КООРДИНАЦИОННАЯ ХИМИЯ, 2015, том 41, № 5, с. 283-287
УДК 541.49
SYNTHESIS, CHARACTERIZATION, AND CRYSTAL STRUCTURE OF A NOVEL CYANIDE-BRIDGED HETERONUCLEAR Co(III)-Mn(III) COMPLEX DERIVED FROM N,N'-ETHYLENE-ôw(CHLOROSALICYLIDENEIMINE)
© 2015 X. H. Shen*, Z. W. Zhang, L. J. Shao, Q. Lian, and C. Liu
Department of Chemistry, Hebei Normal University of Science & Technology, Qinhuangdao, 066600 P.R. China
*E-mail: xihai_shen@163.com Received October 18, 2014
With a bis-Schiff base N,N'-ethylene-bis(5-chlorosalicylideneimine) (H2L) and K3[Co(CN)6], a novel cyanide-bridged heteronuclear Co(III)—Mn(III) complex was prepared and characterized by elemental analysis, IR spectroscopy and X-ray structure determination (CIF file CCDC no. 1029225). The complex crystallizes in the monoclinic space group P2i/c with unit cell dimensions a = 10.741(2), b = 14.015(3), c = = 15.074(3) Â, в = 94.237(2)°, V = 2263.0(8) Â3, Z = 2, R1 = 0.0441, and wR2 = 0.0999. Single crystal X-ray diffraction analysis reveals that two [Mn(L)(OH2)]+ units are linked through a [Co(CN)6]3- bridge, forming a trinuclear Mn—Co—Mn moiety. The Mn—Co—Mn moieties are further linked through K atoms to form a 1D chain. The chains are stacked through interactions. The Mn and Co atoms are in octahedral coordination, and the K atom is in square planar geometry.
DOI: 10.7868/S0132344X15040076
INTRODUCTION
Cyanide-bridged complexes have been given much attention by coordination chemists and molecular magnetism chemists due to their versatile structures and interesting magnetic properties [1—5]. Cyanide salts such as KCN and NaCN are well known as potential bridging material [6—8]. However, they are very poisonous. The cyanide groups in K3[Fe(CN)6], K3[Co(CN)6] and similar compounds can also act as bridging groups to coordinate to other metals, generating homo- or heteronuclear polymeric structures [9—11]. ¿¿s-Schiff bases bearing NNOO donor set derived from ethane-1,2-diamine are preferred to construct complexes with various metal atoms [12—15]. In this paper, a novel cyanide-bridged heteronuclear Co(III)—Mn(III) complex derived from N,N-ethylene-te(5-chlorosalicylide-neimine) (H2L) was prepared.
EXPERIMENTAL
Materials and methods. 5-Chlorosalicylaldehyde and ethane-1,2-diamine were purchased from Ald-rich. Manganese perchlorate, K3[Co(CN)6] and solvents are commercially available and were used without further purification. N,N'-Ethylene-^/s(5-chloro-salicylideneimine) was prepared by condensation of 2 : 1 molar ratio of 5-chlorosalicylaldehyde with ethane-1,2-diamine in methanol [16]. Elemental analyses for carbon, hydrogen, and nitrogen were carried out with an Elementar Vario EL. Infrared spectra
were measured on KBr disks with a Hitachi I-5040 FT-IR spectrophotometer.
CAUTION: Perchlorate salts are potentially explosive and should only be handled in small quantities.
Synthesis ofthe complex. A methanol solution (10 mL) of manganese perchlorate hexahydrate (0.362 g, 1 mmol) was added to a methanol solution (10 mL) ofH2L (0.337 g, 1 mmol). The brown solution was stirred at 60°C for 1 h, and cooled to room temperature. K3[Co(CN)6] (0.332 g, 1 mmol) dissolved in 10 mL of water was poured into a glass tube and layered with 5 mL of methanol. Over this, the brown solution containing the Schiff base manganese complex was carefully layered to avoid fast mixing of the reactants. The tube was then sealed with Parafilm to avoid evaporation. After a week deep brown block-shaped single crystals were found at the bottom of the tube. The yield was 72% on the basis of the manganese precursor.
For C38H32N10O8Cl4KMn2Co
anal. calcd, %: C, 41.25; H, 2.92; N, 12.66. Found, %: C, 41.39; H, 3.01; N, 12.50.
IR (KBr; v, cm-1): 3646 v(O-H); 2140, 2125, 2116 v(CN); 1629 v(C=N).
X-ray structure determination. Data collection for the complex was performed with a Bruker Apex II CCD diffractometer at 298 K. The structure was solved by direct methods with SHELXS-97 and refined by full-matrix least squares (SHELXL-97) on F2 [17]. All non-hy-
Table 1. Crystallographic data and and structure refine- Centre (no. 1029225; deposit@ccdc.cam.ac.uk or ment for the complex http://www.ccdc.cam.ac.uk).
Parameter Value
Formula weight 1106.45
Crystal system Monoclinic
Space group P2x/c
a, Â 10.741(2)
b, Â 14.015(3)
c, Â 15.074(3)
ß, deg 94.237(2)
V, Â3 2263.0(8)
Z 2
Pcalcd g cm-3 1.624
/(000) 1116
p., mm-1 1.301
9 Range, deg 2.39-25.10
Index ranges hkl -12 < h < 12
-14 < k < 16
-17 < l < 17
Reflections collected/unique 19871/4002
Rint 0.0720
Observed with I > 2o(I) 2941
Parameters refined 298
Rastraints 4
Final R index (I > 2a(I)) 0.0441, 0.0999
R index (all data) 0.0715, 0.1115
Goodness-of-fit on F2 1.047
APmaxMPmm « Â~3 0.993/-0.409
drogens were refined anisotropically. The hydrogen atoms of O(3) water molecule were located from a difference Fourier map and refined isotropically with O—H and H—H distances restrained to 0.85(1) and 1.37(2) Â, respectively. The remaining hydrogens were placed geometrically and refined with a riding model, with isotropic displacement coefficients U(H) = 1.2 U(C). Crystallographic data for the complex are summarized in Table 1. Selected bond lengths and angles are listed in Table 2.
Supplementary material for complex has been deposited with the Cambridge Crystallographic Data
RESULTS AND DISCUSSION
The complex was prepared by slow diffusion of the Schiff base manganese complex with K3[Co(CN)6] in a glass tube. Crystals of I are stable in air, and soluble in methanol, ethanol, DMF and DMSO, insoluble in water. The cyanide-bridged heterometallic complex has been characterized by infrared spectroscopy. In the infrared spectrum, three sharp peaks due to the cyanide-stretching vibration were observed at 2140, 2125 and 2116 cm-1, indicating the presence of bridging and non-bridging cyanide ligands in the complex [18]. The intense band at 1629 cm-1 can be assigned to the vibration of the azomethine groups, v(CH=N) [19]. The weak and broad band centered at 3646 cm-1 is attributed to the vibration of the water molecules.
The repeat units of complex I is shown in Fig. 1. The complex crystallizes in monoclinic space group P21/c. Two [Mn(L)(OH2)]+ units are connected by two cyanide groups in a trans position of [Co(CN)6]3- ion to form a hetero trinuclear [Mn2(L)2(OH2)2Co(CN)6]-complex anion. The trinuclear complex anions are further linked by K+ ion to form an 1D chain along the x axis, as shown in Fig. 2. The chains are stacked through TC--TC interactions among the planes of Mn(1)-O(2)-C(12)-C(11)-C(10)-N(2), C(1)-C(2)-C(3)-C(4)-C(5)-C(6) and C(11)-C(12)-C(13)-C(14)-C(15)-C(16) with centroids to cen-troids distances of 3.74-4.82 A. The coordination sphere for the Mn atom is a distorted octahedral, in which four equatorial positions are occupied by two N atoms and two O atoms from the Schiff base ligand, and the other two axial ones come from the N atoms of the bridging cyanide group and the O atom of the coordinated water molecule. As shown in Table 1, the average distances between the Mn atom and the N, O atoms of the Schiff base ligand (1.982(3) and 1.867(2) A) are obviously shorter than the Mn-Ncyanide and Mn-Owater bond lengths with the values 2.333(3) and 2.267(3) A, which gives further information about the elongation octahedron surrounding the Mn3+ ion, typically accounting for the well-known Jahn-Teller effect. The Mn-N and Mn-O bond lengths are in good agreement with the manganese complexes with Ws-Schiff bases [20-22]. The bond angle of O(3)Mn(1)N(3), 171.8(1)° clearly indicates that the three atoms are in a linear configuration, while the angle of C(17)=N(3)-Mn(1) is much bent and deviates obviously from a linear configuration with the value of 144.3(3)°. The intramolecular Mn(III)-Mn(III) separation through bridging [Co(CN)6]3- is 10.22 A, and the intramolecular Mn(III)-Co(III) separation through bridging cyanide group is 5.11 A. The dihedral angle between the two benzene rings of the Schiff base
KOOP,3HHAUHOHHAH XHMH3 tom 41 № 5 2015
SYNTHESIS, CHARACTERIZATION, AND CRYSTAL STRUCTURE 285
Table 2. Selected bond distances (A) and angles (deg) for the complex
Bond d, Â Bond d, Â
K(1)—N(4) 2.774(4) K(1)-O(4) 2.863(5)
Mn(1)-O(1) 1.867(2) Mn(1)-O(2) 1.887(2)
Mn(1)-N(1) 1.982(3) Mn(1)-N(2) 1.986(3)
Mn(1)-O(3) 2.267(3) Mn(1)-N(3) 2.333(3)
Co(1)-C(18) 1.890(4) Co(1)-C(17) 1.900(4)
Co(1)-C(19) 1.911(4)
Angle ю, deg Angle ю, deg
N(4)K(1)O(4) 95.40(13) O(1)Mn(1)N(1) 92.58(11)
O(1)Mn(1)O(2) 92.45(10) O(1)Mn(1)N(2) 174.66(11)
O(2)Mn(1)N(1) 174.93(12) N(1)Mn(1)N(2) 82.64(12)
O(2)Mn(1)N(2) 92.32(11) O(2)Mn(1)O(3) 93.10(10)
O(1)Mn(1)O(3) 89.41(10) N(2)Mn(1)O(3) 87.93(10)
N(1)Mn(1)O(3) 86.30(11) O(2)Mn(1)N(3) 94.58(11)
O(1)Mn(1)N(3) 93.00(12) N(2)Mn(1)N(3) 89.01(12)
N(1)Mn(1)N(3) 85.81(12) C(17)Co(1)C(19) 89.64(15)
O(3)Mn(1)N(3) 171.84(11) C(18)Co(1)C(17) 90.00(14)
C(18)Co(1)C(19) 88.33(15)
Fig. 1. The repeated fragments of the complex with 30% probability thermal ellipsoids. КООРДИНАЦИОННАЯ ХИМИЯ том 41 № 5 2015
Fig. 2. Molecular packing structure of the complex, viewed along the y axis.
ligand is 7.7(3)°. In the [Co(CN)6]3- fragment, the Co atom is surrounded by six cyanide ligands, exhibiting an octahedral coordination geometry. The bond lengths of Co-C vary from 1.890(4) to 1.911(4) A. These Co-C bond lengths are in good agreement with the reported complexes bearing Co(CN)6 bridges [10, 23]. The K atom is coordinated by two cyanide N atoms and two water O atoms, forming a square planar geometry.
ACKNOWLEDGMENTS
This work was supported by the Hebei Normal University of Science & Technology.
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