Encapsulation of Water Cluster, meso-Helical Chain and Tapes in

The [Cd2(bpa)2] structural units as secondary building blocks (SBUs) are extended into metal−organic frameworks (MOFs) in 2 and 3 as 1D chains, whil...
0 downloads 5 Views 940KB Size
Download PDF
Encapsulation of Water Cluster, meso-Helical Chain and Tapes in Metal-Organic Frameworks Based on Double-Stranded Cd(II) Helicates and Carboxylates Lin Cheng, Jian-Bin Lin, Jun-Zhou Gong, Ai-Ping Sun, Bao-Hui Ye,* and Xiao-Ming Chen*

CRYSTAL GROWTH & DESIGN 2006 VOL. 6, NO. 12 2739-2746

MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry and Chemical Engineering, Sun Yat-Sen UniVersity, Guangzhou 510275, China ReceiVed July 10, 2006; ReVised Manuscript ReceiVed September 18, 2006

ABSTRACT: Four new complexes [Cd4(bpa)2(MeCO2)8]‚9H2O (1), {[Cd4(bpa)4(suc)2(H2O)4](suc)2‚17H2O}n (2), {[Cd2(bpa)2(glu)2]‚ 9H2O}n (3), and {[Cd2(bpa)2(adi)2]‚11H2O}n (4) (where bpa ) N,N′-bis(picolinamide)azine, H2suc ) succinic acid, H2glu ) glutaric acid, and H2adi ) adipic acid) have been synthesized by the reactions of the bpa ligand and different Cd(II) carboxylates in similar conditions. Their structures consist of double-stranded helical [Cd2(bpa)2] structural units and various carboxylates. Each of the [Cd2(bpa)2] structural units in 1 is capped at its both ends by acetate-chelated Cd(II) fragments through acetate bridges into discrete tetranuclear species, which are self-assembled into two-dimensional (2D) hydrogen-bonded sheets with cavities. The 2D hydrogenbonded sheets in 1 are threaded by one-dimensional (1D) water tapes featuring (H2O)4 clusters to generate an unprecedented threedimensional (3D) hydrogen-bonded polypseudo-rotaxane architecture. The [Cd2(bpa)2] structural units as secondary building blocks (SBUs) are extended into metal-organic frameworks (MOFs) in 2 and 3 as 1D chains, while in 4 as 2D gridlike sheets by bridging dicarboxylate. These MOFs host meso-helical water chains, (H2O)32 water clusters, and T4(1)4(2)6(2) water tapes, respectively. All of these water morphologies have not been documented so far, and the observations indicate that an SBU and various carboxylate ligands including acetate and alkyl dicarboxylate with different lengths and flexibilities can self-assemble into diverse host frameworks from tetranuclear clusters to 1D chains and ladders, finally to 2D sheets, in which guest water molecules with different morphologies can be tuned to fill the spaces of the host MOFs. Introduction The construction of metal-organic frameworks (MOFs) is an active topical area because of their unusual and interesting structural diversity and potential application in the aspects of zeolite-like materials, molecular absorption, ion exchange, electrical conductivity, and new molecule-based magnets.1-3 Such kinds of compounds can be structurally controlled and hence exhibit tunable chemical and physical properties. However, directed synthesis is still a great challenge because the assembly progress is highly influenced by several factors, such as the metal/ligand nature,4 solvents,5 templates,6 and counterions.7 Recently, the concept of secondary building units (SBUs) has been applied with eminent success to the design of MOFs.2 Such SBUs can be connected into MOFs by appropriately bridging ligands such as alkyl dicarboxylates with hydrogenbond donors and/or acceptors.8,9 Meanwhile, considerable attention has been paid to theoretical and experimental studies of the water clusters due to their important relevance to the structures and functions of liquid water and ice, biological systems, and chemical processes.10 To understand the behavior of water molecules at the molecular level, the structural data of various hydrogen-bonded water clusters and networks in diverse environments are required. So far, a variety of water clusters including (H2O)3,11 (H2O)4,12 (H2O)5,13 (H2O)6,14 (H2O)8,15 (H2O)10,16 (H2O)11,17 (H2O)12,18 (H2O)14,19 (H2O)15,20 (H2O)16,21 (H2O)17,22 (H2O)18,20 (H2O)45,23 one-dimensional (1D) chain,24 1D tape,25 two-dimensional (2D) layer,26 and three-dimensional (3D) water structure27 have been structurally characterized, and they display different configura* To whom correspondence should be addressed. Fax: (86)-20-84112245. Tel: (86)-20-84113986. E-mail: [email protected] (B.-H.Y.); [email protected] (X.-M.C).

tions in a number of crystal hosts. Obviously, these observations have significantly promoted the elucidation of the interactions between water molecules, as well as between the water molecules and the hosts, and enriched water chemistry. To observe new water morphologies, a simple and useful strategy is to use appropriate ligands and SBUs through interlinking of bridging ligands or supramolecular interactions to generate MOFs with void and porous structures that are capable of accommodating water molecules. Recently, we have reported the crystal structure of a double-helical complex [Cd2(bpa)2Cl4]‚H2O [bpa ) N,N′-bis(picolinamide)azine], in which each bpa ligand is twisted into a spiral-like conformation. The uncoordinated amino groups of the ligand can act as hydrogen-bond donors, and the two Cd(II) ions are ligated by two bpa ligands to form a double-stranded binuclear helicate with chirality. Moreover, the lattice water molecules hydrogen bonded to chloride ions form an unprecedented water tape involving cyclic (H2O)4 units.25h This result inspired us to use the [Cd2(bpa)2] as an SBU and different carboxylate ligands to replace the chloride ions and to serve as the linkers for the formation of MOFs that can host new guest water morphologies, in which the alkyl dicarboxylate with different lengths may furnish various MOFs to accommodate different guest water morphologies. This strategy is also attractive for two more reasons. First, the bpa ligand, bearing two bidentate sites, can be fixed in a twisted helical conformation with chirality to mimic the micro-environments in biological systems. Second, rich amino and carboxylate groups allow water molecules to hydrogen bond to the host molecules. We report herein the syntheses and structural characterization of four new complexes [Cd4(bpa)2(MeCO2)8]‚9H2O (1), {[Cd4(bpa)4(suc)2(H2O)4](suc)2‚ 17H2O}n (2), {[Cd2(bpa)2(glu)2]‚9H2O}n (3), and {[Cd2(bpa)2(adi)2]‚11H2O}n (4) (H2suc ) succinic acid, H2glu ) glutaric

10.1021/cg060441f CCC: $33.50 © 2006 American Chemical Society Published on Web 10/26/2006

2740 Crystal Growth & Design, Vol. 6, No. 12, 2006

Cheng et al.

Table 1. Crystal Data and Structure Refinement for 1-4

a

compound

1

2

3

4

formula FW space group a /Å b/Å c/Å R/deg β/deg γ/deg V/Å3 Z Dc/g cm-3 T/K µ/mm-1 R1 (I > 2σ)a wR2 (all data)b GOF

C40H66Cd4N12O25 1564.64 P42/nbc 19.0544(11) 19.0544(11) 31.639(4) 90 90 90 11487.2(17) 8 1.809 100(2) 1.551 0.0570 0.1361 1.036

C64H106Cd4N24O37 2253.37 P1h 16.033(2) 16.744(2) 20.286(3) 68.747(2) 66.944(2) 63.282(2) 4359.3(10) 2 1.717 100(2) 1.064 0.0928 0.2257 1.097

C34H54Cd2N12O17 1127.70 C2/c 20.985(3) 14.837(2) 14.941(2) 90 92.090(3) 90 4648.9(11) 4 1.611 100(2) 0.996 0.0534 0.1396 1.023

C36H62Cd2N12O19 1191.78 C2/c 22.387(2) 13.1645(12) 17.7277(16) 90 103.104(2) 90 5088.6(8) 4 1.556 100(2) 0.917 0.0482 0.0963 1.019

R1 ) ∑||Fo| - |Fc||/∑|Fo|. b wR2 ) [∑w(Fo2 - Fc2)2/∑w(Fo2)2]1/2.

acid and H2adi ) adipic acid). They all contain the doublestranded helical SBU [Cd2(bpa)2], in which 1 is a tetranuclear cluster, while 2, 3, and 4 are 1D and 2D coordination polymers. A (H2O)32 cluster, meso-helical chain, T4(3)6(4)6(4) and T4(1)4(2)6(2) water tapes were encapsulated in the hosts of 2, 3, 1, and 4, respectively, which have not been described so far.10 Experimental Section Materials and Methods. The reagents and solvents employed were commercially available and used as received without further purification. The C, H, and N microanalyses were carried out with a Vario EL elemental analyzer. The FT-IR spectra were recorded from KBr pellets in the range of 400-4000 cm-1 on a Bruker TENSOR 27 FT-IR spectrometer. Powder X-ray diffraction (XRD) intensities were measured on a Rigaku D/max-IIIA diffratometer (Cu-KR, λ ) 1.54056 Å) with a scan rate of 1°/min in the range of 5-60°. TGA analysis was performed on a NETZSCH TG 209 thermal analyzer under nitrogen atmosphere at a scan rate of 10 °C min-1. The DSC curve was obtained on a NETZSCH DSC 204 differential scanning calorimeter at a scan rate of 5 °C min-1. Bpa,28 Cd(suc)‚2H2O,29 Cd(glu)‚5H2O, and Cd(adi)‚2H2O30 were synthesized according to the published procedures, respectively, and checked with elemental analysis. Synthesis of [Cd4(bpa)2(MeCO2)8]‚9H2O (1). Bpa (0.060 g, 0.25 mmol) dissolved in methanol (5 mL) was added to a methanol solution (10 mL) containing Cd(MeCO2)2‚4H2O (0.076 g, 0.25 mmol) and isophthalic acid (0.083 g, 0.5 mmol). The mixture solution was stirred for 12 h at room temperature and then filtered. The filtrate was allowed to evaporate slowly at room temperature. After 4 weeks, pale-yellow block crystals were obtained in 37.6% yield based on Cd(MeCO2)2‚ 4H2O. Anal. Calcd (%) for C40H66Cd4N12O25: C 30.71, H 4.25, N 10.74; found: C 30.68, H 4.27, N 10.75. FT-IR (KBr, cm-1): 3378-3300m, 3167m, 1641m, 1568vs, 1487m, 1411s, 1344m, 1299m, 1017m, 797m, 749m, 675m, 621m. Synthesis of {[Cd4(bpa)4(suc)2(H2O)4](suc)2‚17H2O}n (2). Bpa (0.060 g, 0.25 mmol) dissolved in methanol (5 mL) was added to a suspension aqua solution (10 mL) of Cd(suc)‚2H2O (0.066 g, 0.25 mmol). The mixture solution was stirred for 12 h at room temperature and then filtered. The filtrate was allowed to evaporate slowly at room temperature. After 3 weeks, pale-yellow block crystals were obtained in 65.3% yield based on Cd(II) salt. Anal. Calcd (%) for C64H106Cd4N24O37: C 34.11, H 4.74, N 14.92; found: C 34.07, H 4.76, N 14.85. FT-IR (KBr, cm-1): 3423vs, 2365w, 1628s, 1566vs, 1412m, 1298w, 1171vw, 1015w, 881w, 797w, 748w, 675m. Synthesis of {[Cd2(bpa)2(glu)2]‚9H2O}n (3). The reaction was carried out in a method similar to that for 2, using Cd(glu)‚5H2O (0.083 g, 0.25 mmol) instead of Cd(suc)‚2H2O. The filtrate was allowed to evaporate slowly at room temperature. After 2 weeks, pale-yellow block crystals were obtained in 13.6% yield based on Cd(II) salt. Anal. Calcd (%) for C34H54Cd2N12O17: C 36.21, H 4.83, N 14.90; found: C 36.20, H 4.86, N 14.87. FT-IR (KBr, cm-1): 3429vs, 2955m, 2368w, 1626s, 1566vs, 1406s, 1300m, 1161w, 1053w, 1015m, 891w, 798m, 748w, 675m, 636m.

Synthesis of {[Cd2(bpa)2(adi)2]‚11H2O}n (4). The reaction was carried out in a method similar to that for 2, using Cd(adi)‚2H2O (0.073 g, 0.25 mmol) instead of Cd(suc)‚2H2O. The filtrate was allowed to evaporate slowly at room temperature. After a week, pale-yellow block crystals were obtained in 20.4% yield based on Cd(II) salt. Anal. Calcd (%) for C36H62Cd2N12O19: C 36.28, H 5.24, N 14.10; found: C 36.23, H 5.28, N 14.12. FT-IR (KBr, cm-1): 3441vs, 2928m, 2367w, 1628s, 1566vs, 1410s, 1300m, 1165w, 1016w, 798w, 748w, 679w, 635w. X-ray Crystallography. Diffraction intensities for the compounds were collected on a Bruker Apex CCD area-detector diffractometer (Mo KR, 0.71073 Å). Absorption corrections were applied by using the multiscan propram SADABS.31 The structures were solved with direct methods and refined with the full-matrix least-squares technique with the SHELXTL program package.32 Anisotropic thermal parameters were applied to all the non-hydrogen atoms. The organic hydrogen atoms were generated geometrically (C-H 0.96 Å) and refined with isotropic temperature factors. Hydrogen atoms on oxygen and nitrogen atoms were located from difference maps and refined isotropically with geometric AFIX restraints of 0.85-0.95 Å. The crystallographic data are summarized in Table 1. Selected hydrogen-bond distances and bond angles are listed in Table 2.

Results and Discussion Synthesis. The syntheses were summarized in Scheme 1. When Cd(II) carboxylates were used instead of CdCl2‚2.5H2O, the previously reported double-stranded binuclear [Cd2(bpa)2] structural unit25h could be generated. Various monocarboxylate and alkyl dicarboxylate ligands with different lengths could be used and led to the diverse host structures expected for tuning the water morphologies. When acetate was used, tetranuclear cluster 1 was obtained, which hosts an unprecedented T4(3)6(4)6(4) water tape. When the alkyl dicarboxylate suc, glu, and adi were employed, the [Cd2(bpa)2] SBUs are linked by the dicarboxylate ligands into 1D and 2D MOFs. Interestingly, concomitant with the increase of the length of the dicarboxylate ligands, the MOF structures change from polymeric 1D single chains, ladders, and finally to sheets. Moreover, three different kinds of water morphologies, discrete (H2O)32 cluster, meso-helical water chain, and T4(1)4(2)6(2) water tape as guests, were observed and embedded into the hosts, respectively. Crystal Structure of 1. The crystal structure of 1 consists of a neutral [Cd4(bpa)2(MeCO2)8] molecule and nine lattice water molecules. As shown in Figure 1a, each bpa ligand is twisted into a spiral conformation to ligate two Cd(II) ions, furnishing a double-stranded helical structure. A pair of acetate anions complete a distorted pentagonal-bipyramidal geometry [N1-Cd1-N4 170.7(1)°] for each Cd(II) ion with the diazine nitrogen atoms [Cd1-N1 2.301(4) and Cd1-N4 2.306(4) Å]

Metal-Organic Frameworks and Water Morphology

Crystal Growth & Design, Vol. 6, No. 12, 2006 2741

Table 2. Selected Hydrogen-Bond Lengths (Å) and Bond Angles (°) of 1-4a D-H‚‚‚A

D-H [Å]

O1w-H1wa‚‚‚O4w O1w-H1wb‚‚‚O5 O2w-H2wa‚‚O1w O2w-H2wb‚‚‚O2wC O3w-H3wa‚‚‚O4w O3w-H3wb‚‚‚O3wE O3w-H3wc‚‚‚O3wD O4w-H4wa‚‚‚O7 O4w-H4wb‚‚‚O1wA O5w-H5wa‚‚‚O4 N3-H3b‚‚‚O3A N3-H3c‚‚‚O8D N6-H6b‚‚‚O1A N6-H6c‚‚‚O6F

0.92 0.87 0.95 0.95 0.92 0.85 0.85 0.95 0.86 0.88 0.96(7) 0.90(7) 0.84(8) 0.81(8)

O18-H18C‚‚‚O5J O1w-H1wa‚‚‚O10A O1w-H1wb‚‚‚O3w O2w-H2wa‚‚‚O15 O2w-H2wb‚‚‚O9B O3w-H3wa‚‚‚O9B O3w-H3wb‚‚‚O4w O4w-H4wa‚‚‚O12A O5w-H5wa‚‚‚O4w O5w-H5wb‚‚‚O6w O6w-H6wa‚‚‚O7w O6w-H6wb‚‚‚O14 O7w-H7wa‚‚‚O9w O7w-H7wb‚‚‚O8w O8w-H8wa‚‚‚O9 O8w-H8wa‚‚‚O10 O8w-H8wb‚‚‚O12C O9w-H9wa‚‚‚O13 O9w-H9wa‚‚‚O14 O9w-H9wb‚‚‚O11C O10w-H10q‚‚‚O9w O10w-H10w‚‚‚O11w O11w-H11w‚‚‚O12w O11w-H11q‚‚‚O13w O12w-H12w‚‚‚O8D O12w-H12q‚‚‚O11C O13w-H13w‚‚‚O8D O13w-H13q‚‚‚O13 O14w-H14q‚‚‚O13w O14w-H14w‚‚‚O15w O15w-H15w‚‚‚O16E O16w-H16w‚‚‚O11w O16w-H16Q‚‚‚O17w O17w-H17Q‚‚‚O16E N2-H2C‚‚‚O12wF N2-H2D‚‚‚O18

0.92 0.95 0.95 0.95 0.86 0.95 0.95 0.95 0.95 0.91 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.92 0.95 0.95 0.92 0.95 0.91 0.85 0.90 0.95 0.99 0.95 0.95 0.95 0.90 0.87

H‚‚‚A [Å]

D‚‚‚A [Å]

D-H‚‚‚A [°]

D-H‚‚‚A

D-H [Å]

1.89 1.98 2.07 1.89 1.93 2.00 2.00 1.85 2.02 2.00 2.07(7) 2.02(7) 2.09(8) 2.26(8)

2.797(6) 2.734(6) 2.935(7) 2.838(7) 2.842(7) 2.829(9) 2.762(6) 2.731(5) 2.783(6) 2.869(6) 2.993(6) 2.906(6) 2.893(7) 3.049(6)

169 145 150 172 178 177 158 154 148 170 160(5) 166(6) 159(7) 166(5)

1.92 2.03 1.90 2.03 2.58 1.88 2.30 2.23 1.85 1.87 1.95 1.90 2.01 1.74 2.09 2.36 1.94 2.11 2.43 2.08 1.81 2.22 2.11 2.03 1.99 2.02 2.03 2.03 2.22 2.40 1.81 1.89 1.94 2.16 2.12 2.53

2.834(10) 2.789(13) 2.842(11) 2.803(11) 3.441(15) 2.744(12) 2.906(14) 2.715(13) 2.778(13) 2.774(12) 2.642(18) 2.661(12) 2.778(16) 2.69(2) 3.034(18) 2.974(19) 2.824(16) 3.044(16) 3.053(18) 2.680(15) 2.750(13) 3.053(14) 2.998(13) 2.896(19) 2.878(14) 2.722(13) 2.859(12) 2.774(15) 3.043(13) 2.996(13) 2.786(11) 2.814(17) 2.777(13) 2.749(14) 2.995(12) 2.994(12)

158 135 170 137 180 151 121 111 164 169 128 135 137 177 177 122 153 170 123 120 169 150 154 150 160 129 151 145 151 121 168 163 145 119 164 114

N5-H5A‚‚‚O8G N5-H5B‚‚‚O13B N8-H8A‚‚‚O2wB N8-H8B‚‚‚O2 N11-H11B‚‚‚O17 N11-H11C‚‚‚O9H N14-H14C‚‚‚O17wD N14-H14D‚‚‚O6 N17-H17A‚‚‚O19 N17-H17B‚‚‚O15wI N20-H20A‚‚‚O14J N20-H20B‚‚‚O20 O17-H17C‚‚‚O10H O17-H17D‚‚‚O4H O18-H18D‚‚‚O5w O19-H19A‚‚‚O7K O19-H19B‚‚‚N17 O20-H20C‚‚‚O6wJ O20-H20D‚‚‚O1J

1.08 1.01 1.09 0.93 0.88 0.88 0.87 0.74 0.98 0.95 0.99 0.89 0.92 0.95 0.88 0.85 0.85 0.98 0.86

O1w-H1wa‚‚‚O1A O1w-H1wa‚‚‚O4B O2w-H2wa‚‚‚O2 O2w-H2wb‚‚‚O1w O3w-H3wa‚‚‚O2w O4w-H4wa‚‚‚O2w O4w-H4wb‚‚‚O4wC O5w-H5wa‚‚‚O4A O5w-H5wb‚‚‚O4w N2-H2B‚‚‚O4wD N2-H2C‚‚‚O2D N5-H5B‚‚‚O2E N5-H5C‚‚‚O3E

0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 1.06 0.82 1.04 1.17

O1w-H1wa‚‚‚O3 O1w-H1wb‚‚‚O5wA O2w-H2wa‚‚‚O1w O2w-H2wb‚‚‚O3w O3w-H3wa‚‚‚O4w O4w-H4wb‚‚‚O5w O4w-H4wa‚‚‚O6w O5w-H5wa‚‚‚O2wB O5w-H5wb‚‚‚O2C O6w-H6wa‚‚‚O3 O6w-H6wa‚‚‚O1 N2-H2B‚‚‚O4wA N2-H2C‚‚‚O4E N5-H5B‚‚‚O2wF N5-H5C‚‚‚O2

0.95 0.90 0.97 0.95 0.91 0.95 0.88 0.90 0.97 0.90 0.87 0.85 0.92 0.87 0.87

1

H‚‚‚A [Å]

D‚‚‚A [Å]

D-H‚‚‚A [°]

2.20 1.89 1.80 1.96 2.40 2.03 2.07 2.40 2.10 2.21 1.90 2.45 1.84 1.77 1.89 2.28 2.59 1.79 1.83

2.961(12) 2.872(12) 2.870(13) 2.878(10) 3.095(12) 2.869(12) 2.927(12) 2.992(12) 3.064(12) 3.163(13) 2.841(14) 3.125(12) 2.749(11) 2.696(11) 2.758(11) 2.888(11) 3.064(12) 2.733(11) 2.674(11)

125 162 165 171 136 159 166 138 165 178 159 133 169 163

1.78 1.74 2.29 1.80 2.12 2.06 2.25 1.82 1.92 1.85 2.11 2.00 1.96

2.717(7) 2.591(8) 2.767(9) 2.645(9) 2.847(8) 2.872(10) 2.936(9) 2.755(8) 2.688(9) 2.878(7) 2.847(6) 2.932(7) 2.862(6)

1.86 1.97 1.77 1.97 2.01 2.03 2.01 1.91 1.83 1.94 1.96 2.40 1.98 2.16 2.10

2.746(5) 2.894(5) 2.718(5) 2.817(5) 2.821(5) 2.844(5) 2.834(5) 2.797(5) 2.729(5) 2.782(5) 2.809(5) 3.103(6) 2.864(5) 3.012(5) 2.949(5)

2

2

3

4

168 128 116 161 168 169 147 111 147 133 142 129 166 136 160 149 148 130 155 165 166 147 147 142 155 168 154 155 165 160 161 166 167

a D, donor atom; A, acceptor atom. Symmetry code for 1: A, -1/2 - x, 3/2 - y, z; B, 3/2 - x, 3/2 - y, 1/2 - z; C, 1/2 + x, 1 - y, 1/2 - z; D, -1/2 + x, 2 - y, z; E, x, 3/2 - y, -z; F: -x, -1/2 + y, z. for 2: A, -1 + x, y, z; B, -x, 1 - y, -z; C, 1 - x, 1 - y, -z; D, 1 - x, -y, 1 - z; E: -x, -y, 1 - z; F: -1 + x, 1 + y, z; G, -1 + x, 1 + y, -1 + z; H, -x, 2 - y, -z; I, x, 1 + y, z; J, -x, 1 - y, 1 - z; K, 1 - x, 1 - y, 1 - z. for 3: A: 1/2 x, -3/2 - y, -z; B, 1/2 - x, 1/2 + y, 1/2 - z; C: 1 - x, -1 - y, -z; D, 1 - x, y, -1/2 - z; E, x, -2 - y, -1/2 + z. for 4: A, x, 1 - y, 1/2 + z; B, 1 - x, y, 1/2 - z; C, 1/2 - x, 3/2 - y, -z; D, x, 1 - y, 1/2 + z; E, -x, y, 1/2 - z; F, 1/2 - x, 1/2 + y, 1/2 - z.

Scheme 1.

Summary of the Synthesis

at the equatorial plane and the pyridyl nitrogen atoms [Cd1-N2 2.440(4) and Cd1-N5 2.447(4) Å] at the axial

positions. This pair of acetates at each side of the helicate core link to the terminal Cd2 ions that are chelated by two acetate anions, resulting in a neutral, nanosized tetranuclear cluster with dimensions of ca. 13.52 × 10.12 × 10.12 Å.3 Intramolecular hydrogen bonds are found between the amino groups and acetate groups [N3‚‚‚O3A 2.994(5) and N6‚‚‚O1A 2.891(7) Å] to stabilize the cluster. The tetranuclear cluster is of unique chirality with Λ or ∆ configuration. Meanwhile, with rich exposed amino and carboxylate groups as hydrogen-bond donors and acceptors, the metal clusters are self-assembled into a homochiral squaregrid sheet with cavities (size ca. 8.73 × 8.84 Å2) via intermolecular hydrogen bonds [N3‚‚‚O8 2.908(5) and N6‚‚‚O6 3.049(6) Å] in the ab plane (Figure 1b). These sheets are packed faceto-face to form the largest channels running along the c-axis,

2742 Crystal Growth & Design, Vol. 6, No. 12, 2006

Cheng et al.

Figure 1. Structures of the Cd(II) coordination environments and intramolecular hydrogen bonds (a), the homochirally hydrogen-bonded sheet on the ab plane (b), 3D hydrogen-bonded polypseudo-rotaxane viewed along the b-axis (c), and a schematic presentation with the magenta thread representing the water tape in 1 (d). Symmetry codes: A: -1/2 - x, 3/2 - y, z; B: 3/2 - x, 3/2 - y, 1/2 - z; C: 1/2 + x, 1 - y, 1/2 - z; D: -1/2 + x, 2 - y, z; E: 1/2 + x, 2 - y, z.

where a pair of adjacent sheets with uniform chirality are linked by hydrogen bonds into a double layer through the intersheet lattice O5w water molecule that does not belong to the water tape [O5w‚‚‚O4 2.870(6) Å], whereas there is no such interaction between the double double layers. Each cavity is threaded by a water tape, resulting in an unusual polypseudo-rotaxanetype 3D supramolecular architecture (Figure 1c,d). Although the hydrogen-bonded polypseudo-rotaxane with cationic chains has been reported,33,34 to the best of our knowledge, 1 is the first example of water tapes as threads penetrating the sheets to form a hydrogen-bonded 3D network. Meanwhile, the water molecules in the water tapes are further stabilized by hydrogen bonds with the sheets [O1w‚‚‚O5 2.734(5) and O4w‚‚‚O7 2.730(6) Å], and the shape of the water tape closely follows that of the channel of the host, indicating a complementary relationship between the tape and its host. In the infinite water tape involving cyclic (H2O)4 clusters extended along the c-axis (Figure 2) in 1, O1w and O4w water molecules are hydrogen bonded to each other [O4w‚‚‚O1w 2.801(6) Å] into a cyclic tetramer within the sheet cavity, whereas each O2w and O3w water molecule forms a hydrogen-bonded cyclic tetramer with its three crystallographic-

Figure 2. The T4(3)6(4)6(4) water tape in 1.

ally equivalent ones [O2w‚‚‚O2wC 2.840(8), O3w‚‚‚O3wE 2.762(6) Å] and anchors between the sheets, respectively. These tetramers are linked into a water tape with a T4(3)6(4)6(4) motif, which has never been described so far.10,25 Moreover, O2w and O3w exhibit triangle geometries with one donor and two acceptor hydrogen bonds, while O1w and O4w adopt tetrahedral geometries. The O‚‚‚O distances within the tape are in the range of 2.734(6)-2.935(7) Å, comparable to 2.759 Å in ice Ih, 2.85 Å in liquid water, and 2.874 and 2.950 Å in water tapes with tetramer cluster.10a The O‚‚‚O‚‚‚O angles vary from 81.1 to 113.8°. Crystal Structure of 2. The crystal structure of 2 consists of a pair of [Cd2(bpa)2(suc)(H2O)2]2+, two free suc and

Metal-Organic Frameworks and Water Morphology

Crystal Growth & Design, Vol. 6, No. 12, 2006 2743

Figure 3. Views of the Cd(II) coordination environments and 1D structure with intramolecular hydrogen bonds (a) and 2D host frameworks linked by interchain hydrogen bonds between the aqua ligands and carboxylate groups (b) in 2. Symmetry codes: A: -1 + x, 1 + y, -1 + z.

seventeen lattice water molecules. As shown in Figure 3a, each bpa ligand is also twisted into a spiral conformation to ligate two Cd(II) ions, furnishing a double-stranded helical [Cd2(bpa)2] SBU with a unique chirality. The intradimer Cd1‚‚‚Cd2 (4.83 Å) and Cd3‚‚‚Cd4 (4.82 Å) distances are comparable to that in [Cd2(bpa)2Cl4]‚6H2O (4.82 Å)25h but significantly shorter than that in 1 (5.03 Å). Each SBU is further coordinated by two aqua liagnds and completed by two suc ligands. The intermolecular hydrogen bonds are also found between the amino groups and the carboxylate groups (N‚‚‚O 2.88-2.99 Å). The geometries of Cd1 and Cd4 are distorted octahedral geometry, and the carboxylate groups are in a monodentate coordination fashion, while Cd2 and Cd3 are in distorted pentagonalbipyramidal geometries and the carboxylate groups are in a chelate mode. The suc ligands have two kinds of coordination modes: bis-chelating and bis-monodentate, which are alternately bridged the identically chiral SBU into a homochiral chain. Moreover, the adjacent chains with different chiralities are linked to each other through interchain hydrogen bonds (O‚‚‚O distances of 2.67 and 2.88 Å) between the aqua ligands and the carboxylate groups into 2D host frameworks (Figure 3b). Interestingly, an unprecedented (H2O)32 water cluster containing a central cyclic (H2O)4 was observed in 2 (Figure 4a). Within the cyclic (H2O)4 cluster, each water monomer acts as both a single hydrogen-bond donor and a single hydrogen-bond acceptor and has another hydrogen atom oriented above or below the ring. The four water molecules are virtually coplanar with the hydrogen-bond distance of O16w‚‚‚O17w of 2.777(13) Å, which is comparable to the average hydrogen-bond distance of liquid water tetramer (2.78 Å).35 The uncoordinated suc and (H2O)32 cluster link each other via hydrogen bonds into a 2D guest network (Figure 4b). Finally, these guest sheets are alternately packed with the 2D host layers and exhibit interlayer hydrogen bonds between the suc and the aqua ligands, lattice waters, as well as those between amino groups and free suc into a 3D hydrogen-bonded network (Figure 4c). Crystal Structure of 3. The SBU of 3 is also [Cd2(bpa)2], as those in 1 and 2. However, the SBUs in 3 are linked by four glu ligands in a bis-monodentate fashion into ladder-like chains (Figure 5). Each Cd(II) is six-coordinated. Within each chain, the adjacent SBUs have different chiralities and are arranged alternatively into a meso-chiral chain with intrachain hydrogen bonds between the oxygen atoms of glu and the amino groups

Figure 4. Structures of the (H2O)32 cluster containing a cyclic (H2O)4 (a), a 2D hydrogen-bonded network constructed by free suc ligands and (H2O)32 water clusters (b), and 3D hydrogen-bonded architecture assembled by host and guest (red and white balls) layers (c) in 2. Symmetry codes: a, 1 - x, -y, 1 - z.

of bpa [N2‚‚‚O2 2.845(6), N5‚‚‚O2 2.933(7) and N5‚‚‚O3 2.863(6) Å]. Excluding the van der Waals radii, the channel running along the c-axis has a pore size of ca. 10.0 × 5.7 Å,2 in which the water chains are located. Each water chain is hydrogen bonded to four ladder-like host chains, and each host chain is, in turn, linked to four water chains (Figure 5b). The ladderlike MOF chains act as a template for the formation of the water chains and stabilize them through hydrogen bonds between the glu oxygen atoms and lattice O1w and O5w water molecules [O1w‚‚‚O1 2.718(7), O1w‚‚‚O4 2.590(8) and O5w‚‚‚O4 2.754 (8) Å] along the a-axis, as well as those between the glu oxygen atoms, bpa amino groups, and lattice water molecules O2w and O4w [O2w‚‚‚O2 2.766(8) and O4w‚‚‚N2 2.879 (7) Å] along the b-axis (Figure 5c). There are 9/2 water molecules in each asymmetric unit, in which O2w, O3w, and O4w molecules are connected with each other via hydrogen bonds [O4w‚‚‚O2w 2.871(12) and O2w‚‚‚O3w 2.847(8) Å] into an infinite water chain. The O2w and O4w molecules act as double hydrogen-bond acceptors and donors resulting in tetrahedron geometries, while O3w is a double hydrogen-bond donor as shown in Figure 6a. It is worth noting that the water chain has a pseudo 41-screw axis, in which quarters of the screw distance are of opposite handedness, resulting in a rare meso-helical chain (Figure 6b). Even though meso-helices are widely found in nature, and several mesohelical structures in coordination polymers and organic supramolecules have been found,36 no meso-helical water chain

2744 Crystal Growth & Design, Vol. 6, No. 12, 2006

Cheng et al.

Figure 5. Views of a ladder-like host chain along the a-axis (a), the 3D hydrogen-bonded network along the c-axis (b), and the interactions between the host ladders and the guest water chains via hydrogen bonds (c) in 3.

Figure 6. The structure of a meso-helical water chain extending along the a-axis (a) and viewed along the c-axis (b). Symmetry codes: A: 1 - x, y, 1/2 - z; B: 1 - x, -1 - y, -z; C: x, -1 - y, -1/2 + z; D: x, -1 - y, 1/2 + z; E: 1 - x, -1 - y, 1 - z.

has been described so far.24 The novel water chain obtained here may be attributed to the host chain acting as a “template”. Crystal Structure of 4. Although each Cd(II) ion of 4 has the same coordination geometry as found in 3 and the adi ligand has the same coordination mode as found for glu in 3, the host framework of 4 features a 2D gridlike network (Figure 7a) with

Figure 7. Views of two adjacent sheets on the ac plane (a) and the undulated water tapes that link the sheets into 3D network (b) in 4. In (a), the water molecules are omitted. In (b), the water tapes are presented in a space filling fashion.

the Cd2(bpa)2 SBUs as nodes and adi ligands as linkers, being much different from the chain-like motifs of 2 and 3. These may be attributed to the fact that adi is longer and more flexible

Metal-Organic Frameworks and Water Morphology

Crystal Growth & Design, Vol. 6, No. 12, 2006 2745

Conclusion

Figure 8. Structure of the water tape in 4. Symmetry codes: A: 1 - x, y, 1/2 - z; B: x, 1 - y, - 1/2 + z; C: 1 - x, 1 - y, -z; D: 1 - x, 1 - y, 1 - z.

than suc and glu. In 4, the shortest Cd‚‚‚Cd distances between the SBUs are ca. 10.85 and 11.92 Å, which are much longer than those in 2 (9.25 and 9.23 Å) and 3 (8.21 Å). The intraSBU Cd‚‚‚Cd distance is 4.88 Å in 4, being slightly longer than those in 2 (4.83 and 4.82 Å), 3 (4.83 Å), and [Cd2(bpa)2Cl4]‚ 6H2O (4.82 Å), but shorter than that in 1 (5.03 Å). Each SBU is chiral and the four adjacent ones are of opposite chiralities; thus, the sheet is achiral. The nodes of the 2D sheet are inserted into the cavities of the adjacent ones resulting in ABAB arrangement, in which undulated water tapes are filled between the sheets and link the adjacent sheets into 3D structure (Figure 7b). The detailed structure of the water tape is shown in Figure 8, in which O3w is located on the special position. The water tape involves both planar cyclic tetramers and chair-shaped cyclic hexamers, in which the two adjacent tetramers connect to each other by sharing a corner, while the adjacent tetramer and the hexamer share an edge, giving rise to an extended tape with a T4(1)4(2)6(2) motif. To our knowledge, such an arrangement of water tapes has not been described so far.10b The hydrogen-bonding parameters of the water molecules are summarized in Table 2. The O1w, O2w, and O4w molecules adopt trigonally distorted geometries with double hydrogenbond donors and a hydrogen-bond acceptor, while O3w and O5w display tetrahedral geometries with double hydrogen-bond donors and acceptors. Within the water tape, the O‚‚‚O distances are in range of 2.718(5)-2.894(5) Å with an average of 2.818 Å, which is comparable to that observed in the ice II phase 2.77-2.84 Å.37 The O‚‚‚O‚‚‚O angles vary from 83.8 to 117.6°. Thermogravimetric Properties. The thermogravimetric analyses of the powder samples 1-4 were carried out from 25 to 700 °C under dinitrogen atmosphere. The weight loss of 12.8, 17.0, 12.8, and 14.9% for 1, 2, 3, and 4, respectively, in the range of 25-200 °C (see Figure S1, Supporting Information) corresponds to the loss of the water molecules (calculated 12.1% for 1, 16.8% for 2, 14.4% for 3, and 16.6% for 4), indicating that the water molecules were completely removed at 200 °C. The differential scan calorimetry measurements showed a very sharp endotherm centered at 66.4, 87.6, 73.6, and 61.8 °C with the enthalpies for per water molecule of 50.8, 49.5, 46.1, and 55.2 kJ for 1, 2, 3, and 4, respectively, in which the enthalpies are comparable to those of [Cd2(bpa)2Cl4]‚6H2O (47 kJ mol-1),25h tripeptides hydrates (53 kJ mol-1),38 and theophylline monohydrate (47.3 kJ mol-1).39 To observe the thermal stability of the MOFs upon removal of the guest water molecules, XRD data of all the complexes before and after removing the water molecules were measured (see Figures S4-S7, Supporting Information), indicating that the MOFs remain intact after removal of the guest water molecules.

Among the four complexes 1-4 synthesized by the reactions of the bpa ligand and Cd(II) carboxylates under similar conditions, the structures are altered from a tetranuclear cluster, to a 1D chain, a ladder, finally to a 2D sheet upon incorporation of different carboxylate ligands. In the meantime, the guest molecules with different water morphologies including a discrete (H2O)32 cluster, meso-helical chain, and T4(3)6(4)6(4) and T4(1)4(2)6(2) tapes were observed in the MOF hosts. This work demonstrates that by using an SBU and various carboxylate ligands including monocarboxylate and alkyl dicarboxylate with different lengths and flexibilities, diverse MOFs can be assembled to host lattice water molecules in different morphologies. Acknowledgment. This work was supported by the National Natural Science Foundation of China (Nos. 20531070 and 20371052) and the Scientific and Technological Department of Guangdong Province. Supporting Information Available: TGA and DSC plots of 1-4. X-ray crystallographic file in CIF format for 1-4. This material is available free of charge via the Internet at http://pubs.acs.org.

References (1) (a) Wu, C.-D.; Lin, W. B. Angew. Chem. Int. Ed. 2005, 44, 1958. (b) Dobrzan´ska, D.; Lloyd, G. O.; Raubenheimer, H. G.; Barbour, L. J. J. Am. Chem. Soc. 2005, 127, 13134. (2) (a) Millward, A. R.; Yaghi, O. M. J. Am. Chem. Soc. 2005, 127, 17998. (b) Rosi, N. L.; Kim, J.; Eddaoudi, M.; Chen, B.; O’Keeffe, M.; Yaghi, O. M. J. Am. Chem. Soc. 2005, 127, 1504. (c) Ockwig, N. W.; Gado-friedrichs, O. D.; O’Keeffe, M.; Yaghi, O. M. Acc. Chem. Res. 2005, 38, 176. (3) (a) Takamizawa, S.; Nakata, E.; Yokoyama, H.; Mochizuki, K.; Mori, W. Angew. Chem., Int. Ed. 2003, 42, 4331. (b) Kitagawa, S.; Kitaura, R.; Noro, S.-I. Angew. Chem., Int. Ed. 2004, 43, 2334. (c) Pan, L.; Sander, M. B.; Huang, X.; Li, J.; Smith, M.; Bittner, E.; Bockrath, B.; Johnson, J. K. J. Am. Chem. Soc. 2004, 126, 1308. (4) Banfi, S.; Carlucci, L.; Caruso, E.; Ciani, G.; Proserpio, D. M. Dalton Trans. 2002, 2714. (5) (a) Gable, R. W.; Hoskins, B. F.; Robson, R. Chem. Commun. 1990, 1677. (b) Subramanian, S.; Zaworotko, M. J. Angew. Chem. Int. Ed. 1995, 34, 2127. (c) Long, D.-L.; Blake, A. J.; Champness, N. R.; Wilson, C.; Schroder, M. Chem.-Eur. J. 2002, 8, 2027. (6) (a) Honnigar, T. L.; MacQuarric, D. C.; Rogers, P. D.; Zaworotko, M. J. Angew. Chem., Int. Ed. 1997, 36, 972. (b) Tong, M.-L.; Chen, X.-M.; Ye, B.-H.; Ng, S.-W. Inorg. Chem. 1998, 37, 2645. (c) Gudbjarlson, H.; Poirier, K. M.; Zaworotko, M. J. J. Am. Chem. Soc. 1999, 121, 2599. (d) Su, C.-Y.; Cai, Y.-P.; Chen, C.-L.; Lissner, F.; Kang, B.-S.; Kaim, W. Angew. Chem. Int. Ed. 2002, 41, 3371. (7) (a) Carlucci, L.; Ciani, G.; Proserpio, D. M. Angew. Chem., Int. Ed. 1995, 34, 1895. (b) Tong, M.-L.; Chen, X.-M.; Ye, B.-H.; Ng, S.W. Inorg. Chem. 1998, 37, 5168. (c) Blake, A. J.; Champness, N. R.; Hubberstey, P.; Li, W.-S.; Withersby, M. A.; Schro¨der, M. Coord. Chem. ReV. 1999, 183, 117. (d) Zhu, H.-L.; Tong, Y.-X.; Chen, X.M. J. Chem. Soc. Dalton Trans. 2000, 4182. (8) (a) Livage, C.; Egger, C.; Ferey, G. Chem. Mater. 1999, 11, 1546. (b) Serpaggi, F.; Luxbacher, T.; Cheetham, A. K.; Ferey, G. J. Solid State Chem. 1999, 145, 580. (c) Reineke, T. M.; Eddaoudi, M.; O’Keeffe, M.; Yaghi, O. M. Angew. Chem., Int. Ed. 1999, 38, 2590. (d) Reineke, T. M.; Eddaoudi, M.; Fehr, M.; Kelley, D.; Yaghi, O. M. J. Am. Chem. Soc. 1999, 121, 1651. (e) Pan, L.; Zheng, N.; Wu, Y.; Han, S.; Yang, R.; Huang, X.; Li, J. Inorg. Chem. 2001, 40, 828. (f) Zheng, X. J.; Jin, L. P.; Lu, S. Z. Eur. J. Inorg. Chem. 2002, 3356. (9) Ye, B.-H.; Tong, M.-L.; Chen, X.-M. Coord. Chem. ReV. 2005, 249, 545. (10) (a) Ludwig, R. Angew. Chem. Int. Ed. 2001, 40, 1808 and refs therein. (b) Infantes, L.; Motherwell, S. CrystEngComm 2002, 4, 454. (11) (a) MacGillivray, L. R.; Atwood, J. L. J. Am. Chem. Soc. 1997, 119, 2592. (b) Ghosh, S. K.; Bharadwaj, P. K. Inorg. Chem. 2005, 44, 5553.

2746 Crystal Growth & Design, Vol. 6, No. 12, 2006 (12) (a) Supriya, S.; Das, S. K. New J. Chem. 2003, 27, 1568. (b) Long, L.-S.; Wu, Y.-R.; Huang, R.-B.; Zheng, L.-S. Inorg. Chem. 2004, 43, 3798. (c) Tao, J.; Ma, Z.-J.; Huang, R.-B.; Zheng, L.-S.; Inorg. Chem. 2004, 43, 6133. (d) Ng, M. T.; Deivaraj, T. C.; Klooster, W. T.; McIntyre, G. J.; Vittal, J. J. Chem.-Eur. J. 2004, 10, 5853. (e) Turner, D. R.; Henry, M.; Wilkinson, C.; McIntyre, G. J.; Mason, S. A.; Goeta, A. E.; Steed, J. W. J. Am. Chem. Soc. 2005, 127, 11063. (f) Lakshminarayanan, P. S.; Kumar, D. K.; Ghosh, P. Inorg. Chem. 2005, 44, 7540. (g) Turner, D. R.; Henry, M.; Wilkinson, C.; McIntyre, G. J.; Mason, S. A.; Goeta, A. E.; Steed, J. W. J. Am. Chem. Soc. 2005, 127, 11063. (h) Zuhayra, M.; Kampen, W. U.; Henze, E.; Soti, Z.; Zsolnai, L.; Huttner, G.; Oberdorfer, F. J. Am. Chem. Soc. 2006, 128, 424. (i) Jiang, G.-Q.; Bai, J.-F.; Xing, H.; Li, Y.-Z.; You, X.-Z. Cryst. Growth Des. 2006, 6, 1264. (13) (a) Zabel, V.; Saenger, W.; Masons, S. A. J. Am. Chem. Soc. 1986, 108, 3664. (14) (a) Moorthy, J. N.; Natarajan, R.; Venugopalan, P. Angew. Chem., Int. Ed. 2002, 41, 3417. (b) Doedens, R. J.; Yohannes, E.; Khan, M. I. Chem. Commun. 2002, 62. (c) Ghosh, S. K.; Bharadwaj, P. K. Inorg. Chem. 2003, 42, 8250. (d) Zhao, B.; Cheng, P.; Chen, X.; Cheng, C.; Shi, W.; Liao, D.; Yan, S.; Jiang, Z. J. Am. Chem. Soc. 2004, 126, 3012. (e) Ye, B.-H.; Ding, B.-B.; Weng, Y.-Q.; Chen, X.-M. Inorg. Chem. 2004, 43, 6866. (f) Ghosh, S. K.; Bharadwaj, P. K. Inorg. Chem. 2004, 43, 5180. (g) Lam, C.-K.; Xue, F.; Zhang, J.-P.; Chen, X.-M.; Mak, T. C. W. J. Am. Chem. Soc. 2005, 127, 11536. (h) Liao, Y.-C.; Jiang, Y.-C.; Wang, S.-L. J. Am. Chem. Soc. 2005, 127, 12794. (i) Mukhopadhyay, U.; Bernal, I. Cryst. Growth Des. 2005, 5, 1687. (j) Jiang, Y.-Q.; Xie, Z.-X. Supramol. Chem. 2005, 17, 291. (k) Saha, B. K.; Nangia, A. Chem. Commun. 2006, 1825. (15) (a) Atwood, J. L.; Barbour, L. J.; Ness, T. J.; Raston, C. L.; Raston, P. L. J. Am. Chem. Soc. 2001, 123, 7192. (b) Noro, S.; Kitaura, R.; Kondo, M.; Kitagawa, S.; Ishii, T.; Matsuzaka, H.; Yamashita, M. J. Am. Chem. Soc. 2002, 124, 2568. (c) Doedens, R. J.; Yohannes, E.; Kahn, M. I. Chem. Commun. 2002, 62. (d) Ma, B.-Q.; Sun, H.L.; Gao, S. Chem. Commun. 2005, 2336. (e) Ghosh, S. K.; Bharadwaj, P. K. Eur. J. Inorg. Chem. 2005, 24, 4886. (f) Prasad, T. K.; Rajasekharan, M. V. Cryst. Growth Des. 2006, 6, 488. (16) (a) Michaelides, A.; Skoulika, S.; Bakalbassis, E. G.; Mrozinski, J. Cryst. Growth. Des. 2003, 3, 487. (b) Yoshizawa, M.; Kusukawa, T.; Kawano, M.; Ohhara, T.; Tanaka, I.; Kurihara, K.; Niimura, N.; Fujita, M. J. Am. Chem. Soc. 2005, 127, 2798. (c) Bergougnant, R. D.; Robin, A. Y.; Fromm, K. M. Cryst. Growth Des. 2005, 5, 1691. (d) Li, Y.; Jiang, L.; Feng, X.-L.; Lu, T.-B. Cryst. Growth Des. 2006, 6, 1074. (17) Lakshminarayanan, P. S.; Suresh, E.; Ghosh, P. Angew. Chem. Int. Ed. 2006, 45, 3807. (18) (a) Ghosh, S. K.; Bharadwaj, P. K. Angew. Chem., Int. Ed. 2004, 43, 3577. (b) Neogi, S.; Savitha, G.; Bharadwaj, P. K. Inorg. Chem. 2004, 43, 3771. (19) (a) Ghost, S. K.; Ribas, J.; Fallah, M. S. E.; Bharadwaj, P. K. Inorg. Chem. 2005, 44, 3856. (b) Deshpande, M. S.; Kumbhar, A. S.; Puranik, V. G.; Selvaraj, K. Cryst. Growth Des. 2006, 6, 743. (20) Raghuraman, K.; Katti, K. K.; Barbour, L. J.; Pillarsetty, N.; Barnes, C. L.; Katti, K. V. J. Am. Chem. Soc. 2003, 125, 6955. (21) Ghost, S. K.; Bharadwaj, P. K. Inorg. Chem. 2004, 43, 6887. (22) (a) Beitone, L.; Huguenard, C.; GansmUller, A.; Henry, M.; Taulelle, F.; Loiseau, T.; Fe´rey, G. J. Am. Chem. Soc. 2003, 125, 9102. (b) Henry, M.; Taulelle, F.; Loiseau, T.; Beitone, L.; Fe´rey, G. Chem.Eur. J. 2004, 10, 1366. (23) Lakshminarayanan, P. S.; Suresh, E. I.; Ghost, P. J. Am. Chem. Soc. 2005, 127, 13132. (24) (a) Rau, S.; Ruben, M.; Bu¨ttner, T.; Temme, C.; Dautz, S.; Go¨rls, H.; Rudolph, M.; Walther, D.; Brodkorb, A.; Duati, M.; O’Connor, C.; Vos, J. G. J. Chem. Soc. Dalton Trans. 2000, 3649. (b) Cheng, D.; Khan, M. A.; Houser, R. P. Inorg. Chem. 2001, 40, 6858. (c) Cheruzel, L. E.; Pometun, M. S.; Cecil, M. R.; Mashuta, M. S.; Wittebort, R. J.; Buchanan, R. M. Angew. Chem., Int. Ed. 2003, 42, 5452. (d) Sreenivasulu, B.; Vittal, J. J. Angew. Chem. Int. Ed. 2004, 43, 5769. (e) Mukherjee, A.; Saha, M. K.; Nethaji, M.; Chakravarty,

Cheng et al.

(25)

(26)

(27) (28) (29) (30) (31) (32) (33) (34) (35) (36)

(37) (38) (39)

A. R. Chem. Commun. 2004, 716. (f) Turner, D. R.; Hursthouse, M. B.; Light, M. E.; Steed, J. W. Chem. Comun. 2004, 1354. (g) Banerjee, S.; Murugavel, R. Cryst. Growth Des. 2004, 4, 545. (h) Fei, Z.; Zhao, D.; Geldbach, T. J.; Scopelliti, R.; Dyson, P. J.; Antonijevic, S.; Bodenhausen, G. Angew. Chem. Int. Ed. 2005, 44, 5720. (i) Saha, B. K.; Nangia, A. Chem. Commun. 2005, 3024. (j) Neogi, S.; Bharadwaj, P. K. Inorg. Chem. 2005, 44, 816. (k) Zhang, X.-L.; Ye, B.-H.; Chen, X.-M. Cryst. Growth Des. 2005, 5, 1609. (l) Zhang, X.-L.; Chen, X.-M. Cryst. Growth Des. 2005, 5, 617. (m) Zhou, Z.-H.; Yang, J.-M.; Wan, H.-L. Cryst. Growth Des. 2005, 5, 1826. (n) Kim, H.-J.; Jo, H. J.; Kim, J.; Kim, S.-Y.; Kim, D.; Kim. K. CrystEngComm 2005, 7, 417. (a) Custelcean, R.; Afloroaei, C.; Vlassa, M.; Polverejan, M. Angew. Chem. Int. Ed. 2000, 39, 3094. (b) Pal, S.; Sankaran, N. B.; Samanta, A. Angew. Chem. Int. Ed. 2003, 42, 1741. (c) Ma, B.-Q.; Sun, H.L.; Gao, S. Chem. Commun. 2004, 2220. (d) Ma, B.-Q.; Sun, H.-L.; Gao, S. Chem. Commun. 2005, 2336. (e) Zheng, J.-M.; Batten, S. R.; Du, M. Inorg. Chem. 2005, 44, 3371. (f) Lu, J.; Yu, J.-H.; Chen, X.-Y.; Cheng, P.; Zhang, X.; Xu, J.-Q. Inorg. Chem. 2005, 44, 5978. (g) Liu, Q.-Y.; Xu, L. CrystEngComm 2005, 7, 87. (h) Ye, B.-H.; Sun, A.-P.; Wu, T.-F.; Weng, Y.-Q.; Chen, X.-M. Eur. J. Inorg. Chem. 2005, 1230. (i) Tadokoro, M.; Fukui, S.; Kitajima, T.; Nagao, Y.; Ishimaru, S.; Kitagawa, H.; Isobee, K.; Nakasuji, K. Chem. Commun. 2006, 1274. (j) Li, M.; Chen, S.-P.; Xiang, J.-F.; He, H.J.; Yuan, L.-J.; Sun, J.-T. Cryst. Growth Des. 2006, 6, 1250. (k) Reger, D. L.; Semeniuc, R. F.; Pettinari, C.; Luna-Giles, F.; Smith, M. D. Cryst. Growth Des. 2006, 6, 1068. (a) Janiak, C.; Scharamann, T. G.; Mason, S. A. J. Am. Chem. Soc. 2002, 124, 14010. (b) Rodrı˘ guez-Cuamatzi, P.; Vargas-Dı˘ az, G.; Ho¨pfl, H. Angew. Chem. Int. Ed. 2004, 43, 3041. (c) Ma, B.-Q.; Sun, H.-L.; Gao, S. Angew. Chem. Int. Ed. 2004, 43, 1374. (d) Oxtoby, N. S.; Blake, A. J.; Champness, N. R.; Wilson, C. Chem.Eur. J. 2005, 11, 4643. (e) Zhang, J.-P.; Huang, X.-C.; Lin, Y.-Y.; Chen, X.-M. Inorg. Chem. 2005, 44, 3146. (f) Fei, Z.; Geldbach, T. J.; Zhao, D.; Scopelliti, R.; Dyson, P. J. Inorg. Chem. 2005, 44, 5200. (g) Luan, X.-J.; Chu, Y.-C.; Wang, Y.-Y.; Li, D.-S.; Liu, P.; Shi, Q.-Z. Cryst. Growth Des. 2006, 4, 812. (h) Carballo, R.; Covelo, B.; Ferna´ndez-Hermida, N.; Garcc´a-Marteˇnez, E.; Lago, A. B.; Va´zquez, M.; Va´zquez-Lo´pez, E. M. Cryst. Growth Des. 2006, 6, 629. Carballo, R.; Covelo, B.; Lodeiro, C.; Va´zquez-Lo´pez, E. M. CrystEngComm 2005, 7, 294. Xu, Z.; Thompson, L. K.; Miller, D. O. Inorg. Chem. 1997, 36, 3985. Vaidhyanathan, R.; Natarajan, S.; Rao, C. N. R. Inorg. Chem. 2002, 41, 3985. Sun, J.; Zheng, Y.-Q. Z. Anorg. Allg. Chem. 2003, 629, 1001. Sheldrick, G. M. SADABS 2.05, University of Go¨ttingen 2002. SHELXTL 6.10, Bruker Analytical Instrumentation, Madison, Wisconsin, USA, 2000. Sharma, C. V. K.; Rogers, R. D. Chem. Commun. 1999, 83. Carlucci, L.; Ciani, G.; Proserpio, D. M. Coord. Chem. Rev. 2003, 246, 247. Cruzan, J. D.; Braly, L. B.; Liu, K.; Brown, M. G.; Loeser, J. G.; Saykally, R. J. Science 1996, 271, 59. (a) Airola, K.; Ratilainen, J.; Nyro´nen, T.; Rissanen, K. Inorg. Chim. Acta 1998, 277, 55. (b) Ratilainen, J.; Airola, K.; Frohlich, R.; Nieger, M.; Rissanen, K. Polyhedron 1999, 18, 2265. (c) Plasseraud, L.; Maid, H.; Hampel, H. F.; Saalfrank, R. Chem.-Eur. J. 2001, 7, 4007. (d) Son, S. U.; Park, K. H.; Kim, B. Y.; Chung, Y. K. Cryst. Growth Des. 2003, 3, 507. (e) Blay, G.; Ferna´ndez, I.; Pedro, J.; Ruiz-Garcı˘ a, R.; Muno˜z, M. C.; Cano, J.; Carrasco, R. Eur. J. Org. Chem. 2003, 1627. (f) Yamada, S.; Yasui, M.; Nogamia, T.; Ishida, T. Dalton Trans. 2006, 1622. Gregory, J. K.; Clary, D. C.; Liu, K.; Brown, M. G.; Saykally, R. J. Science 1997, 275, 814. Pometun, M. S.; Gundusharma, U. M.; Richardson, J. F.; Wittebort, R. J. J. Am. Chem. Soc. 2002, 124, 2345. Suihko, E.; Ketolainen, J.; Poso, A.; Ahlgren, M.; Gynther, J.; Paronen, P. Int. J. Pharm. 1997, 158, 47.

CG060441F