УДК 541.49
A HETERO TRINUCLEAR MANGANESE(III)-IRON(II) COMPLEX DERIVED FROM N,N'-^/s(5-CHLOROSALICYLIDENE)-1,2-DIAMINOETHANE: SYNTHESIS, CRYSTAL STRUCTURE, AND ANTIMICROBIAL ACTIVITY
© 2015 X. M. Hu, L. W. Xue*, G. Q. Zhao, and W. C. Yang
College of Chemistry and Chemical Engineering, Pingdingshan University, Pingdingshan Henan, 467000 P.R. China
*E-mail: pdsuchemistry@163.com Received January 1, 2015
A new hetero trinuclear manganese(III)-iron(II) complex, [Mn(ClSalen)(H2O)]2[Fe(CN)5(NO)] • CH3OH • • H2O, where ClSalen is the dianionic form of N,N'-bis(5-chlorosalicylidene)-1,2-diaminoethane, has been prepared and characterized by elemental analyses, IR, and single crystal X-ray crystallographic determination (CIF file CCDC no. 1024666). The crystal of the complex is orthorhombic: space group Pca2b a = = 27.784(2), b = 10.8876(6), c = 15.1755(8) A, V = 4590.5(4) A3, Z = 2, R1 = 0.0596, wR2 = 0.1406. The bis-Schiff base ligand coordinates to the Mn atom through two phenolate O and two imine N atoms. Each Mn atom in the complex is in octahedral coordination, with the equatorial donor atoms come from the Schiff base ligand, and with the axial donor atoms come from a water O atom and a cyanide N atom. The effects of the complex on the antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Candida albi-cans were studied.
DOI: 10.7868/S0132344X15080010
INTRODUCTION
Schiff bases are a kind of important ligands in coordination chemistry [1—3]. In recent years, metal complexes of Schiff bases have attracted dramatically attention due to their versatile biological activity, such as antifungal, antibacterial and antitumor [4—6]. It has been shown that the Schiff base complexes derived from salicylaldehyde and its derivatives with primary amines, bearing the N2O, N2S, NO2 or NSO donor sets, have interesting biological activity [7—10]. In addition, the molecular design of extended structures starting from molecular precursors is of great interest. A preferred way to construct such materials is to use ionic building blocks in which one unit contains a potential bridging ligand and another contains a potential coordination site [11]. In the present paper, the preparation, characterization and antimicrobial activity of a new hetero trinuclear manganese(III)-iron(II) complex, [Mn(ClSalen)(H2O)]2[Fe(CN)5(NO)] • CH3OH • H2O, where ClSalen is the dianionic form ofN,N'-èis(5-chloro-salicylidene)-1,2-diaminoethane (H2ClSalen), is reported.
tometer. X-ray diffraction was carried out on a Bruker SMART 1000 CCD area dffractometer.
Synthesis of the complex. 5-Chlorosalicylaldehyde (0.312 g, 2 mmol) and ethane-1,2-diamine (0.060 g, 1 mmol) were reacted in methanol (30 mL) at ambient temperature for 1 h. To the mixture was added Mn(ClO4)2 • 6H2O (0.362 g, 1 mmol) with stirring for 30 min. Then, the methanol solution of the above brown solution was carefully layered on the top of an aqueous solution (5 mL) of Na2[Fe(CN)5(NO)] • 2H2O (0.298 g, 1 mmol) in a test tube. Deep brown single crystals of the complex, suitable for single crystal X-ray diffraction, were formed after a few days. The yield was 413 mg.
Selected IR data (v, cm-1): 2027 s, v(N3), 1632 s, v(C=N).
For C75H63N2oOi6ClsMn4Fe2
anal. calcd., %: Found, %:
C, 42.58; C, 42.31;
H, 3.00; H, 3.12;
N, 13.24. N, 13.39.
EXPERIMENTAL
Material and methods. 5-Chlorosalicylaldehyde and ethane-1,2-diamine were purchased from Fluka. Other reagents and solvents were analytical grade and used without further purification. Elemental (C, H, and N) analyses were made on a PerkinElmer Model 240B automatic analyser. Infrared (IR) spectra were recorded on an IR-408 Shimadzu 568 spectropho-
X-ray structure determination. Data were collected from a selected crystal mounted on a thin glass fiber. The data for the complex were processed with SAINT [12] and corrected for absorption using SADABS [13]. Multi-scan absorption corrections were applied with y-scans [14]. The structure was solved by direct method using the program SHELXS-97 and refined by full-matrix least-squares techniques on F2 using anisotropic displacement parameters [15]. The water and
Table 1. Crystallographic data and experimental details for the complex
Parameter Value
Habit; color Block; deep brown
Formula weight 2115.5
Temperature, K 298(2)
Crystal size, mm 0.23 x 0.21 x 0.17
Radiation (K, A) Moo (0.71073)
Crystal system Orthorhombic
Space group Pca21
Unit cell dimensions:
a, A 27.783(2)
b, A 10.8876(6)
c, A 15.1755(8)
V, A3 4590.5(4)
Z 2
Pcalcd g cm-3 1.530
F(000) 2138
Absorption coefficient, mm-1 1.146
9 Range for data collection, deg 2.38-25.06
Index ranges, h, k, l -30 < h < 33; -12 < k < 12; -18 < l< 18
Reflections collected 40274
Independent reflections (Rint) 8108 (0.0847)
Reflections with I > 2ct(T) 5531
Number of parameters 581
Restraints 4
Goodness-of-fit on F2 1.074
Final R indices (I > 2ct(I)) R1 = 0.0596, wR2 = 0.1406
R indices (all data) Rx = 0.1105, wR2 = 0.1649
Largest difference peak and hole, e A-3 0.874, -0.348
methanol hydrogen atoms 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) A, respectively. The remaining hydrogen atoms were placed at the calculated positions. Idealized H atoms were refined with isotropic displacement parameters set to 1.2 (1.5 for methyl groups) times the equivalent isotropic U values of the parent carbon atoms. The crystallographic data for the complexes are listed Table 1. Selected bond distances and angles are listed in Table 2.
Supplementary material has been deposited with the Cambridge Crystallographic Data Centre (no. 1024666; deposit@ccdc.cam.ac.uk or http://www.ccdc.cam.ac.uk).
RESULTS AND DISCUSSION
The Schiff base H2ClSalen was readily prepared by the condensation of 1 : 2 molar ratio of ethane-1,2-diamine with 5-chlorosalicylaldehyde in methanol at ambient temperature. The Schiff base was not isolated and used
directly to the synthesis of the complex with Na2[Fe(CN)5(NO)] • 2H2O. Crystals of the complex are very stable at room temperature. The results of the elemental analyses are in accord with the composition suggested for the complex.
In order to compare the IR spectrum of the complex with the free Schiff base, small quantity of H2ClSalen was prepared. The IR spectrum of the Schiff base contains medium C—O absorption band at 1243 cm-1. The band disappeared on complexation and new C-O absorption band appeared at 1093 cm-1 in the spectrum of the complex, indicating that the Schiff base coordinates to the metal atom through de-portonated form. The infrared spectrum of the complex displays intense absorption band at 1618 cm-1, which can be assigned to the C=N stretching frequencies of the Schiff base ligand, whereas for the free Schiff base the corresponding absorption band is observed at higher wave number, 1636 cm-1. The shift of
A HETERO TRINUCLEAR MANGANESE(III)-IRON(II) COMPLEX DERIVED 503
Table 2. Selected bond distances (A) and angles (deg) for the complex
Bond d, A Bond d, A
Fe(1)-N(7) 1.630(8) Fe(1)-C(36) 1.929(8)
Fe(1)-C(35) 1.930(7) Fe(1)-C(37) 1.939(8)
Fe(1)-C(33) 1.941(9) Fe(1)-C(38) 1.951(11)
Mn(1)-O(1) 1.867(5) Mn(1)-O(2) 1.885(5)
Mn(1)-N(2) 1.974(6) Mn(1)-N(1) 1.989(7)
Mn(1)-O(5) 2.238(5) Mn(1)-N(5) 2.326(8)
Mn(2)-O(4) 1.886(5) Mn(2)-O(3) 1.887(5)
Mn(2)-N(3) 1.973(6) Mn(2)-N(4) 1.974(6)
Mn(2)-O(6) 2.246(5) Mn(2)-N(6) 2.327(7)
Angle ro, deg Angle ro, deg
N(7)Fe(1)C(36) 95.9(3) N(7)Fe(1)C(35) 95.6(3)
C(36)Fe(1)C(35) 90.5(3) N(7)Fe(1)C(37) 93.6(3)
C(36)Fe(1)C(37) 89.9(3) C(35)Fe(1)C(37) 170.7(3)
N(7)Fe(1)C(33) 92.5(4) C(36)Fe(1)C(33) 171.5(4)
C(35)Fe(1)C(33) 88.8(3) C(37)Fe(1)C(33) 89.4(3)
N(7)Fe(1)C(38) 178.8(4) C(36)Fe(1)C(38) 83.3(3)
C(35)Fe(1)C(38) 85.4(3) C(37)Fe(1)C(38) 85.5(4)
C(33)Fe(1)C(38) 88.3(4) O(1)Mn(1)O(2) 92.5(2)
O(1)Mn(1)N(2) 174.7(3) O(2)Mn(1)N(2) 92.6(2)
O(1)Mn(1)N(1) 92.8(3) O(2)Mn(1)N(1) 174.7(3)
N(2)Mn(1)N(1) 82.1(3) O(1)Mn(1)O(5) 89.3(2)
O(2)Mn(1)O(5) 93.7(2) N(2)Mn(1)O(5) 89.2(2)
N(1)Mn(1)O(5) 85.7(2) O(1)Mn(1)N(5) 93.6(3)
O(2)Mn(1)N(5) 95.2(3) N(2)Mn(1)N(5) 87.2(3)
N(1)Mn(1)N(5) 85.2(3) O(5)Mn(1)N(5) 170.6(2)
O(4)Mn(2)O(3) 93.7(2) O(4)Mn(2)N(3) 174.5(3)
O(3)Mn(2)N(3) 91.9(2) O(4)Mn(2)N(4) 92.3(3)
O(3)Mn(2)N(4) 174.0(2) N(3)Mn(2)N(4) 82.1(3)
O(4)Mn(2)O(6) 89.2(2) O(3)Mn(2)O(6) 92.9(2)
N(3)Mn(2)O(6) 90.5(2) N(4)Mn(2)O(6) 86.9(2)
O(4)Mn(2)N(6) 92.9(2) O(3)Mn(2)N(6) 92.7(2)
N(3)Mn(2)N(6) 86.9(2) N(4)Mn(2)N(6) 87.3(3)
O(6)Mn(2)N(6) 173.9(2)
the band on complexation indicates coordination of the imine nitrogen to the metal center [16]. In the spectrum of the complex, strong bands observed at 2153 and 2127 cm-1 are assigned to the absorptions of the non-bridging and bridging cyanide groups [17]. The strong band observed at 1911 cm-1 is assigned to the absorption of the NO group.
The molecular structure of the complex is shown in Fig. 1. The complex is a cyanido-bridged heteronucle-ar manganese(III)-iron(II) species, with Mn-Fe separations of 5.15-5.18 A. In addition, there are one water molecule and one methanol molecule in the lattice
of the crystal. In the complex, the Mn atom is coordinated by two phenolate O and two imine N atoms of the Schiff base ligand, defining the equatorial plane, and by one water O atom and one cyanide N atom, occupying the two axial positions, generating an octahedral geometry. The two axial bonds are much longer than the basal bonds, which is caused by the JahnTeller effects. The bond distances subtended at the Mn atoms are comparable to those observed in similar man-ganese(III) complexes with Schiffbases [18-20]. The dihedral angles between the benzene rings C(1)-C(6) and C(11)-C(16), and C(17)-C(22) and C(27)-C(32) of
C(30)
' Cl(4) LC(31) "C(32)
Cl(2) C(15)
C(29) O(4) O(6)
Mn(2) O(3) C(19)
C(20) C(21)TC(22)
C(14) C(13)
C(12) O(2) Mn(1)
c(16>
C(27) XTnnC(3^)iC(11) r((2986r N(9>t C(3O3yqC(9^C(10:
f^^C(24))№ C(8
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