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Syntheses, crystal structures, and magnetic and luminescent properties of a series of lanthanide coordination polymers with chelidamic acid ligand
Polyhedron 29 (2010) 2674–2679
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Polyhedron journal homepage: www.elsevier.com/locate/poly
Syntheses, crystal structures, and magnetic and luminescent properties of a series of lanthanide coordination polymers with chelidamic acid ligand Jian-Ping Zou a,b,*, Sheng-Lian Luo c, Ming-Jun Li c, Xin-Hua Tang c, Qiu-Ju Xing c, Qiang Peng c,**, Guo-Cong Guo b a b c
Key Laboratory of Nondestructive Testing, Nanchang Hangkong University, Ministry of Education, Nanchang, Jiangxi 330063, PR China State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, PR China School of Environmental and Chemical Engineering, Nanchang Hangkong University, Nanchang, Jiangxi 330063, PR China
a r t i c l e
i n f o
Article history: Received 27 February 2010 Accepted 12 June 2010 Available online 19 June 2010 Keywords: Crystal structures Lanthanides Luminescence Metal–organic frameworks Magnetic properties
a b s t r a c t A series of lanthanide(III) complexes with chelidamic acid ligand, [Ln(C7H2NO5)3H2O]nnH2O (Ln = La (1), Y (2), Sm (3), and Nd (4)), [Gd2(C7H2NO5)34H2O]n2nH2O (5) and [Ce(C7H2NO5)1.5H2O]n (6), have been synthesized by hydrothermal method and structurally characterized by single-crystal X-ray diffraction. Complexes 1–4 are isostructural and possess 2D framework. Complex 5 contains two different Gd(III) ions linked through carboxylate group to form a 2D framework. Complex 6 exhibits a (44) topology 2D network. The variable-temperature magnetic properties of 3 and 5 have been investigated. Furthermore, the photoluminescent properties of 1, 2, 3, and 5 at room temperature were also studied. Ó 2010 Elsevier Ltd. All rights reserved.
1. Introduction In recent years, the design and construction of metal–organic frameworks (MOFs) have been widely studied and have attracted extensive interest because of their many practical applications ranging from ion exchange, catalysis, adsorption, separation, and sensor to optoelectronics [1–6]. Many chemical researchers attempted to use various methods to obtain MOFs, and the synthetic method of MOFs has rapidly advanced from the accidental to rational stage [7–9]. Up to now, considerable effort has been focused on the rational design and controlled synthesis of coordination polymers using multidentate ligands such as poly-carboxylate and N-heterocyclic ligands [10–13]. Recently, there is a growing interest in the construction of coordination polymers based on pyridine derivates [14–17]. As a multi-chelating ligand, chelidamic acid (4-hydroxy-pyridine-2,6-dicarboxylic acid) has been of great attraction due to its usage in many areas of science, such as coordinate chemistry, biochemistry, organic chemistry, medical chemistry, and even in HIV investigation [18–23]. In addition, the research on lanthanide complexes is currently of great interest because of their unique physicochemical
* Corresponding author at: Key Laboratory of Nondestructive Testing, Nanchang Hangkong University, Ministry of Education, Nanchang, Jiangxi 330063, PR China. Tel.: +86 791 3953377; fax: +86 791 3953373. ** Corresponding author. E-mail addresses: [email protected] (J.-P. Zou), [email protected] (Q. Peng). 0277-5387/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.poly.2010.06.008
properties and various applications as functional materials [24– 26]. Especially, the magnetic and luminescent properties of lanthanide complexes have aroused much attention for decades [27–30]. Therefore, in order to obtain MOFs with novel structures and good magnetic and luminescent properties, we chose to incorporate lanthanide ions with chelidamic acid. Herein, we report syntheses, crystal structures, and magnetic and luminescent properties of a series of MOFs built from lanthanide complexes with chelidamic acid, [Ln(C7H2NO5)3H2O]nnH2O (Ln = La (1), Y (2), Sm (3), and Nd (4)), [Gd2(C7H2NO5)34H2O]n2nH2O (5) and [Ce(C7H2NO5)1.5H2O]n (6). 2. Experimental 2.1. Materials and measurement All of the chemicals were analytically pure (>99.99%) and used without further purification. UV–Vis spectra were recorded at the room temperature on a computer-controlled PE Lambda 900 UV– Vis spectrometer equipped with an integrating sphere in the wavelength range 200–2000 nm. Elemental analyses (C, H and N) were carried out with an Elementar Vario EL. Photoluminescence analyses were performed on an Edinburgh FLS920 fluorescence spectrometer. Variable-temperature magnetic susceptibility and field dependence magnetization measurements on polycrystalline samples were performed on an MPMS-XL and PPMS 9T Quantum Design SQUID magnetometer.
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2.2. Syntheses
2.3. X-ray crystallographic studies
2.2.1. Synthesis of [Ln(C7H2NO5)3H2O]nnH2O (1–4) (Ln = La,Y, Sm, Nd) A mixture of LnCl3 (Ln = La, Sm and Nd for 1, 3 and 4, respectively) or Y(NO3)3 (for 2) (0.75 mmol), chelidamic acid (0.5 mmol), and water (10 mL) was loaded into a 25-mL Teflon-lined autoclave, and heated at 413 K for 3 days, after which it was cooled to room temperature over 4 days. Light-yellow prismatic crystals of 1 that are stable in air were obtained by filtration of the result solution. Yield: 73% (based on chelidamic acid). Anal. Calc. for 1: C, 21.50; H, 2.57; N, 3.58. Found: C, 21.54; H, 2.60; N, 3.62%. Light-yellow prismatic crystals of 2 that are stable in air were obtained by filtration of the result solution. Yield: 71% (based on chelidamic acid). Anal. Calc. for 2: C, 24.65; H, 2.94; N, 4.10. Found: C, 24.69; H, 2.97; N, 4.14%. Yellow prismatic crystals of 3 that are stable in air were obtained by filtration of the result solution. Yield: 76% (based on chelidamic acid). Anal. Calc. for 3: C, 20.89; H, 2.49; N, 3.48. Found: C, 20.93; H, 2.52; N, 3.51%. Light-yellow prismatic crystals of 4 that are stable in air were obtained by filtration of the result solution. Yield: 68% (based on chelidamic acid). Anal. Calc. for 4: C, 21.21; H, 2.53; N, 3.53. Found: C, 21.24; H, 2.56; N, 3.57%.
Single crystals of 1–6 suitable for X-ray analyses were mounted, respectively, at the apex of a glass fiber for X-ray diffraction data collection. Data sets of 1, 2, 3, and 5 were collected on Rigaku Mercury CCD diffractometer, and those of 4 and 6 were collected on Rigaku AFC7R diffractometer, using a graphite monochromated Mo Ka radiation (k = 0.71073 Å) from a rotating anode generator at 293 K. The intensity data were collected with an x scan technique and corrected for LP factors. All the structures were solved by direct methods and refined on F2 with full-matrix least-squares techniques using Siemens SHELXTL™ version 5 package of crystallographic software [31]. The final refinements included anisotropic displacement parameters for all non-hydrogen atoms and a secondary extinction correction. The H atoms of all water molecules for 1–6 and those of hydroxyl oxygen for 5 and 6 were0 found in difference Fourier map, with O–H distances of 0.85(3) Å A, and refined in riding mode with Uiso(H) values of 1.5 Ueq(O). Other H atoms were allowed to ride on their respective parent atoms with C–H 0 distances of 0.93 Å A, respectively, and were included in the refinement with isotropic displacement parameters Uiso(H) = 1.2 Ueq(C). The crystallographic data of 1–6 are listed in Table 1. Selected bond lengths are given in Table 2.
2.2.2. Synthesis of [Gd2(C7H2NO5)34H2O]n2nH2O (5) The process of synthesis is same to that of 1 except for the dosage of reactant [GdCl3 (0.50 mmol), chelidamic acid (0.75 mmol), and water (10 mL)] Light-yellow prismatic crystals of 5 that are stable in air were obtained by filtration of the result solution. Yield: 79% (based on chelidamic acid). Anal. Calc. for 5: C, 26.11; H, 2.19; N, 4.35. Found: C, 26.15; H, 2.22; N, 4.38%.
2.4. Computational descriptions
2.2.3. Synthesis of [Ce(C7H2NO5)1.5H2O]n (6) The process of synthesis is same to that of 1 except for the dosage of reactant [Ce2O3 (0.50 mmol), chelidamic acid (0.50 mmol), and water (10 mL)] Light-yellow prismatic crystals of 6 that are stable in air were obtained by filtration of the result solution. Yield: 58% (based on chelidamic acid). Anal. Calc. for 6: C, 24.65; H, 0.94; N, 4.36. Found: C, 24.69; H, 1.00; N, 4.40%.
The crystallographic data of 1 determined by X-ray was used to calculate the electronic band structure. Calculation of the electronic band structure along with density of states (DOS) was carried out with density functional theory (DFT) using one of the three nonlocal gradient corrected exchange-correlation functional (GGA-PBE) and performed with the CASTEP code [32], which uses a plane wave basis set for the valence electrons and norm-conserving pseudopotential for the core electrons [33]. The number of plane waves included in the basis was determined by a cutoff energy Ec of 550 eV. Pseudoatomic calculations were performed for H-1s1, C-2s22p2, N-2s22p3, O-2s22p4, and La-5d14s2. The parameters used in the calculations and convergence criteria were set by the default values of the CASTEP code [34].
Table 1 Crystal data and structure refinement parameters for 1–6.
a b
Compounds
1
2
3
4
5
6
Formula Formula weight (g/mol) Crystal color Crystal habit Crystal system Space group a (Å) b (Å) c (Å) b (°) V (Å3) Z k (Å) Dcalcd. (g/cm3) l (mm1) F(0 0 0) R(int) R1a, wR2b Goodness-of-fit (GOF) Dqmax and Dqmin (e Å3)
C7H10LaNO9 391.07 light yellow prism monoclinic P2(1)/n 9.942(2) 7.5576(15) 15.465(3) 105.26(3) 1121.1(4) 4 0.71073 2.317 3.853 752 0.0831 0.0405, 0.1271 0.987 1.347, 1.519
C7H10YNO9 341.07 light yellow prism monoclinic P2(1)/n 9.879(5) 7.569(3) 15.419(8) 105.299(5) 1112.1(10) 4 0.71073 2.037 5.287 680 0.0456 0.0350, 0.0735 0.988 0.436, 0.371
C7H10SmNO9 402.51 yellow block monoclinic P2(1)/n 10.047(3 7.521(2) 15.578(5) 104.753(4) 1138.4(6) 4 0.71073 2.349 5.200 772 0.0257 0.0208, 0.0606 0.991 0.970, 0.969
C7H10NdNO9 396.40 light yellow prism monoclinic P2(1)/n 10.109(2) 7.5421(15) 15.653(3) 104.49(3) 1155.5(4) 4 0.71073 2.279 4.534 764 0.0159 0.0258, 0.0827 1.008 0.914, 0.902
C21H21Gd2N3O21 965.91 light yellow prism monoclinic P2(1)/n 9.616(3) 13.500(4) 22.082(6) 92.583(3) 2863.6(14) 4 0.71073 2.240 4.693 1856 0.0292 0.0231, 0.0642 0.995 0.953, 1.149
C14H10Ce2N2O13 694.48 light yellow prism monoclinic C2/c 7.9916(8) 10.4155(10) 20.951(2) 99.512(2) 1719.9(3) 4 0.71073 2.682 5.309 1312 0.0287 0.0548, 0.1451 0.999 1.293, 1.582
P P R = ||Fo| |Fc||/ |Fo|. P P Rw ¼ f ½wðF 2o F 2c Þ2 = ½wðF 2o Þ2 g1=2 .
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Table 2 Selected bond distances (Å) for 1–6.a Bond
Distance (Å)
Bond
Distance (Å)
1 La(1)–O(5)#1 La(1)–O(3W) La(1)–O(1W) La(1)–O(3) O(5)–C(3) C(1)–C(6)
2.298(3) 2.359(4) 2.375(4) 2.399(3) 1.310(5) 1.510(7)
La(1)–O(2W) La(1)–O(4)#2 La(1)–O(1) La(1)–N(1) C(5)–C(7)
2.400(4) 2.411(3) 2.416(3) 2.462(4) 1.501(6)
2 Y(1)–O(5)#1 Y(1)–O(1W) Y(1)–O(2W) Y(1)–O(3) O(5)–C(3) C(1)–C(6)
2.277(2) 2.336(2) 2.346(2) 2.384(3) 1.327(3) 1.510(4)
Y(1)–O(3W) Y(1)–O(4)#2 Y(1)–O(1) Y(1)–N(1) C(5)–C(7)
2.391(3) 2.393(2) 2.409(2) 2.457(3) 1.498(4)
3 Sm(1)–O(15)#1 Sm(1)–O(1W) Sm(1)–O(3W) Sm(1)–O(11) O(15)–C(13) C(11)–C(16)
2.348(3) 2.424(3) 2.436(3) 2.443(3) 1.322(4) 1.496(5)
Sm(1)-O(12)#2 Sm(1)–O(13) Sm(1)–O(2W) Sm(1)–N(11) C(15)–C(17)
2.446(2) 2.450(3) 2.457(3) 2.508(3) 1.514(5)
4 Nd(1)–O(5)#1 Nd(1)–O(2W) Nd(1)–O(1W) Nd(1)–O(3) O(5)–C(3) C(1)–C(6)
2.375(3) 2.450(3) 2.466(3) 2.471(3) 1.315(4) 1.496(5)
Nd(1)–O(1) Nd(1)–O(2)#2 Nd(1)–O(3W) Nd(1)–N(1) C(5)–C(7)
2.472(3) 2.476(3) 2.485(3) 2.545(3) 1.512(5)
5 Gd(1)–O(22)#1 Gd(1)–O(32) Gd(1)–O(34) Gd(1)–O(4W) Gd(1)–O(11) Gd(1)–O(1W) Gd(1)–O(2W) Gd(1)–O(3W) Gd(2)–O(13) O(1)–C(13) O(2)–C(23) O(3)–C(33) C(31)–C(36)
2.311(3) 2.370(2) 2.383(2) 2.385(3) 2.402(2) 2.424(3) 2.438(3) 2.465(3) 2.427(3) 1.336(4) 1.334(5) 1.329(4) 1.508(5)
Gd(2)–O(31) Gd(2)–O(33) Gd(2)–O(12) Gd(2)–O(21) Gd(2)–O(24) Gd(2)–N(1) Gd(2)–N(2) Gd(2)–N(3) C(11)–C(16) C(15)–C(17) C(21)–C(26) C(25)–C(27) C(31)–C(36) C(35)–C(37)
2.432(3) 2.436(2) 2.472(2) 2.501(3) 2.500(3) 2.497(3) 2.548(3) 2.483(3) 1.507(5) 1.532(5) 1.494(5) 1.511(5) 1.508(5) 1.515(5)
6 Ce(1)–O(3) 2 Ce(1)–O(1) 2 Ce(1)–O(1W) Ce(1)–O(2W) 2 Ce(2)–O(1)#1 O(5)–C(3)
2.505(3) 2.537(4) 2.545(6) 2.595(4) 2.340(3) 1.363(6)
Ce(2)–O(1)#2 Ce(2)–O(3) 2 Ce(2)–O(2W)#3 Ce(2)–O(2W)#4 Ce(1)–N(1) 2 C(1)–C(6) C(5)–C(7)
2.340(3) 2.639(4) 2.690(4) 2.690(4) 2.603(4) 1.509(7) 1.511(7)
a Symmetry transformations used to generate equivalent atoms. For 1: #1 x + 1/2, y + 3/2, z + 1/2; #2 x 1/2, y + 1/2, z + 1/2. For 2: #1 x + 1/2, y + 1/2, z + 1/2; #2 x 1/2, y + 1/2, z + 1/2. For 3: #1 x + 1/2, y + 1/2, z + 1/2; #2 x + 3/2, y 1/ 2, z + 1/2. For 4: #1 x 1/2, y + 3/2, z 1/2; #2 x + 1/2, y 1/2, z + 1/2. For 5: #1 x + 5/2, y 1/2, z + 1/2. For 6: #1 x, y, z + 1/2; #2 x 1, y, z; #3 x 1/2, y + 1/2, z; #4 x 1/2, y + 1/2, z + 1/2.
3. Results and discussion 3.1. Description of crystal structures The X-ray crystallography analyses revealed that 1–4 are isomorphous, so we will choose 1, 5 and 6 for detailed structural discussions. In addition, compounds 1–4 are isomorphous to the previously published Dy, Er and Gd complexes [37], while compound 5 is isomorphous to the previously reported Tb, Pr and Nd complexes [42].
3.1.1. [Ln(C7H2NO5)3H2O]nnH2O (1–4) As shown in Fig. 1a, the asymmetric unit of 1 consists of one La(III) ion, one fully deprotonated chelidamic acid trianionic ligand, three coordinated water molecules, and one discrete water molecule. In 1, the La1 atom is eight-coordinated by one chelated tridentate chelidamic acid ligand, two oxygen atoms (O4B and O5A) and three coordinated water molecules to form a distorted bicapped square-prismatic coordination geometry (Fig. 1a). The La– 0 O bond distances range from 2.298(3) to 2.416(3) Å A and the La–N 0 bond distance is 2.462(4) Å A (Table 2), which are much shorter than those reported for the lanthanum complexes with chelidamic acid [35,36]. Same to the structures of the Dy, Er and Gd complexes reported in the literature [37], the La atoms in 1 are interconnected through the chelidamic acid ligand to generate a 2D architecture (Fig. 1b). Furthermore, the 2D frameworks are further assembled to form a 3D supramolecular network by the hydrogen bonds between water molecules and carboxylate O atoms or hydroxyl groups. 3.1.2. [Gd2(C7H2NO5)34H2O]n2nH2O (5) The asymmetric unit of 5 consists of two Gd(III) ions, three fully deprotonated chelidamic acid anionic ligands, four coordinated water molecules, and two discrete water molecules (Fig. 2a). The Gd1 atom is eight-coordinated with slightly distorted dodecahedral geometry, while the Gd2 atom is nine-coordinated with slightly distorted tricapped trigonal prism geometry. The Gd–O0 and Gd–N bond distances0 in 5 range from 2.311(3) to 2.501(3) Å A and 2.483(3) to 2.548(3) Å A (Table 2), respectively, which all lie in the normal range of those reported Gd complexes with chelidamic acid in the literature [37,38]. Same to the structures of the Tb, Pr and Nd complexes reported in the literature [42], the two different polyhedra comprised by the two different Gd atoms are linked through carboxylate group to form a 2D grid (Fig. 2b), which are further bridged through complex hydrogen bonds between water molecules and carboxylate O atoms or hydroxyl groups to form a 3D supramolecular framework. 3.1.3. [Ce(C7H2NO5)1.5H2O]n (6) The single-crystal X-ray analysis reveals that there are two types of crystallographically independent Ce atoms with different coordination environments in 6 (Fig. 3a). The Ce1 atom is ninecoordinated with a tricapped trigonal prism geometry made up of four oxygen atoms and two nitrogen atoms from two chelated tridentate chelidamic acid ligands and three coordinated water molecules. The Ce2 atom is six-coordinated by four O atoms from four different chelidamic acid ligands and two coordinated water molecules. The Ce–O bond distances range from 2.340(3) to 0 0 2.690(4) Å A and the Ce–N bond distance is 2.603(4) Å A (Table 2), which are much shorter than those reported for Ce complex with chelidamic acid [39] but lie in the normal range of those reported for other Ce complexes in the literature [40,41]. In 6, the Ce1 and Ce2 atoms are linked by carboxylate O atoms (O1 and O3) and coordinated water molecules (O2W) to generate a dinuclear homometallic Ce2O10 unit. The Ce2O10 units as building blocks are further assembled into a highly ordered 2D framework, as shown in Fig. 3b and 3c. A better insight into the 2D network of 6 can be achieved by application of a topological approach. As mentioned above, the architecture of 6 can be reduced to a nodal structure of a (44) topology by considering the Ce2O10 unit as a four-connected node, which is the first example for the lanthanide complexes with chelidamic acid [21,23,35,37,42,43]. 3.2. Magnetic properties For 3, the variable-temperature magnetic susceptibility, vM and vMT are shown in Fig. S1. At 300 K, vMT is equal to
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Fig. 1. (a) View of the coordination unit of 1 with 30% probability of thermal ellipsoids. Hydrogen atoms are omitted for clarity. Symmetry codes for A: 0.5 + x, 1.5 y, 0.5 + z; B: 0.5 x, 0.5 + y, 0.5 z; C: 0.5 + x, 1.5 y, 0.5 + z. (b) View of the 2D network of 1 along the a axis.
0.356 cm3 mol1 K and decreases rapidly to a value of 0.087 cm3 mol1 K at 2 K. The thermal variation of vMT is nearly linear over the whole temperature range, which is similar to that for the reported mononuclear complex [44]. But, interestingly, the value of 0.087 cm3 mol1 K for vMT at 2 K is consistent with the value of 0.089 cm3 mol1 K predicted by theory for one Sm(III) ion and obviously smaller than that for two Sm(III) ions. This behavior indicates that an antiferromagnetic interaction possibly exists between Sm(III) ions at low temperature, although it is very weak. The magnetic behavior of 5 is shown in Fig. S2. For 5, a nonlinear fit via vM = C/(T h) + v0 above 20 K reveals a Curie–Wesis behavior with the Curie constant C = 15.83(2) cm3 mol1 K, the Weiss constant h = 0.50(1)°, and the background susceptibility, v0 = 7.9(3) 104 cm3/mol. The vM value increases with decreasing the temperature, reaching a maximum of 5.30 cm3/ mol at around 3.0 K, and then decreases very quickly. The value of vMT is 15.83 cm3 mol1 K at room temperature, which is close to the value expected for two isolated Gd(III) ions (15.86 cm3 mol1 K). On lowering the temperature, the value of vMT decreases smoothly until approximately 4 K and then decreases at a faster rate, reaching a value of 8.89 cm3 mol1 K at 2 K. This is characteristic of significant antiferromagnetic ordering (TN =
3.0 K), and the magnetic interactions mediated by chelidamic acid group are effective in 5. 3.3. Luminescent properties The solid-state electronic emission spectra of 1, 2 and 5 at room temperature show luminescence features as given in Fig. S3. Complexes 1 and 2 both display green fluorescence with the maximum emission at 509 and 511 nm upon excitation at 355 nm and 360 nm, respectively, while complex 5 displays blue fluorescence with the maximum emission at 445 nm upon excitation at 315 nm. The strongest emission peaks for free chelidamic acid ligand is at about 525 nm, which is due to the p ? p* transition [35]. Compared to the free chelidamic acid ligand, 1 and 2 result in a little blue shift of 16 and 14 nm, respectively, while a large blue shift of 80 nm appears in 5. The results indicate that the emission of 1 and 2 may be both originated from p–p* transition of the ligand, while the emission of 5 may be originated from charge transition between the ligand and the Gd(III) ion [45–48]. The solid-state electronic emission spectrum of 3 at room temperature excited at 366 nm is shown in Fig. S4. The broad and strong emission bands in 420–550 nm (kem = 510 nm) are due to
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Fig. 2. (a) View of the coordination unit of 5 with 30% probability of thermal ellipsoids. Hydrogen atoms are omitted for clarity. Symmetry codes for A: 1 + x, y, z; B: 1.5 x, 0.5 + y, 0.5 z; C: 2.5 x, 0.5 + y, 0.5 z. (b) View of the 2D network built from polyhedra of 5 along the c axis. The H atoms and uncoordinated atoms of pyridine rings and hydroxyl groups are omitted.
Fig. 3. (a) View of the coordination unit of 6 with 30% probability of thermal ellipsoids. Hydrogen atoms are omitted for clarity. Symmetry codes for A: 1 + x, y, z; B: x, y, 0.5 z; C: 0.5 + x, 0.5 + y, z; D: 1 + x, y, z; E: 1 x, y, 0.5 z; F: 0.5 x, 0.5 + y, 0.5 z. (b) View of the 2D network of 6 along the b axis (c) View of the highly ordered 2D framework of 6 along the c axis. The H atoms and uncoordinated atoms of pyridine rings and hydroxyl groups are omitted.
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the p ? p* transition of chelidamic acid ligand. The emission peaks at 559, 595 and 640 nm can be assigned to 4G5/2 ? 6HJ (J = 5/2, 7/ 2, 9/2) transitions of the Sm(III) ion, respectively.
UK; fax: (+44) 1223-336-033; or e-mail: [email protected]. Supplementary data associated with this article can be found, in the online version, at doi:10.1016/j.poly.2010.06.008.
3.4. Band structure and density of state of 1
References
The calculated band structure of 1 along high symmetry points of the first Brillouin zone is plotted in Fig. S5. It is found that the top of valence bands (VBs) and the bottom of conduction bands (CBs) are both relatively flat. The highest energy (0.00 eV) of VBs and the lowest energy (3.11 eV) of CBs in 1 are both localized at the G point. According to the calculation, the solid-state complex 1 thus possesses a direct energy band gap of 3.11 eV, which is close to its experimental values (3.58 eV) shown in Fig. S6. The bands can be assigned according to total and partial densities of states (DOS), as plotted in Fig. S7. The VBs between energy 23.0 and 5.0 eV are mostly formed by O-2s, O-2p, C-2s and C-2p states, mixing with small N-2s, N-2p and La-5d states. And the VBs between energy 5.0 eV and the Fermi level (0.0 eV) are mainly contribution from O-2p and C-2p states mixing with a small amount of La-5d and N2p states, while the CBs between 3.1 and 8.0 eV are almost contribution from C-2p and O-2p states mixing with a small amount of N-2p and La-5d states. Therefore, the origin of the emission band of 1 may be mainly ascribed to intraligand charge transfer (ILCT) where the electrons are transferred from O-2p to C-2p states [49–51]. This analysis is also consistent with the above experimental result. 4. Conclusions
[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22] [23]
In summary, a series of lanthanide(III) complexes with chelidamic acid, [Ln(C7H2NO5)3H2O]nnH2O (Ln = La (1), Y (2), Sm (3), and Nd (4)), [Gd2(C7H2NO5)34H2O]n2nH2O (5) and [Ce(C7H2NO5)1.5H2O]n (6), have been synthesized by hydrothermal reaction. The X-ray diffraction analyses show that complexes 1–4 are isostructural and possess 2D framework. Complex 5 contains two different Gd(III) ions linked through carboxylate group to form a 2D framework. Complex 6 exhibits a (44) topology 2D network, which is the first example for lanthanide complexes with chelidamic acid. The variable-temperature magnetic properties of 3 and 5 have been investigated. Complex 3 shows a weak antiferromagnetic interaction between Sm(III) ions at low temperature, while complex 5 shows an antiferromagnetic ordering interaction between Gd(III) ions. Furthermore, the photoluminescent properties of 1, 2, 3, and 5 at room temperature were also studied. The results indicate that the emission of 1 and 2 may be originated from intraligand charge transfer (ILCT) of the chelidamic acid ligand, and the emission of 5 may be originated from charge transition between the ligand and the Gd(III) ion, while complex 3 exhibits emission for ligands and Sm(III) centers. Acknowledgements We gratefully acknowledge the financial support of the NSF of China (20801026), the NSF of Jiangxi Province (2008GQC0036), the Aviation Science Foundation of China (2008ZF56012), and Open Fund of the Key Laboratory of Nondestructive Testing, Ministry of Education, Nanchang Hangkong University (ZD200929007). Appendix A. Supplementary data CCDC 732621, 732622, 732623, 732624, 732625 and 763809 contain the supplementary crystallographic data for 1, 2, 3, 4, 5 and 6. These data can be obtained free of charge via http:// www.ccdc.cam.ac.uk/conts/retrieving.html, or from the Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ,
[24] [25] [26] [27] [28] [29] [30] [31] [32] [33] [34] [35] [36] [37] [38] [39] [40] [41] [42] [43] [44] [45] [46] [47] [48] [49] [50] [51]
B.F. Hoskins, R. Robson, J. Am. Chem. Soc. 112 (1990) 1546. T. Savaki, T. Dewa, Y. Aoyama, J. Am. Chem. Soc. 120 (1998) 8539. K. Seki, S. Takamizawa, W. Mori, Chem. Lett. (2001) 122. H. Maas, A. Currao, G. Calzaferri, Angew. Chem., Int. Ed. 41 (2002) 2495. H. Tsukube, S. Shinoda, Chem. Rev. 102 (2002) 2389. M.-L. Tong, X.-M. Chen, S.R. Batten, J. Am. Chem. Soc. 125 (2003) 16170. P.J. Hagrman, D. Hagrman, J. Zubieta, Angew. Chem., Int. Ed. 38 (1999) 2638. O. Ohmori, M. Kavano, M. Fujita, J. Am. Chem. Soc. 126 (2004) 16292. A.P. Cote, A.I. Benen, N.W. Ockwig, M. O’Keeffe, A.J. Matzger, O.M. Yaghi, Science 310 (2005) 1166. O.M. Yaghi, M. O’Keeffe, N.W. Ockwig, H.K. Chae, M. Eddaoudi, J. Kim, Nature 423 (2003) 705. H. Furukawa, J. Kim, N.W. Ockwig, M. O’Keeffe, O.M. Yaghi, J. Am. Chem. Soc. 130 (2008) 11650. S.R. Seidel, P.J. Stang, Acc. Chem. Res. 35 (2002) 972. B.-H. Ye, M.-L. Tong, X.-M. Chen, Coord. Chem. Rev. 249 (2005) 545. C.Y. Niu, B.L. Wu, X.F. Zheng, H.Y. Zhang, H.W. Hou, Y.Y. Niu, Z.J. Li, Cryst. Growth Des. 8 (2008) 1566. X.W. Wang, J.Z. Chen, J.H. Liu, Cryst. Growth Des. 7 (2007) 1227. J.P. Zhang, Y.Y. Lin, X.C. Huang, X.M. Chen, J. Am. Chem. Soc. 127 (2005) 5495. M.H. Klingele, S. Brooker, Coord. Chem. Rev. 241 (2003) 119. Y. Nakatsuji, J.S. Bradshaw, P.K. Tse, G. Arena, B.E. Wilson, N.K. Wilson, N.K. Dalley, R.M. Izatt, Chem. Commun. (1985) 749. T. Fessmann, J.D. Kilburn, Angew. Chem., Int. Ed. 38 (1999) 1993. M. Searcey, S. MeClean, B. Madden, A.T. McGown, L.P.G. Wakelin, Anti-Cancer Drug Des. 13 (1998) 837. B. Zhao, H.-L. Gao, X.-Y. Chen, P. Cheng, W. Shi, D.-Z. Liao, S.-P. Yan, Z.-H. Jiang, Chem. Eur. J. 12 (2006) 149. J.-P. Zou, G.-W. Zhou, X. Zhang, M.-S. Wang, Y.-B. Lu, W.-W. Zhou, Z.-J. Zhang, G.-C. Guo, J.-S. Huang, CrystEngComm 11 (2009) 972. H.-L. Gao, B. Zhao, X.-Q. Zhao, Y. Song, P. Cheng, D.-Z. Liao, S.-P. Yan, Inorg. Chem. 47 (2008) 11057. B. Yan, H.J. Zhang, S.B. Wang, J.Z. Ni, Mater. Res. Bull. 33 (1998) 1517. G.F. de Sá, O.L. Malta, Coord. Chem. Rev. 196 (2000) 165. J. Kido, Y. Okamoto, Chem. Rev. 102 (2002) 2357. N. Ishikawa, S. Otsuka, Y. Kaizu, Angew. Chem., Int. Ed. 44 (2005) 731. S.J.A. Pope, B.J. Coe, S. Faulkner, E.V. Bichenkova, X. Yu, K.T. Douglas, J. Am. Chem. Soc. 124 (2004) 9490. W.S. Liu, T.Q. Jiao, Y.Z. Li, Q.Z. Liu, M.Y. Tan, H. Wang, L.F. Wang, J. Am. Chem. Soc. 126 (2004) 2280. L.M. Fu, X.F. Wen, X.C. Ai, Y. Sun, Y.S. Wu, J.P. Zhang, Y. Wang, Angew. Chem., Int. Ed. 44 (2005) 747. Siemens SHELXTL™ Version 5 Reference Manual, Siemens Energy & Automation Inc., Madison, Wisconsin, USA, 1994. M. Segall, P. Linda, M. Probert, C. Pickard, P. Hasnip, S. Clark, M. Payne, Materials Studio CASTEP Version 2.2, 2002. D.R. Hamann, M. Schluter, C. Chiang, Phys. Rev. Lett. 43 (1979) 1494. M. Segall, P. Linda, M. Probert, C. Pickard, P. Hasnip, S. Clark, M. Payne, J. Phys.: Condens. Mat. 14 (2002) 2717. J.-P. Zou, M.-J. Li, Q.-J. Xing, Z.-H. Wen, G.-S. Zeng, A.-Q. Zhang, Q. Peng, G.-C. Guo, Austr. J. Chem. 63 (2010) 942. J.P. Zou, G.W. Zhou, G.C. Guo, L.S. Yan, G.S. Zeng, J.S. Huang, Chin. J. Struct. Chem. 27 (2008) 1323. H.-L. Gao, L. Yi, B. Zhao, X.-Q. Zhao, P. Cheng, D.-Z. Liao, S.-P. Yan, Inorg. Chem. 45 (2006) 5980. A.K. Hall, J.M. Harrowfield, B.W. Skelton, A.H. White, Acta Crystallogr. C 56 (2000) 407. J.-P. Zou, G.-W. Zhou, G.-C. Guo, L.-S. Yan, G.-S. Zeng, J.-S. Huang, Chin. J. Struct. Chem. 28 (2009) 1033. S.K. Ghosh, P.K. Bharadwaj, Inorg. Chem. 43 (2004) 2293. T.K. Prasad, M.V. Rajasekharan, Cryst. Growth Des. 6 (2006) 488. Z. Chen, M. Fang, P. Ren, X.-H. Li, B. Zhao, S. Wei, P. Cheng, Z. Anorg. Allg. Chem. 634 (2008) 382. X. Zhao, Z. Chen, B. Zhao, W. Shi, P. Cheng, Inorg. Chem. Commun. 10 (2007) 1433. Y. Li, F.-K. Zheng, X. Liu, W.-Q. Zou, G.-C. Guo, C.-Z. Lu, J.-S. Huang, Inorg. Chem. 45 (2006) 6308. J.-P. Zhang, Y.-Y. Lin, X.-C. Huang, X.-M. Chen, J. Am. Chem. Soc. 127 (2005) 5495. B. Liu, L. Xu, G.-C. Guo, J.-S. Huang, Inorg. Chem. Commun. 9 (2006) 687. J.-P. Zou, Q. Peng, G.-S. Zeng, Z.-H. Wen, Q.-J. Xing, M.-H. Chen, G.-C. Guo, J.-S. Huang, J. Mol. Struct. 921 (2009) 323. J.-P. Zou, G.-S. Zeng, Z.-H. Wen, Q. Peng, Q.-J. Xing, M.-H. Chen, G.-C. Guo, J.-S. Huang, Inorg. Chim. Acta 362 (2009) 4843. R.-B. Zhang, Z.-J. Li, Y.-Y. Qin, J.-K. Cheng, J. Zhang, Y.-G. Yao, Inorg. Chem. 47 (2008) 4861. F.-Y. Yi, N. Zhao, W. Wu, J.-G. Mao, Inorg. Chem. 48 (2009) 628. J.-P. Zou, Q. Peng, Z.-H. Wen, G.-S. Zeng, Q.-J. Xing, G.-C. Guo, Crsyt. Growth Des. 10 (2010) 2613.
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Syntheses, crystal structures, and magnetic and luminescent properties of a series of lanthanide coordination polymers with chelidamic acid ligand Jian-Ping Zou a,b,*, Sheng-Lian Luo c, Ming-Jun Li c, Xin-Hua Tang c, Qiu-Ju Xing c, Qiang Peng c,**, Guo-Cong Guo b a b c
Key Laboratory of Nondestructive Testing, Nanchang Hangkong University, Ministry of Education, Nanchang, Jiangxi 330063, PR China State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, PR China School of Environmental and Chemical Engineering, Nanchang Hangkong University, Nanchang, Jiangxi 330063, PR China
a r t i c l e
i n f o
Article history: Received 27 February 2010 Accepted 12 June 2010 Available online 19 June 2010 Keywords: Crystal structures Lanthanides Luminescence Metal–organic frameworks Magnetic properties
a b s t r a c t A series of lanthanide(III) complexes with chelidamic acid ligand, [Ln(C7H2NO5)3H2O]nnH2O (Ln = La (1), Y (2), Sm (3), and Nd (4)), [Gd2(C7H2NO5)34H2O]n2nH2O (5) and [Ce(C7H2NO5)1.5H2O]n (6), have been synthesized by hydrothermal method and structurally characterized by single-crystal X-ray diffraction. Complexes 1–4 are isostructural and possess 2D framework. Complex 5 contains two different Gd(III) ions linked through carboxylate group to form a 2D framework. Complex 6 exhibits a (44) topology 2D network. The variable-temperature magnetic properties of 3 and 5 have been investigated. Furthermore, the photoluminescent properties of 1, 2, 3, and 5 at room temperature were also studied. Ó 2010 Elsevier Ltd. All rights reserved.
1. Introduction In recent years, the design and construction of metal–organic frameworks (MOFs) have been widely studied and have attracted extensive interest because of their many practical applications ranging from ion exchange, catalysis, adsorption, separation, and sensor to optoelectronics [1–6]. Many chemical researchers attempted to use various methods to obtain MOFs, and the synthetic method of MOFs has rapidly advanced from the accidental to rational stage [7–9]. Up to now, considerable effort has been focused on the rational design and controlled synthesis of coordination polymers using multidentate ligands such as poly-carboxylate and N-heterocyclic ligands [10–13]. Recently, there is a growing interest in the construction of coordination polymers based on pyridine derivates [14–17]. As a multi-chelating ligand, chelidamic acid (4-hydroxy-pyridine-2,6-dicarboxylic acid) has been of great attraction due to its usage in many areas of science, such as coordinate chemistry, biochemistry, organic chemistry, medical chemistry, and even in HIV investigation [18–23]. In addition, the research on lanthanide complexes is currently of great interest because of their unique physicochemical
* Corresponding author at: Key Laboratory of Nondestructive Testing, Nanchang Hangkong University, Ministry of Education, Nanchang, Jiangxi 330063, PR China. Tel.: +86 791 3953377; fax: +86 791 3953373. ** Corresponding author. E-mail addresses: [email protected] (J.-P. Zou), [email protected] (Q. Peng). 0277-5387/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.poly.2010.06.008
properties and various applications as functional materials [24– 26]. Especially, the magnetic and luminescent properties of lanthanide complexes have aroused much attention for decades [27–30]. Therefore, in order to obtain MOFs with novel structures and good magnetic and luminescent properties, we chose to incorporate lanthanide ions with chelidamic acid. Herein, we report syntheses, crystal structures, and magnetic and luminescent properties of a series of MOFs built from lanthanide complexes with chelidamic acid, [Ln(C7H2NO5)3H2O]nnH2O (Ln = La (1), Y (2), Sm (3), and Nd (4)), [Gd2(C7H2NO5)34H2O]n2nH2O (5) and [Ce(C7H2NO5)1.5H2O]n (6). 2. Experimental 2.1. Materials and measurement All of the chemicals were analytically pure (>99.99%) and used without further purification. UV–Vis spectra were recorded at the room temperature on a computer-controlled PE Lambda 900 UV– Vis spectrometer equipped with an integrating sphere in the wavelength range 200–2000 nm. Elemental analyses (C, H and N) were carried out with an Elementar Vario EL. Photoluminescence analyses were performed on an Edinburgh FLS920 fluorescence spectrometer. Variable-temperature magnetic susceptibility and field dependence magnetization measurements on polycrystalline samples were performed on an MPMS-XL and PPMS 9T Quantum Design SQUID magnetometer.
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2.2. Syntheses
2.3. X-ray crystallographic studies
2.2.1. Synthesis of [Ln(C7H2NO5)3H2O]nnH2O (1–4) (Ln = La,Y, Sm, Nd) A mixture of LnCl3 (Ln = La, Sm and Nd for 1, 3 and 4, respectively) or Y(NO3)3 (for 2) (0.75 mmol), chelidamic acid (0.5 mmol), and water (10 mL) was loaded into a 25-mL Teflon-lined autoclave, and heated at 413 K for 3 days, after which it was cooled to room temperature over 4 days. Light-yellow prismatic crystals of 1 that are stable in air were obtained by filtration of the result solution. Yield: 73% (based on chelidamic acid). Anal. Calc. for 1: C, 21.50; H, 2.57; N, 3.58. Found: C, 21.54; H, 2.60; N, 3.62%. Light-yellow prismatic crystals of 2 that are stable in air were obtained by filtration of the result solution. Yield: 71% (based on chelidamic acid). Anal. Calc. for 2: C, 24.65; H, 2.94; N, 4.10. Found: C, 24.69; H, 2.97; N, 4.14%. Yellow prismatic crystals of 3 that are stable in air were obtained by filtration of the result solution. Yield: 76% (based on chelidamic acid). Anal. Calc. for 3: C, 20.89; H, 2.49; N, 3.48. Found: C, 20.93; H, 2.52; N, 3.51%. Light-yellow prismatic crystals of 4 that are stable in air were obtained by filtration of the result solution. Yield: 68% (based on chelidamic acid). Anal. Calc. for 4: C, 21.21; H, 2.53; N, 3.53. Found: C, 21.24; H, 2.56; N, 3.57%.
Single crystals of 1–6 suitable for X-ray analyses were mounted, respectively, at the apex of a glass fiber for X-ray diffraction data collection. Data sets of 1, 2, 3, and 5 were collected on Rigaku Mercury CCD diffractometer, and those of 4 and 6 were collected on Rigaku AFC7R diffractometer, using a graphite monochromated Mo Ka radiation (k = 0.71073 Å) from a rotating anode generator at 293 K. The intensity data were collected with an x scan technique and corrected for LP factors. All the structures were solved by direct methods and refined on F2 with full-matrix least-squares techniques using Siemens SHELXTL™ version 5 package of crystallographic software [31]. The final refinements included anisotropic displacement parameters for all non-hydrogen atoms and a secondary extinction correction. The H atoms of all water molecules for 1–6 and those of hydroxyl oxygen for 5 and 6 were0 found in difference Fourier map, with O–H distances of 0.85(3) Å A, and refined in riding mode with Uiso(H) values of 1.5 Ueq(O). Other H atoms were allowed to ride on their respective parent atoms with C–H 0 distances of 0.93 Å A, respectively, and were included in the refinement with isotropic displacement parameters Uiso(H) = 1.2 Ueq(C). The crystallographic data of 1–6 are listed in Table 1. Selected bond lengths are given in Table 2.
2.2.2. Synthesis of [Gd2(C7H2NO5)34H2O]n2nH2O (5) The process of synthesis is same to that of 1 except for the dosage of reactant [GdCl3 (0.50 mmol), chelidamic acid (0.75 mmol), and water (10 mL)] Light-yellow prismatic crystals of 5 that are stable in air were obtained by filtration of the result solution. Yield: 79% (based on chelidamic acid). Anal. Calc. for 5: C, 26.11; H, 2.19; N, 4.35. Found: C, 26.15; H, 2.22; N, 4.38%.
2.4. Computational descriptions
2.2.3. Synthesis of [Ce(C7H2NO5)1.5H2O]n (6) The process of synthesis is same to that of 1 except for the dosage of reactant [Ce2O3 (0.50 mmol), chelidamic acid (0.50 mmol), and water (10 mL)] Light-yellow prismatic crystals of 6 that are stable in air were obtained by filtration of the result solution. Yield: 58% (based on chelidamic acid). Anal. Calc. for 6: C, 24.65; H, 0.94; N, 4.36. Found: C, 24.69; H, 1.00; N, 4.40%.
The crystallographic data of 1 determined by X-ray was used to calculate the electronic band structure. Calculation of the electronic band structure along with density of states (DOS) was carried out with density functional theory (DFT) using one of the three nonlocal gradient corrected exchange-correlation functional (GGA-PBE) and performed with the CASTEP code [32], which uses a plane wave basis set for the valence electrons and norm-conserving pseudopotential for the core electrons [33]. The number of plane waves included in the basis was determined by a cutoff energy Ec of 550 eV. Pseudoatomic calculations were performed for H-1s1, C-2s22p2, N-2s22p3, O-2s22p4, and La-5d14s2. The parameters used in the calculations and convergence criteria were set by the default values of the CASTEP code [34].
Table 1 Crystal data and structure refinement parameters for 1–6.
a b
Compounds
1
2
3
4
5
6
Formula Formula weight (g/mol) Crystal color Crystal habit Crystal system Space group a (Å) b (Å) c (Å) b (°) V (Å3) Z k (Å) Dcalcd. (g/cm3) l (mm1) F(0 0 0) R(int) R1a, wR2b Goodness-of-fit (GOF) Dqmax and Dqmin (e Å3)
C7H10LaNO9 391.07 light yellow prism monoclinic P2(1)/n 9.942(2) 7.5576(15) 15.465(3) 105.26(3) 1121.1(4) 4 0.71073 2.317 3.853 752 0.0831 0.0405, 0.1271 0.987 1.347, 1.519
C7H10YNO9 341.07 light yellow prism monoclinic P2(1)/n 9.879(5) 7.569(3) 15.419(8) 105.299(5) 1112.1(10) 4 0.71073 2.037 5.287 680 0.0456 0.0350, 0.0735 0.988 0.436, 0.371
C7H10SmNO9 402.51 yellow block monoclinic P2(1)/n 10.047(3 7.521(2) 15.578(5) 104.753(4) 1138.4(6) 4 0.71073 2.349 5.200 772 0.0257 0.0208, 0.0606 0.991 0.970, 0.969
C7H10NdNO9 396.40 light yellow prism monoclinic P2(1)/n 10.109(2) 7.5421(15) 15.653(3) 104.49(3) 1155.5(4) 4 0.71073 2.279 4.534 764 0.0159 0.0258, 0.0827 1.008 0.914, 0.902
C21H21Gd2N3O21 965.91 light yellow prism monoclinic P2(1)/n 9.616(3) 13.500(4) 22.082(6) 92.583(3) 2863.6(14) 4 0.71073 2.240 4.693 1856 0.0292 0.0231, 0.0642 0.995 0.953, 1.149
C14H10Ce2N2O13 694.48 light yellow prism monoclinic C2/c 7.9916(8) 10.4155(10) 20.951(2) 99.512(2) 1719.9(3) 4 0.71073 2.682 5.309 1312 0.0287 0.0548, 0.1451 0.999 1.293, 1.582
P P R = ||Fo| |Fc||/ |Fo|. P P Rw ¼ f ½wðF 2o F 2c Þ2 = ½wðF 2o Þ2 g1=2 .
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Table 2 Selected bond distances (Å) for 1–6.a Bond
Distance (Å)
Bond
Distance (Å)
1 La(1)–O(5)#1 La(1)–O(3W) La(1)–O(1W) La(1)–O(3) O(5)–C(3) C(1)–C(6)
2.298(3) 2.359(4) 2.375(4) 2.399(3) 1.310(5) 1.510(7)
La(1)–O(2W) La(1)–O(4)#2 La(1)–O(1) La(1)–N(1) C(5)–C(7)
2.400(4) 2.411(3) 2.416(3) 2.462(4) 1.501(6)
2 Y(1)–O(5)#1 Y(1)–O(1W) Y(1)–O(2W) Y(1)–O(3) O(5)–C(3) C(1)–C(6)
2.277(2) 2.336(2) 2.346(2) 2.384(3) 1.327(3) 1.510(4)
Y(1)–O(3W) Y(1)–O(4)#2 Y(1)–O(1) Y(1)–N(1) C(5)–C(7)
2.391(3) 2.393(2) 2.409(2) 2.457(3) 1.498(4)
3 Sm(1)–O(15)#1 Sm(1)–O(1W) Sm(1)–O(3W) Sm(1)–O(11) O(15)–C(13) C(11)–C(16)
2.348(3) 2.424(3) 2.436(3) 2.443(3) 1.322(4) 1.496(5)
Sm(1)-O(12)#2 Sm(1)–O(13) Sm(1)–O(2W) Sm(1)–N(11) C(15)–C(17)
2.446(2) 2.450(3) 2.457(3) 2.508(3) 1.514(5)
4 Nd(1)–O(5)#1 Nd(1)–O(2W) Nd(1)–O(1W) Nd(1)–O(3) O(5)–C(3) C(1)–C(6)
2.375(3) 2.450(3) 2.466(3) 2.471(3) 1.315(4) 1.496(5)
Nd(1)–O(1) Nd(1)–O(2)#2 Nd(1)–O(3W) Nd(1)–N(1) C(5)–C(7)
2.472(3) 2.476(3) 2.485(3) 2.545(3) 1.512(5)
5 Gd(1)–O(22)#1 Gd(1)–O(32) Gd(1)–O(34) Gd(1)–O(4W) Gd(1)–O(11) Gd(1)–O(1W) Gd(1)–O(2W) Gd(1)–O(3W) Gd(2)–O(13) O(1)–C(13) O(2)–C(23) O(3)–C(33) C(31)–C(36)
2.311(3) 2.370(2) 2.383(2) 2.385(3) 2.402(2) 2.424(3) 2.438(3) 2.465(3) 2.427(3) 1.336(4) 1.334(5) 1.329(4) 1.508(5)
Gd(2)–O(31) Gd(2)–O(33) Gd(2)–O(12) Gd(2)–O(21) Gd(2)–O(24) Gd(2)–N(1) Gd(2)–N(2) Gd(2)–N(3) C(11)–C(16) C(15)–C(17) C(21)–C(26) C(25)–C(27) C(31)–C(36) C(35)–C(37)
2.432(3) 2.436(2) 2.472(2) 2.501(3) 2.500(3) 2.497(3) 2.548(3) 2.483(3) 1.507(5) 1.532(5) 1.494(5) 1.511(5) 1.508(5) 1.515(5)
6 Ce(1)–O(3) 2 Ce(1)–O(1) 2 Ce(1)–O(1W) Ce(1)–O(2W) 2 Ce(2)–O(1)#1 O(5)–C(3)
2.505(3) 2.537(4) 2.545(6) 2.595(4) 2.340(3) 1.363(6)
Ce(2)–O(1)#2 Ce(2)–O(3) 2 Ce(2)–O(2W)#3 Ce(2)–O(2W)#4 Ce(1)–N(1) 2 C(1)–C(6) C(5)–C(7)
2.340(3) 2.639(4) 2.690(4) 2.690(4) 2.603(4) 1.509(7) 1.511(7)
a Symmetry transformations used to generate equivalent atoms. For 1: #1 x + 1/2, y + 3/2, z + 1/2; #2 x 1/2, y + 1/2, z + 1/2. For 2: #1 x + 1/2, y + 1/2, z + 1/2; #2 x 1/2, y + 1/2, z + 1/2. For 3: #1 x + 1/2, y + 1/2, z + 1/2; #2 x + 3/2, y 1/ 2, z + 1/2. For 4: #1 x 1/2, y + 3/2, z 1/2; #2 x + 1/2, y 1/2, z + 1/2. For 5: #1 x + 5/2, y 1/2, z + 1/2. For 6: #1 x, y, z + 1/2; #2 x 1, y, z; #3 x 1/2, y + 1/2, z; #4 x 1/2, y + 1/2, z + 1/2.
3. Results and discussion 3.1. Description of crystal structures The X-ray crystallography analyses revealed that 1–4 are isomorphous, so we will choose 1, 5 and 6 for detailed structural discussions. In addition, compounds 1–4 are isomorphous to the previously published Dy, Er and Gd complexes [37], while compound 5 is isomorphous to the previously reported Tb, Pr and Nd complexes [42].
3.1.1. [Ln(C7H2NO5)3H2O]nnH2O (1–4) As shown in Fig. 1a, the asymmetric unit of 1 consists of one La(III) ion, one fully deprotonated chelidamic acid trianionic ligand, three coordinated water molecules, and one discrete water molecule. In 1, the La1 atom is eight-coordinated by one chelated tridentate chelidamic acid ligand, two oxygen atoms (O4B and O5A) and three coordinated water molecules to form a distorted bicapped square-prismatic coordination geometry (Fig. 1a). The La– 0 O bond distances range from 2.298(3) to 2.416(3) Å A and the La–N 0 bond distance is 2.462(4) Å A (Table 2), which are much shorter than those reported for the lanthanum complexes with chelidamic acid [35,36]. Same to the structures of the Dy, Er and Gd complexes reported in the literature [37], the La atoms in 1 are interconnected through the chelidamic acid ligand to generate a 2D architecture (Fig. 1b). Furthermore, the 2D frameworks are further assembled to form a 3D supramolecular network by the hydrogen bonds between water molecules and carboxylate O atoms or hydroxyl groups. 3.1.2. [Gd2(C7H2NO5)34H2O]n2nH2O (5) The asymmetric unit of 5 consists of two Gd(III) ions, three fully deprotonated chelidamic acid anionic ligands, four coordinated water molecules, and two discrete water molecules (Fig. 2a). The Gd1 atom is eight-coordinated with slightly distorted dodecahedral geometry, while the Gd2 atom is nine-coordinated with slightly distorted tricapped trigonal prism geometry. The Gd–O0 and Gd–N bond distances0 in 5 range from 2.311(3) to 2.501(3) Å A and 2.483(3) to 2.548(3) Å A (Table 2), respectively, which all lie in the normal range of those reported Gd complexes with chelidamic acid in the literature [37,38]. Same to the structures of the Tb, Pr and Nd complexes reported in the literature [42], the two different polyhedra comprised by the two different Gd atoms are linked through carboxylate group to form a 2D grid (Fig. 2b), which are further bridged through complex hydrogen bonds between water molecules and carboxylate O atoms or hydroxyl groups to form a 3D supramolecular framework. 3.1.3. [Ce(C7H2NO5)1.5H2O]n (6) The single-crystal X-ray analysis reveals that there are two types of crystallographically independent Ce atoms with different coordination environments in 6 (Fig. 3a). The Ce1 atom is ninecoordinated with a tricapped trigonal prism geometry made up of four oxygen atoms and two nitrogen atoms from two chelated tridentate chelidamic acid ligands and three coordinated water molecules. The Ce2 atom is six-coordinated by four O atoms from four different chelidamic acid ligands and two coordinated water molecules. The Ce–O bond distances range from 2.340(3) to 0 0 2.690(4) Å A and the Ce–N bond distance is 2.603(4) Å A (Table 2), which are much shorter than those reported for Ce complex with chelidamic acid [39] but lie in the normal range of those reported for other Ce complexes in the literature [40,41]. In 6, the Ce1 and Ce2 atoms are linked by carboxylate O atoms (O1 and O3) and coordinated water molecules (O2W) to generate a dinuclear homometallic Ce2O10 unit. The Ce2O10 units as building blocks are further assembled into a highly ordered 2D framework, as shown in Fig. 3b and 3c. A better insight into the 2D network of 6 can be achieved by application of a topological approach. As mentioned above, the architecture of 6 can be reduced to a nodal structure of a (44) topology by considering the Ce2O10 unit as a four-connected node, which is the first example for the lanthanide complexes with chelidamic acid [21,23,35,37,42,43]. 3.2. Magnetic properties For 3, the variable-temperature magnetic susceptibility, vM and vMT are shown in Fig. S1. At 300 K, vMT is equal to
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Fig. 1. (a) View of the coordination unit of 1 with 30% probability of thermal ellipsoids. Hydrogen atoms are omitted for clarity. Symmetry codes for A: 0.5 + x, 1.5 y, 0.5 + z; B: 0.5 x, 0.5 + y, 0.5 z; C: 0.5 + x, 1.5 y, 0.5 + z. (b) View of the 2D network of 1 along the a axis.
0.356 cm3 mol1 K and decreases rapidly to a value of 0.087 cm3 mol1 K at 2 K. The thermal variation of vMT is nearly linear over the whole temperature range, which is similar to that for the reported mononuclear complex [44]. But, interestingly, the value of 0.087 cm3 mol1 K for vMT at 2 K is consistent with the value of 0.089 cm3 mol1 K predicted by theory for one Sm(III) ion and obviously smaller than that for two Sm(III) ions. This behavior indicates that an antiferromagnetic interaction possibly exists between Sm(III) ions at low temperature, although it is very weak. The magnetic behavior of 5 is shown in Fig. S2. For 5, a nonlinear fit via vM = C/(T h) + v0 above 20 K reveals a Curie–Wesis behavior with the Curie constant C = 15.83(2) cm3 mol1 K, the Weiss constant h = 0.50(1)°, and the background susceptibility, v0 = 7.9(3) 104 cm3/mol. The vM value increases with decreasing the temperature, reaching a maximum of 5.30 cm3/ mol at around 3.0 K, and then decreases very quickly. The value of vMT is 15.83 cm3 mol1 K at room temperature, which is close to the value expected for two isolated Gd(III) ions (15.86 cm3 mol1 K). On lowering the temperature, the value of vMT decreases smoothly until approximately 4 K and then decreases at a faster rate, reaching a value of 8.89 cm3 mol1 K at 2 K. This is characteristic of significant antiferromagnetic ordering (TN =
3.0 K), and the magnetic interactions mediated by chelidamic acid group are effective in 5. 3.3. Luminescent properties The solid-state electronic emission spectra of 1, 2 and 5 at room temperature show luminescence features as given in Fig. S3. Complexes 1 and 2 both display green fluorescence with the maximum emission at 509 and 511 nm upon excitation at 355 nm and 360 nm, respectively, while complex 5 displays blue fluorescence with the maximum emission at 445 nm upon excitation at 315 nm. The strongest emission peaks for free chelidamic acid ligand is at about 525 nm, which is due to the p ? p* transition [35]. Compared to the free chelidamic acid ligand, 1 and 2 result in a little blue shift of 16 and 14 nm, respectively, while a large blue shift of 80 nm appears in 5. The results indicate that the emission of 1 and 2 may be both originated from p–p* transition of the ligand, while the emission of 5 may be originated from charge transition between the ligand and the Gd(III) ion [45–48]. The solid-state electronic emission spectrum of 3 at room temperature excited at 366 nm is shown in Fig. S4. The broad and strong emission bands in 420–550 nm (kem = 510 nm) are due to
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Fig. 2. (a) View of the coordination unit of 5 with 30% probability of thermal ellipsoids. Hydrogen atoms are omitted for clarity. Symmetry codes for A: 1 + x, y, z; B: 1.5 x, 0.5 + y, 0.5 z; C: 2.5 x, 0.5 + y, 0.5 z. (b) View of the 2D network built from polyhedra of 5 along the c axis. The H atoms and uncoordinated atoms of pyridine rings and hydroxyl groups are omitted.
Fig. 3. (a) View of the coordination unit of 6 with 30% probability of thermal ellipsoids. Hydrogen atoms are omitted for clarity. Symmetry codes for A: 1 + x, y, z; B: x, y, 0.5 z; C: 0.5 + x, 0.5 + y, z; D: 1 + x, y, z; E: 1 x, y, 0.5 z; F: 0.5 x, 0.5 + y, 0.5 z. (b) View of the 2D network of 6 along the b axis (c) View of the highly ordered 2D framework of 6 along the c axis. The H atoms and uncoordinated atoms of pyridine rings and hydroxyl groups are omitted.
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the p ? p* transition of chelidamic acid ligand. The emission peaks at 559, 595 and 640 nm can be assigned to 4G5/2 ? 6HJ (J = 5/2, 7/ 2, 9/2) transitions of the Sm(III) ion, respectively.
UK; fax: (+44) 1223-336-033; or e-mail: [email protected]. Supplementary data associated with this article can be found, in the online version, at doi:10.1016/j.poly.2010.06.008.
3.4. Band structure and density of state of 1
References
The calculated band structure of 1 along high symmetry points of the first Brillouin zone is plotted in Fig. S5. It is found that the top of valence bands (VBs) and the bottom of conduction bands (CBs) are both relatively flat. The highest energy (0.00 eV) of VBs and the lowest energy (3.11 eV) of CBs in 1 are both localized at the G point. According to the calculation, the solid-state complex 1 thus possesses a direct energy band gap of 3.11 eV, which is close to its experimental values (3.58 eV) shown in Fig. S6. The bands can be assigned according to total and partial densities of states (DOS), as plotted in Fig. S7. The VBs between energy 23.0 and 5.0 eV are mostly formed by O-2s, O-2p, C-2s and C-2p states, mixing with small N-2s, N-2p and La-5d states. And the VBs between energy 5.0 eV and the Fermi level (0.0 eV) are mainly contribution from O-2p and C-2p states mixing with a small amount of La-5d and N2p states, while the CBs between 3.1 and 8.0 eV are almost contribution from C-2p and O-2p states mixing with a small amount of N-2p and La-5d states. Therefore, the origin of the emission band of 1 may be mainly ascribed to intraligand charge transfer (ILCT) where the electrons are transferred from O-2p to C-2p states [49–51]. This analysis is also consistent with the above experimental result. 4. Conclusions
[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22] [23]
In summary, a series of lanthanide(III) complexes with chelidamic acid, [Ln(C7H2NO5)3H2O]nnH2O (Ln = La (1), Y (2), Sm (3), and Nd (4)), [Gd2(C7H2NO5)34H2O]n2nH2O (5) and [Ce(C7H2NO5)1.5H2O]n (6), have been synthesized by hydrothermal reaction. The X-ray diffraction analyses show that complexes 1–4 are isostructural and possess 2D framework. Complex 5 contains two different Gd(III) ions linked through carboxylate group to form a 2D framework. Complex 6 exhibits a (44) topology 2D network, which is the first example for lanthanide complexes with chelidamic acid. The variable-temperature magnetic properties of 3 and 5 have been investigated. Complex 3 shows a weak antiferromagnetic interaction between Sm(III) ions at low temperature, while complex 5 shows an antiferromagnetic ordering interaction between Gd(III) ions. Furthermore, the photoluminescent properties of 1, 2, 3, and 5 at room temperature were also studied. The results indicate that the emission of 1 and 2 may be originated from intraligand charge transfer (ILCT) of the chelidamic acid ligand, and the emission of 5 may be originated from charge transition between the ligand and the Gd(III) ion, while complex 3 exhibits emission for ligands and Sm(III) centers. Acknowledgements We gratefully acknowledge the financial support of the NSF of China (20801026), the NSF of Jiangxi Province (2008GQC0036), the Aviation Science Foundation of China (2008ZF56012), and Open Fund of the Key Laboratory of Nondestructive Testing, Ministry of Education, Nanchang Hangkong University (ZD200929007). Appendix A. Supplementary data CCDC 732621, 732622, 732623, 732624, 732625 and 763809 contain the supplementary crystallographic data for 1, 2, 3, 4, 5 and 6. These data can be obtained free of charge via http:// www.ccdc.cam.ac.uk/conts/retrieving.html, or from the Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ,
[24] [25] [26] [27] [28] [29] [30] [31] [32] [33] [34] [35] [36] [37] [38] [39] [40] [41] [42] [43] [44] [45] [46] [47] [48] [49] [50] [51]
B.F. Hoskins, R. Robson, J. Am. Chem. Soc. 112 (1990) 1546. T. Savaki, T. Dewa, Y. Aoyama, J. Am. Chem. Soc. 120 (1998) 8539. K. Seki, S. Takamizawa, W. Mori, Chem. Lett. (2001) 122. H. Maas, A. Currao, G. Calzaferri, Angew. Chem., Int. Ed. 41 (2002) 2495. H. Tsukube, S. Shinoda, Chem. Rev. 102 (2002) 2389. M.-L. Tong, X.-M. Chen, S.R. Batten, J. Am. Chem. Soc. 125 (2003) 16170. P.J. Hagrman, D. Hagrman, J. Zubieta, Angew. Chem., Int. Ed. 38 (1999) 2638. O. Ohmori, M. Kavano, M. Fujita, J. Am. Chem. Soc. 126 (2004) 16292. A.P. Cote, A.I. Benen, N.W. Ockwig, M. O’Keeffe, A.J. Matzger, O.M. Yaghi, Science 310 (2005) 1166. O.M. Yaghi, M. O’Keeffe, N.W. Ockwig, H.K. Chae, M. Eddaoudi, J. Kim, Nature 423 (2003) 705. H. Furukawa, J. Kim, N.W. Ockwig, M. O’Keeffe, O.M. Yaghi, J. Am. Chem. Soc. 130 (2008) 11650. S.R. Seidel, P.J. Stang, Acc. Chem. Res. 35 (2002) 972. B.-H. Ye, M.-L. Tong, X.-M. Chen, Coord. Chem. Rev. 249 (2005) 545. C.Y. Niu, B.L. Wu, X.F. Zheng, H.Y. Zhang, H.W. Hou, Y.Y. Niu, Z.J. Li, Cryst. Growth Des. 8 (2008) 1566. X.W. Wang, J.Z. Chen, J.H. Liu, Cryst. Growth Des. 7 (2007) 1227. J.P. Zhang, Y.Y. Lin, X.C. Huang, X.M. Chen, J. Am. Chem. Soc. 127 (2005) 5495. M.H. Klingele, S. Brooker, Coord. Chem. Rev. 241 (2003) 119. Y. Nakatsuji, J.S. Bradshaw, P.K. Tse, G. Arena, B.E. Wilson, N.K. Wilson, N.K. Dalley, R.M. Izatt, Chem. Commun. (1985) 749. T. Fessmann, J.D. Kilburn, Angew. Chem., Int. Ed. 38 (1999) 1993. M. Searcey, S. MeClean, B. Madden, A.T. McGown, L.P.G. Wakelin, Anti-Cancer Drug Des. 13 (1998) 837. B. Zhao, H.-L. Gao, X.-Y. Chen, P. Cheng, W. Shi, D.-Z. Liao, S.-P. Yan, Z.-H. Jiang, Chem. Eur. J. 12 (2006) 149. J.-P. Zou, G.-W. Zhou, X. Zhang, M.-S. Wang, Y.-B. Lu, W.-W. Zhou, Z.-J. Zhang, G.-C. Guo, J.-S. Huang, CrystEngComm 11 (2009) 972. H.-L. Gao, B. Zhao, X.-Q. Zhao, Y. Song, P. Cheng, D.-Z. Liao, S.-P. Yan, Inorg. Chem. 47 (2008) 11057. B. Yan, H.J. Zhang, S.B. Wang, J.Z. Ni, Mater. Res. Bull. 33 (1998) 1517. G.F. de Sá, O.L. Malta, Coord. Chem. Rev. 196 (2000) 165. J. Kido, Y. Okamoto, Chem. Rev. 102 (2002) 2357. N. Ishikawa, S. Otsuka, Y. Kaizu, Angew. Chem., Int. Ed. 44 (2005) 731. S.J.A. Pope, B.J. Coe, S. Faulkner, E.V. Bichenkova, X. Yu, K.T. Douglas, J. Am. Chem. Soc. 124 (2004) 9490. W.S. Liu, T.Q. Jiao, Y.Z. Li, Q.Z. Liu, M.Y. Tan, H. Wang, L.F. Wang, J. Am. Chem. Soc. 126 (2004) 2280. L.M. Fu, X.F. Wen, X.C. Ai, Y. Sun, Y.S. Wu, J.P. Zhang, Y. Wang, Angew. Chem., Int. Ed. 44 (2005) 747. Siemens SHELXTL™ Version 5 Reference Manual, Siemens Energy & Automation Inc., Madison, Wisconsin, USA, 1994. M. Segall, P. Linda, M. Probert, C. Pickard, P. Hasnip, S. Clark, M. Payne, Materials Studio CASTEP Version 2.2, 2002. D.R. Hamann, M. Schluter, C. Chiang, Phys. Rev. Lett. 43 (1979) 1494. M. Segall, P. Linda, M. Probert, C. Pickard, P. Hasnip, S. Clark, M. Payne, J. Phys.: Condens. Mat. 14 (2002) 2717. J.-P. Zou, M.-J. Li, Q.-J. Xing, Z.-H. Wen, G.-S. Zeng, A.-Q. Zhang, Q. Peng, G.-C. Guo, Austr. J. Chem. 63 (2010) 942. J.P. Zou, G.W. Zhou, G.C. Guo, L.S. Yan, G.S. Zeng, J.S. Huang, Chin. J. Struct. Chem. 27 (2008) 1323. H.-L. Gao, L. Yi, B. Zhao, X.-Q. Zhao, P. Cheng, D.-Z. Liao, S.-P. Yan, Inorg. Chem. 45 (2006) 5980. A.K. Hall, J.M. Harrowfield, B.W. Skelton, A.H. White, Acta Crystallogr. C 56 (2000) 407. J.-P. Zou, G.-W. Zhou, G.-C. Guo, L.-S. Yan, G.-S. Zeng, J.-S. Huang, Chin. J. Struct. Chem. 28 (2009) 1033. S.K. Ghosh, P.K. Bharadwaj, Inorg. Chem. 43 (2004) 2293. T.K. Prasad, M.V. Rajasekharan, Cryst. Growth Des. 6 (2006) 488. Z. Chen, M. Fang, P. Ren, X.-H. Li, B. Zhao, S. Wei, P. Cheng, Z. Anorg. Allg. Chem. 634 (2008) 382. X. Zhao, Z. Chen, B. Zhao, W. Shi, P. Cheng, Inorg. Chem. Commun. 10 (2007) 1433. Y. Li, F.-K. Zheng, X. Liu, W.-Q. Zou, G.-C. Guo, C.-Z. Lu, J.-S. Huang, Inorg. Chem. 45 (2006) 6308. J.-P. Zhang, Y.-Y. Lin, X.-C. Huang, X.-M. Chen, J. Am. Chem. Soc. 127 (2005) 5495. B. Liu, L. Xu, G.-C. Guo, J.-S. Huang, Inorg. Chem. Commun. 9 (2006) 687. J.-P. Zou, Q. Peng, G.-S. Zeng, Z.-H. Wen, Q.-J. Xing, M.-H. Chen, G.-C. Guo, J.-S. Huang, J. Mol. Struct. 921 (2009) 323. J.-P. Zou, G.-S. Zeng, Z.-H. Wen, Q. Peng, Q.-J. Xing, M.-H. Chen, G.-C. Guo, J.-S. Huang, Inorg. Chim. Acta 362 (2009) 4843. R.-B. Zhang, Z.-J. Li, Y.-Y. Qin, J.-K. Cheng, J. Zhang, Y.-G. Yao, Inorg. Chem. 47 (2008) 4861. F.-Y. Yi, N. Zhao, W. Wu, J.-G. Mao, Inorg. Chem. 48 (2009) 628. J.-P. Zou, Q. Peng, Z.-H. Wen, G.-S. Zeng, Q.-J. Xing, G.-C. Guo, Crsyt. Growth Des. 10 (2010) 2613.