Solvothermal synthesis, structure and properties of a new 3-D Cu(I)–Gd(III) heterometallic coordination framework

Inorganic Chemistry Communications 14 (2011) 944–947

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Inorganic Chemistry Communications j o u r n a l h o m e p a g e : w w w. e l s ev i e r. c o m / l o c a t e / i n o c h e

Solvothermal synthesis, structure and properties of a new 3-D Cu(I)–Gd(III) heterometallic coordination framework Man-Sheng Chen ⁎, Yi-Fang Deng, Chun-Hua Zhang ⁎, Dai-Zhi Kuang, Xue Nie, Yang Liu Department of Chemistry and Materials Science, Hengyang Normal University, Hengyang 421008, China

a r t i c l e

i n f o

Article history: Received 11 January 2011 Accepted 14 March 2011 Available online 22 March 2011 Keywords: Heterometallic complex Metal-organic framework Solvothermal reaction Magnetism

a b s t r a c t A new 3d–4f heterometallic coordination polymer, [CuGd2(INAIP)3(HCOO)(H2O)3]·3H2O (1), [H2INAIP = 5(isonicotinamido)isophthalic acid] has been synthesized and characterized by single crystal X-ray diffraction analysis. The results of structural analyses show that 1 has a two-fold interpenetrated 3D coordination framework with a rare sqc27 topology. In addition, thermogravimetric and magnetic properties were also investigated. © 2011 Elsevier B.V. All rights reserved.

In recent years, the rational design and synthesis of higherdimensional transition -lanthanide metal (d–f) heterometallic networks have attracted increasing attention, which is justified not only by the fascinating structural diversity of the architectures but also by the potential applications of these complexes as important functional solid materials in magnetism, luminescent materials, molecular adsorption, and semiconductors [1–4]. Furthermore, the useful way to synthesize of the heterometallic complexes is the assembly from the mixed metal ions and logic multidentate organic ligands. In general, the multidentate ligands containing both N- and O-donor atoms are usually employed in the construction of 3d–4f heterometallic structures, in keeping with the typical coordination behaviors of lanthanide and transition metal ions under different reaction conditions [5–7]. Compared with those N-heterocyclic acids such as nicotinic acid, pyridine-2,6-dicarboxylic acid and isonicotinic acid, 5(isonicotinamido)isophthalic acid (H2INAIP) can also show richer coordination modes due to its two carboxylate groups and one pyridyl group, accordingly, it is an excellent candidate for the construction of metal organic frameworks [8]. In this paper, we choose it as a logic bridging ligand and report on the synthesis, crystal structure and magnetic properties of a novel 3d–4f heterometallic coordination polymer, [CuGd2(INAIP)3(HCOO)(H2O)3]·3H2O (1) [9]. The formate anion is derived from the hydrolyzed N,N-dimethylformamide (DMF) molecules. Complex 1 crystallizes in the triclinic space group P1 [10]. X-ray diffraction analysis reveals that it is a two-fold interpenetrated 3D heterometallic coordination polymer. As illustrated in Fig. 1a, there is

⁎ Corresponding authors. Tel.: + 86 734 8486797; fax: + 86 734 8484911. E-mail address: [email protected] (C.-H. Zhang). 1387-7003/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.inoche.2011.03.038

one Cu(I) atom, two unique Gd(III) atoms, three INAIP2− ligands, one formate anion, three coordinated and three lattice water molecules in the asymmetric unit of 1. Both Gd(III) atoms are eight-coordinated in distorted bicapped trigonal prismatic arrangement with different coordinated environment. Namely, Gd(1) is eight coordinated with six carboxylate groups O atoms (O10, O11, O15, O16, O17A and O18B) from three different INAIP2− ligands and two O atoms (O2W, O3W) from two water molecules, while Gd(2) is eight coordinated with seven carboxylate groups O atoms (O2, O8, O9, O3C, O4D, O5D and O6) from three different INAIP2− ligands and one formate, the other O atom is (O1W) from one water molecule. The coordination bond lengths and angles around the Gd(III) atom are in the range of 2.280 (6)–2.583(5) Å and 52.7(2)–156.8(2) º, respectively, as listed in Table S1. If the coordination interactions between the carboxylate group and Cu(I) are omitted, the Cu center has a distorted linear coordination environment made up of two N atoms from two bridging INAIP ligands with the average Cu–N bond lengths of 1.909 (6) Å, which is similar to that in such reported complex as [Ln2(bdc)2 (ina)2(H2O)2CuI·Cl] [11]. It is noteworthy that three unique INAIP2− ligands exhibit two coordination modes as depicted in Scheme 1, namely one ligand coordinate to three Gd(III) atoms using its two carboxylate groups in μ2–η1:η1-bismonodentate and μ1–η1:η1-chelate modes and one Cu(I) atom through its pyridyl nitrogen atom, the other ligand only coordinate to two Gd(III) atoms using its two carboxylate groups in the μ1–η1:η1-chelate mode with free coordination of the pyridyl group, which is different from the complexes [LnAg (INAIP)2]·3H2O [8b]. If the coordination interactions between the Cu– N and Cu–O are neglected, the neighboring binuclear subunits are connected via the INAIP2− ligands to form a two-dimensional (2D) layer network lying in the ac plane (Fig. S1). Such 2D nets are further connected together via the Cu–N coordination interactions between

M.-S. Chen et al. / Inorganic Chemistry Communications 14 (2011) 944–947

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Cu N

O

N

NH O

O

NH

O

Gd

O

O

O

O

Gd

Gd

Gd

O

O

Gd

Scheme 1. Coordination modes of INAIP2− ligand observed in complex 1.

Fig. 1. (a) ORTEP drawing of 1 with 30% thermal ellipsoids. Lattice water molecule and hydrogen atoms are omitted for clarity. Symmetry codes: (A) 1+ x, y, z; (B) −x, 2− y, 1 −z; (C) 1− x, 1 −y, 2− z; (D) −1 +x, y, z; (E) 1− x, −y, 1− z. (b) 3D pillared-layer framework of 1 viewed along the a-axis without free water molecules. (c) Topological representation of the two-fold 3D sqc27 structure of 1.

the pyridyl group and Cu(I) to generate a 3D pillared framework as illustrated in Fig. 1b. It is clear that there is a large 1D channel along the a-axis, in order to minimize the hollow cavities and stabilize the framework, the potential voids formed via a single 3D framework show combination with another identical one, giving a two-fold interpenetrated structure of 1. Although complex 1 has an interpenetrating framework, after omitting all the water molecules, PLATON [12] analysis revealed that the 3D structure was composed of little voids of 272.3 Å that represent 11.6% per unit cell volume. Moreover, in 1, the uncoordinated amide group nitrogen atoms and oxygen (water) atoms provide the hydrogen-bonding donor and acceptor, respectively. The detailed data of hydrogen bonds for 1 are shown in Table S2. And the hydrogen bonding interactions with D···A separations in the 2.559(10)–3.269(10) Å region and the bond angels (∠D–H···A) range between 147° and 175°, in the normal

range. Besides, there exist intermolecular π–π stacking interactions in the crystal structure: pyridine rings of INAIP2− ligands N(1)–C(12)–C (21)–C(10)–C(14)–C(13), N(2)–C(15)–C(16)–C(17)–C(18)–C(41), N (3)–C(38)–C(37)–C(39)–C(40)–C(53) and benzene rings of INAIP2− ligands C(1)–C(2)–C(3)–C(4)–C(5)–C(6) and C(28)–C(29)–C(30)–C (31)–C(32)–C(33) with a centroid-to-centroid distance of 3.425(5), 3.535(5) and 3.574(5) Å. Therefore, the hydrogen bonds, the weak Cu–O bond and π–π stacking interactions further consolidate the 3D framework structure. A better insight into the nature of the involved framework can be achieved by the application of a topological approach through reducing multidimensional structures to simple node and connection nets. As described above, each Gd2 is surrounded by six adjacent INAIP2− ligands, so each Gd2 subunit is a six-connected node. Likely, since it links two Gd2 subunits and one Cu(I) atom, the INAIP2− ligand can be considered as a three-connecting node. Consequently, according to the calculation of TOPOS [13], the final framework of 1 belongs to a binodal (3, 6)-connected sqc27 type of topology net, with Schläfli symbol of (4·62)2(44·610·83) (Fig. 1c), which is entirely different from the reported complexes [LnAg(INAIP)2]·3H2O [8b]. The thermogravimetric analysis (TGA) of 1 reveals that there are three stages of weight loss in the temperature range of 20–650 °C (Fig. S2). The first stage, occurring between 20 and 90 °C, is attributed to the loss of three free water molecules per formula (observed weight loss, 3.90%; calcd, 3.90%). The second stage, occurring from 90 to 170 °C, is attributed to the loss of three coordinated water molecules per formula (observed weight loss, 3.94%; calcd, 3.90%). The weight is almost unchanged in the temperature range of 170–280 °C. Above 280 °C, the ligands started to decompose, and the residue had a composition of Gd2O3·CuO for 1 (calcd/found: 32.1/33.3%). The temperature dependence of the magnetic susceptibility of 1 was measured under an applied field of 1000 Oe in the temperature range 1.8–300 K. The plots of χMT vs. T are shown in Fig. 2. As the temperature is lowered from room temperature to 28 K, the χMT value is almost constant (ca.15.85 emu K mol−1), which is closed to the spin-only value of 15.75 emu K mol−1 based on binuclear Gd(III) ions with S = 7/2 and g = 2, indicating basic paramagnetic properties. Below 28 K, a small sharp decrease of χMT was observed, suggesting weak antiferromagnetic coupling between Gd(III) ions mediated by carboxyl groups. To estimate the magnetic interactions, the simple dimer model with Hamiltonian H = −2JS1S2 and S1 = S2 = 7/2, as reported previously [14], can be used here. The expression of the magnetic susceptibility of complex 1 is: 2 2

χM =

2Ng β kT

56 J= kT

×

42 J= kT

30 J=kT

20 J= kT

12 J= kT

6 J= kT

2J = kT

140e + 91e + 55e + 30e + 14e + 5e +e 15e56 J= kT + 13e42 J= kT + 11e30 J= kT + 9e20 J=kT + 7e12 J=kT + 5e6 J=kT + 3e2J = kT + 1

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Fig. 2. Temperature dependence of χMT for 1, the blue solid line shows the best fit to the model.

Fitting of the data to this model leads to g =2.0169 (7) and J = −0.0163(2) cm−1 with R= 2.4 × 10−3 (R = ∑[(χMT)obsd − (χMT)calcd]2/ ∑(χMT)2obsd), where J is the coupling constant. The result indicates that the weak magnetic exchange interaction between the binuclear Gd(III) ions mediated by the bridging carboxylate groups, which is similar to the J values reported in literature [15, 8b], but is entirely different from the reported antiferromagnetic complexes [Cu3(bpy)2Ln2(ip)6(H2O)5], paramagnetic one [GdCu2(L1)4(H2O)2](ClO4)7·6H2O, and ferrimagnetic complex [{Gd(hfac)2(CH3OH)}2{Cu(dmg)(Hdmg)}2] [16]. In summary, a new 3d–4f coordination polymer [CuGd2(INAIP)3 (HCOO)(H2O)3]·3H2O (1) based upon 5-(isonicotinamido)isophthalate has been synthesized and structurally characterized. It possesses a twofold interpenetration structure with sqc27 topology. The successful design and synthesis of the highly ordered Cu(I)–Gd(III) heterometallic coordination polymer provide an appropriate strategy to explore structures and topologies of 3d–4f complexes by careful selection of ligand. Acknowledgments This work was financially supported by the Distinguished Young Cadreman of Hunan Province (2008), Science Foundation of Hengyang Normal University of China (10B67) and Scientific Research Fund of Hunan Provincial Education Department (10 C0473). Appendix A. Supplementary material CCDC-807043 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.2011.03.038. References [1] (a) C.E. Plečnik, S.M. Liu, S.G. Shore, Lanthanide-transition-metal complexes: from ion pairs to extended arrays, Acc. Chem. Res. 36 (2003) 499–508; (b) Y.F. Zhou, M.C. Hong, X.T. Wu, Lanthanide–transition metal coordination polymers based on multiple N- and O-donor ligands, Chem. Commun. (2006) 135–143; (c) A. Bencini, C. Benelli, A. Caneschi, R.L. Carlin, A. Dei, D. Gatteschi, Crystal and molecular structure of and magnetic coupling in two complexes containing gadolinium(III) and copper(II) ions, J. Am. Chem. Soc. 107 (1985) 8128–8136; (e) R.E.P. Winpenny, The structures and magnetic properties of complexes containing 3d- and 4f-metals, Chem. Soc. Rev. 27 (1998) 447–452; (e) Y.C. Liang, R. Cao, W.P. Su, M.C. Hong, W.J. Zhang, Syntheses, structures, and magnetic properties of two gadolinium(III)–copper(II) coordination polymers by a hydrothermal reaction, Angew. Chem. Int. Ed. 39 (2000) 3304–3307.

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[10]

[11]

[12] [13] [14]

(0.1 mmol, 28.7 mg), NaOH (0.15 mmol, 6.1 mg), DMF (4 mL) and ethanol (6 mL) at 140 °C for 4 days under autogenous pressure. Cooling the reactor subsequently to room temperature at a rate of 10 °C /h, yellow crystals of 1 were obtained. IR (cm−1): 3420(m), 2941 (w), 1660 (m), 1551(s), 1525(s), 1447(s), 1374(s), 1238 (m), 1108(m), 835(s), 771(s), 601 (w). Anal. Calcd. For C43H37CuGd2N6O23 (%): C, 37.29, H, 2.67, N, 6.07. Found (%): C, 37.32, H, 2.59, N, 6.03. Although the starting materials are copper(II) salts, the Cu center has an oxidation state of + 1, attributed to a reduction reaction involving the hydrolyzed DMF molecules, which is consistent with a linear geometry for the Cu+ ion. Crystal data for 1: M = 1383.83, Triclinic, P1, a = 10.897(3) Å, b = 15.178(4) Å, c = 15.655(3) Å, α = 70.119(2), β = 81.876(3)° γ = 74.231(2), V = 2339.9(10) Å3, Z = 2, F(000) = 1356, GOF = 1.094, R1 = 0.0522, wR2 = 0.1386 [I N 2σ(I)]. Structural data for 1 was collected on a Bruker Smart Apex CCD with graphitemonochromated Mo-Kα radiation (λ = 0.71073 Å) at 291 (2) K. Their structure was solved by direct methods and refined with the full-matrix least-squares technique using the SHELXS-97 and SHELXL-97 programs. The hydrogen atoms of water molecule in 1 were found directly, whereas all the other hydrogen atoms were generated geometrically and refined isotropically using the riding model. Selected bond lengths and angles with their estimated standard deviations of 1 are listed in Table S1. J.W. Cheng, S.T. Zheng, E. Ma, G.Y. Yang, {LnIII[μ5-К2, К1, К1, К1, К1-1,2(CO2)2C6H4][isonicotine][H2O]}2CuI·X (Ln=Eu, Sm, Nd; X=ClO4–, Cl–): A new pillared-layer approach to heterobimetallic 3d–4f 3D-network solids, Inorg. Chem. 46 (2007) 10534–10538. A.L. Spek, J. Appl. Crystallogr. 36 (2003) 7–13. V.A. Blatov, Multipurpose crystallochemical analysis with the program package TOPOS, IUCr CompComm Newsl. 7 (2006) 4–38. (a) A. Panagiotopoulos, T.F. Zafiropoulos, S.P. Perlepes, E. Bakalbassis, I. MassonRamade, O. Kahn, A. Terzisand, C.P. Raptopoulou, Molecular structure and magnetic properties of acetato-bridged lanthanide(III) dimers, Inorg. Chem. 34 (1995) 4918–4920;

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