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Three complexes based on ligands 1-hydroxybenzotriazole and 1,4-benzenedicarboxylic acid: Synthesis, structures and luminescence properties
Inorganica Chimica Acta 362 (2009) 5183–5189
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Inorganica Chimica Acta journal homepage: www.elsevier.com/locate/ica
Three complexes based on ligands 1-hydroxybenzotriazole and 1,4-benzenedicarboxylic acid: Synthesis, structures and luminescence properties Zhong-Qiang Zhang a,b, Ru-Dan Huang a,*, Yan-Qing Xu a, Li-Qiong Yu a, Zhi-Wei Jiao a, Qin-Lei Zhu a, Chang-Wen Hu a,* a b
Department of Chemistry, School of Science, Beijing Institute of Technology, Beijing 100081, PR China Department of Chemistry, HengShui University, HengShui City, HeBei Province 053000, PR China
a r t i c l e
i n f o
Article history: Received 19 April 2009 Received in revised form 17 August 2009 Accepted 9 September 2009 Available online 16 September 2009 Keywords: 1-Hydroxybenzotriazole 1,4-Benzenedicarboxylic acid Chemical synthesis Crystal structure Luminescence properties
a b s t r a c t Three new complexes, [Mn(OBt)2(H2O)4]3H2O (1) (OBt = 1-hydroxybenzotriazole ion), [Zn2(OBt)2(BDC)(H2O)H2O]n (2) (H2BDC = 1,4-benzenedicarboxylic acid), and [Cu3(OBt)2(BDC)(l3-OH)2(H2O)22H2O]n (3) were synthesized by hydrothermal method and were characterized by elemental analysis, IR spectroscopy, TGA, XRPD, and single-crystal X-ray diffraction. The results from single-crystal X-ray diffraction indicate that 1, 2 and 3 are zero-dimensional (0D), two-dimensional (2D) and two-dimensional (2D) frameworks, respectively. In particular, there are all two crystallographically unique metal ions in the structures of complexes 2 and 3. Complex 2 possesses two helical chains in its structure. In the structure of 3, the chains that are built from tri-copper clusters and l3-O atoms are connected with BDC2 to construct 2D grid structure. The luminescence properties of the three complexes were investigated. Ó 2009 Elsevier B.V. All rights reserved.
1. Introduction The current increasing interest of experts in metal–organic frameworks not only stems from their potential applications in areas such as optoelectronics, magnetism, ion exchange, catalysis, nonlinear optics, fluorescent materials, and porous materials, but also from their intriguing variety of topologies and motifs [1–5]. The compounds that with one or several azole rings in molecule have various types of coordination modes and strong linking ability through bridging with proper metal ions, such as monodentate, bidentate, tridentate, and chelating [6–17]. Benzotriazolate (HBt) and its derivatives are very important compounds which have an azole ring in molecule [18–27]. One of HBt derivatives, HOBt, is a well-known peptide-coupling additive [28,29]. It exhibits corrosion inhibitive properties toward Cu [30,31] and Fe [32,33]. However, there are few relative literatures reported about complexes based on HOBt [29–39]. In the molecule structure of HOBt, one hydroxide substitutes H that connected N(1) of the azole ring (Scheme 1), thus the O atom of hydroxide and two N atoms of azole ring in HOBt can be coordinated to metal ions. In addition, when it coordinates to metal ions, the steric influence of exocyclic O atom on hydroxide is weaker than the influence of N on azole ring. Therefore, HOBt provides more coordination modes and choices than HBt does while HOBt is coordinating to metal ions. * Corresponding authors. Tel.: +86 10 68912668. E-mail address: [email protected] (R.-D. Huang). 0020-1693/$ - see front matter Ó 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.ica.2009.09.031
The motivation for this study was the expectation that HOBt could potentially provide various coordination motifs to form either discrete or consecutive complexes under appropriate synthesis condition, and could built a variety of types for complexes with various novel and attractive topologies. The three coordination modes between HOBt and metal ions are shown in Scheme 1. As a structural building block, HOBt may link metal centers through N(2), N(3) on azole ring or O atoms on hydroxide to provide secondary building units (SBUs). These building blocks can then be linked through the three coordination sites to expand to high-dimensional materials. Otherwise, p–p conjugation including six-member ring and five-member ring that exists in the molecule of HOBt, and the new complexes based on HOBt may exhibit interesting luminescence properties. H2BDC is a important ligand [40–45]. There are a lot of relative literatures illustrating complexes based on H2BDC [40–45]. The two coordination modes between H2BDC and metal ions are shown in Scheme 2. H2BDC is usually employed in the architectures for metal ions coordination polymers [46]. We aimed to explore promising synthetic routes for the construction of metal–organic complexes via combination of HOBt and H2BDC and metal cations. The synthetic strategy is to construct 1D framework using HOBt and metal cations, then achieve new high-dimensional MOFs by BDC2 ions as bridging ligand. In this paper, three novel complexes, [Mn(OBt)2(H2O)4]3H2O, [Zn2(OBt)2(BDC)(H2O)H2O]n and [Cu3(OBt)2(BDC)(l3-OH)2(H2O)2 2H2O]n, were synthesized and were characterized by elemental
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Scheme 1. Three coordinated modes of HOBt in the text.
Scheme 2. Two coordinated modes of H2BDC in the text.
analysis, IR spectroscopy, TGA, XRPD, and single-crystal X-ray. The luminescence properties of the three complexes were investigated as well. 2. Experimental section 2.1. Materials and methods All chemicals and reagents were used as received from commercial sources without further purification. Elemental analyses (C, H and N) were performed on a Perkin–Elmer 2400 CHN Elemental Analyzer. The solid infrared spectra (IR) were obtained from a FT-IR-670 spectrophotometer (Thermo Nicolet USA) in the range of 400–4000 cm 1 by using KBr pellets. XRPD were performed with a Rigaku D/max cA (Japan, k = 0.154060 nm). Thermo-gravimetric analyses (TGA) were performed with a NETSCHZ STA-499C thermoanalyzer under N2 (20–600 °C range) at a heating rate of 10 °C/min. Data collections of X-ray diffraction intensities for the three compounds were performed on Bruker SMART APEX-CCD diffractometer equipped with graphite-monochromated Mo Ka radiation (k = 0.71073 Å). Intensity data were collected at 273 K for 1, 173 K for 2 and 3, respectively. Empirical absorption corrections were applied using the SADABS program. The three structures were solved by direct methods using SHELXTL-97 [47] package of crystallographic software and refined by full-matrix least-squares technique on F2. All non-hydrogen atoms were refined with anisotropic thermal parameters. Hydrogen atoms attached to C, N and O atoms were located at geometrically calculated positions and refined with isotropic thermal parameters included in the final stage of the refine-
Table 1 Crystal data and structure refinements for compounds 1–3 Complex
1
2
3
Formula Formula weight Temperature (K) Crystal system Space group a (Å) b (Å) c (Å) a (°) b (°) c (°) V (Å3) Z Dcalcd (Mg m 3) F(0 0 0) Reflections collected Goodness-of-fit on F2 R1, wR2[I > 2r(I)] R1, wR2 (all data)
C12H22N6OgMn 449.3 273(2) monoclinic P21/c 6.875(2) 9.811(3) 28.102(9) 90 94.159(5) 90 1890.6(11) 4 1.579 932 11378 1.001 0.0699, 0.1828 0.1027, 0.2010
C20H16N6O8Zn2 599.13 173(2) monoclinic P21/c 18.483(3) 5.3787(9) 28.182(4) 90 129.600(7) 90 2158.7(6) 4 1.843 1208 12652 0.982 0.0459, 0.0845 0.0852, 0.0980
C20H22N6O12Cu3 729.07 173(2) monoclinic C2/c 26.223(18) 5.928(4) 16.115(10) 90 97.152(15) 90 2486(3) 4 1.943 1460 7439 0.991 0.0482, 0.1017 0.0819, 0.1188
ment on calculated positions bonded to their carrier atoms. The crystal data and structure refinements for compounds 1–3 are shown in Table 1.
2.2. Synthesis of [Mn(OBt)2(H2O)4]3H2O (1) A mixture of 1-hydroxybenzotriazole 0.0675 g (0.5 mmol) and Mn(CH3COO)24H2O 0.1225 g (0.5 mmol), was stirred in water
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(10 mL), and the pH of the mixture was adjusted to 6.0 with a 2 mol L 1 NH3H2O solution. It was then sealed in a 23 mL Telfon-lined stainless-steel container, which was heated to 110 °C for 72 h and then cooled to room temperature at a rate of 6 °C h 1. Colorless crystals were obtained and then they were solvent in 50 mL water again, then filtrated, the solution was left for 10 days, and colorless club crystals were obtained, and air dried. Yield 38% (based on Mn). Anal. Calc. for complex 1: C, 32.07; H, 4.95; N, 18.71. Found: C, 32.27; H, 5.02; N, 18.43%. IR for complex 1 (Figure S1) (solid KBr pellet, cm 1): 3397.3(s), 3200.0(s), 1561.6(s), 1408.2(s), 1347.9(w), 1276.7(w), 1216.4(w), 1189.0(w), 1156.2(m), 1139.7(w), 1112.3(s), 1052.1(w), 1024.7(w), 942.5(w), 739.7(m), 663.0(m), 619.2(w), 438.4(w). 2.3. Synthesis of [Zn2(OBt)2(BDC)(H2O)H2O]n (2) A mixture of HOBt 0.0675 g (0.5 mmol), H2BDC 0.0657 g (0.4 mmol) and Zn(NO3)24H2O 0.1307 g (0.5 mmol), was stirred in water (10 mL), and the pH of the mixture was adjusted to 7.0 with a 2 mol L 1NaOH solution. It was then sealed in a 23 mL Telfon-lined stainless-steel container, which was heated to 110 °C for 72 h and then cooled to room temperature at a rate of 6 °C h 1. Colorless club crystals were obtained, wished with dehydrated alcohol, and air dried. Yield 56% (based on Zn). Anal. Calc. for complex 2: C, 40.18; H, 2.53; N, 14.22. Found: C, 40.09; H, 2.69; N, 14.03%. IR for complex 2 (Figure S2) (solid KBr pellet, cm 1): 3101.4(m), 1578.1(s), 1506.8(m), 1463.0(m), 1402.7(s), 1287.7(w), 1232.9(w), 1167.1(m), 1139.7(m), 1117.8(m), 1019.2(m), 1002.7(w), 953.4(m), 887.7(m), 854.8(s), 794.5(m), 778.1(m), 761.6(m), 750.7(s), 641.1(w), 613.7(w), 586.3(w), 526.0(m), 454.8(m). 2.4. Synthesis of [Cu3(OBt)2(BDC)(l3-OH)2(H2O)22H2O]n (3) A mixture of HOBt 0.0675 g (0.5 mmol), H2BDC 0.0657 g (0.4 mmol) and CuSO45H2O 0.1284 g (0.5 mmol), was stirred in water (10 mL), and the pH of the mixture was adjusted to 6.0 with a 2 mol L 1NaOH solution. It was then sealed in a 23 mL Telfon-lined stainless-steel container, which was heated to 110 °C for 72 h and then cooled to room temperature at a rate of 6 °C h 1.Green club crystals were obtained, wished with distilled water, and air dried. Yield 62% (based on Cu). Anal. Calc. for complex 3: C, 32.94; H, 3.04; N, 11.52. Found: C, 33.23; H, 2.97; N, 11.45%. IR for complex 3 (Figure S3) (solid KBr pellet, cm 1): 3101.4(m), 1600.0(s), 1501.4(m), 1452.1(s), 1419.2(m), 1402.7(m), 1358.9(s), 1243.8(w), 1216.4(w), 1167.1(m), 1117.8(w), 1019.2(w), 997.3(w), 947.9(w), 805.5(w), 745.2(m), 597.8 (w), 526.0(w), 498.6(m).
3. Result and discussion 3.1. Description of the structures 3.1.1. [Mn(OBt)2(H2O)4]3H2O (1) Single-crystal X-ray diffraction analysis has revealed that the compound [Mn(OBt)2(H2O)4]3H2O crystallizes in the monoclinic system space group P21/n. The unit cell contains four identical [Mn(OBt)2(H2O)4]3H2O formula units. As shown in Fig. 1, Mn(II) is six coordinated with two N atoms from two OBt ions and four O atoms from four H2O molecules, and there are other three lattice water molecules in the structure of [Mn(OBt)2(H2O)4]3H2O. The Mn(1)–N(1) and Mn(1)–N(4) bond lengths are different: the former is 2.273 Å and the latter is 2.262 Å. The bond lengths between
Fig. 1. The structure of [Mn(OBt)2(H2O)4]3H2O, lattice water molecules were omitted.
Table 2 Bond lengths (Å) and angles (°) for complex 1 O(4)–Mn(l) Mn(l)–O(3) Mn(l)–O(6) Mn(l)–O(5) Mn(l)–N(4) Mn(l)–N(1) O(3)–Mn(1)–O(6) O(3)–Mn(1)–O(4) O(6)–Mn(1)–O(4) O(3)–Mn(1)–O(5) O(6 > Mn(1)–O(5) 0(4)–Mn(1)–C(5) O(3)–Mn(1)–N(4) O(6)–Mn(1)–N(4) O(4)–Mn(1)–N(4) O(5)–Mn(1)–N(4) O(3)–Mn(1)–N(1) O(6)–Mn(1)–N(1) O(4)–Mn(1)–N(1) O(5)–Mn(1)–N(1) N(4)–Mn(1)–N(1)
2.217(4) 2.166(4) 2.178(4) 2.216(4) 2.262(3) 2.273(4) 179.46(16) 92.62(15) 86.83(15) 89.53(15) 91.01(15) 176.96(15) 93.00(14) 86.95(14) 87.37(14) 90.38(14) 86.35(14) 93.65(14) 92.34(14) 89.93(14) 179.32(13)
Symmetry transformations used to generate equivalent atoms.
Mn(1) and O atoms from four coordinated H2O molecules are different, too. The N(1)–Mn(1)–N(4) angle is 179.32°. The N–Mn(1)– O(coordinated H2O) angles vary from 86.39° to 93.65°. The angles between Mn(1) and the coordinated H2O molecules vary from 86.83° to 179.46° (Table 2). These angles are almost 90° or 180°. So, Mn(II) adopts a slightly distorted octahedron coordination mode. 3.1.2. [Zn2(OBt)2(BDC)(H2O)H2O]n (2) Compound 2 crystallizes in the monoclinic system space group P21/c. As shown in Fig. 2, Zn(II) is five coordinated with two OBt ions, one BDC2 ions, and one H2O. Each Zn(II) center in the complex adopts a distorted tetragonal pyramid coordination mode, which is defined by one N atom from one OBt ion, one O atom from another OBt ion, two O atoms from a same carboxylic group in one BDC2- ion, and one O atom from one H2O. In complex 2, There are two independent Zn cations and therefore the bonds and angles are different (Table 3) . The distorted tetragonal pyramids by one N atom and four O atoms coordinated with Zn(II) are as parallel chains in the structure of complex 2 (Fig. 3). The two adjacent parallel chains are as a chain unit. A helical chain exists in each chain unit. There are two rightabout helical chains in the structure of complex 2 (Fig. 3 and S12). The repeated unit of the helical chains are all [Zn–(OBt )N3–(OBt )O1–Zn].
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Fig. 2. The structure of complex 2, lattice water molecules were omitted.
Table 3 Bond lengths (Å) and angles (°) for complex 2. Zn(1)–O(2) Zn(1)–N(6)#l Zn(l)–O(1) Zn(1)–O(6)#2 Zn(1)–O(7)#2 Zn(2)–O(4) Zn(2)–O(5) Zn(2)–O(3) Zn(2)–O(8) Zn(2)–n(1) O(3)–N(4) O(7)–Zn(1)#3 O(6)–Zn(1)#3 N(6)–Zn(l)#4 O(2)–Zn(l)–N(6)#l 0(2)–Zn(l)–0(1) N(6)#l–Zn(l)–0(1)
1.9976 2.0035 2.0089 2.0518 2.2955 1.9615 2.565 1.9667 1.9686(8) 2.0078 1.3563 2.2955 2.0518 2.0035 106.4 101.8 105.8
O(2)–Zn(1)–O(6)#2 N(6)#1–Zn(1)–O(6)#2 O(1)–Zn(1)–O(6)#2 O(2)–Zn(1)–O(7)#2 N(6)#l–Zn(1)–O(7)#2 O(1)–Zn(1)–C(7)#2 O(6)#2–Zn(1)–O(7)#2 O(4)–Zn(2)–O(3) O(4)–Zn(2)–O(8) O(3)–Zn(2)–O(8) O(4)–Zn(2)–N(1) O(3)–Zn(2)–N(1) O(8)–Zn(2)–N(1) O(5)–Zn(2)–O(4) O(5)–Zn(2)–O(8) O(5)–Zn(2)–O(3) O(5)–Zn(2)–N(1)
105.9 140.2 89.7 96.7 93.5 148.0 60.1 116.9 114.70(4) 108.03(4) 103.8 109.0 103.37(4) 56.21 91.21 79.50 159.34
Symmetry transformations used to generate equivalent atoms: #1 x, y + 1, z #2x + 1, y 1/2, z + 1/2 #3 x 1, y 1/2, z 1/2 #4 x, y 1, z
The 1-D framework was constructed by OBt and Zn(II). The two adjacent 1D chains were connected by BDC2 ions as bridging ligand to achieve 2D grid structure in complex 2 (Fig. 3 and S13). 3.1.3. [Cu3(OBt)2(BDC)(l3-OH)2(H2O)22H2O]n (3) Compound 3 crystallizes in the monoclinic system space group C2/c. As shown in Fig. 4. There are two crystallographically independent Cu cations in the structure of complex 3. Cu(1) is five coordinated with one O atom (O1) from one OBt ion, one N atom (N3) from another OBt ion, one O atom (O2) from a carboxylic group in one BDC2 ion and two crystallographically equivalent l3-O atoms (O4). The Cu(1)–O(2) and Cu(1)–N(3) bond lengths are 1.921 and 1.9763 Å, and the Cu(1)–O(1) bond length is 2.291 Å, the two bond
lengths between Cu(1)-l3-O are 2.006 and 1.977 Å, respectively. The O–Cu1–O angles and the N–Cu1–O angles are 94.13°, 171.63°, 95.08°, 81.23°, 87.06°, 95.62°, 100.27°,167.40°, 88.55° and 93.43°, respectively (Table 4). So, Cu(1) adopts a distorted tetragonal pyramid coordination mode (Fig. 4). Cu(2) is six coordinated with two crystallographically equivalent N atoms (N2) from two OBt ions, two crystallographically equivalent O atoms (O5) from two H2O molecules, and two crystallographically equivalent l3-O atoms (O4). The two Cu(2)–O(5) bond lengths are 2.4099 Å, and the bond lengths between Cu(2)l3-O are all 1.982 Å. The O–Cu(2)–O angles and the N–Cu(2)–O angles are 180°, 96.06°, 83.96°, 92.29°, 87.73°, 94.08°, and 85.94°, respectively (Table 4). So, Cu(2) adopts a slightly distorted octahedron coordination mode (Fig. 4). Two Cu(1) atoms and one adjacent Cu(2) atoms are connected by a l3-O atom in structure of complex 3 as a tri-copper cluster. The tri-copper cluster and the ligands coordinated the tri-copper cluster are as a SBU. Two Cu(1) atoms in a SBUs are centrosymmetric, and adopt same coordination mode. The adjacent SBUs construct the framework of 1D structure in complex 3 by O(1) atoms and N(3) atoms from OBt ions and l3-O atoms; Every BDC2 ion connects two adjacent chains by O(2) atoms coordinated with Cu(1) atoms, and 2D grid structure of complex 3 are constructed (Fig. 5).
3.2. Luminescence properties The solid-state fluorescence properties of complexes 1–3, HOBt and H2BDC were measured at room temperature (Fig. 6). Their emissions spectra were collected from 220 to 770 nm with excitation wavelengthes at about 341 nm for 1, 340 nm for 2, 358 nm for 3, 357 nm for HOBt, and 320 nm for H2BDC, respectively. The peaks of the emission spectra of complexes 1–3 and two ligands are at
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Fig. 3. The 2D structure of complex 2.
Fig. 4. The structure of complex 3, lattice water molecules were omitted.
392 nm for 1 and 2, 388 nm for 3, 387 nm for HOBt and 381 nm for H2BDC, respectively. The luminescence emission spectra of 3 are the same as the ligand HOBt. The peaks for 3 and HOBt are at 388 and 387 nm,
respectively. The other three weaker emissions for 3 are at 333, 469 and 482 nm, and for HOBt are at 332, 469 and 481 nm. The peaks at 387 or 388 nm would be assigned to the intraligand p–p* transitions emission from the HOBt [48,49]. The other
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Table 4 Bond lengths (Å) and angles (°) for complex 3. Cu(1)–O(2) Cu(1)–N(3)#l Cu(1)–O(4)#2 Cu(1)–O(4) Cu(1)–O(1) Cu(1)–Cu(l)#2 Cu(2)–O(4) Cu(2)–O(4)#3 Cu(2)–N(2)#2 Cu(2)–N(2)#l Cu(2)–O(5)#3 Cu(2)–O(5) O(4)–Cu(l)#2 N(3)–Cu(l)#4 N(2)–Cu(2)#4 O(2)–Cu(l)–N(3)#l
1.921(3) 1.9763(18) 1.977(3) 2.006(3) 2.291(3) 3.024(2) 1.982(3) 1.982(3) 2.0012(17) 2.0012(17) 2.4099(17) 2.4099(17) 1.977(3) 1.9763(18) 2.0012(17) 95.08(11)
O(2)–Cu(1)–O(4)#2 N(3)#l–Cu(1)–O(4)#2 O(2)–Cu(1)–O(4) N(3)#1–Cu(l)–O(4) O(4)#2–Cu(1)– N(1)O(4) O(2)–Cu(1)–O(l) N(3)#1–Cu(1)–O(1) O(4)#2–Cu(1)–O(1) O(4)–Cu(1)–O(1) O(2)–Cu(l)–Cu(l)#2 N(3)#l–Cu(1)–Cu(1)#2 O(4)#2–Cu(1)–Cu(1)#2 O(4)–Cu(1)–Cu(1)#2 O(1)–Cu(l)–Cu(1)#2 O(4)–Cu(2)–0(4)#3 O(4)–Cu(2)–N(2)#2
Symmetry transformations used to generate equivalent atoms #1 x, y + 1, z #2
94.13(12) 167.40(9) 171.63(12) 88.55(10) 81.23(12) 87.06(12) 93.43(10) 95.62(12) 100.27(11) 134.71(10) 128.41(5) 40.98(7) 40.25(8) 100.51(8) 180.00(16) 96.05(9)
x, y + 2,
z #3
x,
y + 3,
O(4)#3–Cu(2)–N(2)#2 O(4)–Cu(2)–N(2)#l O(4)#3–Cu(2)–N(2)#l N(2)#2–Cu(2)–N(2)#1 O(4)–Cu(2)–O(5)#3 O(4)#3–Cu(2)–O(5)#3 N(2)#2–Cu(2)–O(5)#3 N(2)#l–Cu(2)–O(5)#3 O(4)–Cu(2)–O(5) O(4)#3–Cu(2)–O(5) N(2)#2–Cu(2)–O(5) N(2)#l–Cu(2)–O(5) O(5)#3–Cu(2)–O(5) Cu(l)#2–O(4)–Cu(2) Cu(l)#2–O(4)–Cu(l) Cu(3)–O(4)–Cu(l) z #4 x, y
1, z #5
x + 1/2,
y + 3/2
83.95(9) 83.95(9) 96.05(9) 180.00(8) 92.28(9) 87.72(9) 94.07(7) 85.93(7) 87.72(9) 92.28(9) 85.93(7) 94.07(7) 180.0 123.69(15) 98.77(12) 104.64(12) z.
served, and the weaker emissions are the same as ligand HOBt. So, The peak at 392 nm would be assigned to the intra-ligand p– p* transitions emission from the H2BDC [48,49]. The other emissions mainly arise from ligand HOBt, may be assigned to intra-ligand charge-transfer (LCT) [46]. 3.3. Thermal properties As shown in Supporting Information Figures S4, S5 and S6, compounds 1–3 were analyzed by thermogravimetric analysis (TGA) under 20 mL min 1 of flowing nitrogen, while ramping the temperature at a rate of 10 °C min 1 from 20 to 600 °C.
Fig. 5. The topology for 2D structure of complex 3.
Fig. 6. Emission spectra of complexes 1–3 (1–3), HOBt (4) and H2BDC (5) in the solid state at room temperature.
three weaker emissions 332 or 333 nm, 468 or 469 nm and 481 ± 1 nm may be assigned to intra-ligand charge-transfer (LCT) [50]. The peaks of the emission spectra of 1, 2 and the ligand H2BDC are at 392, 392 and 391 nm, respectively. No any weaker emission is in the emission spectra of H2BDC. The other weaker emissions for 1 are at 365 and 470 nm, and for 2 are at 364, 470 and 483 nm. Compared with the emission spectra of HOBt, a slightly red shift of 4 nm in complexes 1 and 2 for the peak has been ob-
3.3.1. [Mn(OBt)2(H2O)4]3H2O S4 exhibited a gradual weight loss of 7.93% between 24 and 116 °C and another weight decrease of 18.84% between 116 and 252 °C. They are corresponding to the release of two lattice water molecules of crystallization (calc. 8.02%) and another five water molecules (calc. 20.05%), respectively. The process was followed by a weight decrease of 57.04% (calc. 57.43%) between 252 and 273 °C, corresponding to the loss of the organic composition in complex 1, and then associated with the bondframe of complex 1 collapsed and decayed. The final amorphous product was corresponding to manganese oxide. 3.3.2. [Zn2(OBt)2(BDC)(H2O)H2O]n The structure of complex 2 did not decay under 205.4 °C in S5. It indicated that the structure of complex 2 was stable under 205.4 °C. Then it exhibited a gradual weight loss of 1.52% between 205.4 and 303.9 °C and another gradual weight loss of 4.36% between 303.9 and 397.8 °C. They are corresponding to the release of 0.5 lattice water molecule of crystallization (calc. 1.50%) and 1.5 water molecules of crystallization (calc. 4.50%), respectively. The process was followed by a weight decrease of 11.23% between 397.8 and 513.1 °C, corresponding to the loss of 0.5 coordinated OBt molecule to Zn(II) (calc. 11.18%). The final amorphous product was not identified. 3.3.3. [Cu3(OBt)2(BDC)(l3-OH)2(H2O)22H2O]n S6 exhibited a gradual weight loss of 9.71% between 24 and 144.2 °C and another weight decrease of 9.53% between 144.2 and 289.9 °C. They are corresponding to the release of two lattice water molecules of crystallization (calc. 9.91%) and two coordinated water molecules to Cu ions (calc. 9.91%), respectively. The bondframe of complex 3 collapsed and decayed when the temperature was higher than 289.9 °C. The final amorphous product was not identified.
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3.4. XRPD measurements An X-ray powder diffraction spectrum was recorded to check the crystallinity of the sample. The experimental spectra of complexes 2 and 3 are almost consistent with those of simulated based on the structure models derived from single-crystal X-ray diffraction data. It was confirmed that the samples are the polycrystalline form of complex 2 and 3. The XRPD spectrum of the two complexes are shown in Supporting Information (Figures S7 and S8). 4. Conclusion With the similar synthesis method and coordination ligand, we obtained entirely different structures of complexes 1–3. Complex 1 is 0D framework.. Complexes 2 and 3 are all complexes with mixed ligands and the framework of 2D structure, and there are all two crystallographically unique metal ions in their structures. There are two helical chains in the structure of complex 2 and no helical chain in complex 3, however, there are tri-copper clusters in the structure of complex 3 and no metal cluster in complex 2. The luminescence properties of complexes 1–3 were investigated. The luminescence emissions spectra of the complex 3 are the same as the ligand HOBt, and the luminescence emissions spectra of complexes 1 and 2 are considered to arise from two ligands HOBt and H2BDC. Acknowledgements This work was supported by the National Natural Science Foundation of China (No. 20371007, 20476011, 20771013/B0101), Excellent Young Scholars Research Fund of Beijing Institute of Technology (No. 1070012047109), Instructed Natural Science Research Fund of office of HeBei Province (No. Z2009132), and Research Fund of HengShui University (No. 2008008). Appendix A. Supplementary material CCDC 698915, 698916 and 698917 contains the supplementary crystallographic data for this paper. These data can be obtained free of charge from The Cambridge Crystallographic Data Centre via http://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.ica.2009.09.031. References [1] J.W. Cheng, S.T. Zheng, G.Y. Yang, Inorg. Chem. 46 (2007) 10261. [2] Y. Gong, W. Tang, W.B. Hou, Z.Y. Zha, C.W. Hu, Inorg. Chem. 45 (2006) 4987. [3] K.S. Park, Z. Ni, A.P. Côté, J.Y. Choi, R.D. Huang, F.J. Uribe-Romo, H.K. Chae, M. O’ Keeffe, O.M. Yaghi, PANS 103 (2006) 10186. [4] T. Tu, W. Assenmacher, H. Peterlik, R. Weisbarth, M. Nieger, K.H. Dötz, Angew. Chem., Int. Ed. 46 (2007) 6368. [5] S. Chuprakov, F.W. Hwang, V. Gevorgyan, Angew. Chem., Int. Ed. 46 (2007) 4757. [6] A. Steffen, T. Braun, B. Neumann, H.G. Stammler, Angew. Chem., Int. Ed. 46 (2007) 8674. [7] L. Yi, X. Yang, T.B. Lu, P. Cheng, Cryst. Growth Des. 5 (2005) 1215. [8] Q.G. Zhai, X.Y. Wu, S.M. Chen, C.Z. Lu, W.B. Yang, Cryst. Growth Des. 6 (2006) 2126.
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Three complexes based on ligands 1-hydroxybenzotriazole and 1,4-benzenedicarboxylic acid: Synthesis, structures and luminescence properties Zhong-Qiang Zhang a,b, Ru-Dan Huang a,*, Yan-Qing Xu a, Li-Qiong Yu a, Zhi-Wei Jiao a, Qin-Lei Zhu a, Chang-Wen Hu a,* a b
Department of Chemistry, School of Science, Beijing Institute of Technology, Beijing 100081, PR China Department of Chemistry, HengShui University, HengShui City, HeBei Province 053000, PR China
a r t i c l e
i n f o
Article history: Received 19 April 2009 Received in revised form 17 August 2009 Accepted 9 September 2009 Available online 16 September 2009 Keywords: 1-Hydroxybenzotriazole 1,4-Benzenedicarboxylic acid Chemical synthesis Crystal structure Luminescence properties
a b s t r a c t Three new complexes, [Mn(OBt)2(H2O)4]3H2O (1) (OBt = 1-hydroxybenzotriazole ion), [Zn2(OBt)2(BDC)(H2O)H2O]n (2) (H2BDC = 1,4-benzenedicarboxylic acid), and [Cu3(OBt)2(BDC)(l3-OH)2(H2O)22H2O]n (3) were synthesized by hydrothermal method and were characterized by elemental analysis, IR spectroscopy, TGA, XRPD, and single-crystal X-ray diffraction. The results from single-crystal X-ray diffraction indicate that 1, 2 and 3 are zero-dimensional (0D), two-dimensional (2D) and two-dimensional (2D) frameworks, respectively. In particular, there are all two crystallographically unique metal ions in the structures of complexes 2 and 3. Complex 2 possesses two helical chains in its structure. In the structure of 3, the chains that are built from tri-copper clusters and l3-O atoms are connected with BDC2 to construct 2D grid structure. The luminescence properties of the three complexes were investigated. Ó 2009 Elsevier B.V. All rights reserved.
1. Introduction The current increasing interest of experts in metal–organic frameworks not only stems from their potential applications in areas such as optoelectronics, magnetism, ion exchange, catalysis, nonlinear optics, fluorescent materials, and porous materials, but also from their intriguing variety of topologies and motifs [1–5]. The compounds that with one or several azole rings in molecule have various types of coordination modes and strong linking ability through bridging with proper metal ions, such as monodentate, bidentate, tridentate, and chelating [6–17]. Benzotriazolate (HBt) and its derivatives are very important compounds which have an azole ring in molecule [18–27]. One of HBt derivatives, HOBt, is a well-known peptide-coupling additive [28,29]. It exhibits corrosion inhibitive properties toward Cu [30,31] and Fe [32,33]. However, there are few relative literatures reported about complexes based on HOBt [29–39]. In the molecule structure of HOBt, one hydroxide substitutes H that connected N(1) of the azole ring (Scheme 1), thus the O atom of hydroxide and two N atoms of azole ring in HOBt can be coordinated to metal ions. In addition, when it coordinates to metal ions, the steric influence of exocyclic O atom on hydroxide is weaker than the influence of N on azole ring. Therefore, HOBt provides more coordination modes and choices than HBt does while HOBt is coordinating to metal ions. * Corresponding authors. Tel.: +86 10 68912668. E-mail address: [email protected] (R.-D. Huang). 0020-1693/$ - see front matter Ó 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.ica.2009.09.031
The motivation for this study was the expectation that HOBt could potentially provide various coordination motifs to form either discrete or consecutive complexes under appropriate synthesis condition, and could built a variety of types for complexes with various novel and attractive topologies. The three coordination modes between HOBt and metal ions are shown in Scheme 1. As a structural building block, HOBt may link metal centers through N(2), N(3) on azole ring or O atoms on hydroxide to provide secondary building units (SBUs). These building blocks can then be linked through the three coordination sites to expand to high-dimensional materials. Otherwise, p–p conjugation including six-member ring and five-member ring that exists in the molecule of HOBt, and the new complexes based on HOBt may exhibit interesting luminescence properties. H2BDC is a important ligand [40–45]. There are a lot of relative literatures illustrating complexes based on H2BDC [40–45]. The two coordination modes between H2BDC and metal ions are shown in Scheme 2. H2BDC is usually employed in the architectures for metal ions coordination polymers [46]. We aimed to explore promising synthetic routes for the construction of metal–organic complexes via combination of HOBt and H2BDC and metal cations. The synthetic strategy is to construct 1D framework using HOBt and metal cations, then achieve new high-dimensional MOFs by BDC2 ions as bridging ligand. In this paper, three novel complexes, [Mn(OBt)2(H2O)4]3H2O, [Zn2(OBt)2(BDC)(H2O)H2O]n and [Cu3(OBt)2(BDC)(l3-OH)2(H2O)2 2H2O]n, were synthesized and were characterized by elemental
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Scheme 1. Three coordinated modes of HOBt in the text.
Scheme 2. Two coordinated modes of H2BDC in the text.
analysis, IR spectroscopy, TGA, XRPD, and single-crystal X-ray. The luminescence properties of the three complexes were investigated as well. 2. Experimental section 2.1. Materials and methods All chemicals and reagents were used as received from commercial sources without further purification. Elemental analyses (C, H and N) were performed on a Perkin–Elmer 2400 CHN Elemental Analyzer. The solid infrared spectra (IR) were obtained from a FT-IR-670 spectrophotometer (Thermo Nicolet USA) in the range of 400–4000 cm 1 by using KBr pellets. XRPD were performed with a Rigaku D/max cA (Japan, k = 0.154060 nm). Thermo-gravimetric analyses (TGA) were performed with a NETSCHZ STA-499C thermoanalyzer under N2 (20–600 °C range) at a heating rate of 10 °C/min. Data collections of X-ray diffraction intensities for the three compounds were performed on Bruker SMART APEX-CCD diffractometer equipped with graphite-monochromated Mo Ka radiation (k = 0.71073 Å). Intensity data were collected at 273 K for 1, 173 K for 2 and 3, respectively. Empirical absorption corrections were applied using the SADABS program. The three structures were solved by direct methods using SHELXTL-97 [47] package of crystallographic software and refined by full-matrix least-squares technique on F2. All non-hydrogen atoms were refined with anisotropic thermal parameters. Hydrogen atoms attached to C, N and O atoms were located at geometrically calculated positions and refined with isotropic thermal parameters included in the final stage of the refine-
Table 1 Crystal data and structure refinements for compounds 1–3 Complex
1
2
3
Formula Formula weight Temperature (K) Crystal system Space group a (Å) b (Å) c (Å) a (°) b (°) c (°) V (Å3) Z Dcalcd (Mg m 3) F(0 0 0) Reflections collected Goodness-of-fit on F2 R1, wR2[I > 2r(I)] R1, wR2 (all data)
C12H22N6OgMn 449.3 273(2) monoclinic P21/c 6.875(2) 9.811(3) 28.102(9) 90 94.159(5) 90 1890.6(11) 4 1.579 932 11378 1.001 0.0699, 0.1828 0.1027, 0.2010
C20H16N6O8Zn2 599.13 173(2) monoclinic P21/c 18.483(3) 5.3787(9) 28.182(4) 90 129.600(7) 90 2158.7(6) 4 1.843 1208 12652 0.982 0.0459, 0.0845 0.0852, 0.0980
C20H22N6O12Cu3 729.07 173(2) monoclinic C2/c 26.223(18) 5.928(4) 16.115(10) 90 97.152(15) 90 2486(3) 4 1.943 1460 7439 0.991 0.0482, 0.1017 0.0819, 0.1188
ment on calculated positions bonded to their carrier atoms. The crystal data and structure refinements for compounds 1–3 are shown in Table 1.
2.2. Synthesis of [Mn(OBt)2(H2O)4]3H2O (1) A mixture of 1-hydroxybenzotriazole 0.0675 g (0.5 mmol) and Mn(CH3COO)24H2O 0.1225 g (0.5 mmol), was stirred in water
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(10 mL), and the pH of the mixture was adjusted to 6.0 with a 2 mol L 1 NH3H2O solution. It was then sealed in a 23 mL Telfon-lined stainless-steel container, which was heated to 110 °C for 72 h and then cooled to room temperature at a rate of 6 °C h 1. Colorless crystals were obtained and then they were solvent in 50 mL water again, then filtrated, the solution was left for 10 days, and colorless club crystals were obtained, and air dried. Yield 38% (based on Mn). Anal. Calc. for complex 1: C, 32.07; H, 4.95; N, 18.71. Found: C, 32.27; H, 5.02; N, 18.43%. IR for complex 1 (Figure S1) (solid KBr pellet, cm 1): 3397.3(s), 3200.0(s), 1561.6(s), 1408.2(s), 1347.9(w), 1276.7(w), 1216.4(w), 1189.0(w), 1156.2(m), 1139.7(w), 1112.3(s), 1052.1(w), 1024.7(w), 942.5(w), 739.7(m), 663.0(m), 619.2(w), 438.4(w). 2.3. Synthesis of [Zn2(OBt)2(BDC)(H2O)H2O]n (2) A mixture of HOBt 0.0675 g (0.5 mmol), H2BDC 0.0657 g (0.4 mmol) and Zn(NO3)24H2O 0.1307 g (0.5 mmol), was stirred in water (10 mL), and the pH of the mixture was adjusted to 7.0 with a 2 mol L 1NaOH solution. It was then sealed in a 23 mL Telfon-lined stainless-steel container, which was heated to 110 °C for 72 h and then cooled to room temperature at a rate of 6 °C h 1. Colorless club crystals were obtained, wished with dehydrated alcohol, and air dried. Yield 56% (based on Zn). Anal. Calc. for complex 2: C, 40.18; H, 2.53; N, 14.22. Found: C, 40.09; H, 2.69; N, 14.03%. IR for complex 2 (Figure S2) (solid KBr pellet, cm 1): 3101.4(m), 1578.1(s), 1506.8(m), 1463.0(m), 1402.7(s), 1287.7(w), 1232.9(w), 1167.1(m), 1139.7(m), 1117.8(m), 1019.2(m), 1002.7(w), 953.4(m), 887.7(m), 854.8(s), 794.5(m), 778.1(m), 761.6(m), 750.7(s), 641.1(w), 613.7(w), 586.3(w), 526.0(m), 454.8(m). 2.4. Synthesis of [Cu3(OBt)2(BDC)(l3-OH)2(H2O)22H2O]n (3) A mixture of HOBt 0.0675 g (0.5 mmol), H2BDC 0.0657 g (0.4 mmol) and CuSO45H2O 0.1284 g (0.5 mmol), was stirred in water (10 mL), and the pH of the mixture was adjusted to 6.0 with a 2 mol L 1NaOH solution. It was then sealed in a 23 mL Telfon-lined stainless-steel container, which was heated to 110 °C for 72 h and then cooled to room temperature at a rate of 6 °C h 1.Green club crystals were obtained, wished with distilled water, and air dried. Yield 62% (based on Cu). Anal. Calc. for complex 3: C, 32.94; H, 3.04; N, 11.52. Found: C, 33.23; H, 2.97; N, 11.45%. IR for complex 3 (Figure S3) (solid KBr pellet, cm 1): 3101.4(m), 1600.0(s), 1501.4(m), 1452.1(s), 1419.2(m), 1402.7(m), 1358.9(s), 1243.8(w), 1216.4(w), 1167.1(m), 1117.8(w), 1019.2(w), 997.3(w), 947.9(w), 805.5(w), 745.2(m), 597.8 (w), 526.0(w), 498.6(m).
3. Result and discussion 3.1. Description of the structures 3.1.1. [Mn(OBt)2(H2O)4]3H2O (1) Single-crystal X-ray diffraction analysis has revealed that the compound [Mn(OBt)2(H2O)4]3H2O crystallizes in the monoclinic system space group P21/n. The unit cell contains four identical [Mn(OBt)2(H2O)4]3H2O formula units. As shown in Fig. 1, Mn(II) is six coordinated with two N atoms from two OBt ions and four O atoms from four H2O molecules, and there are other three lattice water molecules in the structure of [Mn(OBt)2(H2O)4]3H2O. The Mn(1)–N(1) and Mn(1)–N(4) bond lengths are different: the former is 2.273 Å and the latter is 2.262 Å. The bond lengths between
Fig. 1. The structure of [Mn(OBt)2(H2O)4]3H2O, lattice water molecules were omitted.
Table 2 Bond lengths (Å) and angles (°) for complex 1 O(4)–Mn(l) Mn(l)–O(3) Mn(l)–O(6) Mn(l)–O(5) Mn(l)–N(4) Mn(l)–N(1) O(3)–Mn(1)–O(6) O(3)–Mn(1)–O(4) O(6)–Mn(1)–O(4) O(3)–Mn(1)–O(5) O(6 > Mn(1)–O(5) 0(4)–Mn(1)–C(5) O(3)–Mn(1)–N(4) O(6)–Mn(1)–N(4) O(4)–Mn(1)–N(4) O(5)–Mn(1)–N(4) O(3)–Mn(1)–N(1) O(6)–Mn(1)–N(1) O(4)–Mn(1)–N(1) O(5)–Mn(1)–N(1) N(4)–Mn(1)–N(1)
2.217(4) 2.166(4) 2.178(4) 2.216(4) 2.262(3) 2.273(4) 179.46(16) 92.62(15) 86.83(15) 89.53(15) 91.01(15) 176.96(15) 93.00(14) 86.95(14) 87.37(14) 90.38(14) 86.35(14) 93.65(14) 92.34(14) 89.93(14) 179.32(13)
Symmetry transformations used to generate equivalent atoms.
Mn(1) and O atoms from four coordinated H2O molecules are different, too. The N(1)–Mn(1)–N(4) angle is 179.32°. The N–Mn(1)– O(coordinated H2O) angles vary from 86.39° to 93.65°. The angles between Mn(1) and the coordinated H2O molecules vary from 86.83° to 179.46° (Table 2). These angles are almost 90° or 180°. So, Mn(II) adopts a slightly distorted octahedron coordination mode. 3.1.2. [Zn2(OBt)2(BDC)(H2O)H2O]n (2) Compound 2 crystallizes in the monoclinic system space group P21/c. As shown in Fig. 2, Zn(II) is five coordinated with two OBt ions, one BDC2 ions, and one H2O. Each Zn(II) center in the complex adopts a distorted tetragonal pyramid coordination mode, which is defined by one N atom from one OBt ion, one O atom from another OBt ion, two O atoms from a same carboxylic group in one BDC2- ion, and one O atom from one H2O. In complex 2, There are two independent Zn cations and therefore the bonds and angles are different (Table 3) . The distorted tetragonal pyramids by one N atom and four O atoms coordinated with Zn(II) are as parallel chains in the structure of complex 2 (Fig. 3). The two adjacent parallel chains are as a chain unit. A helical chain exists in each chain unit. There are two rightabout helical chains in the structure of complex 2 (Fig. 3 and S12). The repeated unit of the helical chains are all [Zn–(OBt )N3–(OBt )O1–Zn].
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Fig. 2. The structure of complex 2, lattice water molecules were omitted.
Table 3 Bond lengths (Å) and angles (°) for complex 2. Zn(1)–O(2) Zn(1)–N(6)#l Zn(l)–O(1) Zn(1)–O(6)#2 Zn(1)–O(7)#2 Zn(2)–O(4) Zn(2)–O(5) Zn(2)–O(3) Zn(2)–O(8) Zn(2)–n(1) O(3)–N(4) O(7)–Zn(1)#3 O(6)–Zn(1)#3 N(6)–Zn(l)#4 O(2)–Zn(l)–N(6)#l 0(2)–Zn(l)–0(1) N(6)#l–Zn(l)–0(1)
1.9976 2.0035 2.0089 2.0518 2.2955 1.9615 2.565 1.9667 1.9686(8) 2.0078 1.3563 2.2955 2.0518 2.0035 106.4 101.8 105.8
O(2)–Zn(1)–O(6)#2 N(6)#1–Zn(1)–O(6)#2 O(1)–Zn(1)–O(6)#2 O(2)–Zn(1)–O(7)#2 N(6)#l–Zn(1)–O(7)#2 O(1)–Zn(1)–C(7)#2 O(6)#2–Zn(1)–O(7)#2 O(4)–Zn(2)–O(3) O(4)–Zn(2)–O(8) O(3)–Zn(2)–O(8) O(4)–Zn(2)–N(1) O(3)–Zn(2)–N(1) O(8)–Zn(2)–N(1) O(5)–Zn(2)–O(4) O(5)–Zn(2)–O(8) O(5)–Zn(2)–O(3) O(5)–Zn(2)–N(1)
105.9 140.2 89.7 96.7 93.5 148.0 60.1 116.9 114.70(4) 108.03(4) 103.8 109.0 103.37(4) 56.21 91.21 79.50 159.34
Symmetry transformations used to generate equivalent atoms: #1 x, y + 1, z #2x + 1, y 1/2, z + 1/2 #3 x 1, y 1/2, z 1/2 #4 x, y 1, z
The 1-D framework was constructed by OBt and Zn(II). The two adjacent 1D chains were connected by BDC2 ions as bridging ligand to achieve 2D grid structure in complex 2 (Fig. 3 and S13). 3.1.3. [Cu3(OBt)2(BDC)(l3-OH)2(H2O)22H2O]n (3) Compound 3 crystallizes in the monoclinic system space group C2/c. As shown in Fig. 4. There are two crystallographically independent Cu cations in the structure of complex 3. Cu(1) is five coordinated with one O atom (O1) from one OBt ion, one N atom (N3) from another OBt ion, one O atom (O2) from a carboxylic group in one BDC2 ion and two crystallographically equivalent l3-O atoms (O4). The Cu(1)–O(2) and Cu(1)–N(3) bond lengths are 1.921 and 1.9763 Å, and the Cu(1)–O(1) bond length is 2.291 Å, the two bond
lengths between Cu(1)-l3-O are 2.006 and 1.977 Å, respectively. The O–Cu1–O angles and the N–Cu1–O angles are 94.13°, 171.63°, 95.08°, 81.23°, 87.06°, 95.62°, 100.27°,167.40°, 88.55° and 93.43°, respectively (Table 4). So, Cu(1) adopts a distorted tetragonal pyramid coordination mode (Fig. 4). Cu(2) is six coordinated with two crystallographically equivalent N atoms (N2) from two OBt ions, two crystallographically equivalent O atoms (O5) from two H2O molecules, and two crystallographically equivalent l3-O atoms (O4). The two Cu(2)–O(5) bond lengths are 2.4099 Å, and the bond lengths between Cu(2)l3-O are all 1.982 Å. The O–Cu(2)–O angles and the N–Cu(2)–O angles are 180°, 96.06°, 83.96°, 92.29°, 87.73°, 94.08°, and 85.94°, respectively (Table 4). So, Cu(2) adopts a slightly distorted octahedron coordination mode (Fig. 4). Two Cu(1) atoms and one adjacent Cu(2) atoms are connected by a l3-O atom in structure of complex 3 as a tri-copper cluster. The tri-copper cluster and the ligands coordinated the tri-copper cluster are as a SBU. Two Cu(1) atoms in a SBUs are centrosymmetric, and adopt same coordination mode. The adjacent SBUs construct the framework of 1D structure in complex 3 by O(1) atoms and N(3) atoms from OBt ions and l3-O atoms; Every BDC2 ion connects two adjacent chains by O(2) atoms coordinated with Cu(1) atoms, and 2D grid structure of complex 3 are constructed (Fig. 5).
3.2. Luminescence properties The solid-state fluorescence properties of complexes 1–3, HOBt and H2BDC were measured at room temperature (Fig. 6). Their emissions spectra were collected from 220 to 770 nm with excitation wavelengthes at about 341 nm for 1, 340 nm for 2, 358 nm for 3, 357 nm for HOBt, and 320 nm for H2BDC, respectively. The peaks of the emission spectra of complexes 1–3 and two ligands are at
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Fig. 3. The 2D structure of complex 2.
Fig. 4. The structure of complex 3, lattice water molecules were omitted.
392 nm for 1 and 2, 388 nm for 3, 387 nm for HOBt and 381 nm for H2BDC, respectively. The luminescence emission spectra of 3 are the same as the ligand HOBt. The peaks for 3 and HOBt are at 388 and 387 nm,
respectively. The other three weaker emissions for 3 are at 333, 469 and 482 nm, and for HOBt are at 332, 469 and 481 nm. The peaks at 387 or 388 nm would be assigned to the intraligand p–p* transitions emission from the HOBt [48,49]. The other
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Table 4 Bond lengths (Å) and angles (°) for complex 3. Cu(1)–O(2) Cu(1)–N(3)#l Cu(1)–O(4)#2 Cu(1)–O(4) Cu(1)–O(1) Cu(1)–Cu(l)#2 Cu(2)–O(4) Cu(2)–O(4)#3 Cu(2)–N(2)#2 Cu(2)–N(2)#l Cu(2)–O(5)#3 Cu(2)–O(5) O(4)–Cu(l)#2 N(3)–Cu(l)#4 N(2)–Cu(2)#4 O(2)–Cu(l)–N(3)#l
1.921(3) 1.9763(18) 1.977(3) 2.006(3) 2.291(3) 3.024(2) 1.982(3) 1.982(3) 2.0012(17) 2.0012(17) 2.4099(17) 2.4099(17) 1.977(3) 1.9763(18) 2.0012(17) 95.08(11)
O(2)–Cu(1)–O(4)#2 N(3)#l–Cu(1)–O(4)#2 O(2)–Cu(1)–O(4) N(3)#1–Cu(l)–O(4) O(4)#2–Cu(1)– N(1)O(4) O(2)–Cu(1)–O(l) N(3)#1–Cu(1)–O(1) O(4)#2–Cu(1)–O(1) O(4)–Cu(1)–O(1) O(2)–Cu(l)–Cu(l)#2 N(3)#l–Cu(1)–Cu(1)#2 O(4)#2–Cu(1)–Cu(1)#2 O(4)–Cu(1)–Cu(1)#2 O(1)–Cu(l)–Cu(1)#2 O(4)–Cu(2)–0(4)#3 O(4)–Cu(2)–N(2)#2
Symmetry transformations used to generate equivalent atoms #1 x, y + 1, z #2
94.13(12) 167.40(9) 171.63(12) 88.55(10) 81.23(12) 87.06(12) 93.43(10) 95.62(12) 100.27(11) 134.71(10) 128.41(5) 40.98(7) 40.25(8) 100.51(8) 180.00(16) 96.05(9)
x, y + 2,
z #3
x,
y + 3,
O(4)#3–Cu(2)–N(2)#2 O(4)–Cu(2)–N(2)#l O(4)#3–Cu(2)–N(2)#l N(2)#2–Cu(2)–N(2)#1 O(4)–Cu(2)–O(5)#3 O(4)#3–Cu(2)–O(5)#3 N(2)#2–Cu(2)–O(5)#3 N(2)#l–Cu(2)–O(5)#3 O(4)–Cu(2)–O(5) O(4)#3–Cu(2)–O(5) N(2)#2–Cu(2)–O(5) N(2)#l–Cu(2)–O(5) O(5)#3–Cu(2)–O(5) Cu(l)#2–O(4)–Cu(2) Cu(l)#2–O(4)–Cu(l) Cu(3)–O(4)–Cu(l) z #4 x, y
1, z #5
x + 1/2,
y + 3/2
83.95(9) 83.95(9) 96.05(9) 180.00(8) 92.28(9) 87.72(9) 94.07(7) 85.93(7) 87.72(9) 92.28(9) 85.93(7) 94.07(7) 180.0 123.69(15) 98.77(12) 104.64(12) z.
served, and the weaker emissions are the same as ligand HOBt. So, The peak at 392 nm would be assigned to the intra-ligand p– p* transitions emission from the H2BDC [48,49]. The other emissions mainly arise from ligand HOBt, may be assigned to intra-ligand charge-transfer (LCT) [46]. 3.3. Thermal properties As shown in Supporting Information Figures S4, S5 and S6, compounds 1–3 were analyzed by thermogravimetric analysis (TGA) under 20 mL min 1 of flowing nitrogen, while ramping the temperature at a rate of 10 °C min 1 from 20 to 600 °C.
Fig. 5. The topology for 2D structure of complex 3.
Fig. 6. Emission spectra of complexes 1–3 (1–3), HOBt (4) and H2BDC (5) in the solid state at room temperature.
three weaker emissions 332 or 333 nm, 468 or 469 nm and 481 ± 1 nm may be assigned to intra-ligand charge-transfer (LCT) [50]. The peaks of the emission spectra of 1, 2 and the ligand H2BDC are at 392, 392 and 391 nm, respectively. No any weaker emission is in the emission spectra of H2BDC. The other weaker emissions for 1 are at 365 and 470 nm, and for 2 are at 364, 470 and 483 nm. Compared with the emission spectra of HOBt, a slightly red shift of 4 nm in complexes 1 and 2 for the peak has been ob-
3.3.1. [Mn(OBt)2(H2O)4]3H2O S4 exhibited a gradual weight loss of 7.93% between 24 and 116 °C and another weight decrease of 18.84% between 116 and 252 °C. They are corresponding to the release of two lattice water molecules of crystallization (calc. 8.02%) and another five water molecules (calc. 20.05%), respectively. The process was followed by a weight decrease of 57.04% (calc. 57.43%) between 252 and 273 °C, corresponding to the loss of the organic composition in complex 1, and then associated with the bondframe of complex 1 collapsed and decayed. The final amorphous product was corresponding to manganese oxide. 3.3.2. [Zn2(OBt)2(BDC)(H2O)H2O]n The structure of complex 2 did not decay under 205.4 °C in S5. It indicated that the structure of complex 2 was stable under 205.4 °C. Then it exhibited a gradual weight loss of 1.52% between 205.4 and 303.9 °C and another gradual weight loss of 4.36% between 303.9 and 397.8 °C. They are corresponding to the release of 0.5 lattice water molecule of crystallization (calc. 1.50%) and 1.5 water molecules of crystallization (calc. 4.50%), respectively. The process was followed by a weight decrease of 11.23% between 397.8 and 513.1 °C, corresponding to the loss of 0.5 coordinated OBt molecule to Zn(II) (calc. 11.18%). The final amorphous product was not identified. 3.3.3. [Cu3(OBt)2(BDC)(l3-OH)2(H2O)22H2O]n S6 exhibited a gradual weight loss of 9.71% between 24 and 144.2 °C and another weight decrease of 9.53% between 144.2 and 289.9 °C. They are corresponding to the release of two lattice water molecules of crystallization (calc. 9.91%) and two coordinated water molecules to Cu ions (calc. 9.91%), respectively. The bondframe of complex 3 collapsed and decayed when the temperature was higher than 289.9 °C. The final amorphous product was not identified.
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3.4. XRPD measurements An X-ray powder diffraction spectrum was recorded to check the crystallinity of the sample. The experimental spectra of complexes 2 and 3 are almost consistent with those of simulated based on the structure models derived from single-crystal X-ray diffraction data. It was confirmed that the samples are the polycrystalline form of complex 2 and 3. The XRPD spectrum of the two complexes are shown in Supporting Information (Figures S7 and S8). 4. Conclusion With the similar synthesis method and coordination ligand, we obtained entirely different structures of complexes 1–3. Complex 1 is 0D framework.. Complexes 2 and 3 are all complexes with mixed ligands and the framework of 2D structure, and there are all two crystallographically unique metal ions in their structures. There are two helical chains in the structure of complex 2 and no helical chain in complex 3, however, there are tri-copper clusters in the structure of complex 3 and no metal cluster in complex 2. The luminescence properties of complexes 1–3 were investigated. The luminescence emissions spectra of the complex 3 are the same as the ligand HOBt, and the luminescence emissions spectra of complexes 1 and 2 are considered to arise from two ligands HOBt and H2BDC. Acknowledgements This work was supported by the National Natural Science Foundation of China (No. 20371007, 20476011, 20771013/B0101), Excellent Young Scholars Research Fund of Beijing Institute of Technology (No. 1070012047109), Instructed Natural Science Research Fund of office of HeBei Province (No. Z2009132), and Research Fund of HengShui University (No. 2008008). Appendix A. Supplementary material CCDC 698915, 698916 and 698917 contains the supplementary crystallographic data for this paper. These data can be obtained free of charge from The Cambridge Crystallographic Data Centre via http://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.ica.2009.09.031. References [1] J.W. Cheng, S.T. Zheng, G.Y. Yang, Inorg. Chem. 46 (2007) 10261. [2] Y. Gong, W. Tang, W.B. Hou, Z.Y. Zha, C.W. Hu, Inorg. Chem. 45 (2006) 4987. [3] K.S. Park, Z. Ni, A.P. Côté, J.Y. Choi, R.D. Huang, F.J. Uribe-Romo, H.K. Chae, M. O’ Keeffe, O.M. Yaghi, PANS 103 (2006) 10186. [4] T. Tu, W. Assenmacher, H. Peterlik, R. Weisbarth, M. Nieger, K.H. Dötz, Angew. Chem., Int. Ed. 46 (2007) 6368. [5] S. Chuprakov, F.W. Hwang, V. Gevorgyan, Angew. Chem., Int. Ed. 46 (2007) 4757. [6] A. Steffen, T. Braun, B. Neumann, H.G. Stammler, Angew. Chem., Int. Ed. 46 (2007) 8674. [7] L. Yi, X. Yang, T.B. Lu, P. Cheng, Cryst. Growth Des. 5 (2005) 1215. [8] Q.G. Zhai, X.Y. Wu, S.M. Chen, C.Z. Lu, W.B. Yang, Cryst. Growth Des. 6 (2006) 2126.
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