New coordination polymers generated from oxadiazole-containing bidentate ligands and CuCu dimetal units

Solid State Sciences 4 (2002) 1313–1320 www.elsevier.com/locate/ssscie

New coordination polymers generated from oxadiazole-containing bidentate ligands and Cu–Cu dimetal units Yu-Bin Dong a,∗ , Jian-Ping Ma a , Mark D. Smith b , Ru-Qi Huang a , Bo Tang a , Dezhan Chen a , Hans-Conrad zur Loye b,∗ a Department of Chemistry, Shandong Normal University, Jinan 250014, PR China b Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208, USA

Received 5 June 2002; accepted 26 June 2002

Abstract Two new coordination polymers that contain di-copper (Cu2 ) units have been prepared using Cu(OAc)2 ·H2 O in combination with (1,3,4)oxadiazole organic ligands L1 and L2 in MeOH. The compounds were characterized by single crystal X-ray diffraction, IR spectroscopy, and thermogravimetric analysis. The structure of compound 1 (monoclinic, C2/c, a = 19.9952(14) Å, b = 7.5005(5) Å, c = 16.0442(11) Å, β = 109.000(10)◦ , V = 2275.1(3) Å3 , Z = 4) features 1-D zigzag chains that are cross-linked into a novel three-dimensional network by weak noncovalvent π–π interactions between the 3-pyridyl rings on the L1 ligand. Compound 2 (monoclinic, C2/c, a = 27.428(2) Å, b = 13.3833(11) Å, c = 8.6339(7) Å, β = 103.973(2)◦ , V = 3075.5(4) Å3 , Z = 4) also features a zigzag chain motif. In the solid state, small and large hexagonal channels are found in 1 and 2, respectively. Compounds 1 and 2 are new examples of metal dimer-containing coordination polymers.  2002 Éditions scientifiques et médicales Elsevier SAS. All rights reserved. Keywords: Coordination polymers; Framework materials; π –π stacking; (1, 3, 4)-oxadiazole-containing ligands; Cu–Cu unit

1. Introduction Within the field now termed “inorganic/organic coordination polymers” recent efforts to combine transition metal ions or unsaturated coordination metal moieties with organic spacers have been extremely fruitful [1–3]. During the past several years, different classes of compounds fitting this general description have been successfully designed and synthesized. Some of them exhibit encouraging potential for application in catalysis, non-linear optics, gas separation, magnetic properties and molecular recognition [4]. In the long run, this line of research can lead to prediction of the topology and/or the periodicity of crystalline lattices generated from the molecular structures of the participating small building blocks; one can anticipate that the relationship between polymeric structures and physical properties will eventually be elucidated as well. The most efficient approach to access this type of material is via the direct chemical com* Corresponding author.

E-mail addresses: [email protected] (Y.-B. Dong), [email protected] (H-.C. zur Loye).

bination of functional inorganic and organic components, as has been demonstrated by many previous studies [1–3]. So far, several types of bidentate rigid organodiamine ligands, such as 4, 4 -bipyridine, 1,4-bis(4-pyridyl)ethene, 1,4bis(4-pyridyl)ethyne and flexible organodiamine ligands, like 1,4-bis(4-pyridyl)ethane, 1,4-bis(3-pyridyl)-2,3-diaza1,3-butadiene and 2,5-bis(3-pyridyl)-3,4-diaza-2,4-hexadiene [5e, f] have been utilized by us [5] as well as by numerous other research groups [1] to construct coordination polymers. All these bidentate N-donor containing ligands have proven to be among the most important types of organic ligands for the design and construction of coordination polymers exhibiting remarkable polymeric structural motifs. However, in most cases, the ligands that were used to construct coordination polymers did not contain bridging fivemembered heterocyclic rings. To the best of our knowledge, until now only a few coordination networks that contain fivemembered heterocyclic ring-containing ligands have been constructed and include 2,5-bis(4-ethylnylpyridyl)furan reported by Stang very recently [6]. The specific geometry of this type of ligand may result in coordination polymers with novel network patterns not achievable by other rigid linking ligands, such as the rigid linear bidentate ligands mentioned

1293-2558/02/$ – see front matter  2002 Éditions scientifiques et médicales Elsevier SAS. All rights reserved. PII: S 1 2 9 3 - 2 5 5 8 ( 0 2 ) 0 0 0 1 4 - 6

1314

Y.-B. Dong et al. / Solid State Sciences 4 (2002) 1313–1320

according to the literature method [9]. Infrared (IR) samples were prepared as KBr pellets, and spectra were obtained in the 400–4000 cm−1 range using a Perkin-Elmer 1600 FTIR spectrometer. Thermogravimetric analyses were carried out using a TA Instrument SDT 2960 DTA-TGA apparatus in a flowing N2 atmosphere using a heating rate of 10◦ C/min. Elemental analyses were performed on a Perkin-Elmer Model 240C analyzer.

Fig. 1. (1, 3, 4)-oxadiazole-containing organic rigid bidentate ligands.

earlier. Moreover, heteroatoms such as N, S and O with free electron pairs on the five-member heterocyclic ring could be considered as the potential active coordination sites or/and hydrogen bond acceptors to expand polymeric frameworks with coordinative covalent bonds or/and hydrogen bonding interactions. Finally, the 3-pyridyl and 4-pyridyl isomers can have quite different structure directing influences and, as shown, in this paper, result in similar, yet unique, structural architectures. The majority of the research carried out so far has focused on the use of mononuclear coordination centers. Coordination polymers and oligomers containing dimetal clusters have not been explored as much, although numerous bridged dimetal units containing copper, rhodium, molybdenum and ruthenium are known [7] and two reviews describing examples of dimetal tetracarboxylate unit containing one-dimensional polymers appeared recently [7a, b]. The bridged dimetal clusters represent a useful linear ligand that has two Lewis acid binding sites that readily bond to Lewis bases, such as are found in N, N -bipyridine type ligands. These types of polymeric systems are of interest as they may result in interesting spectroscopic or magnetic properties generated from the synergistic effect between two or more metal centers [8]. Herein, we wish to reported two Cu– Cu dimetal unit-containing coordination polymers, namely Cu2 (OAc)4 (L1 ) and Cu2 (OAc)4 (L2 )·3H2O generated from (1, 3, 4)-oxadiazole containing ligands L1 , L2 (Fig. 1) and Cu(OAc)2 ·H2 O in a CH3 OH–H2 O mixed solvent system.

2. Experimental section 2.1. Materials and methods Cu(OAc)2 ·H2 O (Acros) was used as obtained without further purification. Ligands L1 and L2 were prepared

2.1.1. Preparation of Cu2 (OAc)4(L1 ) (1) A MeOH (10 ml) solution of Cu(OAc)2 ·H2 O (40 mg, 2.0 mmol) was added drop wise to a MeOH solution (10 ml) of L1 (22.4 mg, 1.0 mmol) at room temperature. The green solution was allowed to stand at room temperature until deep blue-green crystals formed, which were filtered off and washed with MeOH, and dried in air. Yield: 57%. Anal. calcd. for C20 H20 Cu2 N4 O9 (1): C, 40.85; H, 3.40; N, 9.53. Found: C, 40.80; H, 3.34; N, 9.54. IR (KBr, cm−1 ): 1658(s), 1649(s), 1628(s), 1605(s), 1546(m), 1471(s), 1448(s), 1426(s), 1347(m), 1285(m), 1249(w), 1200(s), 1098(w), 1080(m), 1051(m), 1037(s), 965(m), 813(m), 728(m), 695(s), 676(s). 2.1.2. Preparation of Cu2 (OAc)4(L2 )·3H2 O (2) The procedure is identical to the one used for 1, except that L1 was replaced by L2 . Yield: 91%. Anal. calcd. for C20 H26 Cu2 N4 O12 (1): C, 37.41; H, 4.05; N, 8.73. Found: C, 37.45; H, 4.06; N, 8.70. IR (KBr, cm−1 ): 1650(s), 1647(s), 1615(s), 1570(m), 1545(w), 1487(m), 1449(s), 1433(s), 1328(w), 1275(w), 1275(w), 1220(m), 1060(m), 1011(m), 842(m), 715(m), 678(m). 2.1.3. Single-crystal structure determination Suitable single crystals of 1 and 2 were selected and epoxied in air onto thin glass fibers. X-ray intensity data were measured at 293 K on a Bruker SMART APEX CCDbased diffractometer (Mo Kα radiation, λ = 0.71073 Å). The raw frame data for 1 and 2 were integrated into SHELX-format reflection files and corrected for Lorentz and polarization effects using SAINT [10]. Corrections for incident and diffracted beam absorption effects were applied using SADABS [10]. Neither crystal showed evidence of crystal decay during data collection. Both 1 and 2 crystallize in the space group C2/c as determined by the systematic absences in the intensity data, intensity statistics and the successful solution and refinement of the structures. Both structures were solved by a combination of direct methods and difference Fourier synthesis and refined against F 2 by the full-matrix least squares technique. While solution and refinement of 1 proceeded without incident, the structure of 2 possesses channels running parallel to the crystallographic c-axis, in which five significant isolated electron density peaks were found. These peaks were modeled as partially occupied water oxygens. Their site occupation factors were adjusted to give reasonable thermal parameters. No attempt was made to locate the hydrogen

Y.-B. Dong et al. / Solid State Sciences 4 (2002) 1313–1320

3.2. Structural analysis

Table 1 Crystallographic data for 1 and 2 Formula

Cu2 C20 H20 N4 O9 , 1

1315

Cu2 C20 H26 N4 O12 , 2

Formula weight 587.48 641.53 Crystal system monoclinic monoclinic Space group C2/c C2/c a (Å) 19.9952(14) 27.428(2) b (Å) 7.5005(5) 13.3833(11) c (Å) 16.0442(11) 8.6339(7) 90 90 α (◦ ) 109.0000(10) 103.973(2) β (◦ ) 90 90 γ (◦ ) 2275.1(3) 3075.5(4) V (Å3 ) Z value 4 4 1.715 1.386 ρ calc. (g/cm3 ) µ (Mo Kα) (mm−1 ) 1.929 1.440 Temperature (K) 293(2) 293(2) No. refl. (I > 2σ ) 2294 2268 R valuesa (I > 2σ (I )): 0.0288; 0.0787 0.0654; 0.1597 R1 ; wR2


a R = Fo | − |Fc ||/ |Fo |. wR2 = { [w(Fo2 − Fc2 )2 / 1
[w(Fo2 )2 }1/2 ; w = 1/[σ 2 (Fo2 ) + (aP )2 + bP ], where P is [2Fc2 + max(Fo2 , 0)/3.

atoms on these water molecules. All non-hydrogen atoms were refined with anisotropic displacement parameters except for one of the disordered guest water molecules located in the channels of 2, which was refined isotropically. Hydrogen atoms on the polymer chains were calculated and refined as riding atoms. Crystal data, data collection parameters, and refinement statistics for 1 and 2 are listed in Table 1. Atomic coordinates are given in Tables 2 and 3. Relevant interatomic distances and bond angles for 1 and 2 are given in Tables 4 and 5.

3. Results and discussion 3.1. Synthesis The coordination polymers 1 and 2 were synthesized by solution reactions between L1 and L2 and Cu(OAc)2 ·H2 O. When a solution of Cu(OAc)2 ·H2 O in methanol was treated with L1 or L2 in methanol at ambient temperature, in a metal-to-ligand molar ratio of 2:1, compound 1 and 2 were obtained as deep blue-green polymeric compounds with a zigzag chain structural motif. Both 1 and 2 are insoluble in common organic solvents and water, consistent with their polymeric nature. They are air stable and retain their structural integrity at room temperature indefinitely. In addition to single-crystal diffraction, 1 and 2 were characterized by IR spectroscopy, DTA-TGA, and elemental analyses, the results of which were all consistent with the formulations of 1 and 2 obtained from the single crystal structures.

3.2.1. Compound 1 A chain fragment of 1 is shown in Fig. 2. The binuclear Cu2 (OAc)4 cluster core is situated about an inversion center, and the L1 ligand lies on a two-fold axis of rotation extending through O(1) and the N(2)–N(2)* midpoint. The asymmetric unit therefore contains one Cu atom, two acetate groups, and half a L1 ligand. The Cu–Cu unit is linked by four bidentate CH3 COO− groups that generate a Cu2 (OAc)4 cluster core. The four Cu–O bond lengths range from 1.9609(15) to 1.9721(15) Å (Table 2), which are comparable to similar bonds found in other coordination compounds [11]. In 1, two terminal water ligands on each Cu(II) ion were replaced by nitrogen donors from the L1 ligands. The Cu–N(1) bond distance is 2.1994(15) Å, which is slightly longer than corresponding bond distances in many other known Cu complexes containing pyridyl groups [12]. The Cu–Cu distance is 2.6164(4) Å which is identical to the Cu– Cu distance found in Cu(OAc)2 ·H2 O [13]. In the solid state, compound 1 adopts a 1-D chain motif. The Cu2 (OAc)4 cluster cores are linked together by L1 ligands via coordination bonds between Cu2+ centers and nitrogen donors on the 3-pyridyl rings into an undulating one-dimensional chain running along the crystallographic [10-1] direction (Fig. 3). The two N-donors and one O-donor on the (1, 3, 4)-oxadiazole ring are free. The 3-pyridyl rings and the (1, 3, 4)-oxadiazole group in L1 do not lie in the same plane, but rather are rotated by about 20◦ with respect to one another. The shortest intrachain Cu–Cu separation is 12.64(5) Å and the shortest interchain Cu–Cu separation is 8.37(5) Å. It is worth pointing out, as shown in Fig. 3, that these 1-D chains are bound together into a 3-D network by weak noncovalent π –π interactions [14] through a faceto-face stacking of the 3-pyridyl rings on the L1 ligands. The stacked pyridyl rings are strictly parallel and the ring centroid – ring centroid distance = 3.88 Å. The participation of bidentate organic spacers such as 4, 4 -bipyridine and 1,2-bis(4-pyridyl)ethane in the formation of polymeric frameworks by both coordination and hydrogen bonding interactions is common [15,16]. Sometimes, weak hydrogen bonds are effective in extending the dimensions of a network [17]. A few examples have shown that the organic ligands involved in the nucleation process use both coordination and π –π interactions to build up the framework [5f]. In compound 1, the weak π –π interaction does play a critical role in expanding the dimensionality from 1 to 3. When viewed down the crystallographic c axis, very small channels appear to be present in 1. No guest molecules are located in the channels, however, and the structure contains no solvent-accessible void volume [18]. 3.2.2. Compound 2 A chain fragment of 2 is shown in Fig. 4. The structure of 2 contains the same centrosymmetric Cu2 (OAc)4 cluster core as found in 1. The Cu–Cu, Cu–O and Cu–N distances

1316

Y.-B. Dong et al. / Solid State Sciences 4 (2002) 1313–1320

Table 2 Atomic coordinates (×104 ) and equivalent isotropic displacement parameters (Å2 ×103 ) for 1. Ueq is defined as one third of the trace of the orthogonalized Uij tensor Cu C(1) C(2) C(3) C(4) C(5) C(6) C(7) C(8) C(9) C(10) N(1) N(2) O(1) O(2) O(3) O(4) O(5)

x

y

z

U(eq)

1979(1) 900(1) 496(1) 398(1) 721(1) 1121(1) 203(1) 1584(1) 1069(1) 2532(1) 2522(2) 1209(1) 134(1) 0 1335(1) 2228(1) 2080(1) 2984(1)

1605(1) 277(3) −887(3) −2615(3) −3099(3) −1867(3) −228(3) 4305(3) 5348(4) 353(3) −915(4) −186(2) 1409(2) −1369(2) 3156(2) 4643(2) 114(2) 1584(2)

125(1) 998(1) 1303(1) 973(1) 371(2) 109(2) 1970(1) −1150(1) −1876(2) −1207(1) −1936(2) 407(1) 2146(1) 2500 −766(1) −983(1) −831(1) −1030(1)

33(1) 34(1) 32(1) 41(1) 48(1) 42(1) 33(1) 39(1) 54(1) 39(1) 57(1) 34(1) 50(1) 34(1) 51(1) 45(1) 51(1) 46(1)

Table 3 Atomic coordinates (×104 ) and equivalent isotropic displacement parameters (Å2 ×103 ) for 2. Ueq is defined as one third of the trace of the orthogonalized Uij tensor Cu C(1) C(2) C(3) C(4) C(5) C(6) C(7) C(8) C(9) C(10) N(1) N(2) O(1) O(2) O(3) O(4) O(5) O(1W) O(2W) O(3W) O(4W) O(5W)

x

y

z

U(eq)

7105(1) 6092(2) 5714(2) 5720(2) 6114(2) 6482(2) 5318(2) 7949(2) 8207(3) 7137(2) 6942(3) 6476(1) 5211(2) 5000 6878(1) 7556(2) 7517(2) 8191(2) 9326(5) 5383(8) 5607(9) 5362(19) 100(20)

2844(1) 2906(4) 3265(4) 4252(4) 4848(4) 4416(4) 4690(4) 2215(4) 2031(5) 762(5) −302(5) 3472(3) 5608(3) 4051(4) 1445(3) 866(3) 2559(3) 1989(3) 2594(14) 9577(15) 8900(50) 8660(40) 6940(40)

8965(1) 6405(6) 5194(6) 4751(5) 5544(6) 6708(6) 3489(5) 7803(6) 6465(7) 9561(7) 9322(9) 7164(4) 3159(4) 2500 8787(5) 10521(5) 7452(4) 9196(4) −28(19) 1060(30) 7910(100) 7130(70) 8070(60)

42(1) 51(1) 51(1) 41(1) 45(1) 47(1) 39(1) 53(1) 74(2) 56(1) 94(2) 42(1) 47(1) 44(1) 62(1) 65(1) 60(1) 64(1) 238(7) 136(12) 400(60) 112(18) 130(20)

in the two Cu(II) coordination spheres are equivalent to the corresponding distances found in compound 1 (Table 3). In the solid state, compound 2 adopts a 1-D undulating chain pattern which is slightly different from the 1-D chain found in 1. The 1-D chain of 2, unlike the 1-D chain of 1, can be considered as a perfect sinusoidal chain (Figs. 3 and 5). The period of the sinusoidal chain in 1 is 29.429(14) Å, whereas the period of the sinusoidal chain in 2 is 32.865(15) Å, a consequence of the different relative orientations of the N-donors on the organic spacers. The differ-

ent locations of the coordination donors can be an important factor in directing the self-assembly of coordination polymers, an observation that has been borne out by our previous studies [5](f-g). When viewed down the crystallographic c axis, large hexagonal channels (crystallographic dimensions, 10 ×10 Å2 ) were found in 2. The void volume [18] is 936 Å3 , or 30.4% of the total unit cell volume (Fig. 6). These hexagonal voids are not empty, but are occupied by disordered water guest molecules.

Y.-B. Dong et al. / Solid State Sciences 4 (2002) 1313–1320

1317

Table 4 Interatomic distances (Å) and bond angles (◦ ) with esds ( ) for 1 Cu–O(4) Cu–O(3) Cu–N(1) C(1)–N(1) N(2)–N(2)#2 O(4)–Cu–O(2) O(4)–Cu–N(1) O(4)–Cu–Cu#1 C(1)–N(1)–Cu C(6)–O(1)–C(6)#2 C(1)–C(2)–C(3)

1.9609(15) 1.9660(15) 2.1994(15) 1.334(2) 1.405(3) 88.79(8) 94.03(6) 83.29(4) 120.27(13) 101.9(2) 118.70(17)

Cu–O(2) Cu–O(5) Cu–Cu#1 C(6)–O(1) C(1)–C(2) O(2)–Cu–O(3) O(2)–Cu–N(1) N(1)–Cu–Cu#1 C(7)–O(2)–Cu C(6)–N(2)–N(2)#2 N(1)–C(1)–C(2)

1.9643(16) 1.9721(15) 2.6164(4) 1.359(2) 1.383(3) 168.58(6) 100.04(6) 172.26(5) 119.55(14) 106.03(11) 123.08(18)

Symmetry transformations used to generate equivalent atoms: #1: −x + 1/2, −y + 1/2, −z; #2: −x, −y, −z + 1/2. Table 5 Interatomic distances (Å) and bond angles (◦ ) with esds ( ) for 2 Cu–O(4) Cu–O(3)#1 Cu–N(1) C(1)–N(1) N(2)–N(2)#2 O(4)–Cu–O(2) O(4)–Cu–N(1) O(4)–Cu–Cu#1 C(1)–N(1)–Cu C(6)–O(1)–C(6)#2 C(1)–C(2)–C(3)

1.961(4) 1.960(4) 2.193(4) 1.334(7) 1.413(7) 89.12(18) 94.82(15) 82.59(11) 121.6(4) 102.3(5) 119.3(5)

Cu–O(2) Cu—O(5)#1 Cu–Cu#1 C(6)–O(1) C(1)–C(2) O(2)–Cu–O(3)#1 O(2)–Cu–N(1) N(1)–Cu–Cu#1 C(7)–O(4)–Cu C(6)–N(2)–N(2)#2 N(1)–C(1)–C(2)

1.968(4) 1.962(4) 2.6200(11) 1.364(5) 1.370(7) 168.40(15) 97.44(16) 176.44(12) 125.5(3) 106.2(3) 122.6(5)

Symmetry transformations used to generate equivalent atoms: #1: −x + 1/2, −y + 1/2, −z; #2: −x, −y, −z + 1/2.

Fig. 2. Thermal ellipsoid plot of 1, drawn with 40% probability ellipsoids.

3.3. Thermal analysis Compounds 1 was heated to 400◦ C and 2 was heated to 450◦ C in an atmosphere of flowing N2 . For 1, the loss of the coordinating L1 ligands and the decomposition of Cu(OAc)2 units occurs simultaneously. The single-step weight loss was observed between 210◦ C and 300◦ C with CuO remaining as a black powder (observed 13.8%, calculated 13.6%). The thermal decomposition behavior of 2 is different from that of 1. There are two weight loss steps. The TGA data for 2 show that the first weight loss, of 8.5%, occurs from 90 to 235◦ C, which corresponds to the loss of water guest molecules (calculated 8.4%). On further heating, another weight loss between 240 and 410◦ C is observed, corresponding to the

loss of L2 ligands and the decomposition of the Cu(OAc)2 units. Black, amorphous CuO powder remains as a final product.

4. Conclusions The two compounds, 1 and 2, are two additions to the rapidly growing number of coordination polymers containing di-metal building blocks and the first to have been synthesized with oxadiazole-containing bidentate ligands. In this study we demonstrate that the (1, 3, 4)-oxadiazole containing ligands L1 and L2 are capable of coordinating transition metal centers with both terminal 3- or 4-pyridyl nitrogen

1318

Y.-B. Dong et al. / Solid State Sciences 4 (2002) 1313–1320

Fig. 3. The Cu–Cu dimetal-containing zigzag chains in 1. π –π interactions between neighboring chains are shown as dotted lines. Stacked pyridyl rings are strictly parallel (interplanar angle = 0◦ ). The parallel distance between planes is 3.68 Å and the ring centroid-centroid distance is 3.88 Å.

Fig. 4. Thermal ellipsoid plot of 2 with 40% probability ellipsoids.

Fig. 5. The Cu–Cu dimetal-containing zigzag chain in 2.

donors and of generating novel coordination polymers. The different relative orientations of the N-donors on the two ligands can be considered as a dominating factor in controlling

the structures of the polymers in the solid state. In addition, metal dimer-containing coordination polymers can be obtained by the suitable choice of inorganic dimetal units and

Y.-B. Dong et al. / Solid State Sciences 4 (2002) 1313–1320

1319

Fig. 6. Space-filling projection down the structure of 2. The a-axis is horizontal and the b-axis is vertical in this view. Cu centers and oxygen are shown as green and red balls, respectively. Nitrogen and carbon atoms are shown as blue and gray balls, respectively. Hydrogen and atoms and water guest molecules are omitted for clarity.

organic spacers. We are currently extending these results by combining of these types of ligands with other dimetal precursors. Acknowledgements We are grateful for financial support from the National Natural Science Foundation of China (Nos. 20174023, 20173034, 29975016 and 60047001), Shangdong Natural Science Foundation (Nos. Z2001B01) and Young Scientists Funding of Shandong Province of P.R. China, we also thank for financial support from Starting Funding of China for overseas scholar, Shandong Normal University and Open Fountain of State Key Lab of Crystal Materials. HCzL gratefully acknowledges support from the NSF through grant DMR:0134156. References [1] (a) P.J. Hagrman, D. Hagrman, J. Zubieta, Angew. Chem. Int. Ed. 38 (1999) 2638; (b) A.J. Blake, N.R. Champness, P. Hubberstey, W.-S. Li, M.A. Withersby, M. Schröder, Coord. Chem. Rev. 183 (1999) 117; (c) S. Batten, R. Robson, Angew. Chem. Int. Ed. 37 (1998) 1460. [2] (a) O.M. Yaghi, G. Li, H. Li, Nature 378 (1995) 703; (b) O.M. Yaghi, H. Li, J. Am. Chem. Soc. 117 (1995) 10401; (c) O.M. Yaghi, H. Li, T.L. Groy, J. Am. Chem. Soc. 118 (1996) 9096; (d) M. Fujita, H. Oka, K. Yamaguchi, K. Ogura, Nature 378 (1995) 469;

(e) M. Fujita, Y.J. Kwon, O. Sasaki, K. Yamaguchi, K. Ogura, J. Am. Chem. Soc. 117 (1995) 7287; (f) P. Losier, M.J. Zaworotko, Angew. Chem. Int. Ed. Engl. 35 (1996) 2779; (g) K.N. Power, T.L. Hennigar, M.J. Zaworotko, Chem. Commun. (1998) 595. [3] (a) R.A. Heintz, H. Zhao, X. Ouyang, G. Grandinetti, J. Cowen, K.R. Dunbar, Inorg. Chem. 38 (1999) 144; (b) A. Mayr, J. Guo, Inorg. Chem. 38 (1999) 921; (c) A. Mayr, L.F. Mao, Inorg. Chem. 37 (1998) 5776; (d) L.F. Mao, A. Mayr, Inorg. Chem. 35 (1996) 3183; (e) H.J. Choi, M.P. Suh, J. Am. Chem. Soc. 120 (1998) 10622; (f) C.V.K. Sharma, G.A. Broker, J.G. Huddleston, J.W. Baldwin, R.M. Metzger, R.D. Rogers, J. Am. Chem. Soc. 121 (1999) 1137. [4] (a) M. Fujita, Y.J. Kwon, S. Washizu, K. Ogura, J. Am. Chem. Soc. 116 (1994) 1151; (b) W. Lin, O.R. Evans, R.-G. Xiong, Z. Wang, J. Am. Chem. Soc. 120 (1998) 13272; (c) G.B. Garder, D. Venkataraman, J.S. Moore, S. Lee, Nature 374 (1995) 792; (d) G.B. Garder, Y.-H. Kiang, S. Lee, A. Asgaonkar, D. Venkataraman, J. Am. Chem. Soc. 118 (1996) 6946; (e) O. Kahn, Y. Pei, M. Verdguer, J.P. Renard, J. Sletten, J. Am. Chem. Soc. 110 (1998) 782; (f) K. Inoue, T. Hayamizu, H. Iwamura, D. Hashizume, Y. Ohashi, J. Am. Chem. Soc. 118 (1996) 1803; (g) H. Tamaki, Z.J. Zhong, N. Matsumoto, S. Kida, M. Koikawa, N. Achiwa, Y. Hashimoto, H. Okawa, J. Am. Chem. Soc. 114 (1992) 6974. [5] (a) Y.-B. Dong, R.C. Layland, M.D. Smith, N.G. Pschirer, U.H.F. Bunz, H.-C. zur Loye, Inorg. Chem. 38 (1999) 3056; (b) Y.-B. Dong, R.C. Layland, N.G. Pschirer, M.D. Smith, U.H.F. Bunz, H.-C. zur Loye, Chem. Mater. 11 (1999) 1415;

1320

Y.-B. Dong et al. / Solid State Sciences 4 (2002) 1313–1320

(c) Y.-B. Dong, M.D. Smith, R.C. Layland, H.-C. zur Loye, Inorg. Chem. 38 (1999) 5027; (d) Y.-B. Dong, M.D. Smith, R.C. Layland, H.-C. zur Loye, J. Chem. Soc. Dalton Trans. (2000) 775; (e) Y.-B. Dong, M.D. Smith, R.C. Layland, H.-C. zur Loye, Chem. Mater. 12 (2000) 1156; (f) Y.-B. Dong, M.D. Smith, H.-C. zur Loye, Inorg. Chem. 39 (2000) 4927; (g) D.M. Ciurtin, Y.-B. Dong, M.D. Smith, T. Barclay, H.-C. zur Loye, Inorg. Chem. 40 (2001) 2825. [6] W.M. Eillis, M. Schmitz, A.A. Arif, P.J. Stang, Inorg. Chem. 39 (2000) 2547. [7] (a) M.H. Chisholm, Acc. Chem. Res. 33 (2000) 53; (b) F.A. Cotton, C. Lin, C.A. Murillo, Acct. Chem. Res. 34 (2001) 759; (c) F.A. Cotton, C. Liu, C.A. Murillo, J. Chem. Soc., Dalton Trans. (2001) 499; (d) J. Lu, W.T.A. Harrison, A.J. Jacobson, Chem. Commun. (1996) 399; (f) S.R. Batten, B.F. Hoskins, B. Moubaraki, K.S. Murray, R. Robson, Chem. Commun. (2000) 1095; (g) T. Chandra, J.C. Huffman, J.M. Zaleski, Inorg. Chem. Commun. 4 (2001) 434; (h) G. Smith, E.J. O’Reilly, H.L. Carrell, C.J. Carrell, Polyhedron 15 (2001) 1995; (i) H. Miyasaka, C.S. Campos-Fernandez, J.R. Galan-Mascaros, K.R. Dunbar, Inorg. Chem. 39 (2000) 5870;

[8] [9] [10] [11] [12]

[13] [14] [15]

[16]

[17] [18]

(j) H. Miyasaka, R. Clerac, C.S. Campos-Fernandez, K.R. Dunbar, J. Chem. Soc., Dalton Trans. (2001) 858. J.S. Valentine, A.J. Silverstein, Z.G. Soos, J. Am. Chem. Soc. 96 (1974) 97. Z.-J. Ren, E. Jiang, H.-B. Zhou, Youji Huaxue 15 (1995) 218. Bruker Analytical X-ray Systems, Inc.: Madison, WI, 1998. H.-K. Liu, W.-Y. Sun, W.-X. Tong, T. Yamamoto, N. Ueyama, Inorg. Chem. 38 (1999) 6313. (a) D. Hagrman, R.P. Hammond, R. Haushalter, J. Zubieta; (b) I. Unamuno, J.M. Gutiérrez-Zorrilla, A. Luque, P. Román, L. Lezama, R. Calvo, T. Rojo, Inorg. Chem. 37 (1998) 6452; (c) Y. Akhriff, J. Server-Carrió, A. Sancho, J. García-lozano, E. Eserivá, J.V. Folgado, L. Soto, Inorg. Chem. 38 (1999) 1174. J.N. van Niekerk, F.R.L. Schoening, Acta Cryst. 6 (1953) 227. G.R. Desiraju, A. Gavezzotti, Acta Crystallogr. B 45 (1989) 473. (a) C.V.K. Sharma, R.D. Rogers, Chem. Commun. (1998) 1083; (b) D.M.L. Goodgame, S. Menzer, A.M. Smith, D.J. Williams. Chem. Commun. (1997) 339. (a) G.D. Munno, D. Armentano, T. Poerio, M. Julve, J.A. Real, J. Chem. Soc., Dalton Trans. (1999) 1813; (b) N. Moliner, J.A. Real, M.C. Munoz, R. Martinez-Manez, J.M.C. Juan, J. Chem. Soc., Dalton Trans. (1999) 1375. L. Carlucci, G. Ciani, D.M. Proserpio, A. Sironi, J. Chem. Soc., Dalton Trans. (1997) 1801. A.L. Spek, Solvent-accessible void volume calculations performed with PLATON, Utrecht University, Utrecht, The Netherlands, 1998.