1), O2-Mn1-N2 92.5(1), N1-Mn1-N2
8
8
3.8(1), O1-Mn1-N3 97.2(1), O2-Mn1-N3 100.2(1), N1-Mn1-N3 92.2(1), N2-Mn1-N3 89.7(1), O1-Mn1-O2A 91.6(1), O2-Mn1-O2A 78.4(1), N1-Mn1-O2A 88.9(1), N2-Mn1-O2A
1.7(1), N3-Mn1-O2A 171.2(1).

Z.-L. You et al. / Inorganic Chemistry Communications 19 (2012) 47–50
49
Fig. 2. Molecular packing of the complex, viewed along the a axis. Hydrogen bonds are shown as thin dashed lines.
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