An Infinite Two-Dimensional Hybrid Water-Chloride Network, Self-Assembled in a Hydrophobic Terpyridine Iron(II) Matrix Ricardo R. Fernandes,† Alexander M. Kirillov,† M. Fátima C. Guedes da Silva,†,‡ Zhen Ma,† José A. L. da Silva,† João J. R. Fraústo da Silva,† and Armando J. L. Pombeiro*,†
CRYSTAL GROWTH & DESIGN 2008 VOL. 8, NO. 3 782–785
Centro de Química Estrutural, Complexo I, Instituto Superior Técnico, TU-Lisbon, AV. RoVisco Pais, 1049-001 Lisbon, Portugal, and UniVersidade Luso´fona de Humanidades e Tecnologias, AV. do Campo Grande, 376, 1749-024, Lisbon, Portugal ReceiVed October 18, 2007; ReVised Manuscript ReceiVed January 7, 2008
ABSTRACT: An unprecedented two-dimensional water-chloride anionic {[(H2O)20(Cl)4]4–}n network has been structurally identified in
a hydrophobic matrix of the iron(II) compound [FeL2]Cl2 · 10H2O (L ) 4′-phenyl-2,2′:6′,2″-terpyridine). Its intricate relief geometry has been described as a set of 10 nonequivalent alternating cycles of different sizes ranging from tetra- to octanuclear {[(H2O)x(Cl)y]y–}z (x ) 2–6, y ) 0–2, z ) 4–6, 8) fragments. In contrast to the blooming research on structural characterization of a wide variety of water clusters in different crystalline materials,1 much less attention has been focused on the identification and description of hybrid hydrogen-bonded water assemblies with other solvents, small molecules, or counterions.1c,2 In particular, the combination of chloride ions and water is one of the most commonly found in natural environments (e.g., seawater or sea-salt aerosols), and thus the investigation of water-chloride interactions has been the object of numerous theoretical studies.3 However, only recently a few water-chloride associates incorporated in various crystal matrixes have been identified and structurally characterized,4,5 including examples of (i) discrete cyclic [(H2O)4(Cl)]–,4a [(H2O)4(Cl)2]2–,4b and [(H2O)6(Cl)2]2– 4c clusters, and (ii) various one- or two-dimensional (1D or 2D) hydrogen-bonded networks generated from crystallization water and chloride counterions with {[(H2O)4(Cl2)]2–}n,5b {[(H2O)6(Cl)2]2–}n,5b [(H2O)7(HCl)2]n,5c {[(H2O)11(Cl)7]7–}n,5d {[(H2O)14(Cl)2]2–}n,5e {[(H2O)14(Cl)4]4–}n,5a and {[(H2O)14(Cl)5]5–}n5f compositions. These studies are also believed to provide a contribution toward the understanding of the hydration phenomena of chloride ions in nature and have importance in biochemistry, catalysis, supramolecular chemistry, and design of crystalline materials.5 In pursuit of our interest in the self-assembly synthesis and crystallization of various transition metal compounds in aqueous media, we have recently described the [(H2O)10]n,6a (H2O)6,6b and [(H2O)4(Cl)2]2– 4b clusters hosted by Cu/Na or Ni metal-organic matrixes. Continuing this research, we report herein the isolation and structural characterization of a unique 2D water-chloride anionic layer {[(H2O)20(Cl)4]4–}n within the crystal structure of the bis-terpyridine iron(II) compound [FeL2]Cl2 · 10H2O (1′) (L ) 4′phenyl-2,2′:6′,2″-terpyridine). Although this compound has been obtained unexpectedly, a search in the Cambridge Structural Database (CSD)7,8 points out that various terpyridine containing hosts tend to stabilize water-chloride associates, thus also supporting the recognized ability of terpyridine ligands in supramolecular chemistry and crystal engineering.9,10 Hence, the simple combination of FeCl2 · 2H2O and L in tetrahydrofuran (THF) solution at room temperature provides the formation of a deep purple solid formulated as [FeL2]Cl2 · FeCl2 · 5H2O (1) on the basis of elemental analysis, FAB+-MS and IR spectroscopy.11 This compound reveals a high affinity for water and, upon recrystallization from a MeOH/H2O (v/v ) 9/1) mixture, * To whom correspondence should be sent. Fax: +351-21-846 4455. E-mail:
[email protected]. † Instituto Superior Técnico. ‡ Universidade Luso´fona de Humanidades e Tecnologias.
Figure 1. Perspective representations (arbitrary views) of hybrid water-chloride hydrogen-bonded assemblies in the crystal cell of 1′; H2O molecules and chloride ions are shown as colored sticks and balls, respectively. (a) Minimal repeating {[(H2O)20(Cl)4]4–}n fragment with atom numbering scheme. (b) Nonplanar infinite polycyclic 2D anionic layer generated by linkage of four {[(H2O)20(Cl)4]4–}n fragments (a) represented by different colors; the numbers are those of Table 1 and define the 10 nonequivalent alternating cycles of different size.
leads to single crystals of 1′ with a higher water content, which have been characterized by single-crystal X-ray analysis.12 The asymmetric unit of 1′ is composed of a cationic [FeL2]2+ part, two chloride anions, and 10 independent crystallization water molecules (with all their H atoms located in the difference Fourier map), the latter occupying a considerable portion of the crystal cell. The iron atom possesses a significantly distorted octahedral coordination environment filled by two tridentate terpyridine moieties arranged in a nearly perpendicular fashion (Figure S1, Supporting Information). Most of the bonding parameters within [FeL2]2+ are comparable to those reported for other iron compounds
10.1021/cg7010315 CCC: $40.75 2008 American Chemical Society Published on Web 02/08/2008
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Crystal Growth & Design, Vol. 8, No. 3, 2008 783 Table 1. Description of Cyclic Fragments within the {[(H2O)20(Cl)4]4–}n Network in 1′
entry/cycle number
number of O/Cl atoms
formula
atom numbering scheme
geometry
most lengthy separation, Å
color codea
1 2 3 4 5 6 7 8 9 10
4 4 4 4 4 5 5 5 6 8
(H2O)4 (H2O)4 [(H2O)3(Cl)][(H2O)3(Cl)][(H2O)2(Cl)2]2(H2O)5 [(H2O)4(Cl)][(H2O)4(Cl)][(H2O)4(Cl)2]2[(H2O)6(Cl)2]2-
O3–O4–O3–O4 O6–O7–O6–O7 O2–O4–O3–Cl2 O6–O7–O9–Cl1 O9–Cl1–O9–Cl1 O2–O4–O3–O10–O8 O1–O5–O7–O9–Cl1 O1–O5–Cl2–O8–O10 O2–O8–Cl2–O2–O8–Cl2 O1–O10–O3–Cl2–O5–O7–O6–Cl1
planar planar nonplanar nonplanar planar nonplanar nonplanar nonplanar nonplanar nonplanar
O3 · · · O3, 4.28 O7 · · · O7, 4.42 O4 · · · Cl2, 4.66 O7 · · · Cl1, 4.61 Cl · · · Cl1, 4.76 O2 · · · O10, 4.55 O7 · · · Cl1, 5.25 O10 · · · Cl2, 5.29 Cl2 · · · Cl2, 7.12 Cl1 · · · Cl2, 7.91
light brown light gray blue green pink red pale yellow orange yellow pale blue
a
Color codes are those of Figure 2.
Figure 2. Fragment of nonplanar infinite polycyclic 2D anionic layer in the crystal cell of 1′. The 10 nonequivalent alternating water or water-chloride cycles are shown by different colors (see Table 1 for color codes).
bearing two terpyridine ligands.13 The most interesting feature of the crystal structure of 1′ consists in the extensive hydrogen bonding interactions of all the lattice–water molecules and chloride counterions (Table S1, Supporting Information), leading to the formation of a hybrid water-chloride polymeric assembly possessing minimal repeating {[(H2O)20(Cl)4]4–}n fragments (Figure 1a). These are further interlinked by hydrogen bonds generating a nonplanar 2D water-chloride anionic layer (Figure 1b). Hence, the multicyclic {[(H2O)20(Cl)4]4–}n fragment is constructed by means of 12 nonequivalent O–H · · · O interactions with O · · · O distances ranging from 2.727 to 2.914 Å and eight O–H · · · Cl hydrogen bonds with O · · · Cl separations varying in the 3.178–3.234 Å range (Table S1, Supporting Information). Both average O · · · O [∼2.82 Å] and O · · · Cl [∼3.20 Å] separations are comparable to those found in liquid water (i.e., 2.85 Å)14 and various types of H2O clusters1,6 or hybrid H2O-Cl associates.4,5 Eight of ten water molecules participate in the formation of three hydrogen bonds each (donating two and accepting one hydrogen), while the O3 and O7 H2O molecules along with both Cl1 and Cl2 ions are involved in four hydrogen-bonding contacts. The resulting 2D network can be considered as a set of alternating cyclic fragments (Figure 1b) which are classified in Table 1 and additionally shown by different colors in Figure 2. Altogether there are 10 different cycles, that is, five tetranuclear, three pentanuclear, one hexanuclear, and one octanuclear fragment (Figures 1b and 2, Table 1). Three of them (cycles 1, 2, and 6) are composed of only water molecules, whereas the other seven rings are water-chloride hybrids with one or two Cl atoms. The most lengthy O · · · O, O · · · Cl, or Cl · · · Cl nonbonding separations within rings vary from 4.28 to 7.91 Å (Table 1, cycles 1 and 10, respectively). Most of the cycles are nonplanar (except those derived from the three symmetry generated tetrameric fragments, cycles 1, 2, and 4), thus contributing to the formation of an intricate relief geometry of the water-chloride layer, possessing average O · · · O · · · O, O · · · Cl · · · O, and O · · · O · · · Cl angles of ca. 104.9, 105.9, and 114.6°, respectively (Table S2, Supporting Information). The unprecedented character of the
Figure 3. Fragment of the crystal packing diagram of 1′ along the a axis showing the intercalation of two water-chloride layers (represented by space filling model) into the metal-organic matrix (depicted as sticks); color codes within H2O-Cl layers: O red, Cl green, H grey.
water-chloride assembly in 1′ has been confirmed by a thorough search in the CSD,7,15 since the manual analysis of 156 potentially significant entries with the minimal [(H2O)3(Cl)]– core obtained within the searching algorithm15 did not match a similar topology. Nevertheless, we were able to find several other interesting examples16 of infinite 2D and three-dimensional (3D) water-chloride networks, most of them exhibiting strong interactions with metal-organic matrixes. The crystal packing diagram of 1′ along the a axis (Figure 3) shows that 2D water-chloride anionic layers occupy the free space between hydrophobic arrays of metal-organic units, with an interlayer separation of 12.2125(13) Å that is equivalent to the b unit cell dimension.12 In contrast to most of the previously identified water clusters,1,6 water-chloride networks,5,16 and extended assemblies,1c the incorporation of {[(H2O)20(Cl)4]4–}n sheets in 1′ is not supported by strong intermolecular interactions with the terpyridine iron matrix. Nevertheless, four weak C–H · · · O hydrogen bonds [avg d(D · · · A) ) 3.39 Å] between some terpyridine CH atoms and lattice–water molecules (Table S1, Figure S2, Supporting Information) lead to the formation of a 3D supramolecular framework. The thermal gravimetric analysis (combined TG-DSC) of 117 (Figure S3, Supporting Information) shows the stepwise elimination of lattice–water in the broad 50–305 °C temperature interval, in accord with the detection on the differential scanning calorimetry
784 Crystal Growth & Design, Vol. 8, No. 3, 2008 curve (DSC) of three major endothermic processes in ca. 50–170, 170–200, and 200–305 °C ranges with maxima at ca. 165, 190, and 280 °C, corresponding to the stepwise loss of ca. two, one, and two H2O molecules, respectively (the overall mass loss of 9.1% is in accord with the calculated value of 9.4% for the elimination of all five water molecules). In accord, the initial broad and intense IR ν(H2O) and δ(H2O) bands of 1 (maxima at 3462 and 1656 cm–1, respectively) gradually decrease in intensity on heating the sample up to ca. 305 °C, while the other bands remain almost unchangeable. Further heating above 305 °C leads to the sequential decomposition of the bis-terpyridine iron unit. These observations have also been supported by the IR spectra of the products remaining after heating the sample at different temperatures. The elimination of the last portions of water in 1 at temperatures as high as 250–305 °C is not commonly observed (although it is not unprecedented18) for crystalline materials with hosted water clusters, and can be related to the presence and extensive hydrogen-bonding of chloride ions in the crystal cell, tending to form the O–H(water) · · · Cl hydrogen bonds ca. 2.5 times stronger in energy than the corresponding O–H(water) · · · O(water) ones.5a The strong binding of crystallization water in 1 is also confirmed by its FAB+-MS analysis that reveals the rather uncommon formation of the fragments bearing from one to five H2O molecules.11 The exposure to water vapors for ca. 8 h of an almost completely dehydrated (as confirmed by weighing and IR spectroscopy) product after thermolysis of 1 (at 250 °C19 for 30 min) results in the reabsorption of water molecules giving a material with weight and IR spectrum identical to those of the initial sample 1, thus corroborating the reversibility of the water escape and binding process. In conclusion, we have synthesized and structurally characterized a new type of 2D hybrid water-chloride anionic multicyclic {[(H2O)20(Cl)4]4–}n network self-assembled in a hydrophobic matrix of the bis-terpyridine iron(II) complex, that is, [FeL2]Cl2 · 10H2O 1′. On the basis of the recent description and detailed analysis of the related {[(H2O)14(Cl)4]4–}n layers5a and taking into consideration that the water-chloride assembly in 1′ does not possess strong interactions with the metal-organic units, the crystal structure of 1′ can alternatively be defined as an unusual set of water-chloride “hosts” with bis-terpyridine iron “guests”. Moreover, the present study extends the still limited number5 of well-identified examples of large polymeric 2D water-chloride assemblies intercalated in crystalline materials and shows that terpyridine compounds can provide rather suitable matrixes to stabilize and store water-chloride aggregates. Further work is currently in progress aiming at searching for possible applications in nanoelectrical devices, as well as understanding how the modification of the terpyridine ligand or the replacement of chlorides by other counterions with a high accepting ability toward hydrogen-bonds can affect the type and topology of the hybrid water containing associates within various terpyridine transition metal complexes.
Acknowledgment. This work has been partially supported by the Foundation for Science and Technology (FCT) and its POCI 2010 programme (FEDER funded), and by a HRTM Marie Curie Research Training Network (AQUACHEM project, CMTN-CT2003-503864). The authors gratefully acknowledge Prof. Maria Filipa Ribeiro for kindly running the TG-DSC analysis, Dr. Laurent Benisvy, Dr. Maximilian N. Kopylovich, and Mr. Yauhen Y. Karabach for helpful discussions. Supporting Information Available: Additional figures (Figures S1–S3) with structural fragments of 1′ and TG-DSC analysis of 1, Tables S1 and S2 with hydrogen-bond geometry in 1′ and bond angles within the H2O-Cl network, details for the general experimental procedures and X-ray crystal structure analysis and refinement, crystallographic information file (CIF), and the CSD refcodes for terpyridine compounds with water-chloride aggregates. This information is available free of charge via the Internet at http://pubs.acs.org.
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References (1) (a) Mascal, M.; Infantes, L.; Chisholm, J. Angew. Chem., Int. Ed. 2006, 45, 32 and references therein. (b) Infantes, L.; Motherwell, S. CrystEngComm 2002, 4, 454. (c) Infantes, L.; Chisholm, J.; Motherwell, S. CrystEngComm 2003, 5, 480. (d) Supriya, S.; Das, S. K. J. Cluster Sci. 2003, 14, 337. (2) (a) Das, M. C.; Bharadwaj, P. K. Eur. J. Inorg. Chem. 2007, 1229. (b) Ravikumar, I.; Lakshminarayanan, P. S.; Suresh, E.; Ghosh, P. Cryst. Growth Des. 2006, 6, 2630. (c) Ren, P.; Ding, B.; Shi, W.; Wang, Y.; Lu, T. B.; Cheng, P. Inorg. Chim. Acta 2006, 359, 3824. (d) Li, Z. G.; Xu, J. W.; Via, H. Q.; Hu, N. H. Inorg. Chem. Commun. 2006, 9, 969. (e) Lakshminarayanan, P. S.; Kumar, D. K.; Ghosh, P. Inorg. Chem. 2005, 44, 7540. (f) Raghuraman, K.; Katti, K. K.; Barbour, L. J.; Pillarsetty, N.; Barnes, C. L.; Katti, K. V. J. Am. Chem. Soc. 2003, 125, 6955. (3) (a) Jungwirth, P.; Tobias, D. J. J. Phys. Chem. B. 2002, 106, 6361. (b) Tobias, D. J.; Jungwirth, P.; Parrinello, M. J. Chem. Phys. 2001, 114, 7036. (c) Choi, J. H.; Kuwata, K. T.; Cao, Y. B.; Okumura, M. J. Phys. Chem. A. 1998, 102, 503. (d) Xantheas, S. S. J. Phys. Chem. 1996, 100, 9703. (e) Markovich, G.; Pollack, S.; Giniger, R.; Cheshnovsky, O. J. Chem. Phys. 1994, 101, 9344. (f) Combariza, J. E.; Kestner, N. R.; Jortner, J. J. Chem. Phys. 1994, 100, 2851. (g) Perera, L.; Berkowitz, M. L. J. Chem. Phys. 1991, 95, 1954. (h) Dang, L. X.; Rice, J. E.; Caldwell, J.; Kollman, P. A. J. Am. Chem. Soc. 1991, 113, 2481. (4) (a) Custelcean, R.; Gorbunova, M. G. J. Am. Chem. Soc. 2005, 127, 16362. (b) Kopylovich, M. N.; Tronova, E. A.; Haukka, M.; Kirillov, A. M.; Kukushkin, V. Yu.; Fraústo da Silva, J. J. R.; Pombeiro, A. J. L. Eur. J. Inorg. Chem. 2007, 4621. (c) Butchard, J. R.; Curnow, O. J.; Garrett, D. J.; Maclagan, R. G. A. R. Angew. Chem., Int. Ed. 2006, 45, 7550. (5) (a) Reger, D. L.; Semeniuc, R. F.; Pettinari, C.; Luna-Giles, F.; Smith, M. D. Cryst. Growth. Des. 2006, 6, 1068 and references therein. (b) Saha, M. K.; Bernal, I. Inorg. Chem. Commun. 2005, 8, 871. (c) Prabhakar, M.; Zacharias, P. S.; Das, S. K. Inorg. Chem. Commun. 2006, 9, 899. (d) Lakshminarayanan, P. S.; Suresh, E.; Ghosh, P. Angew. Chem., Int. Ed. 2006, 45, 3807. (e) Ghosh, A. K.; Ghoshal, D.; Ribas, J.; Mostafa, G.; Chaudhuri, N. R. Cryst. Growth. Des. 2006, 6, 36. (f) Deshpande, M. S.; Kumbhar, A. S.; Puranik, V. G.; Selvaraj, K. Cryst. Growth Des. 2006, 6, 743. (6) (a) Karabach, Y. Y.; Kirillov, A. M.; da Silva, M. F. C. G.; Kopylovich, M. N.; Pombeiro, A. J. L. Cryst. Growth Des. 2006, 6, 2200. (b) Kirillova, M. V.; Kirillov, A. M.; da Silva, M. F. C. G.; Kopylovich, M. N.; Fraústo da Silva, J. J. R.; Pombeiro, A. J. L. Inorg. Chim. Acta 2008, doi:10.1016/j.ica.2006.12.016. (7) The Cambridge Structural Database (CSD). Allen, F. H. Acta Crystallogr. 2002, B58, 380. (8) The searching algorithm in the ConQuest Version 1.9 (CSD version 5.28, August 2007) constrained to the presence of any terpyridine moiety and at least one crystallization water molecule and one chloride counter ion resulted in 43 analyzable hits from which 40 compounds contain diverse water-chloride aggregates (there are 29 and 11 examples of infinite (mostly 1D) networks and discrete clusters, respectively). See the Supporting Information for the CSD refcodes. (9) For a recent review, see Constable, E. C. Chem. Soc. ReV. 2007, 36, 246. (10) For recent examples of supramolecular terpyridine compounds, see (a) Beves, J. E.; Constable, E. C.; Housecroft, C. E.; Kepert, C. J.; Price, D. J. CrystEngComm 2007, 9, 456. (b) Zhou, X.-P.; Ni, W.-X.; Zhan, S.-Z.; Ni, J.; Li, D.; Yin, Y.-G. Inorg. Chem. 2007, 46, 2345. (c) Shi, W.-J.; Hou, L.; Li, D.; Yin, Y.-G. Inorg. Chim. Acta 2007, 360, 588. (d) Beves, J. E.; Constable, E. C.; Housecroft, C. E.; Kepert, C. J.; Neuburger, M.; Price, D. J.; Schaffner, S. CrystEngComm 2007, 9, 1073. (e) Beves, J. E.; Constable, E. C.; Housecroft, C. E.; Neuburger, M.; Schaffner, S. Inorg. Chem. Commun. 2007, 10, 1185. (f) Beves, J. E.; Constable, E. C.; Housecroft, C. E.; Kepert, C. J.; Price, D. J. CrystEngComm 2007, 9, 353. (11) Synthesis of 1: FeCl2 · 2H2O (82 mg, 0.50 mmol) and 4′-phenyl-2,2′: 6′,2″-terpyridine (L) (154 mg, 0.50 mmol) were combined in a THF (20 mL) solution with continuous stirring at room temperature. The resulting deep purple suspension was stirred for 1 h, filtered off, washed with THF (3 × 15 mL), and dried in vacuo to afford a deep purple solid 1 (196 mg, 41%). 1 exhibits a high affinity for water and upon recrystallization gives derivatives with a higher varying content of crystallization water. 1 is soluble in H2O, MeOH, EtOH, MeCN, CH2Cl2, and CHCl3. mp > 305 °C (dec.). Elemental analysis. Found: C 52.96, H 3.76, N 8.36. Calcld. for C42H40Cl4Fe2N6O5: C 52.42, H 4.19, N 8.73. FAB+-MS: m/z: 835 {[FeL2]Cl2 · 5H2O + H}+, 816
Communications {[FeL2]Cl2 · 4H2O}+, 796 {[FeL2]Cl2 · 3H2O–2H}+, 781 {[FeL2]Cl2 · 2H2O + H}+, 763 {[FeL2]Cl2 · H2O + H}+, 709 {[FeL2]Cl}+, 674 {[FeL2]}+, 435 {[FeL]Cl2}+, 400 {[FeL]Cl}+, 364 {[FeL]–H}+, 311 {L–2H}+. IR (KBr): νmax/cm–1: 3462 (m br) ν(H2O), 3060 (w), 2968 (w) and 2859 (w) ν(CH), 1656 (m br) δ(H2O), 1611 (s), 1538 (w), 1466 (m), 1416 (s), 1243 (m), 1159 (w), 1058 (m), 877 (s), 792 (s), 766 (vs), 896 (m), 655 (w), 506 (m) and 461 (m) (other bands). The X-ray quality crystals of [FeL2]Cl2 · 10H2O (1′) were grown by slow evaporation, in air at ca. 20 °C, of a MeOH/H2O (v/v ) 9/1) solution of 1. (12) Crystal data: 1′: C42H50Cl2FeN6O10, M ) 925.63, triclinic, a ) 10.1851(10), b ) 12.2125(13), c ) 19.5622(19) Å, R ) 76.602(6), β ) 87.890(7), γ ) 67.321(6)°, U ) 2180.3(4) Å3, T ) 150(2) K, space group P1j, Z ) 2, µ(Mo-KR) ) 0.532 mm-1, 32310 reflections measured, 8363 unique (Rint ) 0.0719) which were used in all calculations, R1 ) 0.0469, wR2 ) 0.0952, R1 ) 0.0943, wR2 ) 0.1121 (all data). (13) (a) McMurtrie, J.; Dance, I. CrystEngComm 2005, 7, 230. (b) Nakayama, Y.; Baba, Y.; Yasuda, H.; Kawakita, K.; Ueyama, N. Macromolecules 2003, 36, 7953. (c) Kabir, M. K.; Tobita, H.; Matsuo, H.; Nagayoshi, K.; Yamada, K.; Adachi, K.; Sugiyama, Y.; Kitagawa, S.; Kawata, S. Cryst. Growth Des. 2003, 3, 791. (14) Ludwig, R. Angew. Chem., Int. Ed. 2001, 40, 1808.
Crystal Growth & Design, Vol. 8, No. 3, 2008 785 (15) The searching algorithm in the ConQuest Version 1.9 (CSD version 5.28, May 2007) was constrained to the presence of (i) at least one tetranuclear [(H2O)3(Cl)]– ring (i.e., minimal cyclic fragment in our water-chloride network) with d(O · · · O) ) 2.2–3.2 Å and d(O · · · Cl) ) 2.6–3.6 Å, and (ii) at least one crystallization water molecule and one chloride counter ion. All symmetry-related contacts were taken into consideration. (16) For 2D networks with the [(H2O)3(Cl)]– core, see the CSD refcodes: AGETAH, AMIJAH, BEXVIJ, EXOWIX, FANJUA, GAFGIE, HIQCIT, LUNHUX, LUQCEF, PAYBEW, TESDEB, TXCDNA, WAQREL, WIXVUU, ZUHCOW. For 3D network, see the CSD refcode: LUKZEW. (17) This analysis was run on 1 since we were unable to get 1′ in a sufficient amount due to the varying content of crystallization water in the samples obtained upon recrystallization of 1. (18) (a) Das, S.; Bhardwaj, P. K. Cryst. Growth. Des. 2006, 6, 187. (b) Wang, J.; Zheng, L.-L.; Li, C.-J.; Zheng, Y.-Z.; Tong, M.-L. Cryst. Growth. Des. 2006, 6, 357. (c) Ghosh, S. K.; Ribas, J.; El Fallah, M. S.; Bharadwaj, P. K. Inorg. Chem. 2005, 44, 3856. (19) A temperature below 305 °C has been used to avoid the eventual decomposition of the compound upon rather prolonged heating.
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