Hydrogen-Bonded 3-D Network Structures of Lanthanide Aquo Ions

Hydrogen-Bonded 3-D Network Structures of Lanthanide Aquo Ions and 4,4′-Bipyridine with Carbaborane Anions Luis Cunha-Silva, Aleema Westcott, Nina Whitford, and Michaele J. Hardie* School of Chemistry, UniVersity of Leeds, Leeds LS2 9JT, UK

CRYSTAL GROWTH & DESIGN 2006 VOL. 6, NO. 3 726-735

ReceiVed September 28, 2005; ReVised Manuscript ReceiVed December 9, 2005

W This paper contains enhanced objects available on the Internet at http://pubs.acs.org/crystal. ABSTRACT: A series of three-dimensional (3-D) hydrogen-bonded structures of lanthanide aquo ions and 4,4′-bipyridine (bpy) or protonated bpyH+ as ligands and hydrogen-bonding tectons have been characterized by single-crystal X-ray crystallography, with both Cl- and [Co(C2B9H11)2]- counteranions. All show related structures with unidirectional rectangular channels filled by additional bpy molecules for the complexes [Yb(H2O)8](bpy)2.5Cl3‚6.5(H2O) and [Yb(H2O)8]4(bpy)9.5Cl12‚24.5(H2O) or by [Co(C2B9H11)2]anions for the complexes [Ln(bpy)(H2O)8]2(bpy)10[Co(C2B9H11)2]6‚1.5(EtOH)‚15(H2O) where Ln ) La, Ce, [Sm(H2O)5(bpy)2(EtOH)][Sm(H2O)6(bpyH)(EtOH)](bpyH)(bpy)10[Co(C2B9H11)2]8‚EtOH‚9(H2O), and [Ln(H2O)6(bpy)(bpyH0.5)]2[Ln(H2O)7(bpy)](bpyH)2(bpy)14[Co(C2B9H11)2]12‚n(EtOH)‚5(H2O) where Ln ) Gd, Tb, and Ho. The smaller (CB11H12)- anion does not template a similar structure; instead the complex [(bpyH)3(bpy)(CB11H12)3] is isolated with a one-dimensional (1-D) hydrogen-bonded ladder structure. Introduction The study of hydrogen-bonded network structures forms an important aspect of crystal engineering that seeks to control and understand the way that molecules interact or orient themselves in the crystalline state. Hydrogen-bonded networks of organic1 and coordination compounds2 have been extensively studied over the past few years. Networks of coordination compounds or polymeric coordination networks are often positively charged and require anionic counterions. Although they are not necessarily incorporated into the network structure itself, anions may have an influence on the geometry and topology of the network formed. Weakly coordinating anions such as PF6- and BF4are often favored for such systems. We have been studying the effects on network structures of using more unusual weakly coordinating anions, namely, various carbaborane anions, for systems that have been previously well studied with traditional anions.3 As part of these studies, we have investigated hydrogenbonded networks of lanthanide aquo ions with 4,4′-bipyridine () bpy) using monoanionic carbaborane counteranions. Initially, we looked at the commercially available cobalt(III) bis(dicarbollide) or cobalticarborane, [Co(C2B9H11)2]-, and (CB11H12)-. These carbaborane anions are weakly coordinating and have been used as counteranions for coordination networks,3-5 and as counterions for hydrogen-bonded networks of molecular hosts with metal cations.6 It is also notable that the C-H groups of carbaboranes are acidic; hence they are capable themselves of forming hydrogen-bonding interactions.7

The bpy molecule can act as a linear bridging hydrogen-bond acceptor, or it can easily be protonated to give hydrogen-bond * To whom correspondence should be addressed. Fax: +44 113 343 6565. Tel: +44 113 343 6458. E-mail: [email protected].

donor properties. Metal aquo complexes are good hydrogenbond donors, and the high coordination numbers of lanthanide cations means that there is the potential for forming network structures with high connectivities.5,8 There are a number of reported examples of metal aquo cations forming two- and threedimensional (2-D and 3-D) hydrogen-bonded networks with bpy or protonated bpyH+ with both lanthanide metal cations9-16 and transition metals.17 In the transition metal complexes, the bpy molecules tend to fulfill two roles, as both bridging bidentate ligands and bridging linear hydrogen-bond acceptors. Binding of metal centers by bpy ligands is less prevalent in the lanthanide complexes, and where it does occur, it is usually a monodentate rather than a bidentate bridging interaction, with one exception. Complexes of lanthanide salts with bpy have been reported for nitrate,9-14 picrate,15 and chloride16 counteranions, although only the nitrate complexes have been thoroughly investigated. The nitrate complexes show a range of structures.9-14 In all cases, the nitrate anions bind in a chelating manner to the lanthanide cation. Types of network structures include interpenetrating 2-D networks,10 3-D networks with small nitrate containing cavities,11 3-D networks without significant cavities,10,12 and unusual self-catenating 3-D hydrogen-bonded arrays including those of (bpyH+)[Ln(NO3)(H2O)2(bpy)] where Ln ) La, Pr, Nd11,13 and [Ln-µ2-(NO3)(NO3)2(H2O)4]2‚(bpy)4 where Ln ) La, Pr, Ce.14 These nitrate complexes, along with related 1,2-bis(4-pyridyl)ethane complexes have recently been reviewed.18 Known picrate complexes form 3-D network structures.15 There are two known examples of chloride complexes with isomorphic structures, namely, the unhydrated complexes [M(H2O)8]Cl3‚(bpy)2 where M ) Y, Gd.16 These complexes form a 3-D hydrogen-bonded lattice structure, which is topologically the same as the self-catenating nitrate complexes and is discussed in more detail below. While other complexes of lanthanide chlorides with 4,4′-bipyridine have been reported, they have not been structurally characterized.19 It is notable that, despite all molecular components being apolar, half of the known Ln-aquo-bpy structures crystallize in polar space groups. The [M(H2O)8]Cl3‚(bpy)2 complexes, for instance, both show a strong piezoelectric effect.16 2-D and 3-D network structures are also known from hydrogen-bonding interactions between

10.1021/cg050504e CCC: $33.50 © 2006 American Chemical Society Published on Web 01/19/2006

Hydrogen-Bonded 3-D Network Structures

bpy and encapsulated lanthanide complexes, where the encapsulating ligand has available hydrogen-bond donor groups.20 We report herein a series of new aquo-lanthanide/bpy complexes with hydrogen-bonded network structures. All of the complexes have related structures, featuring 3-D networks with rectangular channels. The chloride complexes [Yb(H2O)8](bpy)2.5Cl3‚6.5(H2O) (2) and [Yb(H2O)8]4(bpy)9.5Cl12‚24.5(H2O) (3) are structurally quite distinct from the previously reported chloride complexes. Use of the large [Co(C2B9H11)2]- anion results in complexes with considerably larger rectangular channels, in the complexes [Ln(bpy)(H2O)8]2(bpy)10[Co(C2B9H11)2]6‚1.5(EtOH)‚ 15(H2O) where Ln ) La (4), Ce (5); [Sm(H2O)5(bpy)2(EtOH)][Sm(H2O)6(bpyH)(EtOH)](bpyH)(bpy)10[Co(C2B9H11)2]8‚EtOH‚ 9(H2O) (6); and [Ln(H2O)6(bpy)(bpyH0.5)]2[Ln(H2O)7(bpy)](bpyH)2(bpy)14[Co(C2B9H11)2]12‚8.5(EtOH)‚5(H2O) where Ln ) Gd (7), ) Tb (8), or ) Ho (9). Use of the smaller (CB11H12)anion does not give lanthanide-containing crystalline complexes; instead the hydrogen-bonded complex [(bpyH)3(bpy)(CB11H12)3] (10) is isolated. Experimental Section Synthesis. Ag[Co(C2B9H11)2] was synthesized by a literature procedure,21 and all other chemicals were used as supplied from commercial sources. Most complexes were highly solvated and lost single crystallinity on exposure to the atmosphere; hence, microanalyses were not performed. [Yb(H2O)8](bpy)2.5Cl3‚6.5(H2O) (2) and [Yb(H2O)8]4(bpy)9.5Cl12‚ 24.5(H2O) (3). YbCl3‚6H2O (5 mg, 0.013 mmol) was dissolved in water and added to a solution of 4,4′-bipyridine (4 equiv) in EtOH for 2 and acetone for 3. The overall solvent mix was 95:5 EtOH/acetone:H2O. Colorless crystals appeared after several days of slow evaporation. IR, (KBr disk, cm-1) 2: 3347, 3374, 3112, 3001, 2331, 2342, 2082, 1597, 1507, 1492, 1408, 1217, 1098, 1008, 792, 601; 3: 3441, 3377, 3089, 3000, 2064, 1619, 1512, 1499, 1400, 1216, 1081, 1002, 812, 724, 628. [Ln(bpy)(H2O)8]2(bpy)10[Co(C2B9H11)2]6‚1.5(EtOH)‚15(H2O) Ln ) La (4), Ce (5). LaCl3‚7H2O (7.1 mg, 0.0191 mmol) was dissolved in ethanol and mixed with Ag[Co(C2B9H11)2] (24.7 mg, 0.0573 mmol) that was also dissolved in ethanol. The mixture was filtered to remove AgCl and 4,4′-bipyridine (5.97 mg, 0.0191 mmol) added, and the solution was left to slowly evaporate for several days to give crystals of 4: IR, (KBr disk, cm-1) 4 3368, 2928, 2547, 2364, 2353, 1607, 1592, 1527, 1497, 1403, 1208, 1096, 993, 804, 724, 668. CeCl3‚7H2O (9.0 mg, 24.1 µmol) was dissolved in water and added to a solution of Ag[Co(C2B9H11)2] (17.6 mg, 40.8 µmol) in EtOH. The formed precipitate was filtered, and a solution of bpy (16.0 mg, 0.1 mmol) in EtOH was added. The overall solvent mixture was 95:5 EtOH/ H2O. Yellow needle crystals of 5 appeared after several days of slow evaporation. IR data (cm-1): 3370, 2571, 1596, 1536, 1487, 1410, 1319, 1288, 1218, 1135, 1097, 1065, 984, 922, 806, 750, 666, 616. [Sm(H2O)5(bpy)2(EtOH)][Sm(H2O)6(bpyH)(EtOH)](bpyH)(bpy)10[Co(C2B9H11)2]8‚EtOH‚ 9(H2O) (6). SmCl3‚6H2O (9.9 mg, 24.4 µmol), Ag[Co(C2B9H11)2] (18.0 mg, 41.7 µmol), and bpy (3.9 mg, 24.2 µmol) were treated as for 5. After several days of slow evaporation, yellow needles of 6 were formed. IR data (cm-1): 3365, 2539, 1938, 1603, 1537, 1408, 1320, 1217, 1138, 1095, 1063, 1040, 983, 915, 887, 797, 685, 618. [Ln(H2O)6(bpy)(bpyH0.5)]2[Ln(H2O)7(bpy)](bpyH)2(bpy)14[Co(C2B9H11)2]12‚n(EtOH)‚5(H2O) where Ln ) Gd (7), ) Tb (8), and ) Ho (9). GdCl3‚6H2O (6.7 mg, 0.0180 mmol), Ag[Co(C2B9H11)2] (7.6 mg, 0.0176 mmol), 4,4′-bipyridine (3.1 mg, 0.0198 mmol) along with pyrazine (5.2 mg, 0.0649 mmol) were treated as for complex 6. The solution was left to slowly evaporate for two weeks to give yellow crystals of 7. IR selected data (cm-1) 3233, 2523, 2159, 2029, 1975, 1630, 1535, 1407, 1316, 1215, 1138, 1095, 1061, 1015, 886, 853, 803, 726, 620. TbCl3‚6H2O (7.8 mg, 24.4 µmol), Ag[Co(C2B9H11)2] (21.3 mg, 49.3 µmol), and bpy (3.2 mg, 20.5 µmol) were treated as for 5 to give yellow needles of 8 that appeared after several days of slow evaporation. IR data (cm-1): 3371, 2568, 1611, 1515, 1491, 1409, 1219, 1204, 1138, 1097, 1042, 1015, 984, 919, 885, 804, 724, 688.

Crystal Growth & Design, Vol. 6, No. 3, 2006 727 HoCl3‚6H2O (6.3 mg, 16.7 µmol), Ag[Co(C2B9H11)2] (21.5 mg, 49.8 µmol), and bpy (3.0 mg, 19.2 µmol) were treated as for 5. Yellow needle crystals of 9 were obtained after several days of slow evaporation. IR data (cm-1): 3332, 2923, 2554, 1931, 1840, 1599, 1535, 1512, 1592, 1409, 1353, 1321, 1218, 1137, 11122, 1018, 962, 921, 873, 804, 728, 686. [(bpyH)3(bpy)(CB11H12)3] 10. TbCl3‚6H2O (6.4 mg, 18.2 µmol), Ag(CB11H12) (12.9 mg, 46.7 µmol), and bpy (3.0 mg, 19.2 µmol) were treated as for 5. Colorless block crystals of 10 were isolated after several days of slow evaporation. IR data (cm-1): 3347, 2560, 2036, 1965, 1642, 1494, 1416, 1350, 1336, 1303, 1204, 1207, 1089, 1063, 1025, 981, 948, 889, 796, 719, 666. X-ray Crystallography. Single crystals of complexes 2-9 were mounted on a glass fiber under oil, and X-ray data were collected at 150(1) K on either a Nonius KappaCCD diffractometer with graphite monochromated Mo KR radiation (λ ) 0.71073 Å) or a Bruker-Nonius X8 diffractometer with an Mo-rotating anode. Data were corrected for Lorenztian and polarization effects and absorption corrections were applied using multiscan methods. The structures were solved by direct methods using SHELXS-9722 and refined by full-matrix (complexes 2 and 10) or block-matrix least-squares on F2 using SHELXL-97.23 C-H, N-H, and B-H hydrogens were included at calculated positions. Unless indicated, all non-hydrogen atoms were refined anisotropically. C positions within carbaborane cages were determined by examining bond lengths and displacement parameters. Details of the data collections and structure refinements are given in Table 1, and any additional details are given below. The disorder model for complex 2 involved two bpy molecules refined with two adjacent C atoms in each ring being split over two positions each at 50% occupancy, while a third bpy was modeled as being disordered over two positions, each at 50% occupancy, with one C atom located on an inversion center being shared between both bpy positions. Some Cl- and some solvent water positions were refined at 50% occupancy. Complex 3 was also refined with some Cl- and some solvent water positions at 50% occupancy, and eight of the disordered water O atoms were refined isotropically. In complex 4, a disordered bpy and water molecules were refined isotropically, and their H positions were not included. Bond lengths within the disordered bpy were restrained to chemically reasonable values. Structure was refined as an inversion twin with a final Flack parameter 0.53(1). Crystals obtained for complex 6 were of poor quality as indicated by the very high Rint value. The crystals were weakly scattering, and data were only collected to a 2θ value of 45°, although even at this resolution the data were weak as indicated by the high Rσ value to 0.1408. This poor quality data leads to some problems with the structure refinement, with only heavy atoms refined anisotropically, and restraints were employed on some carbaborane and ethanol bond lengths. Structure was refined as an inversion twin with a final Flack parameter 0.23(2). The crystal structure of complex 6 is of sufficient quality to establish structural features and connectivities, but positional parameters have higher than usual associated errors. In complex 8, a low occupancy EtOH was refined isotropically.

Results and Discussion Chloride-Containing Complexes. The crystal structures of [M(H2O)8]Cl3‚2(bpy) where M ) Y, Gd were determined two decades ago by Bukowka-Strzyzewska and Tosik.16 The structures were analyzed largely in terms of the coordination environment of the metal cations and hydrogen-bonding interactions, but the extended network structure was not discussed. This is worth revisiting, however, as the structure is a rare example of an 8-connected self-penetrating net. The [M(H2O)8]3+ cation has a dodecahedral geometry and the aquo ligands hydrogen bond to Cl- anions and bipy molecules, shown for [Gd(H2O)8]Cl3‚(bpy)2 (1) in Figure 1a. Each [M(H2O)8]3+ cation hydrogen bonds to six Cl- anion arranged octahedrally around the cation, while each Cl- hydrogen bonds to two [M(H2O)8]3+ cations in a linear fashion. This creates a 3-D cubelike network with R-Po related topology. Each bpy molecule hydrogen bonds between two [M(H2O)8]3+ cations, spanning the diagonal of each cube, and there are two such linkages per cube that run in

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Table 1. Details of Data Collections and Structure Refinements

formula Mr cryst color and shape cryst size (mm) cryst syst space group a (Å) b (Å) c (Å) R (°) β (°) γ (°) U (Å3) Z Fc (g cm-3) F(000) µ (cm-1) instrument 2θ range (°) no. data collected no. unique data Rint no. obs. data (I > 2σ(I)) no. parameters no. restraints R1 (obs data) wR2 (all data) S min, max residual e density (e Å3)

2

3

4

6

8

C25H49Cl3N5O14.5Yb 931.08 yellow, needle 0.40 × 0.30 × 0.12 triclinic P1h 10.0648(1) 13.9909(1) 14.8050(2) 86.59(1) 78.30(1) 71.016(1) 1930.35(4) 2 1.602 942 2.696 KappaCCD 3.08-54.9 25451 8539 0.0556 8429

C95H189Cl12N19O56.5Yb4 3619.21 yellow, needle 0.33 × 0.28 × 0.12 triclinic P1h 14.1542(1) 14.8380(1) 37.0101(3) 97.00(1) 93.23(1) 93.91(1) 7680.6(1) 2 1.565 3656 2.707 KappaCCD 2.9-55.08 106323 34265 0.0699 27238

C147H299B108Co8La2N24O32.5 4839.84 yellow, needle 0.38 × 0.36 × 0.04 orthorhombic Pca21 20.9619(2) 32.1632(2) 35.4247(3) 90 90 90 23883.4(3) 4 1.346 9916 0.955 KappaCCD 2.32-50.00 100047 37326 0.0895 27192

C178H341B144Co8N28O23Sm2 5570.57 yellow, needle 0.40 × 0.13 × 0.07 triclinic P1 13.6449(1) 15.4157(1) 35.6350(4) 84.673(1) 89.820(1) 68.820(1) 6955.42(10) 1 1.330 2849 0.940 KappaCCD 3.18-44.80 70812 34705 0.1678 30013

C275H531B216Co12N42O32.5Tb3 8465.30 yellow, needle 0.38 × 0.06 × 0.04 triclinic P1h 13.6898(9) 28.882(2) 54.376(4) 97.574(4) 95.523(4) 94.999(4) 21104(3) 2 1.332 8668 1.015 X8 1.94-54.26 617487 91689 0.0930 65010

1056.81 colorless, plate 0.22 × 0.10 × 0.03 monoclinic P21/c 16.4751(12) 19.6033(15) 37.759(3) 90 95.101(4) 90 12146.6(16) 8 1.156 4400 0.06 X8 2.34-50.00 119082 21398 0.0623 10090

610 0 0.0575 0.1637 1.218 -3.580, 1.830

1734 0 0.0513 0.1567 1.024 -2.462, 2.634

2834 27 0.0709 0.2294 1.017 -1.255, 1.435

1588 52 0.1414 0.3832 0.994 -2.84, 3.640

5233 0 0.0770 0.1886 1.110 -1.781, 2.278

1508 0 0.1092 0.3723 1.024 -0.454, 1.261

opposite directions to create a cross-like cross-section when viewed down the a-axis. This gives a self-penetrating or selfcatenating effect, as illustrated in Figure 1b where, for instance, the circuit shown in red is threaded by the one shown in blue. Self-penetrating networks are relatively rare,24 but it is notable that they occur for a number of Ln/aquo/bpy complexes.11,13,14,16 Various LnCl3 salts were mixed with four equivalents of 4,4′bipyridine in 95:5 EtOH/H2O solutions. Crystals suitable for X-ray analysis were only obtained for YbCl3 in the complex 2. A further complex, 3, was isolated in a similar manner but from a different solvent system. The extended structures of complexes 2 and 3 are closely related, although show differing inclusion of guest molecules. The structure of complex 2 is highly disordered with the bpy molecules and two of the three chlorides showing positional disorder. The [Yb(H2O)8]3+ cation within 2 has a square antiprismatic geometry, unlike the dodecahedral geometry seen in complex 1, with Yb-O bond lengths ranging from 2.305(6) to 2.391(6) Å. Two of the three crystallographically independent bpy molecules hydrogen bond to two [Yb(H2O)8]3+ cations at O‚‚‚N distances ranging from 2.708 to 2.734 Å. These bpy molecules are disordered such that, within each aromatic ring, two adjacent C positions are disordered across two sites. Each [Yb(H2O)8]3+ cation hydrogen bonds directly to four bpy molecules, creating chain motifs. Parallel strands of these chains are linked into a rectangular 2-D grid array by hydrogen-bonding interactions between the [Yb(H2O)8]3+ cations and two Clanions at O‚‚‚Cl distances ranging from 3.086 to 3.122 Å, and a direct [Yb(H2O)8]3+...[Yb(H2O)8]3+ hydrogen bond at a O‚‚‚O distance of 3.187 Å. Note that only one of the Cl- anions is at full occupancy, and the other is at 50% occupancy.25 One such grid is shown in Figure 2. The rectangular grids are linked to a 3-D hydrogen-bonded network through further hydrogenbonding interactions between the [Yb(H2O)8]3+ cations and another disordered Cl-† at O‚‚‚Cl distances of 3.175 and 3.277

10 C43H71B33N8

Å, and through Yb-OH2‚‚‚OH2‚‚‚Cl-‚‚‚H2O-Yb interactions (O‚‚‚O separations 2.631 and 2.706 Å, O‚‚‚Cl- distances 3.124 and 3.34 Å). The 3-D network structure is shown in Figure 3 and features rectangular channels running in one direction only. The channels are filled by additional disordered water and Clsites and a further guest bpy molecule. The guest bpy is also disordered across two parallel positions that share a single C site. The guest bpy molecules sit in the center of the channels and form multiple edge-to-face π-stacking interactions with the hydrogen-bonding bpy molecules, with C-H‚‚‚π distances typically 2.749 to 2.942 Å and C-H‚‚‚π angles 123.7-146.8°. Complex 3 is grown from a different solvent system, namely, acetone/water, and features a similar 3-D hydrogen-bonded network structure. In 3, all bpy groups are crystallographically ordered, and there are four crystallographically distinct [Yb(H2O)8]3+ cations, all with square antiprismatic geometry. Nine of the twelve Cl- anions are fully ordered, while the remaining three Cl- anions are disordered over six positions, each at 50% occupancy. Many of the solvent water positions are also at 50% occupancy. Each of the [Yb(H2O)8]3+ cations hydrogen bonds to four bpy molecules, while each of these bpy molecules is a hydrogen-bond acceptor for two [Yb(H2O)8]3+ cations, creating the same chain motif as seen for complex 2. Again as for complex 2, the chains are linked into the 3-D network by a variety of hydrogen-bonding interactions between the [Yb(H2O)8]3+ cations, additional water molecules, and Cl- anions, Figure 4a. There are extensive face-to-face π-stacking interactions between the bpy molecules of the network, with centroid separations ranging from 3.552 to 3.717 Å. The network is essentially the same as the network of complex 2, although the exact hydrogen-bonding connectivities between Cl- and water molecules differ slightly between the two complexes. In complex 3, the 3-D net has rectangular channels that run along the a direction. There are three crystallographically distinct channels, two of which contain guest water and bpy, in a manner


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Figure 3. Extended structure of 2: (a) rectangular channels; (b) view along the c axis. Guest bpy are shown in light blue, and additional solvent water and disordered Cl- positions within the channels are not shown. Figure 1. Extended structure of [Gd(H2O)8]Cl3‚2(bpy).12 (a) Hydrogenbonding interactions with Cl- shown as yellow spheres; (b) network connectivity illustrating the self-penetrating nature of the 8-connected net (see text).

Figure 2. Section of the crystal structure of [Yb(H2O)8](bpy)2.5Cl3‚6.5(H2O) (2) showing hydrogen-bonding interactions between disordered bpy molecules, [Yb(H2O)8]3+ cations, and Cl- anions to form a rectangular grid structure. Cl- is shown as yellow spheres, and water is shown as red spheres.

similar to the inclusion of additional bpy in complex 2 (type A channel). Here, the more ordered structure allows for elucidation of the interactions within the channels. The guest bpy molecules hydrogen bond with water to form a (bpy)‚‚‚(H2O)‚‚‚(H2O)‚‚‚ (bpy) chain at O‚‚‚N separations 2.823 to 2.860 and O‚‚‚O separations 2.757 and 2.723 Å, Figure 4b. The water molecules

within this chain also hydrogen bond to a Cl- anion (O‚‚‚Cl separation 4.276 Å) or water (O‚‚‚O separation 2.722 Å), which, in turn, hydrogen bonds to [Yb(H2O)8]3+. There is extensive hydrogen bonding between Cl- anions and water/aquo positions. The guest bpy molecules also form edge-to-face π-stacking interactions with other bpy molecules. The third channel contains only disordered water molecules, despite being a size similar to the bpy-containing channels (type B channel). The type of channel varies along the c axis, with an AAABAAAB repeat pattern. Complexes 2 and 3 differ significantly from 1 both in terms of the metal cation geometry and degree of hydration of the complex. The high level of hydration of 2 and 3 affords more opportunity for forming hydrogen-bonding interactions and a considerably more open network structure results. Cobalticarborane-Containing Complexes. The large cobalticarborane anion, [Co(C2B9H11)2]-, is commercially available as a Na+ salt that is easily converted to the Ag+ salt.21 This can be subsequently used in metathesis reactions with LnCl3‚6(H2O) salts to give aqueous solutions containing Ln[Co(C2B9H11)2]3. Addition of 4,4′-bipyridine in EtOH, followed by slow evaporation, gives crystalline products suitable for single-crystal X-ray studies for the lanthanides Ln(III), Ce(III), Sm(III), Gd(III), and Tb(III). Some other lanthanide salts gave crystalline products that were too small or of too poor a quality for single-crystal X-ray structure determination. The complexes all show 3-D hydrogen-bonded network structures of related topology and [Co(C2B9H11)2]- anions in rectangular channels


Cunha-Silva et al.

Figure 5. Structure of [La(bpy)(H2O)8]2(bpy)10[Co(C2B9H11)2]6‚1.5(EtOH)‚15(H2O) (4). (a) Hydrogen-bonding interactions of [La(bpy)(H2O)8]3+ cations; (b) 2-D sheet structure in the ab plane. EtOH molecules are shown in dark green.

Figure 4. Crystal structure of [Yb(H2O)8]4(bpy)9.5Cl12‚24.5(H2O) (3). Guest bpy molecules are shown in blue, uncomplexed water are shown as red spheres, and chlorides are shown as yellow spheres. (a) Full packing diagram shows a 3-D hydrogen-bonded network with channels containing either bpy and water guests or water guests only; (b) detail of hydrogen-bonded chain formed within rectangular channels.

but show subtle differences in coordination chemistry and hydrogen-bonding modes, with three distinct structural types formed. The complexes [Ln(bpy)(H2O)8]2(bpy)10[Co(C2B9H11)2]6‚1.5(EtOH)‚15(H2O) where Ln ) La (4) and Ce (5) are isostructural. Only the La(III) complex 4 will be presented in detail here with a full structural determination of complex 5 available as Supporting Information.26 There are two crystallographically independent [La(bpy)(H2O)8]3+ cations in the complex. Both have a monocapped square antiprismatic geometry with an O in the capping position, and La2 has the more regular geometry. La-O bond lengths range from 2.514(6) to 2.606(8) Å, and La-N bond lengths are 2.792(7) and 2.719(7) Å. The primary hydrogen-bonding interactions around each cationic complex are shown in Figure 5a. Overall, [La1(bpy)(H2O)8]3+ directly hydrogen bonds to three bpy molecules, numerous water positions (some of which are partially occupied), and an ethanol, while [La2(bpy)(H2O)8]3+ hydrogen bonds to four bpy molecules, numerous water positions and a partially occupied ethanol. N‚‚‚O hydrogen-bonding distances range from 2.657 to 2.941 Å, and O‚‚‚O hydrogen-bonding distances range from 2.694 to 3.007 Å. The bpy ligands and uncoordinated molecules bridge between [La(bpy)(H2O)8]3+ cations through hydrogen-bonding interactions. The most direct of these are between the coordinated bpy

of [La1(bpy)(H2O)8]3+ and an aquo ligand of the La2 complex, whereas the coordinated bpy ligand of [La2(bpy)(H2O)8]3+ hydrogen bonds to [La1(bpy)(H2O)8]3+ indirectly, via an ethanol molecule, Figure 5a. All uncoordinated bpy molecules hydrogen bond to an aquo ligand of a [La(bpy)(H2O)8]3+ cation through one N, while the other end of the bpy forms an N‚‚‚(H2O)n‚‚‚ H2O-La bridge via either one or two water molecules. There are also numerous La-OH2‚‚‚(H2O)n‚‚‚H2O-La hydrogenbonding linkages, with O‚‚‚O distances between uncoordinated water molecules ranging from 2.601 to 2.780 Å. A 2-D sheet structure is formed in the ab plane as shown in Figure 5b. The C4-C4′ twist of crystallographically independent bpy molecules within this sheet are complementary for adjacent bpy which maximizes π-stacking interactions. Adjacent aryl rings are roughly coplanar with a slightly slipped orientation and centroid separations ranging from 3.611 to 3.826 Å; aside from one separation of 4.541 Å, this last separation is well outside the expected range for π-stacking interactions.27 Comparing this network with that shown for complex 2 in Figure 2, it can be seen that the networks are closely related, but that of complex 4 is expanded. In both cases, there are parallel strands of cations, but in complex 4 these are offset. Six bpy molecules hydrogen bond between six [Yb(H2O)8]3+ cations in 2, while in 4 there are eight bpy molecules hydrogen bonding between six [La(bpy)(H2O)8]3+ cations. In the overall 3-D network structure of complex 4, the 2-D sheets are linked together through further La-OH2‚‚bpy‚‚ (H2O)n‚‚‚H2O-La hydrogen-bonding bridges, Figure 6. The bpy molecules that act as struts between the 2-D sheets have an angled orientation with a direction that alternates in the x direction. One of these bpy molecules shows a translational disorder. Again, adjacent bpy molecules have centroid separations suggestive of π-stacking interactions, with values between 3.623 and 3.847 Å. The 3-D hydrogen-bonding network features large rectangular channels. As for complexes 2 and 3, these channels are unidirectional, but in this case they are lined by bpy molecules on all four sides. Note that the formation of unidirectional channels is one way that interpenetration of


Figure 6. Packing diagram of complex 4, showing 3-D hydrogenbonded network structure and [Co(C2B9H11)2]- anions in channels. W A 3D rotatable image of the packing structure for complex 4 in PDB format is available.

networks can be avoided.28 Each channel is occupied by two tiers of [Co(C2B9H11)2]- anions that form zigzag chains within the channels. There are a number of close B-H‚‚‚H-C distances between neighboring [Co(C2B9H11)2]- anions, indicating the presence of dihydrogen bonding.29 The closest interactions are at separations 1.769, 1.876, and 2.288 Å, which are similar to those previously reported for dihydrogen interactions between [Co(C2B9H11)2]- anions.30 The Sm complex isolated in a similar manner was of composition [Sm(H2O)5(bpy)2(EtOH)][Sm(H2O)6(bpyH)(EtOH)](bpyH)(bpy)10[Co(C2B9H11)2]8‚EtOH‚9(H2O) (6), determined from the crystal structure. There are eight anions in the asymmetric unit, which requires that two bpy molecules be protonated to achieve charge balance. These were determined


as being those showing inter-bpy N‚‚‚N distances and orientations consistent with the formation of N-H‚‚‚N hydrogen bonding. There are two distinct Sm(III) complex cations in complex 6, [Sm1(H2O)5(bpy)2(EtOH)]3+ and [Sm2(H2O)6(bpyH)(EtOH)]4+. Both have distorted square antiprismatic coordination geometries with Sm-O bond lengths ranging from 2.39(6) to 2.58(4) Å and Sm-N bond lengths ranging from 2.567(16) to 2.611(17) Å. The two bpy ligands in the cation [Sm1(H2O)5(bpy)2(EtOH)]3+ are approximately trans with an N-Sm-N angle of 142.6(5)°. Some of the primary hydrogen-bonding interactions around both types of complex cation of 6 are shown in Figure 7a. [Sm1(H2O)5(bpy)2(EtOH)]3+ hydrogen bonds to six bpy molecules, one water, and one ethanol through O-H groups of its aquo and ethanol ligands. [Sm2(H2O)6(bpyH)(EtOH)]4+ likewise hydrogen bonds to six bpy molecules, a bpyH+ cation, and three waters. O‚‚‚N distances are in the range of 2.65-2.82 Å. There is an indirect hydrogen-bonding link between the Sm centers through Sm1-EtOH‚‚‚bpy‚‚‚H2O-Sm2 interactions. A more extended view of the hydrogen-bonding interactions in the ac plane is given in Figure 7b, which shows the hydrogen-bonding interactions of the coordinated bpy and bpyH+ ligands. These also link between Sm1 and Sm2 type cations through Sm1bpy‚‚‚H+bpy‚‚‚H2O-Sm2 and more direct Sm2-bpyH+‚‚‚bpySm1 hydrogen bonds at N‚‚‚N distances of 2.62 and 2.67 Å and N‚‚‚O distance of 2.73 Å. This 2-D sheet structure is coplanar, and there is little evidence of π-stacking interactions within the sheet, with centroid separations between adjacent bpy aryl rings ranging from 4.12 to over 6 Å. Overall, complex 6 has a 3-D hydrogen-bonded network structure with the 2-D sheets described above linked together in the b direction by hydrogen bonding and π-stacking bpy molecules. Typical hydrogen-bonding interactions between the sheets involve Sm-OH2‚‚‚bpy‚‚‚H2O-Sm and Sm-OH2‚‚‚ bpy‚‚‚EtOH‚‚‚H2O-Sm linkages with the bpy molecules forming struts between the 2-D layers. Note that not all bpy molecules show direct or indirect hydrogen-bonding links to two Sm centers, but the rows of bpy “struts” show extensive π-stacking interactions with adjacent aryl rings in coplanar and slipped arrangements with centroid separations ranging from 3.54 to 4.26 Å. The 3-D network has unidirectional channels

Figure 7. Structure of [Sm(H2O)5(bpy)2(EtOH)][Sm(H2O)6(bpyH)(EtOH)](bpyH)(bpy)10[Co(C2B9H11)2]8‚EtOH‚9(H2O) (6). (a) Coordination spheres and hydrogen bonding around complex cations; (b) hydrogen bonding between complex cations to form 2-D sheet structure.


Figure 8. Packing diagram for complex 6. W A 3D rotatable image of the packing structure in PDB format is available.

with a rectangular cross-section that are occupied by a twotiered zigzagging column of [Co(C2B9H11)2]- anions, similar to those observed in complexes 4 and 5. In complex 6, most C-H‚‚‚H-B contacts are beyond the usual distance expected for dihydrogen bonding, although there are isolated contacts at around 2 Å. Gd(III), Tb(III), and Ho(III) form isostructural complexes with the general formula [Ln(H2O)6(bpy)(bpyH0.5)]2[Ln(H2O)7(bpy)](bpyH)2(bpy)14[Co(C2B9H11)2]12‚n(EtOH)‚5(H2O) where Ln ) Gd (7), ) Tb (8), and ) Ho (9). Only the Tb complex 8 will

Cunha-Silva et al.

be discussed in detail, with the full crystal structure of complexes 7 and 9 available as Supporting Information.26 The complex [Tb(H2O)6(bpy)(bpyH0.5)]2[Tb(H2O)7(bpy)](bpyH)2(bpy)14[Co(C2B9H11)2]12‚8.5(EtOH)‚5(H2O) (8) has a particularly long, ca. 54 Å, unit cell length, and the given formula represents the asymmetric unit. There are three crystallographically independent Tb cations all with slightly distorted square antiprismatic geometries. Tb1 is within a mono-bipyridine complex [Tb(H2O)7(bpy)]3+ with Tb-O bond lengths ranging from 2.336(5) to 2.430(5) Å and a Tb-N bond length of 2.606(6) Å. Tb2 and Tb3 are within geometrically very similar bis-bipyridine [Tb(H2O)6(bpy)(bpyH0.5)]3.5+ complexes, where Tb-O bond lengths range from 2.358(4) to 2.460(4) Å and Tb-N distances are between 2.540(4) and 2.578(5) Å. The two bpy ligands are arranged in an approximately trans manner with N-Tb-N angles of 144.02(16) and 141.71(16)°. In each complex, one of the bpy molecules is partially protonated. The complex cations show extensive hydrogen-bonding interactions. [Tb1(H2O)7(bpy)]3+ cations form hydrogen-bonding pairs through interactions of the coordinated bpy of one complex and an aquo ligand of the other at an N‚‚‚O distance of 2.777 Å, Figure 9a. There are further hydrogen-bonding interactions to two uncoordinated bpy molecules, a bpyH+ cation, three EtOH molecules, and two water molecules, with O‚‚‚N distances from 2.682 to 2.759 Å and O‚‚‚O separations ranging from 2.484 to 2.710 Å, Figure 9a. The complex cations [Tb2(H2O)6(bpy)(bpyH0.5)]3.5+ and [Tb3(H2O)6(bpy)(bpyH0.5)]3.5+ show very similar hydrogen-bonding regimes, Figure 9b. Each hydrogen bonds to five bpy molecules via Tb-OH2‚‚‚N interactions (O‚‚‚N separations between 2.634 and 2.761 Å) all with similar orientations for each Tb center. Tb2 also hydrogen bonds to three ethanol molecules, while Tb3 hydrogen bonds to two ethanol molecules and one water (O‚‚‚O separations 2.642 to 2.930 Å). There are indirect hydrogen-bonding links between Tb2 and Tb3 through Tb-OH2‚‚‚bpy‚‚‚EtOH‚‚‚H2O-Tb interactions. The coordinated bpy ligands are also involved in hydrogen bonding, either to an uncoordinated bpyH+ cation (N‚‚‚N 2.697 and 2.653 Å), Figure 9b, or to a symmetry equivalent coordinated bpy of an adjacent complex cation. Hydrogen-bonding links form the sheet structure shown in Figure 9c. Rows of crystallographically equivalent Tb cations separated by 13.69 Å (the a unit cell length) are linked together in a coplanar manner by a variety of hydrogen-bonding

Figure 9. X-ray structure of [Tb(H2O)6(bpy)(bpyH0.5)]2[Tb(H2O)7(bpy)](bpyH)2(bpy)14[Co(C2B9H11)2]12‚8.5(EtOH)‚5(H2O) (8). Coordination and hydrogen-bonding environments of (a) Tb1, and (b) Tb2 and Tb3; (c) 2-D hydrogen-bonded sheet structure. EtOH shown in green. Symmetry operation for Tb1′: 2 - x, 1 - y, 1 - z.



Figure 10. Detail of one channel from the overall 3-D hydrogenbonded network structure of complex 8.

interactions. The coordinated bpy ligands of [Tb1(H2O)7(bpy)]3+ cations are orthogonal to the plane, while coordinated bpy ligands of [Tb2/3(H2O)6(bpy)(bpyH0.5)]3.5+ cations are within the plane. There are short linkages via one bpy of the type TbOH2‚‚‚bpy‚‚‚EtOH/H2O‚‚‚OH2-Tb, and longer linkages via two bpy molecules of the types Tb-bpy‚‚‚H+bpy‚‚‚OH2-Tb, and Tb-bpyH+‚‚‚bpy-Tb. This latter type occurs between two crystallographically equivalent [Tb2(H2O)6(bpy)(bpyH0.5)]3.5+ cations, as well as between two crystallographically equivalent [Tb3(H2O)6(bpy)(bpyH0.5)]3.5+ cations across inversion centers. Note that only one of each pair of two crystallographically equivalent [Tb(H2O)6(bpy)(bpyH0.5)]3.5+ cations will genuinely have a protonated bpyH+ ligand, but this is averaged in the crystal structure to give 50% occupancy at each H position. This is a very similar 2-D network to that seen in complex 6, with differences arising in the coordination spheres of the lanthanide cations. There is no evidence of significant π-stacking interactions within this sheet, with closest aryl centroid separations of 4.231 Å. As for complexes 2-6, the 2-D hydrogen-bonded sheets are linked together by further hydrogen-bonding interactions between water, EtOH, bpy, and cationic molecular fragments. The bpy molecules linking the 2-D sheets have roughly parallel orientations and show multiple π-stacking interactions with typical centroid separations between 3.544 and 4.251 Å. This forms a 3-D network structure with large unidirectional channels. One such channel is shown in detail in Figure 10. Note that the channels do not have a regular rectangular cross-section. The full packing diagram for complex 8 is shown in Figure 11, and, as for the other cobalticarborane containing complexes, channels are occupied by a zigzagging chain of [Co(C2B9H11)2]- anions. As for complex 4, the [Co(C2B9H11)2]- anions in complex 7 show C-H‚‚‚H-B dihydrogen interactions with closest contacts in the range 1.963 to 2.289 Å. All Ln/aquo/bpy/[Co(C2B9H11)2] complexes isolated and structurally characterized show closely related 3-D hydrogenbonded structures. The large, weakly coordinating [Co(C2B9H11)2]- anions do not interact directly or indirectly with the lanthanide complex cations; instead they occupy large rectangular channels, and indeed they template the formation of these channels. There are three structural types that correlate with different lanthanide cation sizes. The larger La(III) and Ce(III) form mono-bpy nine coordinate complex cations, and the intermediate-sized Sm(III) and smaller Tb(III) and Ho(III) form eight coordinate complexes with a mixture of one or two bpy ligands. The Sm(III) and Tb(III)/Ho(III) complexes are most

Figure 11. Unit cell diagram of complex 8 viewed down the b axis, with channels viewed from above highlighting the zigzagging nature of the array of guest [Co(C2B9H11)2]- anions within the channels. W A 3D rotatable image in PDB format is available.

closely related with very similar hydrogen-bonding patterns but show differences in the cation coordination environments. The sizes of the channels show some variation, with the complexes that have a higher [Co(C2B9H11)]- to Ln(III) ratio having larger channels. Complex 4 with three anions per La(III) has the shortest Ln‚‚‚Ln distances along the corners of the channels at 10.63 to 18.46 Å, while complexes 6 and 8 with four anions per Ln(III) have Ln‚‚‚Ln distances of 13.65 to 18.31 Å for 6 and 13.46 to 18.75 Å for 8. It is interesting to note that the structures reported here also bear some resemblance to the series of [Ln(4,4′-bipyridine-N,N′-dioxide)4]‚3[Co(C2B9H11)2] complexes reported by Schroder et al.5 These complexes are coordination networks where the eight coordinate Ln3+ cations are bridged by the 4,4′-bipyridine-N,N′-dioxide to form a 3-D network structure of R-Po-related 6-connected topology. Like the complexes reported herein, these structures have rectangular channels that are filled by [Co(C2B9H11)2]- anions; however, these channels run in two perpendicular directions, unlike the unidirectional channels found in complexes 4-9. Icosahedral Carborane-Containing Complexes. Experiments similar to those with lanthanide salts and [Co(C2B9H11)2]were also performed with the smaller icosahedral carbaborane anion (CB11H12)-. Crystalline material suitable for single-crystal X-ray analysis was obtained from reaction mixtures with M ) Y, Gd, and Tb. In all cases, however, the isolated product did


Cunha-Silva et al.

Conclusions

Figure 12. Hydrogen-bonded inclined ladder structure from the X-ray structure of complex [(bpyH)3(bpy)(CB11H12)3] (10).

Figure 13. Packing diagram of complex 10 viewed down the c axis, illustrating the layered nature of the structure. W A 3D rotatable image of the packing structure in PDB format is available.

not contain a metal ion, rather having the formula [(bpyH)3(bpy)(CB11H12)3] (10). The given stoichiometry represents the asymmetric unit of the crystal structure. Charge balance is achieved through the protonation of six bpy molecules, presumably from an ethanol proton source. Hydrogen positions were not located from the difference map, and which bpy molecules are protonated was determined from inter-bpy N‚‚‚N distances consistent with the formation of N-H‚‚‚N hydrogen bonding, and the assumption that no bpy molecules are doubly protonated. Complex 10 features a range of N-H‚‚‚N and C-H‚‚‚N hydrogen-bonding interactions that combine to give an infinite inclined ladder structure, shown in Figure 12. There are two types of connecting bpy/bpyH+ molecules: those that are simple linear connectors forming N-H‚‚‚N hydrogen bonds that constitute the “rungs” of the ladder; and the three-connecting “sides” of the ladder that hydrogen bond together through long C-H‚‚‚N interactions and to the linear connecting bpy/bpyH+ molecules through N-H‚‚‚N hydrogen bonds. N-H‚‚‚N interatomic distances range from 1.819 to 1.944 Å with corresponding N‚‚‚N distances 2.669 to 2.791 Å, while C-H‚‚‚N distances range from 2.384 to 2.425 Å with C‚‚‚N distances 3.227 to 3.265 Å. Within the ladder structure pairs of bpyH+ or bpy molecules form π-stacking interactions with one short and one long centroid separation, which range from 3.672 to 3.866 Å for the short interactions and 4.076 to 4.546 Å for the longer separations. Excluding bpy-containing metal complexes, there have been surprisingly few examples of N-H‚‚‚N hydrogen bonding in bpyH+ compounds, with known examples forming simple linear chain structures.31 Most other known examples of organic hydrogen-bonded complexes of bpyH+ have hydrogen-bonding interactions between the bpyH+ and counteranions.32 The hydrogen-bonded ladders form layers throughout the structure with adjacent layers interacting via edge-to-face C-H‚‚‚π interactions. Layers of bipy/bipyH+ are separated by layers of (CB11H12)- anions, Figure 13. There are no close C-H‚‚‚H-B distances between (CB11H12)- anions, indicating that there is no dihydrogen bonding in this complex.

Previously reported examples of lanthanide ion/bpy hydrogenbonded systems have had network structures without significant channels or cavities, largely due to interpenetration or selfcatenation. In many of these cases, the anion coordiates to the lanthanide cation. Use of the large [Co(C2B9H11)2]- anion, which does not interact directly with the lanthanide cation, templates a 3-D hydrogen-bonded structure with large rectangular and unidirectional channels, which effectively prevents any occurrence of interpenetration. Minor variations occur in these complexes according to the size of the lanthanide cation. Similar but smaller channels are stabilized by bpy guests in chloride complexes where additional waters molecules have also crystallized in the complex, which provide multiple additional hydrogen-bonding sites. The (CB11H12)- anion, on the other hand, appears to have the wrong steric properties to stablize a 3-D hydrogen-bonded [Ln(H2O)n(bpy)m]/bpy/H2O network of the type seen for complexes 4-9. (CB11H12)- is too large to be accommodated in the channels observed for the chloride complexes 2 and 3 but too small for the channels of complexes 4-9. Given the range of anionic carbaboranes available,33 it can be expected that the exploration this Ln/aquo/bpy system with other carbaborane anions will yield numerous interesting structural and network variations in the future. Acknowledgment. We thank the Fundac¸ a˜o para a Cieˆncia e a Tecnologia, Ministe´rio da Cieˆncia, Tecnologia e Ensino Superior, Portugal, for a fellowship for L.C.S. (SFRH/BPD/ 14410/2003), the EPSRC for equipment funding (GR/R61949/ 01), and the University of Leeds for additional funding. Supporting Information Available: Crystallographic information (CIF files) for complexes 2-10 are available free of charge via the Internet at http://pubs.acs.org.

References (1) (a) Burrows, A. D. Struct. Bond. 2004, 108, 55. (b) Desiraju, G. R. Angew. Chem., Int. Ed. Engl. 1995, 34, 2311. (c) Subramanian, S.; Zaworotko, M. J. Coord. Chem. ReV. 1994, 137, 357. (d) Aakeroy, C. B.; Seddon, K. R. Chem. Soc. ReV. 1993, 22, 397. (2) (a) Brammer, L. Chem. Soc. ReV. 2004, 33, 476. (b) Beatty, A. M. Coord. Chem. ReV. 2003, 246, 131. (c) Aakeroy, C. B.; Beatty, A. M. Aust. J. Chem. 2001, 54, 409. (d) Braga, D.; Grepioni, F. Acc. Chem. Res. 2000, 33, 601. (3) Westcott, A.; Whitford, N.; Hardie, M. J. Inorg. Chem. 2004, 43, 3663. (4) (a) Hardie, M. J.; Sumby, C. J. Inorg. Chem. 2004, 43, 6872. (b) Malic, N.; Nichols, P. J.; Raston, C. L. Chem. Commun. 2002, 16. (c) Hardie, M. J.; Raston, C. L. Cryst. Growth Des. 2001, 1, 53. (d) Hardie, M. J.; Raston, C. L. Angew. Chem., Int. Ed. 2000, 39, 3835. (5) Long, D.-L.; Blake, A. J.; Champness, N. R.; Wilson, C.; Schroder, M. Angew. Chem., Int. Ed. 2001, 40, 2444. (6) (a) Ahmad, R.; Dix, I.; Hardie, M. J. Inorg. Chem. 2003, 42, 2182. (b) Hardie, M. J.; Raston, C. L.; Salinas, A. Chem. Commun. 2001, 1850. (7) For review see Fox, M. A.; Hughes, A. K. Coord. Chem. ReV. 2004, 248, 457. (8) For example Hill, R. J.; Long, D.-L.; Champness, N. R.; Hubberstey, P.; Schroder, M. Acc. Chem. Res. 2005, 38, 335. (9) (a) Weakley, T. J. R. Acta Crystallogr. Sect. C 1989, 45, 525. (b) Bukowska-Strzyzewska, M.; Tosik, A. Inorg. Chim. Acta 1978, 30, 189. (10) Weakley, T. J. R. Inorg. Chim. Acta 1984, 95, 317. (11) Al-Rasoul, K. T.; Weakley, T. J. R. Inorg. Chim. Acta 1982, 60, 191. (12) Al-Rasoul, K. T.; Drew, M. G. B. Acta Crystallogr., Sect. C 1987, C43, 2081. (13) Krishnamohan Sharma, C. V.; Rogers, R. D. Chem. Commun. 1999, 83. (14) Weakley, T. J. R. Inorg. Chim. Acta 1982, 63, 161.

Hydrogen-Bonded 3-D Network Structures (15) Laing, H.; Liang, F.-P.; Chen, Z.-L.; Hu, R.-X.; Yu, K.-B. J. Ind. Chem. Soc. 2001, 78, 438. (16) (a) Bukowska-Strzyzewska, M.; Tosik, A. Acta Crystallogr., Sect. B 1982, 38, 950. (b) Bukowska-Strzyzewska, M.; Tosik, A. Acta Crystallogr. Sect. B 1982, 38, 265. (17) For example (a) Dong, Y. B.; Smith, M. D.; Layland, R. C.; zur Loye, H.-C. J. Chem. Soc., Dalton Trans. 2000, 775. (b) Tong, M.L.; Lee, H. K.; Chen, X.-M.; Huang, R.-B.; Mak, T. C. W. J. Chem. Soc., Dalton Trans. 1999, 3657. (c) Tong, M.-L.; Cai, J.-W.; Yu, X.-L.; Chen, X.-M.; Ng, S. W.; Mak, T. C. W. Aust. J. Chem. 1998, 51, 637. (d) Carlucci, L.; Ciani, G.; Proserpio, D. M.; Sironi, A. J. Chem. Soc., Dalton Trans. 1997, 1801. (e) Blake, A. J.; Hill, S. J.; Hubberstey, P.; Li, W.-S. J. Chem. Soc., Dalton Trans. 1997, 913. (18) Broker, G. A.; Klingshirn, M. A.; Rogers, R. D. J. Alloy Comput. 2002, 344, 123. (19) Czakis-Sulikowska, D. M.; Radwanska-Doczekalska, J. Rocz. Chem. 1976, 50, 2181. (20) Su, C.-Y.; Kang, B.-S.; Liu, H.-Q.; Wang, Q.-G.; Mak, T. C. W. Chem. Commun. 1998, 1551. (21) Xie, Z.; Jelinek, T.; Bau, R.; Reed, C. A. J. Am. Chem. Soc. 1994, 116, 1907. (22) Sheldrick, G. M. SHELXS-97, University of Go¨ttingen, Germany, 1997. (23) Sheldrick, G. M. SHELXL-97, University of Go¨ttingen, Germany, 1997. (24) For reviews see (a) Carlucci, L.; Ciani, G.; Proserpio, D. M. Coord. Chem. ReV. 2003, 246, 247. (b) Batten, S. R. CrystEngComm 2001, 3, 67. (25) These disordered Cl- positions are refined at 50% occupancy however are situated close to disordered water positions, also at 50% occupancy, that can affect similar hydrogen-bonding connectivity. (26) Unit cell parameters for complex 5: orthorhombic, a ) 21.0823(1), b ) 32.1080(3), c ) 35.4399(3) Å. Unit cell parameters for complex


(27) (28) (29)

(30) (31)

(32)

(33)

7: triclinic, a ) 13.6324(1), b ) 25.8631(2), c ) 54.1286(4) Å, R ) 97.360(1), β ) 95.380(1), γ ) 94.850(1)°. Unit cell parameters for complex 9: triclinic, a ) 13.7506(13), b ) 29.0051(25), c ) 54.6099(49) Å, R ) 97.532(4), β ) 95.524(4), γ ) 94.950(4)°. Janiak, C. J. Chem. Soc., Dalton Trans. 2000, 3885. Rosi, N. L.; Eddaoudi, M.; Kim, J.; O’Keeffe, M.; Yaghi, O. M. Angew. Chem., Int. Ed. 2002, 41, 284. (a) Custelcean, R.; Jackson, J. E. Chem. ReV. 2001, 101, 1968. (b) Crabtree, R. H.; Siegbahn, P. E. M.; Eisenstein, O.; Rheingold, A. L.; Koetzle, T. F. Acc. Chem. Res. 1996, 29, 348. Hardie, M. J.; Raston, C. L. Chem. Commun. 2001, 905. (a) Biradha, K.; Mahata, G. Cryst. Growth Des. 2005, 5, 49. (b) Hemamalini, M.; Muthiah, P. T.; Bocelli, G.; Cantoni, A. Acta Crystallogr., Sect. C 2004, 60, o284. (c) Xu, H.; Xie, J.; Ren, X.; Chen, Y. Acta Crystallogr., Sect. E 2002, 58, m750. (d) Iyere, P. A.; Boadi, W. Y.; Brooks, R. S.; Atwood, D.; Parkin, S. Acta Crystallogr., Sect. E 2002, 58, o825. For example (a) Farrell, D. M. M.; Ferguson, G.; Lough, A. J.; Glidewell, C. Acta Crystallogr., Sect. B 2002, 58, 530. (b) Kawata, S.; Adachi, K.; Sugiyama, Y.; Kabir, M. K.; Kaizaki, S. CrystEngComm 2002, 4, 496. (c) Reetz, M. T.; Hoger, S.; Harms, K. Angew. Chem., Int. Ed. Engl. 1994, 33, 181. For example (a) Jelinek, T.; Kilner, C. A.; Thornton-Pett, M.; Kennedy, J. D. Chem. Commun. 2001, 1790. (b) Nestor, K.; Stibr, B.; Kennedy, J. D.; Thornton-Pett, M.; Jelinek, T. Collect. Czech. Chem. Commun. 1992, 57, 1268. (c) Tsang, C.-W.; Yang, Q.; Sze, E. T.-P.; Mak, T. C. W.; Chan, D. T. W.; Xie, Z. Inorg. Chem. 2000, 39, 5851. (d) Mortimer, M. D.; Knobler, C. B.; Hawthorne, M. F. Inorg. Chem. 1996, 35, 5750. (e) Jelinek, T.; Baldwin, P.; Scheidt, W. R.; Reed, C. A. Inorg. Chem. 1993, 32, 1982.

CG050504E

Hydrogen-Bonded 3-D Network Structures of Lanthanide Aquo Ions

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