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Syntheses, structures and urease inhibitory activities of mononuclear cobalt(III) and 1D cobalt(II) complexes with ligands derived from 3-formylsalicylic acid
Inorganic Chemistry Communications 12 (2009) 1116–1119
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Inorganic Chemistry Communications journal homepage: www.elsevier.com/locate/inoche
Syntheses, structures and urease inhibitory activities of mononuclear cobalt(III) and 1D cobalt(II) complexes with ligands derived from 3-formylsalicylic acid Kui Cheng, Qing-Zhong Zheng, Hai-Liang Zhu * State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing 210093, PR China
a r t i c l e
i n f o
Article history: Received 19 June 2009 Accepted 3 September 2009 Available online 9 September 2009 Keywords: Cobalt complexes Crystal structures Inhibitory activities Jack Bean Urease
a b s t r a c t h i [CoIII(L1)2] (NO3) 1, CoII3 ðL2Þ2 ðC5 H5 NÞ6 2ðClO4 Þ 2 (where L1 = (3-carboxysalicylidene)-(2-hydroxyamin noethylamine), L2 = (3-carboxysalicylidene)-phenylmethylamine) were synthesized and characterized by elemental analysis, single crystal X-ray diffraction and tested for inhibitive enzymatic activity on Jack Bean Urease(jbU). 1 is a mononuclear complex and the center cobalt atom is chelated by donors of N4O2 possessing a well defined octahedral configuration, and 2 contains two environmentally different cobalt centers, by the l2 carboxyl groups bridging the repeat units extending into a one-dimension configuration. Both of the mononuclear neutral molecules 1 and polymeric (1D chain) 2 are future connected via huge inter- and intra-molecular O-H O and C–H O bonds exhibiting a network structure. The enzymatic activity study indicated that the two complexes are showed potent inhibitions against jbU, with IC50 20.31 ± 0.53 lM of 1 and 22.24 ± 0.67 lM of 2, which are about 2 times more than 42.12 ± 0.08 lM of acetohydroxamic acid as positive reference. Ó 2009 Elsevier B.V. All rights reserved.
Salen-type ligands are one of the most important coordinating ligands systems [1], and Schiff base ligands derived from 3-formylsalicylic acid are belonging to this family [2]. Among this kind of Schiff base ligands, carboxylate, phenol-oxygen and amido group are all very good bridging groups. If there are vacant coordination sites around the metal ions and at the presence of these bridging groups, they can get saturated by self-assembly [2]. Frequently, such complexes have interesting single molecule magnets (SMMs) [3], magnetic and electronic properties or display unusual structural features [4–6]. Recently, Schiff base complexes were investigated as inhibitor in prostate cancer cells [7a], tumor cells [7b], and some of the salen-type Schiff base complexes were reported possess well inhibitory activities against xanthine oxidase and excellent antibacterial activities [7c,7d]. Compared to the magnetism, electronic, and catalysis of applications, the examples of biology activity study of complexes with coordinating ligands derived from 3-formylsalicylic acid have never been reported previously. In order to expending the application of the complexes, also the continue research of jbU inhibitor from Schiff base complexes [8], in this study, we presentation the synthesized and inhibitory activities of complexes derived from 3-formylsalicylic acid. 3-Formylsalicylic acid was prepared after the method of Duff and Bills [9]. HL1 and H2L2 (Scheme 1) are prepared by the condensation of 3-formylsalicylic acid with 2-hydroxyaminoethylamine * Corresponding author. Tel.: +86 25 8359 2672; fax: +86 25 8359 2572. E-mail address: [email protected] (H.-L. Zhu). 1387-7003/$ - see front matter Ó 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.inoche.2009.09.001
or phenylmethylamine (where L1 = (3-carboxysalicylidene)-(2hydroxyaminoethylamine), L2 = (3-carboxysalicylidene)-phenylmethylamine) [10]. In this work, 1 [CoIII(L1)2] (NO3), derived from HL1 (0.2 mmol, 50.6 mg) h with cobalt nitrate (0.1immol, 29.1 mg) in 10 ml methanol. 2, CoII3 ðL2Þ2 ðC5 H5 NÞ6 2ðClO4 Þ , was prepared n according the following procedure. Pyridine (1 ml) added after H2L2 (0.2 mmol, 51.3 mg) and cobalt perchlorate (0.1 mmol, 35.6 mg) mixed in 10 ml methanol in 15 min. X-ray quality black block-shaped single crystals were formed by slow evaporation of the solution in air for a few days. Yield: 88.3%, mp 278 °C for 1 and yield: 76.7%, mp 293 °C for 2 [11]. (Caution! Perchlorate salts are potentially explosive.) X-ray crystallography [12] reveals that 1 is a mononuclear structure (Fig. 1a), and 2 (Fig. 2a) contains two environmentally different cobalt centers, by the l2 carboxyl groups bridging the repeat units extending into a one-dimension configuration. The Xray crystal structure display that 1 is a slightly distorted octahedral (4 + 2) coordination geometry in which the N3O donors are bond to the metal atom in the basal plane and N2/O1 donors displays an axial-equatorial mode of bonding. The contribution of intermolecular O8–H8 O3ii lead to forming a one-dimensional chain along the c axis (Table 1 and Fig. 1b), which are future interdigitated by O4–H4 O11i, C9–H9B O9iv and C20–H20 O10iv (Fig. 1c) to form a network configuration. Fig. 2a gives a perspective view of the complex molecules in 2 together with the atomic labeling system. It is a polynuclear polymer including two different sixcoordinated cobalt (II) units, by the l2 carboxyl groups bridging the repeat units extending into a one-dimension chain, which are
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K. Cheng et al. / Inorganic Chemistry Communications 12 (2009) 1116–1119
N
HN
N
OH OH
OH HO
HO
O
HL1
O
H 2L2
Scheme 1. Schematic views of the Schiff bases.
future connect via intermolecular C8–H8 O4i/C19–H19–O7ii bond and C8–H8 O4i/C22–H22 O4iii exhibiting a 2D configuration (Table 1 and Fig. 2b). The smallest unit of 2 contains three cobalt (II) atoms, two tetradentate Schiff base ligands (L2), eight pyridine molecules and two perchlorate anions. The bond distances Co–O are relatively similar and range from 2.036(2) up to 2.076(2) Å. In the two complexes, the bond lengths of Co–N are from 1.901(2) Å for 1 to 2.058(2) Å for 2 (amine N atom). The bond lengths of Co–N (pyridine N atoms) are obviously longer than the Co–N (amine N atom). The slightly distortions of octahedral coordination are revealed by the bond angles between the apical and basal donor atoms. In 1, the bond angles N3–Co1–N4 and N3–
Fig. 1c. The hydrogen bond around the nitrate anions in 1.
Table 1 Hydrogen bond distances (Å) and bond angles (°) for 1and 2. D–H A
d(D–H)
d(H A)
d(D A)
Angle(D–H A)
O(2)–H(2) O(1) O(4)–H(4) O(11)i O(6)–H(6) O(5) O(8)–H(8) O(3)ii C(8)–H(8A) O(6)iii C(9)–H(9A) O(7)iii C(9)–H(9B) O(9)iv C(11)–H(11B) N(3) C(20)–H(20) O(10)iv C(23)–H(23A) N(1) C(23)–H(23B) O(1) 2 C(3)–H(3) O(1) C(8)–H(8) O(4)i C(8)–H(8) O(6)i C(19)–H(19) O(7)ii C(21)–H(21) O(1) C(22)–H(22) O(4)iii C(25)–H(25) O(1)iv
0.82 0.82 0.82 0.82 0.93 0.97 0.97 0.97 0.93 0.97 0.97
1.75 1.95 1.75 2.35 2.48 2.34 2.54 2.47 2.44 2.48 2.55
2.509(3) 2.753(6) 2.508(3) 3.125(4) 3.411(3) 3.278(4) 3.259(4) 3.087(4) 3.116(4) 3.004(4) 3.033(4)
152 167 152 157 175 162 131 122 130 114 111
0.93 0.93 0.93 0.93 0.93 0.93 0.93
2.38 2.56 2.59 2.52 2.50 2.49 2.49
2.709(4) 3.326(5) 3.500(7) 3.230(7) 3.111(4) 3.194(5) 3.054(4)
100 140 166 133 123 133 120
Symmetry transformations used to generate equivalent atoms for 1:(i) x,1/2y,1/ 2+z, (ii) x,3/2y,1/2+z, (iii) x,1/2+y,1/2z, (iv) 1x,1/2+y,1/2z; 2: (i) 1x,1y,z, (ii) x,y,1z, (iii) 1+x, y, z, (iv) 1x, 1y, 1z.
Fig. 1a. Molecular structure of 1. Displacement ellipsoids are drawn at the 30% probability level. Selected bond lengths (Å) and bond angles (°): Co1–O1 1.9051(2), Co1–O5 1.8999(2), Co1–N1 1.9001(2), Co1–N2 1.985(2), Co1–N3 1.8967(2), Co1–N4 1.989(2), O1–Co1–N1 93.34(8), O1–Co1–N3 86.55(8), N1–Co1–O5 87.20(8), N3– Co1–O5 93.41(8), N2–Co1–N1 85.91(9), N2–Co1–N3 94.23(9), O1–Co1–O5 89.82(8), N2–Co1–O5 88.06(8), N4–Co1–N1 93.72(9), N4–Co1–N2 93.10(9), N4– Co1–N3 85.66(9), N4–Co1–O1 89.03(9), N4–Co1–O5 178.56(8), N2–Co1–O1 177.78(8), N1–Co1–N3 179.38(9).
Co1–N2 deviate from 90° by 4.30(1)° and 4.23(9)°, respectively. And in 2, the greatest deviation of the bond angles from those of an ideal geometry is found for O3A–Co2–O3 with 81.45(8)° and O2–Co2–N2 with 101.96(9)°. All the other bond angles are close to the ideal values of 90° or 180°. For the equatorial ligands in these polyhedral, the average deviations from their least-squares planes were calculated to be only
Fig. 1b. The line configuration 1 along the c axis.
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Fig. 2a. Molecular structure of 2. Displacement ellipsoids are drawn at the 30% probability level and H atoms are omitted for clarity. Selected bond lengths (Å) and bond angles (°): Co1–O1 2.064(2), Co1–N2 2.219(3), Co1–N3 2.218(3), Co2–O2 2.036(2), Co2–N1 2.058(2), Co2–N5 2.217(3), Co2–O2 2.036(2), Co2–O4 2.095(3), Co2–O3 2.076(2), Co2–N4 2.334(3), Co2–Co2A 3.145(3), O1–Co1–O1A 180.00(1), O1–Co1–N3 91.22(9), O1A–Co1–N3 88.78(9), O1–Co1–N3A 88.78(9), O1A–Co1–N3A 91.22(9), N3–Co1–N3A 180.00(1), O1–Co1–N2 94.76(9), O1A–Co1–N2 85.24(9), N3–Co1–N2 93.78(10), N3A–Co1–N2 86.22(10), O1–Co1–N2A 85.24(9), O1A–Co1–N2A 94.76(9), N3–Co1–N2A 86.22(10), N3A–Co1–N2A 93.78(10), N2–Co1–N2A 180.00(1), O2–Co2–N1 101.96(9), O2–Co2–O3A 87.45(8), N1–Co2–O3A 169.50(9), O2–Co2–O3 168.76(8), N1–Co2–O3 88.98(9), O3A–Co2–O3 81.45(8), O2–Co2–N5 90.46(9), N1–Co2–N5 90.80(10), O3A–Co2–N5 93.80(9), O3–Co2–N5 92.00(9), O2–Co2––N4 84.89(9), N1–Co2–N4 86.82(10), O3A–Co2–N4 89.42(9), O3–Co2–N4 93.22(9), N5–Co2–N4 174.23(10).
Table 2 Inhibition of urease by complexes, ligands and metal ions.
a
Fig. 2b. Via C–HO bond form a 2D configuration along the ac plane in 2. Pyridine molecules around Co2/Co2A and benzene ring of phenylmethylamine are omitted for clarity.
0.0082(5) Å for Co1 in 1 and 0.0477(3) Å for Co2 in 2, indicating the high planarity of each unit. In 2, the four-member bridging rings Co2–O3–Co2A–O3A is coplanar with Co2Co2A separation 3.145(3) Å. The chelate ring formed by the atoms Co2, N1, C8, C6, C7 and O2 has a boat conformation. The diagonally positioned atoms, Co2 and C6, are shifted from the least-squares plane (defined by the atoms O3, C7, C8, and N1) by 0.247(3) and 0.045(4) Å, respectively. The measurement of urease inhibitory activities was carried out according to the literature reported by Toru Tanaka [13]. Generally, the assay mixture, containing 25 lL of Jack Bean Urease (10 kU/L) and 25 lL of the tested complexes of various concentrations (dissolved in the solution of DMSO: H2O = 1:1 (v/v)), was preincubated for 1 h at 37 °C in a 96-well assay plate. Then 0.2 mL of 100 mM Hepes(N-[2-hydroxyethyl]piperazine-N-[2-ethanesulfonic acid]) buffer at pH 6.8 [14] containing 500 mM urea and 0.002% phenol red were added and incubated at 37 °C. The reaction time, which was required to produce enough ammonium carbonate to raise the pH of a Hepes buffer from 6.8 to 7.7, was measured by microplate reader (570 nm) with the end-point being determined by the color of phenol red indicator. jbU inhibitory activity was expressed
Tested materials
IC50a (lM)
1 2 HL1 H2L2 Cobalt nitrate Cobalt perchlorate Acetohydroxamic acid
20.31 ± 0.53 22.24 ± 0.67 >100 >100 >100 >100 42.12 ± 0.08
All IC50 values were expressed as means ±S.D. values of the three parallel tests.
as the percentage inhibition of jbU in the above assay mixture system or as the concentration that results in half-maximal enzyme velocity (IC50) when the active >50% inhibition at 50 lg/mL. The results concerning the inhibition of the complexes, their corresponding ligands (HL1 and H2L2) and control ions (cobalt (II) nitrate, cobalt (II) perchlorate) on jbU were summarized in Table 2. The research result demonstrate that both of the two complexes showed higher inhibitory activity against urease than that of the corresponding ligands and the cobalt salts, with IC50 20.31 ± 0.53 lM of 1 and 22.24 ± 0.67 lM of 2, and about 2 times higher than 42.12 ± 0.08 lM of acetohydroxamic acid co-assayed as a positive reference against the enzyme. The urease inhibitory activity of the two complexes are also higher than the other cobalt (II) complexes [8c,15], indicating the cobalt complexes with ligands derived from 3-formylsalicylic acid have better inhibitory activity than the cobalt complexes derived from salicylaldehyde. The reason is not very clear at present. As structure considered, 3-formylsalicylic acid has one more carboxyl group than salicylaldehyde. This group gives more chance to the formation of inter- and intra-molecular O–H O and C–H O bonds and may provide more chance to integration with jbU. We also found that the category of the metal ions have a essential influence on jbU inhibitory activity, and the cobalt(II/III) complexes is not as active as Cu(II), Ni(II) or Mn(II) complexes [8b,8d]. In summary, in this study, the synthesis, structures and inhibitory activity against jbU of the two octahedral cobalt (II/III) complexes derived from 3-formylsalicylic acid are presented. We have found the inhibitory activity is increasing when the ligands coordinated with the cobalt ions. The jbU inhibitory activity depends on the category of the metal ions and the kind of ligands. According the research results, we observed that the more the hydrogen bonds and active groups in complex, such as hydroxyl and carboxyl groups, the higher the jbU inhibitory activity is.
K. Cheng et al. / Inorganic Chemistry Communications 12 (2009) 1116–1119
Acknowledgments The authors thank the National Natural Science Foundation of PR China, for Research Grant No. 30772627 and Anhui Provincial Natural Science Foundation of PR China, with Grant No. 070416274X. Appendix A. Supplementary material CCDC 748343 and 748344 contains the supplementary crystallographic data for this paper. These data can be obtained free of charge from The Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif. Supplementary data associated with this article can be found, in the online version, at doi:10.1016/j.inoche.2009.09.001. References [1] P.G. Cozzi, Chem. Soc. Rev. 33 (2004) 410. [2] A. Erxleben, Inorg. Chem. 40 (2001) 208. [3] (a) S. Osa, T. Kido, N. Matsumoto, N. Re, A. Pochaba, J. Mrozinski, J. Am. Chem. Soc. 126 (2004) 420; (b) T. Kido, Y. Ikuta, Y. Sunatsuki, Y. Ogawa, N. Matsumoto, Inorg. Chem. 42 (2003) 398. [4] R.J. Tao, F.A. Li, S.Q. Zang, Y.X. Cheng, Q.L. Wang, J.Y. Niu, D.Z. Liao, Polyhedron 25 (2006) 2153. [5] S. Akine, A. Akimoto, T. Shiga, H. Oshio, T. Nabeshima, Inorg. Chem. 47 (2008) 875. [6] F. Tuna, L. Patron, Y. Journaux, M. Andruh, W. Plass, J.C. Trombe, J. Chem. Soc. Dalton Trans. (1999) 539.
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[7] (a) S. Adsule, V. Barve, D. Chen, F. Ahmed, Q.-P. Dou, S. Padhye, F.H. Sarkar, J. Med. Chem. 49 (2006) 7242; (b) V. Barve, F. Ahmed, S. Adsule, S. Banerjee, S. Kulkarni, P. Katiyar, C.E. Anson, A.K. Powell, S. Padhye, F.H. Sarkar, J. Med. Chem. 49 (2006) 3800; (c) Z.L. You, D.H. Shi, C. Xu, Q. Zhang, H.L. Zhu, Eur. J. Med. Chem. 43 (2008) 862; (d) L. Shi, R.F. Fang, J.Y. Xue, Z.P. Xiao, S.H. Tan, H.L. Zhu, Aust. J. Chem. 61 (2008) 288. [8] (a) K. Cheng, Z.L. You, H.L. Zhu, Aust. J. Chem. 60 (2007) 375; (b) Z.-L. You, D.-H. Shi, H.-L. Zhu, Inorg. Chem. Commun. 9 (2006) 642; (c) D.H. Shi, Z.L. You, C. Xu, Q. Zhang, H.L. Zhu, Inorg. Chem. Commun. 10 (2007) 404; (d) Y.G. Li, D.H. Shi, H.L. Zhu, H. Yan, S.W. Ng, Inorg. Chim. Acta. 360 (2007) 2881. [9] J.C. Duff, E.J. Bills, J. Chem. Soc. (1932) 1987. [10] Anal. Calc. for C12H16N2O4 (HL1): C, 55.9; H, 6.3; N, 10.9%. Found: C, 56.1; H, 6.4; N, 11.1%. Anal. Calc. for C15H13NO3: C, 70.4; H, 4.9; N, 5.4%. Found: C, 70.6; H, 5.1; N, 5.5%. Selected IR data (KBr, cm–1): HL1, m 1653 (s, C@N); HL2, m 1637 (s, C@N). [11] Anal. Calc. for C24H30N5CoO11 (1): C, 46.0; H, 4.7; N, 11.1%. Found: C, 46.2; H, 4.9; N, 11.2%. Anal. Calc. for C70H62N10Co3Cl2O14 (2): C, 55.4; H, 3.9; N, 9.0%. Found: C, 55.5; H, 4.1; N, 9.2%. [12] Crystal data for 1 (C24H30N5CoO11): Mt = 623.46, monoclinic, space group P21/ c, a = 16.3208(2), b = 9.6618(1), c = 17.1750(2) Å, b = 95.18(2)°, V = 2697.2 (5) Å3, Z = 4, qcalcd = 1.535 g cm–3, l(Mo Ka) = 0.706 mm–1, R1 = 0.0483, wR2 = 0.1389 (all data), T = 298 K. Crystal data for 2 (C70H62N10Co3Cl2O14): Mt = 1514.99, triclinic, space group P 1, a = 11.2732(1), b = 11.4640(1), c = 13.6745(2) Å, a = 83.41(2), b = 76.08(2), c = 89.74(2)°, V = 1703.5(3) Å3, Z = 1, qcalcd = 1.477 g cm–3, l(Mo Ka) = 0.874 mm–1, R1 = 0.0488, wR2 = 0.1313 (all data), T = 298 K. [13] T. Tanaka, M. Kawase, S. Tani, Life Sci. 73 (2003) 2985. [14] W. Zaborska, B. Krajewska, Z. Olech, J. Enzyme Inhib. Med. Chem. 19 (2004) 65. [15] Z.-L. You, P. Zhou, Inorg. Chem. Commun. 10 (2007) 1273.
Contents lists available at ScienceDirect
Inorganic Chemistry Communications journal homepage: www.elsevier.com/locate/inoche
Syntheses, structures and urease inhibitory activities of mononuclear cobalt(III) and 1D cobalt(II) complexes with ligands derived from 3-formylsalicylic acid Kui Cheng, Qing-Zhong Zheng, Hai-Liang Zhu * State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing 210093, PR China
a r t i c l e
i n f o
Article history: Received 19 June 2009 Accepted 3 September 2009 Available online 9 September 2009 Keywords: Cobalt complexes Crystal structures Inhibitory activities Jack Bean Urease
a b s t r a c t h i [CoIII(L1)2] (NO3) 1, CoII3 ðL2Þ2 ðC5 H5 NÞ6 2ðClO4 Þ 2 (where L1 = (3-carboxysalicylidene)-(2-hydroxyamin noethylamine), L2 = (3-carboxysalicylidene)-phenylmethylamine) were synthesized and characterized by elemental analysis, single crystal X-ray diffraction and tested for inhibitive enzymatic activity on Jack Bean Urease(jbU). 1 is a mononuclear complex and the center cobalt atom is chelated by donors of N4O2 possessing a well defined octahedral configuration, and 2 contains two environmentally different cobalt centers, by the l2 carboxyl groups bridging the repeat units extending into a one-dimension configuration. Both of the mononuclear neutral molecules 1 and polymeric (1D chain) 2 are future connected via huge inter- and intra-molecular O-H O and C–H O bonds exhibiting a network structure. The enzymatic activity study indicated that the two complexes are showed potent inhibitions against jbU, with IC50 20.31 ± 0.53 lM of 1 and 22.24 ± 0.67 lM of 2, which are about 2 times more than 42.12 ± 0.08 lM of acetohydroxamic acid as positive reference. Ó 2009 Elsevier B.V. All rights reserved.
Salen-type ligands are one of the most important coordinating ligands systems [1], and Schiff base ligands derived from 3-formylsalicylic acid are belonging to this family [2]. Among this kind of Schiff base ligands, carboxylate, phenol-oxygen and amido group are all very good bridging groups. If there are vacant coordination sites around the metal ions and at the presence of these bridging groups, they can get saturated by self-assembly [2]. Frequently, such complexes have interesting single molecule magnets (SMMs) [3], magnetic and electronic properties or display unusual structural features [4–6]. Recently, Schiff base complexes were investigated as inhibitor in prostate cancer cells [7a], tumor cells [7b], and some of the salen-type Schiff base complexes were reported possess well inhibitory activities against xanthine oxidase and excellent antibacterial activities [7c,7d]. Compared to the magnetism, electronic, and catalysis of applications, the examples of biology activity study of complexes with coordinating ligands derived from 3-formylsalicylic acid have never been reported previously. In order to expending the application of the complexes, also the continue research of jbU inhibitor from Schiff base complexes [8], in this study, we presentation the synthesized and inhibitory activities of complexes derived from 3-formylsalicylic acid. 3-Formylsalicylic acid was prepared after the method of Duff and Bills [9]. HL1 and H2L2 (Scheme 1) are prepared by the condensation of 3-formylsalicylic acid with 2-hydroxyaminoethylamine * Corresponding author. Tel.: +86 25 8359 2672; fax: +86 25 8359 2572. E-mail address: [email protected] (H.-L. Zhu). 1387-7003/$ - see front matter Ó 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.inoche.2009.09.001
or phenylmethylamine (where L1 = (3-carboxysalicylidene)-(2hydroxyaminoethylamine), L2 = (3-carboxysalicylidene)-phenylmethylamine) [10]. In this work, 1 [CoIII(L1)2] (NO3), derived from HL1 (0.2 mmol, 50.6 mg) h with cobalt nitrate (0.1immol, 29.1 mg) in 10 ml methanol. 2, CoII3 ðL2Þ2 ðC5 H5 NÞ6 2ðClO4 Þ , was prepared n according the following procedure. Pyridine (1 ml) added after H2L2 (0.2 mmol, 51.3 mg) and cobalt perchlorate (0.1 mmol, 35.6 mg) mixed in 10 ml methanol in 15 min. X-ray quality black block-shaped single crystals were formed by slow evaporation of the solution in air for a few days. Yield: 88.3%, mp 278 °C for 1 and yield: 76.7%, mp 293 °C for 2 [11]. (Caution! Perchlorate salts are potentially explosive.) X-ray crystallography [12] reveals that 1 is a mononuclear structure (Fig. 1a), and 2 (Fig. 2a) contains two environmentally different cobalt centers, by the l2 carboxyl groups bridging the repeat units extending into a one-dimension configuration. The Xray crystal structure display that 1 is a slightly distorted octahedral (4 + 2) coordination geometry in which the N3O donors are bond to the metal atom in the basal plane and N2/O1 donors displays an axial-equatorial mode of bonding. The contribution of intermolecular O8–H8 O3ii lead to forming a one-dimensional chain along the c axis (Table 1 and Fig. 1b), which are future interdigitated by O4–H4 O11i, C9–H9B O9iv and C20–H20 O10iv (Fig. 1c) to form a network configuration. Fig. 2a gives a perspective view of the complex molecules in 2 together with the atomic labeling system. It is a polynuclear polymer including two different sixcoordinated cobalt (II) units, by the l2 carboxyl groups bridging the repeat units extending into a one-dimension chain, which are
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K. Cheng et al. / Inorganic Chemistry Communications 12 (2009) 1116–1119
N
HN
N
OH OH
OH HO
HO
O
HL1
O
H 2L2
Scheme 1. Schematic views of the Schiff bases.
future connect via intermolecular C8–H8 O4i/C19–H19–O7ii bond and C8–H8 O4i/C22–H22 O4iii exhibiting a 2D configuration (Table 1 and Fig. 2b). The smallest unit of 2 contains three cobalt (II) atoms, two tetradentate Schiff base ligands (L2), eight pyridine molecules and two perchlorate anions. The bond distances Co–O are relatively similar and range from 2.036(2) up to 2.076(2) Å. In the two complexes, the bond lengths of Co–N are from 1.901(2) Å for 1 to 2.058(2) Å for 2 (amine N atom). The bond lengths of Co–N (pyridine N atoms) are obviously longer than the Co–N (amine N atom). The slightly distortions of octahedral coordination are revealed by the bond angles between the apical and basal donor atoms. In 1, the bond angles N3–Co1–N4 and N3–
Fig. 1c. The hydrogen bond around the nitrate anions in 1.
Table 1 Hydrogen bond distances (Å) and bond angles (°) for 1and 2. D–H A
d(D–H)
d(H A)
d(D A)
Angle(D–H A)
O(2)–H(2) O(1) O(4)–H(4) O(11)i O(6)–H(6) O(5) O(8)–H(8) O(3)ii C(8)–H(8A) O(6)iii C(9)–H(9A) O(7)iii C(9)–H(9B) O(9)iv C(11)–H(11B) N(3) C(20)–H(20) O(10)iv C(23)–H(23A) N(1) C(23)–H(23B) O(1) 2 C(3)–H(3) O(1) C(8)–H(8) O(4)i C(8)–H(8) O(6)i C(19)–H(19) O(7)ii C(21)–H(21) O(1) C(22)–H(22) O(4)iii C(25)–H(25) O(1)iv
0.82 0.82 0.82 0.82 0.93 0.97 0.97 0.97 0.93 0.97 0.97
1.75 1.95 1.75 2.35 2.48 2.34 2.54 2.47 2.44 2.48 2.55
2.509(3) 2.753(6) 2.508(3) 3.125(4) 3.411(3) 3.278(4) 3.259(4) 3.087(4) 3.116(4) 3.004(4) 3.033(4)
152 167 152 157 175 162 131 122 130 114 111
0.93 0.93 0.93 0.93 0.93 0.93 0.93
2.38 2.56 2.59 2.52 2.50 2.49 2.49
2.709(4) 3.326(5) 3.500(7) 3.230(7) 3.111(4) 3.194(5) 3.054(4)
100 140 166 133 123 133 120
Symmetry transformations used to generate equivalent atoms for 1:(i) x,1/2y,1/ 2+z, (ii) x,3/2y,1/2+z, (iii) x,1/2+y,1/2z, (iv) 1x,1/2+y,1/2z; 2: (i) 1x,1y,z, (ii) x,y,1z, (iii) 1+x, y, z, (iv) 1x, 1y, 1z.
Fig. 1a. Molecular structure of 1. Displacement ellipsoids are drawn at the 30% probability level. Selected bond lengths (Å) and bond angles (°): Co1–O1 1.9051(2), Co1–O5 1.8999(2), Co1–N1 1.9001(2), Co1–N2 1.985(2), Co1–N3 1.8967(2), Co1–N4 1.989(2), O1–Co1–N1 93.34(8), O1–Co1–N3 86.55(8), N1–Co1–O5 87.20(8), N3– Co1–O5 93.41(8), N2–Co1–N1 85.91(9), N2–Co1–N3 94.23(9), O1–Co1–O5 89.82(8), N2–Co1–O5 88.06(8), N4–Co1–N1 93.72(9), N4–Co1–N2 93.10(9), N4– Co1–N3 85.66(9), N4–Co1–O1 89.03(9), N4–Co1–O5 178.56(8), N2–Co1–O1 177.78(8), N1–Co1–N3 179.38(9).
Co1–N2 deviate from 90° by 4.30(1)° and 4.23(9)°, respectively. And in 2, the greatest deviation of the bond angles from those of an ideal geometry is found for O3A–Co2–O3 with 81.45(8)° and O2–Co2–N2 with 101.96(9)°. All the other bond angles are close to the ideal values of 90° or 180°. For the equatorial ligands in these polyhedral, the average deviations from their least-squares planes were calculated to be only
Fig. 1b. The line configuration 1 along the c axis.
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K. Cheng et al. / Inorganic Chemistry Communications 12 (2009) 1116–1119
Fig. 2a. Molecular structure of 2. Displacement ellipsoids are drawn at the 30% probability level and H atoms are omitted for clarity. Selected bond lengths (Å) and bond angles (°): Co1–O1 2.064(2), Co1–N2 2.219(3), Co1–N3 2.218(3), Co2–O2 2.036(2), Co2–N1 2.058(2), Co2–N5 2.217(3), Co2–O2 2.036(2), Co2–O4 2.095(3), Co2–O3 2.076(2), Co2–N4 2.334(3), Co2–Co2A 3.145(3), O1–Co1–O1A 180.00(1), O1–Co1–N3 91.22(9), O1A–Co1–N3 88.78(9), O1–Co1–N3A 88.78(9), O1A–Co1–N3A 91.22(9), N3–Co1–N3A 180.00(1), O1–Co1–N2 94.76(9), O1A–Co1–N2 85.24(9), N3–Co1–N2 93.78(10), N3A–Co1–N2 86.22(10), O1–Co1–N2A 85.24(9), O1A–Co1–N2A 94.76(9), N3–Co1–N2A 86.22(10), N3A–Co1–N2A 93.78(10), N2–Co1–N2A 180.00(1), O2–Co2–N1 101.96(9), O2–Co2–O3A 87.45(8), N1–Co2–O3A 169.50(9), O2–Co2–O3 168.76(8), N1–Co2–O3 88.98(9), O3A–Co2–O3 81.45(8), O2–Co2–N5 90.46(9), N1–Co2–N5 90.80(10), O3A–Co2–N5 93.80(9), O3–Co2–N5 92.00(9), O2–Co2––N4 84.89(9), N1–Co2–N4 86.82(10), O3A–Co2–N4 89.42(9), O3–Co2–N4 93.22(9), N5–Co2–N4 174.23(10).
Table 2 Inhibition of urease by complexes, ligands and metal ions.
a
Fig. 2b. Via C–HO bond form a 2D configuration along the ac plane in 2. Pyridine molecules around Co2/Co2A and benzene ring of phenylmethylamine are omitted for clarity.
0.0082(5) Å for Co1 in 1 and 0.0477(3) Å for Co2 in 2, indicating the high planarity of each unit. In 2, the four-member bridging rings Co2–O3–Co2A–O3A is coplanar with Co2Co2A separation 3.145(3) Å. The chelate ring formed by the atoms Co2, N1, C8, C6, C7 and O2 has a boat conformation. The diagonally positioned atoms, Co2 and C6, are shifted from the least-squares plane (defined by the atoms O3, C7, C8, and N1) by 0.247(3) and 0.045(4) Å, respectively. The measurement of urease inhibitory activities was carried out according to the literature reported by Toru Tanaka [13]. Generally, the assay mixture, containing 25 lL of Jack Bean Urease (10 kU/L) and 25 lL of the tested complexes of various concentrations (dissolved in the solution of DMSO: H2O = 1:1 (v/v)), was preincubated for 1 h at 37 °C in a 96-well assay plate. Then 0.2 mL of 100 mM Hepes(N-[2-hydroxyethyl]piperazine-N-[2-ethanesulfonic acid]) buffer at pH 6.8 [14] containing 500 mM urea and 0.002% phenol red were added and incubated at 37 °C. The reaction time, which was required to produce enough ammonium carbonate to raise the pH of a Hepes buffer from 6.8 to 7.7, was measured by microplate reader (570 nm) with the end-point being determined by the color of phenol red indicator. jbU inhibitory activity was expressed
Tested materials
IC50a (lM)
1 2 HL1 H2L2 Cobalt nitrate Cobalt perchlorate Acetohydroxamic acid
20.31 ± 0.53 22.24 ± 0.67 >100 >100 >100 >100 42.12 ± 0.08
All IC50 values were expressed as means ±S.D. values of the three parallel tests.
as the percentage inhibition of jbU in the above assay mixture system or as the concentration that results in half-maximal enzyme velocity (IC50) when the active >50% inhibition at 50 lg/mL. The results concerning the inhibition of the complexes, their corresponding ligands (HL1 and H2L2) and control ions (cobalt (II) nitrate, cobalt (II) perchlorate) on jbU were summarized in Table 2. The research result demonstrate that both of the two complexes showed higher inhibitory activity against urease than that of the corresponding ligands and the cobalt salts, with IC50 20.31 ± 0.53 lM of 1 and 22.24 ± 0.67 lM of 2, and about 2 times higher than 42.12 ± 0.08 lM of acetohydroxamic acid co-assayed as a positive reference against the enzyme. The urease inhibitory activity of the two complexes are also higher than the other cobalt (II) complexes [8c,15], indicating the cobalt complexes with ligands derived from 3-formylsalicylic acid have better inhibitory activity than the cobalt complexes derived from salicylaldehyde. The reason is not very clear at present. As structure considered, 3-formylsalicylic acid has one more carboxyl group than salicylaldehyde. This group gives more chance to the formation of inter- and intra-molecular O–H O and C–H O bonds and may provide more chance to integration with jbU. We also found that the category of the metal ions have a essential influence on jbU inhibitory activity, and the cobalt(II/III) complexes is not as active as Cu(II), Ni(II) or Mn(II) complexes [8b,8d]. In summary, in this study, the synthesis, structures and inhibitory activity against jbU of the two octahedral cobalt (II/III) complexes derived from 3-formylsalicylic acid are presented. We have found the inhibitory activity is increasing when the ligands coordinated with the cobalt ions. The jbU inhibitory activity depends on the category of the metal ions and the kind of ligands. According the research results, we observed that the more the hydrogen bonds and active groups in complex, such as hydroxyl and carboxyl groups, the higher the jbU inhibitory activity is.
K. Cheng et al. / Inorganic Chemistry Communications 12 (2009) 1116–1119
Acknowledgments The authors thank the National Natural Science Foundation of PR China, for Research Grant No. 30772627 and Anhui Provincial Natural Science Foundation of PR China, with Grant No. 070416274X. Appendix A. Supplementary material CCDC 748343 and 748344 contains the supplementary crystallographic data for this paper. These data can be obtained free of charge from The Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif. Supplementary data associated with this article can be found, in the online version, at doi:10.1016/j.inoche.2009.09.001. References [1] P.G. Cozzi, Chem. Soc. Rev. 33 (2004) 410. [2] A. Erxleben, Inorg. Chem. 40 (2001) 208. [3] (a) S. Osa, T. Kido, N. Matsumoto, N. Re, A. Pochaba, J. Mrozinski, J. Am. Chem. Soc. 126 (2004) 420; (b) T. Kido, Y. Ikuta, Y. Sunatsuki, Y. Ogawa, N. Matsumoto, Inorg. Chem. 42 (2003) 398. [4] R.J. Tao, F.A. Li, S.Q. Zang, Y.X. Cheng, Q.L. Wang, J.Y. Niu, D.Z. Liao, Polyhedron 25 (2006) 2153. [5] S. Akine, A. Akimoto, T. Shiga, H. Oshio, T. Nabeshima, Inorg. Chem. 47 (2008) 875. [6] F. Tuna, L. Patron, Y. Journaux, M. Andruh, W. Plass, J.C. Trombe, J. Chem. Soc. Dalton Trans. (1999) 539.
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[7] (a) S. Adsule, V. Barve, D. Chen, F. Ahmed, Q.-P. Dou, S. Padhye, F.H. Sarkar, J. Med. Chem. 49 (2006) 7242; (b) V. Barve, F. Ahmed, S. Adsule, S. Banerjee, S. Kulkarni, P. Katiyar, C.E. Anson, A.K. Powell, S. Padhye, F.H. Sarkar, J. Med. Chem. 49 (2006) 3800; (c) Z.L. You, D.H. Shi, C. Xu, Q. Zhang, H.L. Zhu, Eur. J. Med. Chem. 43 (2008) 862; (d) L. Shi, R.F. Fang, J.Y. Xue, Z.P. Xiao, S.H. Tan, H.L. Zhu, Aust. J. Chem. 61 (2008) 288. [8] (a) K. Cheng, Z.L. You, H.L. Zhu, Aust. J. Chem. 60 (2007) 375; (b) Z.-L. You, D.-H. Shi, H.-L. Zhu, Inorg. Chem. Commun. 9 (2006) 642; (c) D.H. Shi, Z.L. You, C. Xu, Q. Zhang, H.L. Zhu, Inorg. Chem. Commun. 10 (2007) 404; (d) Y.G. Li, D.H. Shi, H.L. Zhu, H. Yan, S.W. Ng, Inorg. Chim. Acta. 360 (2007) 2881. [9] J.C. Duff, E.J. Bills, J. Chem. Soc. (1932) 1987. [10] Anal. Calc. for C12H16N2O4 (HL1): C, 55.9; H, 6.3; N, 10.9%. Found: C, 56.1; H, 6.4; N, 11.1%. Anal. Calc. for C15H13NO3: C, 70.4; H, 4.9; N, 5.4%. Found: C, 70.6; H, 5.1; N, 5.5%. Selected IR data (KBr, cm–1): HL1, m 1653 (s, C@N); HL2, m 1637 (s, C@N). [11] Anal. Calc. for C24H30N5CoO11 (1): C, 46.0; H, 4.7; N, 11.1%. Found: C, 46.2; H, 4.9; N, 11.2%. Anal. Calc. for C70H62N10Co3Cl2O14 (2): C, 55.4; H, 3.9; N, 9.0%. Found: C, 55.5; H, 4.1; N, 9.2%. [12] Crystal data for 1 (C24H30N5CoO11): Mt = 623.46, monoclinic, space group P21/ c, a = 16.3208(2), b = 9.6618(1), c = 17.1750(2) Å, b = 95.18(2)°, V = 2697.2 (5) Å3, Z = 4, qcalcd = 1.535 g cm–3, l(Mo Ka) = 0.706 mm–1, R1 = 0.0483, wR2 = 0.1389 (all data), T = 298 K. Crystal data for 2 (C70H62N10Co3Cl2O14): Mt = 1514.99, triclinic, space group P 1, a = 11.2732(1), b = 11.4640(1), c = 13.6745(2) Å, a = 83.41(2), b = 76.08(2), c = 89.74(2)°, V = 1703.5(3) Å3, Z = 1, qcalcd = 1.477 g cm–3, l(Mo Ka) = 0.874 mm–1, R1 = 0.0488, wR2 = 0.1313 (all data), T = 298 K. [13] T. Tanaka, M. Kawase, S. Tani, Life Sci. 73 (2003) 2985. [14] W. Zaborska, B. Krajewska, Z. Olech, J. Enzyme Inhib. Med. Chem. 19 (2004) 65. [15] Z.-L. You, P. Zhou, Inorg. Chem. Commun. 10 (2007) 1273.