КООРДИНАЦИОННАЯ ХИМИЯ, 2015, том 41, № 3, с. 178-182
УДК 541.49
SYNTHESIS, STRUCTURES, AND BIOLOGICAL ACTIVITY OF TERBIUM(III) AND COBALT(III) COMPLEXES DERIVED FROM TRIPODAL SCHIFF BASES
© 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 August 8, 2014
Terbium(III) (I) and cobalt(III) (II) complexes derived from tripodal Schiff bases tris(2-((5-chlorosali-cylidene)amino)ethyl)amine (H3La) and tris(2-((4-methoxysalicylidene)amino)ethyl)amine (H3Lb), respectively, have been prepared and characterized by elemental analyses, IR, and single crystal X-ray crystal-lographic determination (CIF files CCDC nos. 1021371 (I) and 1021372 (II)). The crystal of [Tb(La)3] (I) is monoclinic: space group P2x/n, a = 12.689(1), b = 15.301(1), c = 15.099(1) А, в = 110.484(2)°, V = = 2746.2(4) А3, Z = 4, Rx = 0.0314, wR2 = 0.0801. The crystal of [Co(Lb)3)]2 • MeCN (II) is triclinic: space
group P1 , a = 12.3031(6), b = 13.7209(7), c = 17.884(1) А, a = 83.785(2)°, в = 88.144(2)°, у = 87.873(1)°, V= = 2998.0(3) А3, Z = 2, Rl = 0.0669, wR2 = 0.1538. The tripodal Schiff base ligands coordinate to the metal atoms through three phenolate O and three imine N atoms. The Tb atom in complex I is in a monocapped octahedral coordination, and the Co atom in complex II is in octahedral coordination. The effects of the complexes on the antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Candida albicans were studied.
DOI: 10.7868/S0132344X15030044
INTRODUCTION
Schiff bases bearing C=N double bonds are a kind of important ligands in coordination chemistry [1—3]. Metal complexes with Schiff bases have attracted considerable 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 have interesting biological activities [7—10]. Tripodal Schiff bases are interesting because of their special coordination sphere [11—13]. In the present paper, the preparation, characterization and antimicrobial activity of a new terbium(III) complex, [Tb(La)3] (I), and a new cobalt(III) complex, [Co(Lb)3)]2 • MeCN (II), where La and Lb are the deprotonated forms of tris(2-((5-cho-rosalicylidene)amino)ethyl)amine (H3La) and tris(2-((4-methoxysalicylidene)amino)ethyl)amine (H3Lb), respectively, are reported.
EXPERIMENTAL
Material and methods. 5-Chlorosalicylaldehyde, 4-methoxysalicylaldehyde and tris(2-aminoeth-yl)amine 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 spectrophotometer. X-ray diffraction was carried out on a Bruker SMART 1000 CCD area diffractometer.
Synthesis of [Tb(La)3] (I). 5-Chlorosalicylaldehyde (0.47 g, 3.0 mmol) and tris(2-aminoethyl)amine (0.15 g, 1.0 mmol) were reacted in methanol (30 mL) at ambient temperature for 30 min. Then, terbium(III) nitrate hexahydrate (0.45 g, 1.0 mmol) dissolved in methanol (10 mL) was added dropwise to the solution. The mixture was stirred at room temperature for 1 h to give yellow solution. The solution was allowed to slow evaporate in an uncapped vial. Several days later, block crystals of the complex were obtained. The yield was 28%.
For C27H24N4O3Cl3Tb
anal. calcd., %: C, 45.18; H, 3.37; N, 7.81. Found, % C, 44.97; H, 3.45; N, 7.72.
Selected IR data (v, cm-1): 1629 s, v(C=N).
Synthesis of [Co(Lb)3)]2 • MeCN (II). 4-Methoxy-salicylaldehyde (0.46 g, 3.0 mmol) and tris(2-amino-ethyl)amine (0.15 g, 1.0 mmol) were reacted in methanol (30 mL) at ambient temperature for 30 min. Then, cobalt(II) hexafluoroacetylacetonate (0.47 g, 1. 0 mmol) dissolved in methanol and acetonitrile (10 mL, V: V = 1 : 1) was added dropwise to the solution. The mixture was stirred at room temperature for 1 h to give brown solution. The solution was allowed to slow
Table 1. Crystallographic data and experimental details for I and II
Parameter Value
I II
Habit; color Block; yellow Block; brown
Formula weight 717.8 1250.1
Temperature, K 298(2) 298(2)
Crystal size, mm 0.21 x 0.19 x 0.17 0.25 x 0.23 x 0.20
Radiation (K, A) Moo (0.71073) Mo^a (0.71073)
Crystal system Monoclinic Triclinic
Space group P21/n PI
Unit cell dimensions:
a, A 12.689(1) 12.3031(6)
b, A 15.301(1) 13.7209(7)
c, A 15.099(1) 17.884(1)
a, deg 90 83.785(2)
ß, deg 110.484(2) 88.144(2)
Y, deg 90 87.873(1)
V, A3 2746.2(4) 2998.0(3)
Z 4 2
P calcd g cm-3 1.736 1.385
F(000) 1416 1308
Absorption coefficient, mm-1 2.904 0.623
9 Range for data collection, deg 2.88-25.50 2.19-25.09
Index ranges, h, k, l -15 < h < 15, -18 < k < 18, -18 < l< 18 -14 < h < 14, -15 < k < 16, -21 < l < 21
Reflections collected 24412 27788
Independent reflections (Rint) 5100 (0.0428) 10589 (0.0465)
Reflections with I > 2o(I) 4212 6452
Data/parameters 5100/343 10589/772
Restraints 0 0
Goodness-of-fit on F 2 1.075 1.025
Final R indices (I > 2a(I)) Ri = 0.0314, wR2 = 0.0801 R1 = 0.0669, wR2 = 0.1538
R indices (all data) R1 = 0.0414, wR2 = 0.0884 R1 = 0.1251, wR2 = 0.1844
Largest difference peak and hole, e A-3 0.628, -0.962 0.353, -0.535
evaporate in an uncapped vial. Several days later, block crystals ofthe complex were obtained. The yield was 36%.
For C62H69N9O12Co2
anal. calcd., %: C, 59.57; H, 5.56; N, 10.08. Found, %: C, 59.38; H, 5.67; N, 10.23.
Selected IR data (v, cm-1): 1623 s, v(C=N).
X-ray structure determination. Data were collected from selected crystals mounted on glass fibers. The data for the two complexes were processed with SAINT [14] and corrected for absorption using SADABS [15]. Multiscan absorption corrections were applied with
y-scans [16]. The structures were solved by direct methods using the program SHELXS-97 and refined by full-matrix least-squares techniques on F2 using anisotropic displacement parameters [17]. 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 given in Table 1. Selected bond distances and angles are listed in Table 2.
Supplementary material has been deposited with the Cambridge Crystallographic Data Centre
KOOP,3HHAUHOHHAH XHMH3 tom 41 № 3 2015
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HU et al.
Table 2. Selected bond distances (A) and angles (deg) for I and II
Bond
d, A
Bond
d, A
I
Tb(1)-O(1) Tb(1)-O(3) Tb(1)-N(2)
2.219(3) 2.208(3) 2.510(4)
Tb(1)-O(2) Tb(1)-N(1) Tb(1)-N(3)
2.206(3) 2.508(3) 2.495(3)
II
Co(1)- O(1) 1.886(3) Co(1)- O(5) 1.909(3)
Co(1)- O(3) 2.091(3) Co(1)- N(2) 2.042(3)
Co(1)- N(3) 2.340(4) Co(1)- N(4) 2.074(3)
Co(2)- O(7) 1.898(3) Co(2)- O(9) 1.981(3)
Co(2)- O(11) 1.991(3) Co(2)- N(6) 2.191(4)
Co(2)- -N(7) 2.194(4) Co(2)- N(8) 2.053(4)
Angle ro, deg Angle ro, deg
O(2)Tb(1)O(3) 87.87(12) O(2)Tb(1)O(1) 95.89(11)
O(3)Tb(1)O(1) 93.67(11) O(2)Tb(1)N(3) 160.17(11)
O(3)Tb(1)N(3) 72.82(11) O(1)Tb(1)N(3) 89.96(11)
O(2)Tb(1)N(1) 91.70(11) O(3)Tb(1)N(1) 165.89(12)
O(1)Tb(1)N(1) 72.33(11) N(3)Tb(1)N(1) 108.13(11)
O(2)Tb(1)N(2) 73.34(11) O(3)Tb(1)N(2) 87.09(12)
O(1)Tb(1)N(2) 169.18(12) N(3)Tb(1)N(2) 100.56(11)
N(1)Tb(1)N(2) 106.30(12) O(2)Tb(1)N(4) 124.30(10)
O(3)Tb(1)N(4) 124.91(10) O(1)Tb(1)N(4) 121.29(12)
N(3)Tb(1)N(4) 66.75(10) N(1)Tb(1)N(4) 66.32(10)
N(2)Tb(1)N(4) 66.12(12) II
O(1)Co(1)O(5) 89.06(12) O(1)Co(1)N(2) 169.24(13)
O(5)Co(1)N(2) 84.41(12) O(1)Co(1)N(4) 90.74(13)
O(5)Co(1)N(4) 173.91(13) N(2)Co(1)N(4) 96.66(13)
O(1)Co(1)O(3) 86.07(12) O(5)Co(1)O(3) 100.46(12)
N(2)Co(1)O(3) 86.72(13) N(4)Co(1)O(3) 85.60(13)
O(1)Co(1)N(3) 83.85(13) O(5)Co(1)N(3) 84.07(13)
N(2)Co(1)N(3) 103.90(14) N(4)Co(1)N(3) 89.86(13)
O(3)Co(1)N(3) 168.88(12) O(7)Co(2)O(9) 88.20(13)
O(7)Co(2)O(11) 92.43(13) O(9)Co(2)O(11) 91.74(13)
O(7)Co(2)N(8) 175.70(15) O(9)Co(2)N(8) 88.71(14)
O(11)Co(2)N(8) 84.68(13) O(7)Co(2)N(6) 82.35(13)
O(9)Co(2)N(6) 169.89(13) O(11)Co(2)N(6) 85.12(14)
N(8)Co(2)N(6) 100.53(15) O(7)Co(2)N(7) 87.05(15)
O(9)Co(2)N(7) 83.40(14) O(11)Co(2)N(7) 175.13(14)
N(8)Co(2)N(7) 95.56(15) N(6)Co(2)N(7) 99.60(15)
(nos. 1021371 (I) and 1021372 (II); deposit@ccdc.cam. ac.uk or http://www.ccdc.cam.ac.uk).
RESULTS AND DISCUSSION
The Schiffbases H3La and H3Lb were readily prepared by the condensation of1 : 3 molar ratio of tris(2-amino-ethyl)amine with 5-chlorosalicylaldehyde and 4-meth-oxysalicylaldehyde, respectively, at ambient temperature. The Schiff bases were not isolated and used directly to the synthesis of the complexes with metal salts. The complexes are very stable at room temperature in the solid state and soluble in common organic solvents, such as methanol, ethanol and acetonitrile. The results of the elemental analyses are in accord with the composition suggested for the complexes.
In order to compare the IR spectra of the complexes with the free Schiff bases, small quantities of H3La and H3Lb were prepared. The IR spectra of the Schiff bases contain strong C-O absorption bands in the region 1240-1255 cm-1. The bands disappeared on complexation, and new C-O absorption bands appeared in the region 1085-1112 cm-1 in the spectra of the complexes, indicating that the Schiff bases coordinate to the metal atoms through deprotonated form. The infrared spectra of complexes I and II display intense absorption bands at 1629 and 1623 cm-1, respectively, which can be assigned to the C=N stretching frequencies of the Schiff base ligands, whereas for the free Schiff bases the corresponding absorption bands are observed at higher wave numbers, 1630-1650 cm-1. The shift of these band
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