Two 3D Coordination Frameworks Based on Nanosized Huge Ln26

Publication Date (Web): April 30, 2010 .... Complexes: Comparing and Contrasting the Design, Synthesis, and Functionality of Metal–Organic Materials...
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DOI: 10.1021/cg9014064

Two 3D Coordination Frameworks Based on Nanosized Huge Ln26 (Ln = Dy and Gd) Spherical Clusters

2010, Vol. 10 2548–2552

Lian Huang,† Lijie Han,‡ Wenjun Feng,‡ Lei Zheng,† Zhibin Zhang,† Yan Xu,*,† Qi Chen,‡ Dunru Zhu,† and Shuyun Niu‡ †

State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing 210009, P. R. China, and ‡Institute of Chemistry for Functionalized Materials, College of Chemistry and Chemical Engineering, Liaoning Normal University, No. 850, Huanghe Road, Dalian, 116029, P. R. China Received November 10, 2009; Revised Manuscript Received April 16, 2010

ABSTRACT: Two novel three-dimensional (3D) coordination polymers Zn1.5Dy26(IN)25(CH3COO)8(CO3)11(OH)26(H2O)29 (1) and Zn1.5Gd26(IN)26(CH3COO)7(CO3)11(OH)26(H2O)28 (2) based on the linkages of large nanosized spherical hydroxo Ln26 clusters and zinc centers by organic ligands have been hydrothermally synthesized. Metal organic framework (MOF) 1 crystallizes in the triclinic space group P1, with a = 21.107(2) A˚, b = 21.185(2) A˚, c = 36.323(4) A˚, R = 89.001(2)°, β = 82.486(2)°, γ = 68.359(2)°, V = 14960(3) A˚3, Z = 2. MOF 2 crystallizes in the triclinic space group P1, a = 19.6213(15) A˚, b = 22.1850(17) A˚, c = 34.654(3) A˚, R = 88.5340(210)°, β = 85.6520(10)°, γ = 72.9790(19)° V = 14382.5(19) A˚3, Z = 2. Structural analysis indicates that both 3D polymers can be constructed using the building unit of CO3@Ln26 (Dy for 1, Gd for 2) and exhibit similar topological frameworks. During the synthesis, three ligands were used. CO32- plays a very important role in the formation of the spherical Ln26 cluster. CH3COO- makes the Ln26 cluster stable and reduces steric restriction. The isonicotinate (IN) stabilizes the cluster and links the clusters and the Zn centers.

Introduction The design and synthesis of nanosized clusters are of great interest due to their intriguing structural diversity and rich electronic, optical, catalytic, and magnetic properties associated with their size effects.1 Although the large M-O (transition metal-oxygen) cluster chemistry is well-established and many giant clusters of molybdenum,2 silver,3 manganese,4 copper,5 and nickel6 have been prepared successfully, the analogous lanthanides are much less developed,7-15 because of the difficulty to control the coordination for lanthanides. Compared with a number of huge transition metal clusters, only a few clusters such as [Ln7],8 [Ln8],9 [Ln10],10 [Ln12],11 [Ln14],12 [Ln15],13 [Ln20],14a [Ln26],15 and Er6014b in the either pure lanthanide-based clusters or mixed 3d-4f heterometallic systems have been reported. Therefore, the design of nanoscale high-nuclearity clusters for lanthanides is still challenging. One synthetic strategy used in the preparation of lanthanide clusters is to control the hydrolysis of lanthanide salts using supporting ligands. As the presence of hydrophobic groups on the surface of the cluster core prevents further connection, most of the huge hydroxo lanthanide clusters reported are discrete.7,8b In the past few years, a very important advance in lanthanide chemistry has been the study of the magnetic interactions within 3d-4f metals in the solid materials. Some mixed lanthanide/transition metals coordination polymers16 and clusters17 have been reported, in which the high-nuclearity lanthanide cluster cores of Dy4,18 Yb6,19 Ho7, Yb7,8a Dy14,12 and transition metal ions are connected by organic ligands. In general, the ligands coordinated to metal ions are favorable of the formation and stability of the metal clusters. More *To whom correspondence should be addressed. E-mail: yanxu@njut. edu.cn. pubs.acs.org/crystal

Published on Web 04/30/2010

recently, the preparation of [Er7(μ3-O)(μ3-OH)6(bdc)3](IN)9[Cu3X4] (X = Cl or Br, IN = isonicotinate)8b demonstrates that if a second ligand was introduced, the cooperativity of the two ligands could lead to a new lanthanide framework. Here we designed and synthesized two novel three-dimensional (3D) coordination polymers: Zn1.5Dy26(IN)25(CH3COO)8(CO3)11(OH)26(H2O)29 (1) and Zn1.5Gd26(IN)26(CH3COO)7(CO3)11(OH)26(H2O)28 (2), which are based on the linkages of large nanosized spherical hydroxo Ln26 clusters and Zn centers by organic ligands, and both metal organic frameworks (MOFs) keep a similar topological 3D framework. During the synthesis, three ligands were used: CO32- plays a very important role in constructing the spherical Ln26 cluster; CH3COO- makes the Ln26 cluster stable and reduces the steric restriction; isonicotinate (IN) stabilizes the cluster and links the nanosized Ln26 clusters and the Zn centers. Experimental Section General Remarks. All chemicals purchased were of reagent grade and used without further purification. The products were characterized by thermal analysis, single crystal X-ray diffraction (XRD), IR spectra, and optical properties. The C, H, and N elemental analyses were performed on a Perkin-Elmer 2400 CHN elemental analyzer. Infrared spectra were recorded with KBr pellets on a Nicolet 170SXFT/IR spectrometer. Synthesis of 1. A mixture of Dy2O3 (189 mg, 0.507 mmol), Zn(OAC)2 (30 mg, 0.229 mmol), isonicotinic acid (247 mg, 1.945 mmol), HCOOH (29 mg, 0.630 mmol), and H2O (8 mL) was stirred for 12 h in the air until all reagents dissolve, and then the pH of the solution was adjusted to 2 with HCl (36-38%). Finally, this solution was sealed in a 25 mL Teflon-lined autoclave and kept at 170 °C for seven days. Light-yellow block crystals of 1 were obtained (112 mg, yield of 30% based on Dy), which were washed with deionized water and dried at room temperature for 24 h. IR (cm-1): 3612 (s), 3409 (s), 1800(w), 1602(vs), 1550(vs), 1420(vs), 1222(w), 1060(w), 1003(w), 833(w), 771(s), 711(s), 680(s). Elemental r 2010 American Chemical Society

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Table 1. Crystal Data and Structure Refinements for 1 and 2a empirical formula fw T (K) λ (A˚) crystal system space group a (A˚) b (A˚) c (A˚) R (°) β (°) γ (°) V (A˚3) Z F(000) θ range limiting indices reflections collected/unique absorption coefficient R1 (I > 2σ(I)] wR2 (I > 2σ(I)]

2 Gd26C181H207N26O152Zn1.5 9365.28 150(2) 0.71073 triclinic P1 19.6213(15) 22.1850(17) 34.654(3) 88.5340(10) 85.6520(10) 72.9790(10) 14382.5(19) 2 8800 1.75-25.75° -23 eh e 23 -27 e k e 25 -42 e l e37 53790/38135 [R(int) = 0.0404] 6.122 mm-1 0.0665 0.1784

)

Note R1 = Σ Fo| - |Fc /Σ|Fo|; wR2 = Σ(w(Fo2 - Fc2)2]/Σ(w(Fo2)2]1/2. )

a

1 Dy26C177H208N25O154Zn1.5 9472.74 150(2) 0.71073 triclinic P1 21.107(2) 21.185(2) 36.323(4) 89.001(2) 82.486(2) 68.359(2) 14960(3) 2 8876 1.87-25.00° -25 e h e 15 -25 e k e 24 -43 e l e42 51400/31988 [R(int) = 0.0609] 6.616 mm-1 0.0670 0.1677

analysis calc.: C, 22.42, H, 2.20, N, 3.69%; found: C, 22.50, H, 2.25, N, 3.74%. Synthesis of 2. By replacing Dy2O3 with Gd2O3, colorless block crystals of 2 were prepared (120 mg, yield of 36% based on Gd). A mixture of Gd2O3 (181 mg, 0.499 mmol), Zn(OAC)2 (34 mg, 0.186 mmol), isonicotinic acid (236 mg, 1.858 mmol), HCOOH (31 mg, 0.674 mmol), and H2O (8 mL) was stirred for 12 h in the air until all reagents dissolve, and then the pH of the solution was adjusted to 2 with HCl (36-38%). Then, this solution was sealed in a 25 mL Teflon-lined autoclave and kept at 170 °C for seven days. Colorless block crystals of 2 were obtained, which were washed with deionized water and dried at room temperature for 24 h. IR (cm-1): 3615 (s), 3410 (s), 1802(w), 1604(vs), 1551(vs), 1416(vs), 1223(w), 1061(w), 1003(w), 863(w), 833(w), 770(s), 712(s), 679(s). Elemental analysis calc.: C, 23.19, H, 2.21, N, 3.89%; found: C, 23.26, H, 2.16, N, 3.82%. Single-Crystal X-ray Structure Determination. Single crystals of both compounds were carefully selected under a microscope and glued at the tip of a thin glass fiber with cynoacrylate adhesive. Both data were performed on a Bruker Apex2 CCD equipped with a normal focus at 150 K, sealed tube X-ray source (Mo-KR radiation, λ = 0.71073 A˚) operating at 50 kV and 30 mA. Both structures were solved by direct methods and refined by full-matrix leastsquares using the SHELX97 program package. All the metal atoms were refined anisotropically, while the remaining O, C, and N atoms of the organic ligands for both compounds were refined isotropically. The hydrogen atoms of the organic moieties were included in calculated positions, assigned isotropic displacement parameters, and allowed to ride on their parent atoms. However, H atoms for all water and OH- groups are not located. Some ligands in 2 are disordered; the occupancy factors for C12c, C13c, C14c, N27c, C16c, C14b, N27b, C12b, C13b, C14b, and C16b are 0.5. Crystallographic data and relevant information are presented in Table 1.

Results and Discussion Crystal Structure of 1. Compared with the reported discrete Ln26 cluster of [Dy26(OH)20(O)6(NO3)9I]36þ,15 we replaced NO3- by CO32- to reinforce the huge Dy26 cluster and introduced a third ligand CH3COO- to reduce the steric restriction. A 3D coordination polymer 1 based on the CO3@ Dy26 nanosized clusters was obtained. Since compound 1 crystallizes in the low-symmetry triclinic space

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group P1, the asymmetric unit of 1 consists of 26 Dy3þ ions, 2 Zn2þ cations, 25 IN- ligands, 8 CH3COO- ligands, 11 CO32- anions, 26 μ3-OH, and 26 water molecules. The single crystal X-ray structural analysis reveals that the structure of the 3D coordination polymer 1 is constructed from nanosized spherical Dy26 clusters and bridging Zn2þ centers. As reported in other lanthanides, there are two coordination models for Dy ions; that is, Dy(14), Dy(15), Dy(24), and Dy(26) ions are nine-coordinated, and the remaining Dy ions are eight-coordinated by μ3-OH, terminal water, and ligands including IN-, CH3COO-, and CO32-. Four DyOx polyhedra are connected to each other to form a Dy4 building unit by sharing four μ3-OH groups (Figure 1a), while three DyOx polyhedra share a μ3-OH to make another building unit of Dy3. Five Dy4 units are linked by six Dy3 rings to construct a Dy26 cage (Figure S1, Supporting Information), which is further connected by nine CO32- anions to generate a spherical cluster shell, while one free CO32- anion is cached, and located at the center of Dy26 cluster, as shown in Figure 2. The ligands IN-, CH3COO-, terminal water molecule, and one CO32- anion complete the coordination of Dy ions and make the CO3@Dy26 cluster stable. The diameter of the spherical cluster shell including organic ligands is about 2.1 nm. In the structure of 1, Zn(1) and Zn(2) are six and four coordinated, respectively [Zn(IN)2(H2O)4 for Zn(1), and Zn(IN)3(H2O) for Zn(2)]. As shown in Figure 3, octahedral coordinated Zn(1) is located at an inversion center, and acts as the bridge of two Dy26 clusters, while tetrahedral coordinated Zn(2) is located at a general position, and connects three Dy26 cores to form a 2D coordination layer parallel to the crystallographic [111] direction. Interestingly, along the [011] direction, the neighboring Dy26 clusters are bridged by [Zn(H2O)4(IN)2]2þ to constitute zigzag chains (Figure 4), which are very rare in the coordination polymers of lanthanides. Adjacent layers are connected to each other by other chains [-Dy26-IN]n (Figure 5) to form the 3D framework of 1 along the c axis. The 1D channels of framework 1 with dimensions of about 1.9  1.9 nm are occupied by coordination water, lattice water, and terminal ligands of IN- and CH3COO-. The cross section of the channel (Figure 6) shows a 72-membered ring (72MR) comprising 4 Zn, 8 N, 32 C, 16 O, and 12 Dy atoms. Although MOFs containing 18 MRs, 20 MRs, 24MRs, 30MRs, and 48 MRs are well documented, to the best of our knowledge, 72MRs have not been reported previously, which is bigger than any other reported coordination polymers for lanthanides. Crystal Structure of 2. When the Dy2O3 was replaced by Gd2O3, a similar topological 3D MOF of Zn15Gd26(IN)26(CH3COO)7(CO3)11(OH)26(H2O)28 (2) was obtained. Compared with the central cluster CO3@ Dy26 in 1, the nanosized cluster anion [Gd26(IN)26(CH3COO)7(CO3)11(OH)26(H2O)13]3consists of 26 Gd atoms, 11 CO32- anions, 26 IN- ligands, 7 CH3COO- anions, 26 μ3-OH, and 18 coordination water molecules, as shown in Figure 7. Four Dy atoms are ninecoordinated in 1, while six Gd atoms are nine-coordinated, including Gd(1), Gd(8), Gd(12), Gd(13), Gd(17), and Gd(19). Although nanosized Ln26 building units and the environments of bridging Zn2þ in both frameworks 1 and 2 are very similar, due to the differences in bond angles and coordination between Dy and Gd, the structure of framework 2 is slightly different from 1. First of all, no clear [-CO3@Gd26-Zn-]n zigzag chain is observed in 2 to compare with 1. Second, the dimensions of the 1D channel in framework

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Figure 1. The structures of building unit Dy4 (a) and Dy3 (b).

Figure 2. (a) The structure of the central core [CO3@Dy26(CO3)9(OH)26] in 1; (b) the building unit [Dy26(IN)25(CH3COO)8(CO3)11(OH)26(H2O)11]3-.

Figure 4. The structure of zigzag chain constructed by Dy26 and bridging Zn centers in 1.

Figure 3. The 2D coordination layer constructed by Dy26 clusters and Zn centers parallel to crystallographic [1 1 1] direction in 1.

2 are about 1.25  2.64 nm, which is much narrower, but longer than 1, as shown in Figure 8. The cross section of the nanotube in 2 includes 14 Gd atoms. It is worth noting that the a axis of 2 [19.6213(15) A˚] is shorter than that of 1 [21.107(2) A˚] while the b axis is longer. Optical Properties of 1 and 2. The excitation and emission spectra of pure 1 in the solid state at room temperature are

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Figure 5. The structure of linear chain constructed by Dy26 and bridging IN- in 1.

Figure 7. The building unit of [Gd26(IN)26(CH3COO)7(CO3)11(OH)26(H2O)13]3- in 2.

Figure 6. The cross section of the nanotube in 1, which shows a 72MR comprising 4 Zn, 8 N, 32 C, 16 O, and 12 Dy atoms.

shown in Figure S5, Supporting Information. The blue fluorescence for 1 can be observed, where the maximum emission wavelength is at 408 nm. Correspondingly, the peak with the maximum excited light at ca. 343 nm can be observed in the excitation spectra. The neutral ligand HIN displays a very weak emission at 431 nm in the UV region, corresponding to the excited light at 330 nm. The enhanced fluorescence efficiency of MOF 1 is attributed to the coordination of the IN- ligand to the Zn(II) and Dy(III) ions, which effectively increases the rigidity of the ligand and reduces the loss of energy by radiation thermal vibrations. The energy difference in Zn and Dy ions caused by the coordination environment makes the blue shift of the emission from UV light to the blue color region. As shown in Figure S6, Supporting Information, in the blue fluorescence of 2, the maximum emission is at 410 nm, while the maximum excited light at 353.5 nm was observed in the excitation spectra of 2. The fluorescence intensity of 2 is much stronger than 1, although both spectra were measured under the same conditions. It is because there are the more IN- ligands and connections of Gd-IN in 2 than those in 1. TG Analysis. Thermal analyses in Figure S3, Supporting Information presents that the total weight loss of compound 1 is 45.50% in the temperature range of 30-1100 °C, which is in agreement with the calculated value (47.09%). The weight loss of 2.40% in the range of 30-90 °C corresponds to the loss of the free H2O (the calculated value is 2.47%). The weight loss of 3.00% in the range of 91-150 °C can be attributed to the removal of coordinated H2O (calculated value is 3.06%). The weight loss of 40.00% in 151-1100 °C, which can be related with the loss of OH-, CH3COO-, IN-, and CO2 groups (calculated value is 41.96%).

Figure 8. The cross section of the nanotube in 2.

The total loss of compound 2 is 42.18% from 30 to 1100 °C (the calculated value is 48.51%). The first step loss (2.10%) in the range of 30-90 °C is attributed to the removal of free H2O (the calculated value is 1.92%). The second step loss of 3.30% (calculated: 3.46%) in the range of 91-200 °C is attributed to the loss of coordinated water. The last loss of 36.78% (calculated value is 43.13%) corresponds to the release of the OH- and the organic part including the CH3COO-, IN-, and CO2 from 201 to 1100 °C (Figure S4, Supporting Information). Conclusions In conclusion, we have successfully prepared two novel 3D coordination polymers constructed from large distinct nanosized spherical clusters CO3@ Ln26 and Zn centers using three kinds of ligands under hydrothermal conditions. The formation of both 1 and 2 demonstrates that replacing a part of bigger ligands by smaller ones can reduce the steric restriction and make it possible to obtain a 3D polymer made of very large lanthanide clusters. The linkages between nanosized Ln26@CO3 and Zn centers through IN- ligands result in two novel 3D open framework topologies. The preparation of 1 and 2 provides a perspective toward 3d-4f mixed solid state materials and demonstrates that it is possible to synthesize new structural functional materials using nanosized lanthanide clusters as building blocks.

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Acknowledgment. This work was supported by the National Natural Science Foundation of China (20771050, 20771059 and 20971068). Supporting Information Available: Crystallographic information files; the molecular structure of 1; the structure of Dy26 cage in 1; TG curves of 1 and 2; excitation and emission spectra of 1 and 2 in the solid state at room temperature; experimental and simulated XRD patterns for 1 and 2. This material is available free of charge via the Internet at http://pubs.acs.org.

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References (1) (a) Sessoli, R.; Gatteschi, D.; Caneschi, A.; Novak, M. A. Nature 1993, 365, 141. (b) Clusters and Colloids: From Theory to Applications; Schmidt, G., Ed.; Weinheim: VCH, 1994. (c) Gatteschi, D. Adv. Mater. 1994, 6, 635. (d) Physics and Chemistry of Metal Cluster Compounds; de Jongh, L. J., Ed.; Kluwer: Dordrecht, 1994. (e) Alivisatos, A. P. Science 1996, 271, 933. (2) (a) M€ uller, A.; Serain, C. Acc. Chem. Res. 2000, 33, 2. (b) Liu, T. B. Diemann, E.; Li, H. L.; Dress, A.W. M.; M€uller, A. Nature 2003, 426, 59. (3) Wang, X. J.; Langetepe, T.; Persau, C.; Kang, B. S.; Sheldrick, G. M.; Fenske, D. Angew. Chem., Int. Ed. 2002, 41, 3818. (4) Tasiopoulos, A. J.; Vinslava, A.; Wernsdorfer, W.; Abboud, K. A.; Christou, G. Angew. Chem., Int. Ed. 2004, 43, 2117. (5) Krautscheid, H.; Fenske, D.; Baum, G.; Semmelmann, M. Angew. Chem., Int. Ed. Engl. 1993, 32, 1303. (6) Fenske, D.; Ohmer, J.; Hachgenei, J. Angew. Chem., Int. Ed. Engl. 1985, 24, 993. (7) (a) Br€ ugstein, M. R.; Roesky, P. W. Angew. Chem., Int. Ed. 2000, 39, 549. (b) Zhang, D.-S.; Ma, B.-Q.; Jin, T.-Z.; Gao, S.; Yan, C.-H.; Mak, T. C.W. New J. Chem. 2000, 24, 61. (c) Wang, R.; Carducci, M. D.; Zheng, Z. Inorg. Chem. 2000, 39, 1836. (d) Wang, R.; Song, D.;

(12) (13) (14) (15) (16)

(17) (18) (19)

Wang, S. Chem. Commun. 2002, 368. (e) Br€ugstein, M. R.; Gamer, M. T.; Roesky, P. W. J. Am. Chem. Soc. 2004, 126, 5213. (a) Zheng, X.-J.; Jin, L.-P.; Gao, S. Inorg. Chem. 2004, 43, 1600. (b) Cheng, J.-W.; Zhang, J.; Zheng, S.-T.; Zhang, M.-B.; Yang, G.-Y. Angew. Chem., Int. Ed. 2006, 45, 73. (a) Xu, J.; Raymond, K. N. Angew. Chem., Int. Ed. 2000, 39, 2745. (b) Kajiwara, T.; Wu, H.; Ito, T.; Iki, N.; Miyano, S. Angew. Chem., Int. Ed. 2004, 43, 1832. (a) Westin, L. G.; Kritikos, M.; Caneschi, A. Chem. Commun. 2003, 1012. (b) Poncelet, O.; Hubert-Pfalzgraf, L. G.; Daran, J.-C.; Astier, R. J. Chem. Soc. Chem. Commun. 1989, 1846. (a) Wang, R.; Selby, H. D.; Liu, H.; Carducci, M. D.; Jin, T.; Zheng, Z.; Anthis, J. W.; Staples, R. J. Inorg. Chem. 2002, 41, 278. (b) Zheng, Z. Chem. Commun. 2001, 2521. Zhang, M.-B.; Zhang, J.; Zheng, S.-T; Yang, G.-Y. Angew. Chem., Int. Ed. 2005, 44, 1385. (a) Wang, R.; Zheng, Z.; Jin, T.; Staples, R. J. Angew. Chem., Int. Ed. 1999, 38, 1813. (b) Anwander, R. Angew. Chem., Int. Ed. 1998, 37, 599. (a) Kong, X.; Ren, Y.; Long, L.; Zheng, Z.; Huang, R.; Zheng, L. J. Am. Chem. Soc. 2007, 129, 7016. (b) Kong, X.; Wu, Y.; Long, L.; Zheng, L.; Zheng, Z. J. Am. Chem. Soc. 2009, 131, 6918. Gu, X.-j.; Xue, D.-f. Inorg. Chem. 2007, 46, 3212. (a) Zhao, B.; Cheng, P.; Dai, Y.; Cheng, C.; Liao, D.-Z.; Yan, S.-P.; Jiang, Z.- H.; Wang, G.-L. Angew. Chem., Int. Ed. 2003, 42, 934. (b) Figuerola, A.; Diaz, C.; El Fallah, M. S.; Ribas, J.; Maestro, M.; Mahia, J. Chem. Commun. 2001, 1204. (c) Deacon, G. B.; Forsyth, C. M.; Behrsing, T.; Konstas, K.; Forsyth, M. Chem. Commun. 2002, 2820. Chen, X.; Aubin, S. M. J.; Wu, Y.; Yang, Y.; Mak, T. C.W.; Hendrickson, D. N. J. Am. Chem. Soc. 1995, 117, 9600. Ma, B.; Zhang, D.; Gao, S.; Jin, T.; Yan, C.; Xu, G. Angew. Chem., Int. Ed. 2000, 39, 3644. Liu, J.; Meyers, E. A.; Shore, S. G. Inorg. Chem. 1998, 37, 5410.