Structural diversity and fluorescent properties of copper(II) complexes constructed by 5-sulfosalicylate and 2,2′-bipyridine

Journal of Molecular Structure 827 (2007) 188–194 www.elsevier.com/locate/molstruc

Structural diversity and fluorescent properties of copper(II) complexes constructed by 5-sulfosalicylate and 2,2 0-bipyridine Sai-Rong Fan, Long-Guan Zhu

*

Department of Chemistry, Zhejiang University, Hangzhou 310027, People’s Republic of China Received 28 February 2006; received in revised form 11 May 2006; accepted 13 May 2006 Available online 21 June 2006

Abstract Two structurally diverse complexes, [Cu4(CH3COO)2(ssal)2(2,2 0 -bipy)4(H2O)2]6H2O (1) and {[Cu(ssal)(2,2 0 -bipy)][Cu2(ssal)(2,2 0 bipy)2(H2O)2](H2O)}n (2) [ssal = 5-sulfosalicylate trianion; 2,2 0 -bipy = 2,2 0 -bipyridine], have been strategically synthesized and characterized by elemental analyses, IR, fluorescent spectra, and single crystal X-ray analyses. The structure of complex 1 is a tetranuclear species where both the carboxyl and phenoxo chelate to the copper atom and the carboxyl also bridges two copper atoms, while complex 2 features a charge transfer species with two cationic and anionic chains, in which both the carboxyl and sulfonyl are coordinated to copper atoms. Fluorescent properties of complexes 1 and 2 suggest interesting potential applications in photoactive materials.  2006 Elsevier B.V. All rights reserved. Keywords: Structural diversity; Crystal structure; Copper complex; 5-Sulfosalicylate; Fluorescent property

1. Introduction The synthesis and construction of metal-organic coordination polymers have been rapidly developed in the recent decade due to their interests in both structural diversities and potential applications as functional materials [1–4]. Coordination polymers with diverse architectures, such as linear or zigzag chains, ladders, helices, honeycombs, square grids, brick walls, and interwoven diamondoids, will naturally lead to different functional properties, therefore structural diversities can provide valuable information between structures and properties [5–10]. Furthermore, the rational design and construction of specific architectures are beneficial for preparing functional materials. To achieve such target, we have selected a derivative of salicylic acid, 5-sulfosalicylic acid (H3ssal), to explore its structural diversities and interesting topologies [11]. Very recently, increasing attention has been focused on this H3ssal ligand and its metal complexes showing interesting biological activities [12,13], such as anti-ulcer, anti-microbial, anti-fungal, and *

Corresponding author. Tel.: +86 571 87963867;fax: +86 571 87951895. E-mail address: [email protected] (L.-G. Zhu).

0022-2860/$ - see front matter  2006 Elsevier B.V. All rights reserved. doi:10.1016/j.molstruc.2006.05.019

anti-inflammatory activities. The H3ssal ligand involves three functional groups, ASO3H, ACOOH and AOH, which can be partly or fully deprotonated in five forms (Scheme 1), fabricating many novel architectures (The notations, H3ssal, H2ssal, Hssal2, and ssal3, stand for 5-sulfosalicylic acid, singly, doubly, and fully deprotonated 5-sulfosalicylates, respectively). The coordination modes reported in the references are summarized in Scheme 2. Three diverse complexes based on the same system of the Cu2+/2,2 0 -bipy/H3ssal have been reported in our laboratory and other groups, {[Cu3(ssal)2(2,2 0 -bipy)2(H2O)4] Æ 4H2O}n (3) [14], [Cu(Hssal)(2,2 0 -bipy)(H2O)2]n (4) [15], and [Cu(H2ssal)(2,2 0 -bipy)2] Æ H2ssal (5) [16]. As part of our systematic investigations of the Cu2+/2,2 0 -bipy/H3ssal system, another two new complexes with different topologies are presented here. 2. Experimental 2.1. Materials and physical measurements 5-Sulfosalicylic acid dihydrate was purchased from the Acros Organics and was of reagent grade. C, H, and N

S.-R. Fan, L.-G. Zhu / Journal of Molecular Structure 827 (2007) 188–194

COOH OH -

HO3S

-

HO3S

O3S

O-

OH

OH

OH

COO-

COO-

COO-

COOH

189

-

O3S

O3S

Scheme 1. Five forms for 5-sulfosalicylic acid and 5-sulfosalicylate.

OH

O

OH O

OH

OH

O

M

O

O

M

O

O

(9)

M

M

O

O

OH O S

O O M

M

(10)

O

S O

OH

M O

M

(8)

M O O

O

O

S M

S O

H

O

S

M

O

M

O

M

O

O

(7)

M M

O M

(6)

O

O

O

O

M

M

M

S

(5)

O

(4)

O

O

O

O

S

S

O

O M

O

O

O

S M

(3)

O M

M O

O

O M

O

O

M

OH

O

O

(2)

(1)

M

OH

S

M

O M

O

OH

O

O

O

OH

M

S O

M

OH O

S O

O

O M

M O

M

O

O

(12)

(11)

Scheme 2. Coordination modes of 5-sulfosalicylate in metal complexes.

elemental analyses were carried out on a Perkin-Elmer analyzer model 1110. The infrared spectra were taken on a Nicolet Nexus 470 infrared spectrophotometer as KBr pellets in the 400–4000 cm1 region. Thermogravimetric analysis (TGA) was carried out on a Delta Series TA-SDT Q600 in nitrogen atmosphere from room temperature to 800 C (heating rate = 10 C min1) using aluminium crucibles. The photoluminescence study was carried out on powdered sample in the solid state at room temperature using Hitachi 850 spectrometer. 2.2. Preparation of the complexes [Cu4(CH3COO)2(ssal)2 (2,2 0 -bipy)4(H2O)2] Æ 6H2O (1). Twenty milliliters of aqueous solution containing copper acetate hydrate (0.081 g, 0.4 mmol) and 5-sulfosalicylic acid dihydrate (0.052 g, 0.2 mmol) was slowly added to a previously prepared methanol solution (5 mL) containing 2,2 0 -bipyridine (0.063 g, 0.4 mmol). Then the resulting solution was allowed to slowly evaporate. After 3 days, well-formed blue crystals were obtained. Anal.Calc. (found): C, 44.33(43.74); H, 3.85(4.28); N, 7.13(6.89)%. IR (KBr pellet, cm1): 3423(s), 3114(m), 1605(s), 1557(s), 1533(m), 1496(w), 1474(s), 1448(s), 1423(s), 1378(w), 1323(m), 1256(m), 1197(m), 1149(m), 1131(w), 1087(w), 1059(w), 1034(s), 912(w), 830(w), 770(m), 732(w), 679(w), 656(w), 607(m), 587(m), 447(w), 420(w). Eight water mole-

cules were confirmed by TG analysis (Fig. 1a). In the range of 76 C–143 C weight loss was 8.95% (calcd. 9.17%). {[Cu(ssal)(2,20 -bipy)][Cu2(ssal)(2,20 -bipy)2(H2O)2] Æ (H2O)2}n (2). A mixture of copper acetate hydrate (0.075 g, 0.4 mmol), 5-sulfosalicylic acid dihydrate (0.100 g, 0.4 mmol), 2,2 0 bipyridine (0.092 g, 0.5 mmol), and water (10 mL) was heated at 413 K for 12 h in a 20 mL Teflon-lined stainless steel autoclave. After cooling to room temperature, green crystals were obtained. Anal.Calc. (found): C, 45.50(45.37); H, 3.30(3.41); N, 7.24(6.95)%. IR (KBr pellet, cm1): 3610(m), 3448(m), 1603(s), 1571(m), 1550(m), 1512(w), 1471(s), 1447(s), 1428(m), 1417(w), 1328(w), 1261(w), 1214(s), 1167(m), 1140(m), 1128(m), 1078(w), 1058(w), 1028(s), 906(w), 834(w), 773(w), 759(w), 730(w), 674(w), 644(w), 631(w), 602(s), 583(w), 435(w), 414(w). Four water molecules were confirmed by TG analysis (Fig. 1b). Weight loss in the temperature range of 74 C to 132 C was 5.87% (calcd. 6.20%). 2.3. Single crystal structure determination Suitable crystals of 1 and 2 were mounted on the tip of a fiber and transferred to the goniometer of a Bruker Smart CCD detector with graphite monochromatized MoKa ˚ ). Data integration, correction radiation (k = 0.71073 A for Lorentz and polarization effects, and final cell refinement were performed by SMART and SAINT [17], respec-

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S.-R. Fan, L.-G. Zhu / Journal of Molecular Structure 827 (2007) 188–194

Fig. 1. TG curves for 1 (a) and for 2 (b).

tively, and the data were further corrected for absorption using the program SADABS [18]. All of two structures were solved initially by direct methods and then completed by full matrix least squares on F2 followed by difference Fourier synthesis using the SHELXL-97 program [19] in the WinGX environment [20]. In all two structures, the non-hydrogen atoms were refined with anisotropic displacement parameters. Hydrogen atoms bonded to the carbon atoms were placed in calculated positions and refined ˚ and Uiso(H) = 1.2Ueq(C). as riding, with CAH = 0.93 A The water hydrogen atoms were located in the difference Fourier maps and refined with an OAH distance restraint ˚ ]. The drawings of the molecules were realized [0.85 (1) A Table 1 Crystallographic data and refinement parameters for complexes 1 and 2 Complex

1

2

Empirical formula Mr Crystal size (mm3) Crystal system Space group ˚) a(A ˚) b(A ˚) c(A a() b() c() V(A3) Z Dc(g/m3) l(mm1) 2h range Collected reflections Unique reflections Observed reflections Parameters F(100) T(K) R1, wR2[I > 2r (I)] R1, wR2[all data] GOF Largest peak and ˚ 3) hole(e Æ A

C58H60Cu4 N8O24S2 1571.42 0.37 · 0.15 · 0.08 Monoclinic P21/n 12.8199(13) 33.890(3) 7.2734(7) 90 95.092(2) 90 3147.5(5) 2 1.658 1.488 50.0 16193 5451 5142 434 1608 293(2) 0.077, 0.151 0.083, 0.153 1.288 0.616, 0.681

C44H38Cu3 N6O16S2 1161.54 0.28 · 0.17 · 0.14 Triclinic P1 8.6730(19) 9.320(2) 14.037(3) 80.429(4) 81.957(4) 84.640(4) 1105.0(4) 1 1.746 1.608 52.2 8685 7744 7542 640 591 293(2) 0.049, 0.117 0.050, 0.117 1.122 0.776, 0.846

with the help of ORTEP-3 for Windows [21]. Crystallographic data and refinement parameters for the two complexes are given in Table 1. 3. Results and discussion 3.1. Synthesis For the system of Cu2+/2,2 0 -bipy/H3ssal, totally five complexes with various topologies have been prepared by the combination of synthesis strategies, solvents, reaction temperature, starting materials, and molar ratios, which can largely influence the formation of final products. It has not possible, however, to synthesize copper-5-sulfosalicylate complexes using copper(II) chloride or copper(II) sulfate as a reactant. The starting material used in the syntheses of complexes 1–4 is copper acetate while in the case of complex 5 it is copper nitrate. Complexes 1, 3, 4, and 5 were synthesized by the typical mixed-solution method and the hydrothermal reaction was used to obtain complex 2. The syntheses of complexes 1, 3, and 4 proceeded similarly but with different molar ratio of starting materials. In complex 4, the H3ssal is doubly deprotonated due to excess H3ssal used (ratio of Cu2+: H3ssal = 1:2). It has been found that the higher the pH of the solution is, the easier the deprotonation of the ligand H3ssal is. Therefore, in complexes 1 and 3, the H3ssal ligands are fully deprotonated because the molar ratios of Cu2+: H3ssal are only 1:1. Based on discussion above, it is concluded that the stoichiometry of the reactants should be carefully controlled. When the higher solution concentration using copper(II) nitrate instead of copper(II) acetate was used, complex 5 was formed; such synthesis conditions were expected to produce less deprotonated species. Hydrothermal synthesis is very useful in the synthesis of novel metal-organic framework complexes, therefore this method was employed in this study. After many unsuccessful tries, it has been found that a similar mixture used in the synthesis of complex 3 under hydrothermal conditions led to a new complex, 2, which is an infinite chain species with multi-copper geometries.

S.-R. Fan, L.-G. Zhu / Journal of Molecular Structure 827 (2007) 188–194

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3.2. IR spectra

Table 2 ˚ ) and angles () for complex 1 Selected bond lengths (A

The IR spectra of only complexes 1–4 can be discussed because of the absence of the IR of complex 5 in the reported work [16]. Comparing the IR of H3ssal ligand with those of complexes 1–4, the characteristic vibration peaks of both COOH and SO3H near 1680 cm1 were absent, indicating these protons were deprotonated. In the IR spectra of 1– 4, the broad band around 3430 cm1 indicates the presence of the m(OAH) stretching frequency of coordinated water molecules. In the region where m(OAH) phenoxo deformation occurs, two absorption bands are observed for 1 at 1474 and 1449 cm1, for 2 at 1471 and 1447 cm1, for 3 at 1474 and 1448 cm1, and for 4 at 1476 and 1446 cm1, respectively. In the reported work [22], a peak at about 1627 cm1 which also occurs in complex 4 was attributed to the m(CAC) vibration while this peak is absent in complexes 1–3, therefore the peak should be, in our opinion, attributed to the vibration of OAH(Hssal2). In the spectra of 1 and 2, mas(COO) and ms(COO) were observed at 1557 and 1423 cm1 for 1 and at 1550 and 1428 cm1 for 2, respectively. The characteristic vibrations of SO3 are at 1198, 1151, and 1132 cm1 in 1, 1214, 1167, and 1140 cm1 in 2, 1197, 1154, and 1131 cm1 in 3, and 1225, 1151, and 1123 cm1 in 4 for masSO3, respectively.

Cu1–O1 Cu1–O3 Cu1–N1 Cu1–N2 Cu1–O3i

3.3. Description of the molecular structures X-ray single crystal analysis reveals that complex 1 features a tetra-nuclear copper (II) species and six lattice water molecules. The molecular structure of complex 1 with the atomic labeling scheme is shown in Fig. 2. Selected bond lengths and angles are listed in Table 2. The structure has

O3–Cu1–O1 O1–Cu1–N1 O3–Cu1–O3i O3–Cu1–N2 N2–Cu1–O3i O7–Cu2–O2 O2–Cu2–N3 O7–Cu2–O9 O7–Cu2–N4 N4–Cu2–O9

1.905(4) 1.887(4) 1.988(5) 2.003(5) 2.779(5) 93.64(17) 91.01(18) 81.81(19) 94.04(18) 84.50(16) 95.88(17) 164.22(17) 89.41(18) 167.46(18) 100.95(19)

Cu2–O2 Cu2–O7 Cu2–O9 Cu2–N3 Cu2–N4 O1–Cu1–O3i O1–Cu1–N2 O3–Cu1–N1 N1–Cu1–O3i N1–Cu1–N2 O2–Cu2–O9 O2–Cu2–N4 O7–Cu2–N3 N3–Cu2–O9 N4–Cu2–N3

1.983(4) 1.930(4) 2.191(4) 2.032(4) 2.019(4) 104.77(18) 168.7(2) 175.10(19) 98.50(16) 81.14(19) 103.42(18) 88.62(17) 92.98(18) 89.67(19) 80.16(19)

Symmetry code, i: 1  x, y, 1  z.

a symmetry center and there are two independent copper atoms per unit. These two copper atoms are coordinated in square pyramidal geometries. The geometry of the Cu1 atom is completed by two nitrogen donors from one 2,2 0 bipy, one carboxyl oxygen atom, and two phenoxo oxygen atoms from two ssal3 ligands. The O3i (symmetry code, i: 1  x, y, 1  z) atom occupies the apical position with a longer Cu1–O3i distance due to the John-Teller effect. The coordination environment of the Cu2 atom consists of two nitrogen atoms of one 2,2 0 -bipy, one carboxylate oxygen atom of one ssal3 ligand, one oxygen atom from one water molecule, and one oxygen atom from the acetate ligand. The O9 atom from the water molecule is located ˚ distance. The ssal3 in the apical position with a 2.191(4) A ligand is fully deprotonated and uses the carboxyl and

Fig. 2. ORTEP view of the molecular structure for complex 1. Lattice water molecules and hydrogen atoms have been omitted for clarity.

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S.-R. Fan, L.-G. Zhu / Journal of Molecular Structure 827 (2007) 188–194 Table 4 ˚ ) and angles () for complex 2 Selected bond lengths (A

Table 3 ˚ , ) for complex 1 Hydrogen-bonding geometry parameters (A DAH  A i

O9–H9B  O8 O10–H10A  O5ii O10–H10B  O4iii O11–H11A  O6 O11–H11B  O12iv O12–H12A  O11v O12–H12B  O6i

DAH

H  A

D  A

DAH  A

0.856(4) 0.858(6) 0.862(6) 0.862(7) 0.863(8) 0.863(7) 0.867(7)

1.943(4) 2.103(5) 1.978(6) 2.141(6) 2.090(8) 2.071(8) 2.071(8)

2.657(6) 2.910(8) 2.840(8) 2.901(9) 2.762(11) 2.762(11) 2.774(9)

140.1(4) 156.6(4) 179.0(5) 146.7(5) 134.3(6) 136.5(7) 154.2(6)

Symmetry codes, i: x, y, z + 1; ii: x + 1, y, z + 1; iii: x + 1, y, z; iv: x, y + 1/2, z  1/2; v: x, y + 1/2, z + 1/2.

phenoxo groups to coordinate three metal atoms while the sulfonyl group is noncoordinating. The carboxylate of ssal3 acts as a bridging linker with anti-screw mode and the separation of Cu1  Cu2 by this carboxylate is ˚ . The phenoxo oxygen atom bridges two cop5.1514(10) A ˚. per atoms with the Cu1  Cu1i separation of 3.5750(16) A The tetramers are stacked by face-to-face p–p interactions between 2,2 0 -bipyridine ligands and between 2,2 0 -bipyridine and 5-sulfosalicylate with the centroid-to-centroid dis˚ and 3.684(4) A ˚ , respectively. Extensive tances of 3.743(4) A hydrogen-bonding OAH  O interactions give rise to a three-dimensional architecture and consolidate the crystal packing (Table 3). Complex 2 is a charge transfer species, which consists of a cation, an anion, and lattice water molecules (Fig. 3). Selected bond lengths and angles for 2 are given in Table 4. In both anionic and cationic species all copper atoms adopt a square pyramidal geometry. In the cation, the coordination geometry around Cu1 is completed by two nitrogen atoms from one 2,2 0 -bipy and three oxygen atoms from one carboxyl, one phenoxo, and one sulfonyl of two ssal3 ligands. The CuAO and CuAN bond lengths com-

Cu1–O1 Cu1–O5i Cu1–N2 Cu2–O13 Cu2–N3 Cu3–O7 Cu3–O12ii Cu3–N6 O3–Cu1–O1 O1–Cu1–N1 O3–Cu1–O5i O3–Cu1–N2 N2–Cu1–O5i O13–Cu2–O2 O2–Cu2–N3 O13–Cu2–O14 O13–Cu2–N4 N4–Cu2–O14 O9–Cu3–O7 O7–Cu3–N5 O9–Cu3–O12ii O9–Cu3–N6 N6–Cu3–O12ii

1.933(4) 2.274(5) 2.004(5) 1.959(4) 2.020(5) 1.901(5) 2.355(6) 2.007(5) 93.54(18) 170.7(2) 97.7(2) 162.9(2) 97.48(19) 88.97(19) 161.11(18) 91.66(18) 174.0(2) 92.79(19) 94.28(19) 166.7(2) 94.5(2) 164.1(2) 87.2(2)

Cu1–O3 Cu1–N1 Cu2–O2 Cu2–O14 Cu2–N4 Cu3–O9 Cu3–N5 O1–Cu1–O5i O1–Cu1–N2 O3–Cu1–N1 N1–Cu1–O5i N2–Cu1–N1 O2–Cu2–O14 O2–Cu2–N4 O13–Cu2–N3 N3–Cu2–O14 N4–Cu2–N3 O7–Cu3–O12ii O7–Cu3–N6 O9–Cu3–N5 N5–Cu3–O12ii N6–Cu3–N5

1.889(5) 2.010(5) 1.982(4) 2.160(5) 1.984(5) 1.875(4) 2.017(5) 95.62(19) 92.69(19) 90.9(2) 91.8(2) 80.9(2) 96.63(18) 94.5(2) 94.5(2) 101.80(19) 80.6(2) 104.8(2) 92.6(2) 90.6(2) 87.2(2) 79.8(2)

Symmetry codes, i: x  1, y, z; ii: 1 + x, y, z.

pare favorably with salicylate-copper complexes with Nheterocycle ligands [23,24]. The Cu2 atom is coordinated by two nitrogen atoms of one 2,2 0 -bipy, one carboxylate oxygen atom, and two terminal waters. Atoms O2, O13, N3, and N4 occupy the basal plane, while O14 atom is located in the apical position. The carboxylate of the ssal3 in the cation bridges Cu1 and Cu2 with the ˚ . The ssal3 ligand links three separation of 4.5480(13) A copper atoms and extends the cation into one-dimensional chain (Fig. 4). In the anionic unit of complex 2, the square

Fig. 3. ORTEP view of an asymmetrical unit of the molecular structure for complex 2. Hydrogen atoms have been omitted for clarity.

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193

Fig. 4. View of one-dimensional chains for complex 2. Hydrogen atoms and lattice water molecules have been omitted for clarity.

Table 5 ˚ ,) for complex 2 Hydrogen-bonding geometry parameters (A DAH  A

DAH

H  A

D  A

DAH  A

O13–H13A  O4i O13–H13B  O11ii O14–H14B  O8iii O15–H15A  O4 O15–H15B  O10iv

0.857(4) 0.860(5) 0.855(4) 0.871(7) 0.858(6)

2.062(5) 1.995(6) 1.966(4) 2.203(6) 2.123(5)

2.707(6) 2.753(8) 2.708(6) 3.041(9) 2.962(8)

131.5(3) 146.6(3) 144.5(4) 161.3(5) 165.7(5)

Symmetry codes, i: x  1, y, z; ii: x + 1, y + 1, z; iii: x + 1, y, z; iv: x + 2, y + 1, z.

pyramidal geometry for Cu3 is similar to the environment of Cu1, but the ssal3 coordination mode is different from that of the cation. The ssal3 ligand only links two copper ˚ and extends the atoms with the separation of 8.6730(19) A anion into a one-dimensional chain. Therefore, the crystal packing of complex 2 consists of two independent cationic and anionic chains (Fig. 4). The cationic chain and anionic chain are stacked by face-to-face p–p interactions between 2,2 0 -bipyridine ligands with the centroid-to-centroid dis˚ and 3.689(4) A ˚ . Abundant hydrogen tances of 3.633(4) A bonds between these two chains generate a two-dimensional layer (Table 5). Comparison of five complexes in coordination modes and structural topologies gives rise to some valuable information. The 5-sulfosalicylates in complexes 1–3 lose all protons while they are doubly and singly deprotonated in complexes 4 and 5, respectively. In complex 1, the ssal3 ligand only involves in the coordination of carboxyl and phenoxo groups. In complexes 2 and 3, ssal3 ligands coor-

dinate to metal ions using three functional groups and form linear chains with charge-transfer species and trinuclear motifs, respectively. In complex 5, the singly deprotonated 5-sulfosalicylate only monodentately coordinates to metal atom using its sulfonyl group and generates a monomer. 3.4. Fluorescent emission An intense fluorescent emission of complexes 1–4 at 471.6 nm for 1 (Fig. 5a), 470.3 nm for 2 (Fig. 5b), 471.7 nm for 3, and 469.9 nm for 4 (kex = 210 nm) was observed in the solid state at room temperature, which is red-shifted about 20 nm compared to that of H3ssal ligand (450 nm). Peaks in complexes 3 and 4 are stronger than those in complexes 1 and 2. Such fluorescent feature is assigned to the ligand-to-metal charge transfer with some r-donations from the cooperation of 2,2 0 -bipyridine and 5-sulfosalicylate ligands. Moreover, the emissions in complexes 1–4 are stronger than that of free ligand, which is probably caused by the enhancement of the conformational rigidity of coordinated ligands and reduces the irradiative decay of the intra-ligand excited states. Therefore, this study suggests that these complexes might be excellent candidates for potentially photoactive materials. 4. Conclusion In summary, two metal complexes based on the Cu2+/2,2 0 -bipy/H3ssal system, in addition to previously

Fig. 5. Emission spectra for 1 (a) and for 2 (b).

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reported {[Cu3(ssal)2(2,2 0 -bipy)2 (H2O)4] Æ 4H2O}n (3), [Cu(Hssal)(2,2 0 -bipy)(H2O)2]n (4), and [Cu(H2ssal)(2,2 0 bipy)2] Æ H2ssal (5), have been synthesized. The structures of these five complexes show remarkably different topologies: monomer for 5, tetramer for 1, linear chain for 4, infinite chain with trinuclear motifs for 3, and linear chains with cationic and anionic components for 2. The diverse product slate clearly illustrates that different novel structures based on the same system can be designed and prepared by the combination of reactants, solvents, reaction temperature, molar ratio, and synthesis strategies, and are of great benefit for designing and controlling the frameworks of functional materials. 5. Supplementary materials Crystallographic data (excluding structure factors) for the structural analysis have been deposited with the Cambridge Crystallographic Data Center as supplementary publication Nos. 299657 and 299658 for compounds 1 and 2, respectively. Copies of the data can be obtained free of charge via www.ccdc.ac.uk/conts/retrieving.html (or from The Director, CCDC, 12 Union Road, Cambridge CB2 1EZ, UK, fax: +44 1223 336 033. E-mail: [email protected].). Acknowledgment This work was supported by the National Natural Science Foundation of China (50073019). References [1] X. Liu, J.H. Guo, W.J. Zheng, D.Z. Liao, Chin. J. Struct. Chem. 21 (2002) 347.

[2] M. Eddaoudi, J. Kim, D. Vodak, A. Sudik, J. Wachter, M. O’Keeffe, O.M. Yaghi, PNAS 99 (2002) 4900. [3] O.M. Yaghi, M. O’Keeffe, N.W. Ockwig, H.K. Chae, M. Eddaoudi, J. Kim, Nature (London) 423 (2003) 705. [4] L.G. Zhu, X.P. Xiao, J.Y. Lu, Inorg. Chem. Commun. 7 (2004) 94. [5] (a) C. Pigaet, G. Bernardinelli, G. Hopfgartner, Chem. Rev. 97 (1997) 2005; (b) T.J. Prior, M.J. Rosseinsky, Inorg. Chem. 42 (2003) 1564. [6] R. Kitaura, K. Seki, G. Akiyama, S. Kitagawa, Angew. Chem. Int. Ed. 42 (2003) 428. [7] H. Abourahma, B. Moulton, V. Kravtsov, Z.J. Zaworotko, J. Amer. Chem. Soc. 124 (2002) 9990. [8] H. Abourahma, G.J. McManus, B. Moulton, R.D.B. Walsh, M.J. Zaworotko, Macromol. Symp. 196 (2003) 213. [9] L. Pan, B.S. Finkel, X.Y. Huang, J. Li, Chem. Commun. (2001) 105. [10] S.Q. Zang, Y. Su, Y.Z. Li, H.Z. Zhu, Q.J. Meng, Inorg. Chem. Commun. 9 (2006) 337. [11] S.R. Fan, L.G. Zhu, Chin. J. Chem. 23 (2005) 1292. [12] P.V. Khadikar, S. Joshi, S.G. Kashkhedikar, B.D. Heda, Indian J. Pharm. Sci. 46 (1984) 209. [13] P.V. Khadikar, S.M. Ali, B. Pol, B.D. Heda, Acta Microbiol. Hung. 33 (1986) 97. [14] W.G. Wang, J. Zhang, L.J. Song, Z.F. Ju, Inorg. Chem. Comm. 7 (2004) 858. [15] S.R. Fan, L.G. Zhu, H.P. Xiao, S.W. Ng, Acta Cryst. E61 (2005) m509. [16] S. Gao, L.H. Huo, H. Zhao, S.W. Ng, Acta Cryst. E61 (2005) m290. [17] Bruker AXS Inc., SAINT (version 6.02a) and SMART (version 5.618), Madison, Wisconsin, USA, 2002. [18] G.M. Sheldrick, SADABS Program for Bruker Area Detector Absorption Correction, University of Go¨ttingen, Germany, 1997. [19] G.M. Sheldrick, SHELXL-97, Program for the Refinement of Crystal Structures, University of Go¨ttingen, Germany, 1997. [20] L.J. Farrugia, J. Appl. Cryst. 32 (1999) 837. [21] L.J. Farrugia, J. Appl. Cryst. 30 (1997) 565. [22] Z.F. Chen, S.M. Shi, R.X. Hu, M. Zhang, H. Liang, Z.Y. Zhou, Chin. J. Chem. 21 (2003) 1059. [23] L.G. Zhu, S. Kitagawa, H. Miyasaka, H.C. Chang, Inorg. Chim. Acta 355 (2003) 121. [24] P. Lemoine, B. Viossat, G. Morgant, F.T. Greenaway, A. Tomas, N. Dung, J.R.J. Sorenson, J. Inorg. Biochem. 89 (2002) 18.