Cyano-Bridged Ln - American Chemical Society

CRYSTAL GROWTH & DESIGN

Cyano-Bridged LnIII-FeIII Complexes with Alterative Monosulfoxides as Blocking Ligands

2008 VOL. 8, NO. 8 2780–2792

Jian-Rong Li,†,‡ Wen-Tong Chen,‡ Ming-Liang Tong,§ Guo-Cong Guo,‡ Ying Tao,† Qun Yu,† Wei-Chao Song,† and Xian-He Bu*,† Department of Chemistry, Nankai UniVersity, Tianjin 300071, China, State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, China and MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, State Key Laboratory of Optoelectronic Materials and Technologies, School of Chemistry and Chemical Engineering, Sun Yat-Sen UniVersity, Guangzhou 510275, China ReceiVed October 17, 2007; ReVised Manuscript ReceiVed May 7, 2008

ABSTRACT: The self-assembly reactions of Ln(NO3)3 · aq (Ln ) La, Nd, Sm, Gd, Dy, Er, and Yb) with K3[Fe(CN)6] and three monosulfoxide ligands, dimethylsulfoxide (DMSO), diethylsulfoxide (DESO), and tetramethylene sulfoxide (TMSO), respectively, in water give rise to three series of 21 LnIII-FeIII complexes with ten kinds of compositions and structures: cis-[Fe(CN)4(µ-CN)2La(H2O)3(DMSO)3]n · nH2O (1), [Fe(CN)5(µ-CN)Ln(H2O)3(DMSO)4] · H2O [Ln ) Nd (2), Dy (5)], [Fe(CN)5(µCN)Ln(H2O)4(DMSO)3] · H2O [Ln ) Sm (3), Gd (4)], trans-[Fe(CN)4(µ-CN)2Ln(H2O)(DMSO)4]n [Ln ) Er (6), Yb (7)], [Fe(CN)6][La(H2O)6(DESO)3] (8), trans-[Fe(CN)4(µ-CN)2Ln(H2O)4(DESO)2]n · 2nH2O [Ln ) Nd (9), Sm (10), Gd (11), Dy (12), Er (13)], cis-[Fe(CN)4(µ-CN)2Yb(H2O)3(DESO)2]n · 2nH2O (14), [Fe(CN)5(µ-CN)Ln(H2O)3(TMSO)4] · 1.5H2O [Ln ) La (15), Nd (16), Gd (18)], cis-[Fe(CN)4(µ-CN)2Sm(H2O)4(TMSO)2]n (17) and cis-[Fe(CN)4(µ-CN)2Ln(H2O)3(TMSO)2]n · nH2O [Ln ) Dy (19), Er (20), Yb (21)]. The X-ray structure analyses show that 2-5, 15, 16, and 18 have cyano-bridged dinuclear structures; 1, 6, 7, 9-14, 17, and 19-21 form one-dimensional (1D) chain structures; but 8 is an ionic compound without cyano-bridging. For those complexes with 1D structure, there are also different configurations ascribed to the cis- or trans-coordination of bridging CNmoieties to the FeIII ion. The coordination of two CN- moieties to one LnIII ion is all-trans (N-Ln-N > 90°), mainly due to the steric effect of Fe(CN)63- entities. Further, such complexes feature extensive O-H · · · O and O-H · · · N hydrogen bonds that give rise to different three-dimensional (3D) supramolecular structures and stabilize and influence these structures. The differences of composition and structure of these complexes may be attributed to the structural differences of the three monosulfoxide blocking ligands, as well as different lanthanide ions to some extent, although a general rule (or underlying relationship) can not be deduced. Introduction There has been continued interest in the design and syntheses of molecule-based magnetic materials composed of cyanobridged bimetallic assemblies because of their remarkable magnetic, magnetic-optical, and optoelectronic properties.1 These studies have been mainly focused on transition metals and have led to some exciting results.1a–d,2 Although some advances in this field have also led to the isolation of some discrete or supramolecular polynuclear 4f-3d cyano-bridged complexes, systematic investigations are relatively rare.3 Indeed, it is known that the lanthanide ions (LnIII) exhibit large and anisotropic magnetic moments and can form hard magnets when incorporated into a solid. On the other hand, lanthanide ions have rich coordination chemistry with higher coordination numbers and greater coordination flexibility, which often lead to unanticipated but remarkable structures.4 The general synthetic approach for such metal assemblies is to utilize hexacyanometalate ions, such as [Fe(CN)6]3- and [Cr(CN)6]3-, as building blocks to react with lanthanide salts in a 1:1 stoichiometry, in the presence of an organic blocking ligand (BL). Since 1998, when the first dinuclear 4f-3d cyanide-bridged complex, [Sm(DMF)4(H2O)4Fe(CN)6] · H2O, with N,N-dimethylformamide (DMF) molecule as a blocking ligand was reported,5 complexes with various stages of hydration and organic blocking ligands have been investigated.3c,6,7 For example, very * To whom correspondence should be addressed. E-mail: buxh@ nankai.edu.cn. † Nankai University. ‡ State Key Laboratory of Structural Chemistry. § Sun Yat-Sen University.

Scheme 1

recently Diaz et al.7 studied systematically LnIII-FeIII, LnIII-CrIII complexes with DMF and bpy as blocking ligands, respectively, almost across all LnIII ions with the aim to explore the structures and magnetic interactions. On the basis of the literature, structural changes are observed when using different blocking ligands, solvents, or reaction stoichiometries or changing the specific lanthanide ion. To some extent, the suitable use of blocking organic ligands can adjust the compositions and structures of the resulting complexes, thereby giving various molecular architectures and magnetic phenomena. Thus, until now the major emphasis in this topic was the search for proper organic blocking ligands. Recently, we have designed and prepared several cyano-bridged LnIII-FeIII and LnIII-CoIII complexes with dimethylsulfoxide (DMSO) as blocking ligands, and investigated the nature of the magnetic interaction between the LnIII and FeIII ions in such complexes.8 As an expansion of this work, we synthesized systematically and characterized other 21 LnIII-FeIII complexes with three monosulfoxide compounds as blocking ligands (Scheme 1). LaIII, NdIII, SmIII, GdIII, DyIII, ErIII and YbIII were selected as representatives of the whole lanthanide series. Three monosulfoxide ligands, DMSO, dieth-

10.1021/cg7010277 CCC: $40.75  2008 American Chemical Society Published on Web 07/18/2008

Cyano-Bridged LnIII-FeIII Complexes

Crystal Growth & Design, Vol. 8, No. 8, 2008 2781

Table 1. Crystallographic Data and Structural Refinement Details for Complexes 1-7 complex formula fw crystal system space group a (Å) b (Å) c (Å) β (deg) V (Å3) Fc (g cm-3) Z µ (mm-1) reflns collected indep reflns parameters goodness-of-fit R1 [I > 2σ(I)] wR2 [all data]

1

2

3

4

5

6

7

C12H26LaFeN6O7S3 657.33 orthorhombic P212121 9.6217(2) 14.9689(2) 17.3965(4) 90 2505.55(8) 1.743 4 2.552 7543 4342 313 1.111 0.0231 0.056

C14H32NdFeN6O8S4 740.79 monoclinic P21 8.8623(3) 13.7085(5) 12.3108(3) 91.939(2) 1494.77(8) 1.646 2 2.526 4991 3858 328 1.008 0.0418 0.1045

C12H28SmFeN6O8S3 686.78 orthorhombic P212121 10.350(2) 13.752(3) 18.176(4) 90 2587.0(9) 1.763 4 3.095 24642 5853 330 1.162 0.0199 0.0437

C12H28GdFeN6O8S3 693.68 orthorhombic P212121 10.293(2) 13.720(3) 18.164(4) 90 2565.3(9) 1.796 4 3.418 24945 5851 330 1.137 0.0137 0.0318

C14H32DyFeN6O8S4 759.05 monoclinic P21/n 14.889(4) 13.674(3) 15.359(5) 108.45(1) 2966(1) 1.700 4 3.314 22228 5383 365 1.076 0.0363 0.1034

C14H26ErFeN6O5S4 709.76 monoclinic P21/n 8.4727(17) 20.320(4) 15.048(3) 99.01(3) 2558.8(9) 1.842 4 4.186 20777 4973 325 1.133 0.0233 0.0511

C14H26YbFeN6O5S4 715.54 monoclinic P21/n 8.4623(3) 20.2975(7) 15.0453(5) 99.0770(10) 2551.87(15) 1.862 4 4.573 4407 4407 299 0.968 0.0539 0.1365


8

9

10

11

12

13

14

C18H42LaFeN6O9S3 777.52 monoclinic P21/m 9.368(4) 18.641(8) 9.444(4) 100.486(7) 1621.5(11) 1.592 2 1.989 9330 3445 242 1.007 0.0417 0.0869

C14H32NdFeN6O8S2 676.67 monoclinic C2/c 18.130(10) 9.637(5) 16.431(9) 103.653(9) 2790(3) 1.611 4 2.554 7756 2863 181 0.964 0.0327 0.0605

C14H32SmFeN6O8S2 682.78 monoclinic C2/c 18.027(7) 9.645(4) 16.384(6) 103.690(5) 2767.7(18) 1.639 4 2.820 6336 2821 182 1.039 0.0262 0.0565

C14H32GdFeN6O8S2 689.68 monoclinic C2/c 17.975(9) 9.656(5) 16.401(9) 103.764(8) 2765(3) 1.657 4 3.098 7703 2829 182 1.036 0.0185 0.0415

C14H32DyFeN6O8S2 694.93 monoclinic C2/c 17.855(4) 9.630(2) 16.344(3) 103.80(3) 2729.1(9) 1.691 4 3.446 10227 2487 182 1.103 0.0153 0.0380

C14H32ErFeN6O8S2 699.69 monoclinic C2/c 17.824(6) 9.639(3) 16.383(5) 103.982(5) 2731.5(16) 1.701 4 3.780 7626 2798 182 1.045 0.0253 0.0536

C14H30YbFeN6O7S2 687.45 monoclinic P21/n 10.573(4) 19.930(6) 12.506(4) 97.641(5) 2611.9(15) 1.748 4 4.315 13703 4857 357 1.040 0.0380 0.0713


15

16

17

18

19

20

21

C22H41LaFeN6O8.5S4 848.61 monoclinic P21/c 13.31150(10) 14.4543(2) 18.30690(10) 91.90 3520.47(6) 1.601 4 1.896 10235 6102 432 0.764 0.0497 0.1371

C22H41NdFeN6O8.5S4 853.94 monoclinic P21/c 13.162(3) 14.356(3) 18.139(4) 91.95(3) 3425.5(12) 1.656 4 2.218 30844 7720 432 1.035 0.0576 0.1256

C14H24SmFeN6O6S2 642.71 orthorhombic Pnma 13.1078(8) 13.9000(8) 13.0177(8) 90 2371.8(2) 1.800 4 3.279 6520 2166 167 1.140 0.0249 0.0644

C22H41GdFeN6O8.5S4 866.95 monoclinic P21/c 13.1631(2) 14.32570(10) 18.1284(3) 91.8150(10) 3416.77(8) 1.685 4 2.645 10151 5916 432 0.713 0.0416 0.1122

C14H24DyFeN6O6S2 654.86 orthorhombic Pnma 12.8739(19) 14.308(2) 12.9221(19) 90 2380.3(6) 1.827 4 3.939 2940 2821 178 0.810 0.0457 0.0867

C14H24ErFeN6O6S2 659.62 orthorhombic Pnma 12.8367(2) 14.2948(4) 12.8653(4) 90 2360.76(11) 1.856 4 4.362 7135 2178 178 1.016 0.0520 0.1310

C14H24YbFeN6O6S2 665.40 orthorhombic Pnma 12.815(3) 14.302(3) 12.845(3) 90 2354.3(8) 1.877 4 4.781 16709 2259 195 1.033 0.0534 0.1286

ylsulfoxide (DESO), and tetramethylene sulfoxide (TMSO), are structurally closely related to each other, but with different sizes and shapes of alkyl groups. By carrying out this work, we are trying to explore the influences of the blocking ligands and the lanthanide ions on the complex compositions and structures that combine elements of design toward crystal engineering and the study of magnetic properties. Herein, we report the syntheses and crystal structures of such complexes, as well as a general

comparison dicussion based on modifing structures by the alteration of blocking ligands and lanthanide ions. Experimental Section Elemental analyses (C, H, and N) were carried out with a PerkinElmer 240C analyzer. IR spectra were measured on a Tensor 27 OPUS (Bruker) FT-IR spectrometer with KBr pellets.

2782 Crystal Growth & Design, Vol. 8, No. 8, 2008

Li et al.

Figure 1. (a) 1D chain structure of 1 with hydrogen atoms omitted (symmetry code: A, 1 + x, y, z; B, x - 1, y, z). (b) Local hydrogen-bonding linkages (symmetry code: A, -3/2 - x, -y, z -1/2; B, x -1/2, 1/2 - y, -z; C, -1 - x, y -1/2, 1/2 - z; D, -3/2 - x, -y, 1/2 + z; E, x - 1, y, z; F, 1/2 + x, 1/2 - y, - z; G, -1 - x, 1/2 + y, 1/2 -z; H, 1 + x, y, z). (c) 3D hydrogen-bonded framework. Table 4. Selected Bond Lengths (Å) and Angles (deg) for 1a La(1)-O(1) La(1)-O(2) La(1)-O(3) La(1)-O(1W) La(1)-O(2W) La(1)-O(3W) La(1)-N(1) La(1)-N(6A) N(1)-La(1)-N(6A) C(6)-Fe(1)-C(1) C(1)-N(1)-La(1) C(6)-N(6)-La(1B) N(1)-C(1)-Fe(1) N(6)-C(6)-Fe(1) a

2.4350(12) 2.4331(13) 2.4121(11) 2.5256(12) 2.5468(12) 2.5429(12) 2.6904(15) 2.6879(13) 145.34(4) 94.06(7) 173.24(14) 141.57(12) 176.23(15) 173.75(15)

Symmetry code: A, x + 1, y, z; B, x - 1, y, z

Preparations of the Complexes. All chemicals and solvents used in the syntheses were of reagent grade and used without further purification. Ln(NO3)3 · nH2O compounds were obtained by the reaction of lanthanide oxide (>99.9%) and nitrate acid. DMSO and TMSO were purchased from Aldrich. DESO was synthesized by oxidizing diethylsulfur using concentrated nitric acid. Safety note: Cyanide salts are toxic and should be handled with caution. All complexes were prepared using the similar procedure as follows. To a solution of Ln(NO3)3 (0.2 mmol) in H2O/DMSO, H2O/DESO, or H2O/TMSO (3 mL, about 2:1 volume ratio) was slowly added an equal molar amount of K3[Fe(CN)6] in 4 mL of water with stirring, and an orange solid soon precipitated. The resulting solution was continuously stirred for 20 min and then filtered. The filtration was left to stand, and the solvents were evaporated at room temperature. Orange prism crystals were collected after about 2 weeks and washed with a little water and methanol. cis-[Fe(CN)4(µ-CN)2La(H2O)3(DMSO)3]n · nH2O (1). Yield ∼50%. Anal. Calcd for C12H26LaFeN6O7S3 (657.31): C, 21.93; H, 3.99; N, 12.79. Found: C, 21.71; H, 4.06; N, 12.94. IR (cm-1): 3387s, 3022m, 2317w, 2117s, 1662m, 1642m, 1405m, 1319m, 1022s, 957s, 715m. [Fe(CN)5(µ-CN)Ln(H2O)3(DMSO)4] · H2O. For 2, Ln ) NdIII. Yield ∼50%. Anal. Calcd for C14H32NdFeN6O8S4 (740.77): C, 22.70;

H, 4.35; N, 11.34. Found: C, 22.52; H, 4.28; N, 11.47. IR (cm-1): 3339m, 3039w, 2293w, 2115s, 1660m, 1630m, 1422m, 1322m, 1005s, 964m, 724w. For 5, Ln ) DyIII. Yield ∼52%. Anal. Calcd for C14H32DyFeN6O8S4 (759.03): C, 22.15; H, 4.25; N, 11.07. Found: C, 22.39; H, 4.48; N, 10.99. IR (cm-1): 3163m, 3015m, 2307w, 2116s, 1679m, 1653w, 1413m, 1317m, 1003s, 961m, 718m. [Fe(CN)5(µ-CN)Ln(H2O)4(DMSO)3] · H2O. For 3, Ln ) SmIII. Yield ∼50%. Anal. Calcd for C12H28SmFeN6O8S3 (686.78): C, 20.99; H, 4.11; N, 12.24. Found: C, 21.17; H, 4.28; N, 11.99. IR (cm-1): 3196m, 3031w, 2309w, 2130s, 1684m, 1627m, 1419m, 1321m, 1015s, 957w, 944m, 718m. For 4, Ln ) GdIII. Yield ∼50%. Anal. Calcd for C12H28GdFeN6O8S3 (693.67): C, 20.78; H, 4.07; N, 12.12. Found: C, 20.57; H, 4.24; N, 12.39. IR (cm-1): 3177m, 3002w, 2309w, 2132s, 1683m, 1626m, 1419m, 1320m, 1016s, 988m, 959m, 945m, 718m. trans-[Fe(CN)4(µ-CN)2Ln(H2O)(DMSO)4]n. For 6, Ln ) ErIII. Yield ∼45%. Anal. Calcd for C14H26ErFeN6O5S4 (709.74): C, 23.69; H, 3.69; N, 11.84. Found: C, 23.47; H, 3.51; N, 11.58. IR (cm-1): 3196m, 3015m, 2319w, 2138s, 1683m, 1418m, 1318m, 1003s, 962m, 940m, 718w. For 7, Ln ) Yb. Yield ∼40%. Anal. Calcd for C14H26YbFeN6O5S4 (715.52): C, 23.50; H, 3.66; N, 11.75. Found: C, 23.34; H, 3.71; N, 11.40. IR (cm-1): 3177m, 3016m, 2319w, 2131s, 1683m, 1413m, 1318m, 1003s, 962m, 943m, 717w. [Fe(CN)6][La(H2O)6(DESO)3] (8). Yield ∼40%. Anal. Calcd for C18H42LaFeN6O9S3 (777.50): C, 27.81; H, 5.44; N, 10.81. Found: C, 27.43; H, 5.52; N, 10.56. IR (cm-1): 3201m, 3043m, 2289w, 2155s, 1674m, 1403m, 1298m, 1007s, 957m, 926m, 707w. trans-[Fe(CN)4(µ-CN)2Ln(H2O)4(DESO)2]n · 2nH2O. For 9, Ln ) NdIII. Yield ∼50%. Anal. Calcd for C14H32NdFeN6O8S2 (676.65): C, 24.85; H, 4.77; N, 12.42. Found: C, 24.75; H, 4.83; N, 12.31. IR (cm-1): 3492m, 3215m, 2982w, 2320w, 2142s, 2122s, 1629m, 1456m, 1383m, 1256w, 1015s, 973m, 695m. For 10, Ln ) SmIII. Yield ∼56%. Anal. Calcd for C14H32SmFeN6O8S2 (682.77): C, 24.63; H, 4.72; N, 12.31. Found: C, 24.88; H, 4.59; N, 12.44. IR (cm-1): 3535m, 3216m, 2986w, 2320w, 2144s, 2123s, 1634m, 1457m, 1383m, 1251w, 1018s, 982m, 659m. For 11, Ln ) GdIII. Yield ∼50%. Anal. Calcd for C14H32GdFeN6O8S2 (689.66): C, 24.38; H, 4.68; N, 12.19. Found: C, 24.08; H, 4.47; N, 12.00. IR (cm-1): 3532m, 3215m, 2987w, 2320w, 2145s, 2123s, 1635m, 1458m, 1383m, 1251w, 1027s, 982m, 659m. For 12, Ln ) DyIII. Yield ∼45%. Anal. Calcd for C14H32DyFeN6O8S2 (694.91): C, 24.20; H, 4.64; N, 12.09. Found: C, 24.04; H, 4.85; N, 11.98. IR (cm-1): 3529m, 3215m, 2988w, 2320w, 2145s, 2123s,


Crystal Growth & Design, Vol. 8, No. 8, 2008 2783 Table 5. Selected Bond Lengths (Å) and Angles (deg) for 2 and 5 complex Ln(1)-O(1) Ln(1)-O(2) Ln(1)-O(3) Ln(1)-O(4) Ln(1)-O(1W) Ln(1)-O(2W) Ln(1)-O(3W) Ln(1)-N(1) C(1)-N(1)-Ln(1) N(1)-C(1)-Fe(1)

Figure 2. (a) Dinuclear structure of 2 with hydrogen atoms omitted. (b) Local hydrogen-bonding linkages (symmetry code: A, 1 + x, y, 1 + z; B, 1 + x, y, z; C, 1 - x, y - 1/2, 2 - z; D, 1 - x, y + 1/2, 2 z; E, x - 1, y, z; F, x - 1, y, z - 1). (c) 3D hydrogen-bonded framework. 1634m, 1458m, 1384m, 1252w, 1030s, 982m, 659m. For 13, Ln ) ErIII. Yield ∼45%. Anal. Calcd for C14H32ErFeN6O8S2 (699.67): C, 24.03; H, 4.61; N, 12.01. Found: C, 24.35; H, 4.79; N, 11.82. IR (cm-1): 3521m, 3219m, 2989w, 2322w, 2142s, 2125s, 1636m, 1461m, 1380m, 1251w, 1032s, 987m, 658m. cis-[Fe(CN)4(µ-CN)2Yb(H2O)3(DESO)2]n · 2nH2O (14). Yield ∼45%. Anal. Calcd for C14H30YbFeN6O7S2 (687.44): C, 24.46; H, 4.40; N,

2

5

2.471(3) 2.491(3) 2.317(3) 2.372(3) 2.432(4) 2.385(3) 2.614(3) 2.598(3) 169.0(3) 174.9(6)

2.408(3) 2.383(3) 2.388(5) 2.382(3) 2.529(3) 2.452(3) 2.474(3) 2.602(4) 169.9(4) 175.1(4)

12.23. Found: C, 24.67; H, 4.53; N, 12.01. IR (cm-1): 3451m, 3014m, 2980w, 2302w, 2131s, 1625m, 1459m, 1381m, 1248w, 1021s, 988m, 633m. [Fe(CN)5(µ-CN)Ln(H2O)3(TMSO)4] · 1.5H2O. For 15, Ln ) LaIII. Yield ∼56%. Anal. Calcd for C22H41LaFeN6O8.5S4 (848.60): C, 31.14; H, 4.87; N, 9.90. Found: C, 30.98; H, 4.51; N, 10.01. IR (cm-1): 3397m, 2952w, 2309w, 2116s, 1640m, 1447m, 1385m, 1304w, 1099w, 1010m, 970s, 639m. For 16, Ln ) NdIII. Yield ∼48%. Anal. Calcd for C22H41NdFeN6O8.5S4 (853.93): C, 30.94; H, 4.84; N, 9.84. Found: C, 30.73; H, 4.62; N, 9.66. IR (cm-1): 3334m, 2947w, 2319w, 2116s, 1645m, 1447m, 1409m, 1304w, 1099w, 1011m, 970s, 640m. For 18, Ln ) GdIII. Yield ∼50%. Anal. Calcd for C22H41GdFeN6O8.5S4 (866.94): C, 30.48; H, 4.77; N, 9.69. Found: C, 30.22; H, 4.54; N, 9.51. IR (cm-1): 3385m, 2963m, 2320w, 2162m, 2129s, 1636m, 1447m, 1411m, 1306w, 1095w, 1006m, 987s, 594m. cis-[Fe(CN)4(µ-CN)2Sm(H2O)4(TMSO)2]n (17). Yield ∼50%. Anal. Calcd for C14H24SmFeN6O6S2 (642.71): C, 26.16; H, 3.76; N, 13.08. Found: C, 26.01; H, 3.57; N, 12.94. IR (cm-1): 3363m, 2963m, 2320w, 2160m, 2129s, 1646m, 1448m, 1411m, 1306w, 1094w, 984s, 592m. cis-[Fe(CN)4(µ-CN)2Ln(H2O)3(TMSO)2]n · nH2O. For 19, Ln ) DyIII. Yield ∼55%. Anal. Calcd for C14H24DyFeN6O6S2 (654.85): C, 25.68; H, 3.69; N, 12.83. Found: C, 25.51; H, 3.49; N, 13.02. IR (cm-1): 3356m, 2971m, 2311w, 2139m, 2116s, 1692m, 1641m, 1447m, 1409m, 1304w, 1098w, 1014m, 973s, 767m, 641m. For 20, Ln ) ErIII. Yield ∼50%. Anal. Calcd for C14H24ErFeN6O6S2 (659.61): C, 25.49; H, 3.67; N, 12.74. Found: C, 25.33; H, 3.74; N, 12.92. IR (cm-1): 3438m, 3134m, 2310w, 2140m, 2123s, 1694m, 1623m, 1445m, 1407m, 1304w, 1097w, 1020s, 989s, 768m, 668m. For 21, Ln ) YbIII. Yield ∼35%. Anal. Calcd for C14H24YbFeN6O6S2 (665.39): C, 25.27; H, 3.64; N, 12.63. Found: C, 25.51; H, 3.42; N, 12.83. IR (cm-1): 3439m, 3133m, 2310w, 2142m, 2123s, 1694m, 1622m, 1445m, 1407m, 1303w, 1097w, 1023s, 990s, 768m, 688m. X-ray Crystal Structure Determination. The intensity data collection for suitable crystals of complexes 1, 2, 7, 15, and 17-20 were taken on a Siemens SMART CCD diffractometer, and others on a Rigaku RAXIS-RAPID diffractometer with graphite-monochromated Mo KR radiation (λ ) 0.71073 Å) at 293(2) K. The program SAINT9 was used for integration of the diffraction profiles. All structures were solved by direct methods using the SHELXS program of the SHELXTL package and refined with SHELXL.10 Metal atoms were found from E-maps, and other non-hydrogen atoms were located in successive difference Fourier syntheses. The final refinement was performed by full matrix least-squares methods with anisotropic thermal parameters for non-hydrogen atoms on F2. Hydrogen atoms of sulfoxide ligands were included in the calculated positions and refined with isotropic thermal parameters riding in on the parent atoms. Except for 2, in which the water hydrogen atoms could not be located, the hydrogen atoms of water molecules of all complexes were located from difference Fourier maps and restrained to O-H ) 0.85(1) Å. In some complexes, sulfur atoms of ligands were disordered and refined using suitable modes with restraint. Selected crystallographic parameters are summarized in Tables 1–3, and further details containing bond parameters as a CIF file, as well as hydrogen bond parameters (Tables 1S, 3S-21S), are provided in Supporting Information.

Result and Discussion Synthesis and General Characterizations. In the investigations of cyano-bridged heterometallic complexes, most works


Li et al. Table 6. Selected Bond Lengths (Å) and Angles (deg) for 3 and 4 complex Ln(1)-O(1) Ln(1)-O(2) Ln(1)-O(3) Ln(1)-O(1W) Ln(1)-O(2W) Ln(1)-O(3W) Ln(1)-O(4W) Ln(1)-N(1) C(1)-N(1)-Ln(1) N(1)-C(1)-Fe(1)

3

4

2.357(2) 2.412(2) 2.384(2) 2.410(3) 2.533(3) 2.435(2) 2.403(2) 2.547(3) 161.4(3) 176.1(3)

2.3405(15) 2.3855(15) 2.3652(15) 2.3938(18) 2.5241(18) 2.4033(17) 2.3712(16) 2.5194(18) 160.86(18) 175.9(2)

similar reaction condition, by a solution (H2O and BL) selfassembly method, being widely used in other relative systems, and the reactive or structural control seems to be impossible in this system, as discussed below. Three structurally related monosulfoxide ligands, DMSO, DESO, and TMSO, were selected as organic blocking ligand, with the aim to explore the influences of them on the compositions and structures of the resulting complexes, considering their different sizes and shapes. The use of fewer BL (1:8 and 1:10 ratio with H2O) was initially expected to form higher dimensional complexes.

Figure 3. (a) Dinuclear structure of 3 with hydrogen atoms omitted. (b) Local hydrogen-bonding linkages (symmetry code, A, 1/2 - x, 1 - y, z - 1/2; B, 1 - x, y - 1/2, 3/2 - z; C, 3/2 - x, 1 - y, z - 1/2; D, x - 1/2, 3/2 + y, 1 - z; E, 1 - x, y + 1/2, 3/2 - z; F, x - 1, y, z). (c) 3D hydrogen-bonded framework.

are focused on the exploitation of coligands (or blocking ligands) and the exploration of the synthesis method. Recently, we reported several cyano-bridged LnIII-FeIII and LnIII-CoIII complexes with DMSO as blocking ligand.8 Such complexes were synthesized by a ball-milling method, which was estimated as a facile approach to effectively control the molar ratio of reactants, organic ligands and solvents. In contrast, the 21 LnIII-FeIII complexes reported herein were synthesized, in the

Figure 4. (a) 1D chain structure of 7 with hydrogen atoms omitted (symmetry code: A, 5/2 - x, 1/2 + y, 5/2 - z; B, 5/2 - x, y - 1/2, 5/2 - z). (b) Local hydrogen-bonding linkages (symmetry code: A, 3 - x, 2 - y, 2 - z; B, 2 - x, 2 - y, 2 - z; C, 1 + x, y, z; D, x - 1, y, z.). (c) 3D hydrogen-bonded framework.



Table 7. Selected Bond Lengths (Å) and Angles (deg) for 6 and 7a complex Ln(1)-O(1) Ln(1)-O(2) Ln(1)-O(3) Ln(1)-O(4) Ln(1)-O(1W) Ln(1)-N(1) Ln(1)-N(2) N1-Ln1-N2 C1-Fe1-C2 C(1)-N(1)-Ln(1) C(2A)-N(2)-Ln(1) N(1)-C(1)-Fe(1) N(2B)-C(2)-Fe(1)

6

7

2.298(3) 2.297(3) 2.295(2) 2.280(3) 2.305(2) 2.377(3) 2.371(3) 169.96(11) 175.10(13) 156.4(3) 161.7(3) 174.2(3) 176.0(3)

2.259(2) 2.290(2) 2.269(2) 2.255(3) 2.292(2) 2.356(3) 2.334(3) 169.74(10) 174.68(14) 156.1(3) 162.9(3) 174.8(3) 175.3(3)

a Symmetry code: A, -x + 5/2, y + 1/2, -z + 5/2; B, -x + 5/2, y - 1/2, -z + 5/2

However, orange precipitates but not crystals were always formed after several days. The XRPD characterization of the precipitate for selected complexes showed that the XRPD pattern is not the same as that simulated from X-ray single crystal data. We did not attempt to further determine the structures of such precipitates. For all of the crystal products 1-21, elemental analyses (C, H, and N) are basically consistent with the formulations demonstrated by the X-ray analysis. The IR spectra of such complexes show characteristic CtN stretching vibration bands in the range of 2100-2200 cm-1. In some cases, the splitting of ν(CtN) suggests the presence of both bridged and terminal CN- coordination. The strong bands near 1000 cm-1 are assigned to the SdO stretching vibrations of monosulfoxide ligands. In addition, such complexes are air-stable and insoluble in methanol and acetone. Crystal Structure Descriptions. cis-[Fe(CN)4(µ-CN)2La(H2O)3(DMSO)3]n · nH2O (1). Complex 1 crystallizes in the monoclinic system, space group P212121. The structure consists of a 1D wavy chain polymer (Figure 1a) being made by the cyano-bridged alternating array of Fe(CN)63- and La(H2O)3(DMSO)33+ fragments and crystallization water molecules. The LaIII ion is eight-coordinated by three DMSO molecules, three water molecules, and two nitrogen atoms of bridging cyanide ligands, to give a distorted square antiprism geometry. As listed in Table 4, three La-O(DMSO) lengths are almost equivalent with an average value of 2.427(1) Å, being shorter than La-O(H2O) (average bond distance 2.537(1) Å), indicating that DMSO has a stronger affinity to LaIII ion than that of H2O in this complex. Two La-N bonds are also almost equal with the average length of 2.689(2) Å. Six cyanide ligands coordinate the FeIII ion in a slightly distorted octahedral geometry, with similar Fe-C bond distances. Each Fe(CN)63entity bridges two LaIII ions using two cis cyanide ligands, but each LaIII ion contacts two Fe(CN)63- fragments in a trans fashion with a N-La-N angle of 145.34(4)°, giving a wavy chain. The intrachain distances between the two metal atoms across the cyanide bridges are 5.765(2) Å for La1 · · · Fe1 and 5.390(1) Å for La1B · · · Fe1. It is interesting that all FeIII and LaIII ions in the chain are coplanar and the Fe1-La1-Fe1A and La1-Fe1A-La1A angles are equivalent with a size of 119.7(3)°. Also, the La · · · La separation of 9.622(1) Å across one Fe(CN)63- fragment is equal to the Fe · · · Fe distance across one La(H2O)3(DMSO)33+. The bridging cyanides coordinate to the LaIII ions in a basically linear and a bend fashion with C1-N1-La1 and C6-N6-La1B angles of 173.24(14)° and 141.57(12)°, respectively. In addition, in 1, the chains are arranged parallelly along the a direction and linked to each other

Figure 5. (a) Structure of 8 with hydrogen atoms omitted (symmetry code: A, x, 3/2 - y, z; B, -1 - x, 2 - y, 2 - z). (b) Local hydrogenbonding linkages (symmetry code: B, x, 3/2 - y, z; C, x, 3/2 - y, 1 + z; D, x - 1, y, z; E, x - 1, 3/2 - y, z; F, x + 1, y, z). (c) 3D hydrogenbonded framework.

by hydrogen bonds between coordinated and crystallization water molecules and terminal nitrogen atoms of cyanides, as well as among water molecules to form a 3D supramolecular framework (Figure 1b and c). Hydrogen bond parameters are given in Table 1S of Supporting Information. Crystallization

2786 Crystal Growth & Design, Vol. 8, No. 8, 2008 Table 8. Selected Bond Lengths (Å) for 8 La(1)-O(1) La(1)-O(2) La(1)-O(1W) La(1)-O(2W) La(1)-O(3W) La(1)-O(4W)

2.429(3) 2.443(2) 2.673(3) 2.5805(19) 2.665(3) 2.608(2)

of 1 in a chiral space group can be ascribed to the arrangement of such chains, viz., molecular parking, but not the chain itself. [Fe(CN)5(µ-CN)Ln(H2O)3(DMSO)4] · H2O [Ln ) NdIII (2), DyIII (5). Complexes 2 and 5 have similar molecular structures but crystallize in different space groups, P21 for 2 and P21/n for 5. Attempts to refine 2 in a high symmetric space group (P21/n or P21/c) are unsuccessful. Indeed, the structure of 5 is also isomorphous to a reported complex [Fe(CN)5(µCN)Nd(H2O)3(DMSO)4] · H2O, a polymorph of 2 reported by us.8 The structures of them consist of a cyano-bridged array of Fe(CN)63- and Ln(H2O)3(DMSO)43+ fragments as a dinuclear molecule and a crystallization water molecule. As an example,

Figure 6. (a) Structure of 9 with hydrogen atoms omitted (symmetry code: A, 1 - x, y, 1/2 - z; B, 1/2 - x, 1/2 - y, - z; C, 3/2 - x, 1/2 - y, 1 - z). (b) Local hydrogen-bonding linkages (symmetry code: A, x - 1/2, 1/2 + y, z; B, 1/2 - x, 1/2 + y, 1/2 - z; C, x, y - 1, z; D, 1/2 - x, 1/2 - y, - z; E, 1 - x, y, 1/2 - z; F, x, - y, z - 1/2; G, 1 - x, -y, -z; H, x, 1 + y, z; I, 1/2 - x, -1/2 - y, -z; J, 1/2 - x, 3/2 - y, -z). (c) 3D hydrogen-bonded framework.

Li et al.

the structure of 2 is shown in Figure 2, and the selected bond distances and angles of both are given in Table 5. The LnIII ion eight-coordinates to four DMSO molecules, three water molecules, and one nitrogen atoms of bridging cyanide ligands, to give a distorted square antiprism geometry. The distances of Ln-O bonds range from 2.317(3) to 2.614(3) Å with an average of 2.440(3) Å for 2 and from 2.382(3) to 2.529(3) with an average of 2.431(1) Å for 5. The average Ln-O distance of 2 is longer than that of 5, being in accordance with the variation of the radius of the LnIII ions. Six cyanide ligands coordinate the FeIII ion in a distorted octahedral geometry, with normal Fe-C bond distances. Each Fe(CN)63- entity bridges a LnIII ions in a basically linear mode with C1-N1-Ln1 angles of 169.0(3)° for 2 and 169.9(4)° for 5, to form a dinuclear molecule (Figure 2a). The intramolecular Ln · · · Fe distance is 5.681(3) for 2 and 5.671(1) Å for 5. In the crystal structure, such dinuclear units and crystallization water molecules are linked together by O-H · · · N and O-H · · · O hydrogen bonds to form a 3D network (Figure 2b and c for 2; 5 has a different hydrogen-bonding linkage). Hydrogen bond parameters are listed in Tables 2S and 5S in Supporting Information. [Fe(CN)5(µ-CN)Ln(H2O)4(DMSO)3] · H2O [Ln ) SmIII (3), GdIII (4)]. Complexes 3 and 4 are isostructural and have a dinuclear structure similar to those of 2 and 5, with the only difference being in the coordination environments of LnIII ion. The molecular structure of 3 is shown in Figure 3a, and the selected bond distances and angles are listed in Table 6. In 3 and 4, the LnIII ion is also eight-coordinated, but to three DMSO and four water molecules, as well as one nitrogen atom of the bridging cyanide ligand. The distances of the Ln-O bonds range from 2.357(2) to 2.533(3) Å with an average of 2.419(2) Å for 3 and 2.3405(15) to 2.524(2) with an average of 2.398(2) Å for 4. However, there exists a Ln-O bond obviously longer than others, Ln(1)-O(2W) ) 2.533(3) Å in 3 and 2.524(2) Å in 4. The difference of average bond distances is coincident with the variation of the radius of the LnIII ions. The C1-N1-Ln1 angles are 161.4(3)° and 160.9(2)° for 3 and 4, respectively, and the intramolecular Ln · · · Fe distance is 5.547(2) Å for 3 and 5.514(3) Å for 4. Similarly, in the structure, these dinuclear molecules and crystallization water are contacted by hydrogen bonds to form a 3D network. The local hydrogen bond linkages are shown in Figure 3b for 3 and the 3D hydrogenbonded structure is in Figure 3c. Hydrogen bond parameters are listed in Tables 3S and 4S in Supporting Information. trans-[Fe(CN)4(µ-CN)2Ln(H2O)(DMSO)4]n [Ln ) ErIII (6), YbIII (7)]. Complexes 6 and 7 are isostructural and perform a 1D helical chain structure constructed by cyano-bridging Fe(CN)63- and Ln(H2O)(DMSO)43+ fragments. The structure of 7 is shown in Figure 4a, and the selected bond distances and angles of both are listed in Table 7. Different from those in 1-5, the LnIII in 6 and 7 is located in a slightly distorted pentagonal bipyramid coordination environment, formed by four DMSO molecules and one water molecules in equatorial plane and two nitrogen atoms in apical positions. In the equatorial plane, both the O-Ln-O angles and Ln-O distances fall in a narrow range, with the former being in 69.49(9)-75.60(10)° for 6 and 69.34(9)-75.20(9)° for 7, and the latter being 2.280(3)-2.305(2) Å for 6 and 2.255(3)-2.292(2) Å for 7. All of oxygen atoms are almost coplanar with a mean deviation of 0.140(3) Å for 6 and 0.1377(3) Å for 7, and the center LnIII ion deviates from this plane by 0.0318(2) Å for 6 and 0.0351(3) Å for 7. The trans axial coordination of two nitrogen atoms is also basically linear with the N-Ln-N angle of 167.0(1)° for 6 and 169.7(1)° for 7. The bridging cyanides coordinate to the



Table 9. Selected Bond Lengths (Å) and Angles (deg) for 9-13a complex Ln(1)-O(1) Ln(1)-O(1W) Ln(1)-O(2W) Ln(1)-N(1) C(1)-N(1)-Ln(1) N(1)-C(1)-Fe(1) N(1A)-Nd(1)-N(1) C(1B)-Fe(1)-C(1) a

9

10

11

12

13

2.3136(18) 2.4483(18) 2.5384(19) 2.5624(18) 177.27(17) 177.75(18) 142.13(8) 180.0(2)

2.2866(15) 2.4176(15) 2.5015(16) 2.5421(15) 177.54(15) 177.99(16) 141.93(7) 180.0(2)

2.2659(19) 2.397(2) 2.481(2) 2.524(2) 178.18(19) 177.5(2) 141.97(10) 180.0(2)

2.2343(17) 2.3643(17) 2.4501(19) 2.4969(19) 178.41(18) 177.74(19) 141.98(9) 180.0(2)

2.214(3) 2.341(3) 2.431(3) 2.480(3) 178.5(3) 177.9(3) 142.12(13) 180.0(2)

Symmetry code: A, -x + 1, y, -z + 1/2; B, -x + 1/2, -y + 1/2, -z Table 10. Selected Bond Lengths (Å) and Angles (deg) for 14a Yb(1)-O(1) Yb(1)-O(2) Yb(1)-O(1W) Yb(1)-O(2W) Yb(1)-O(3W) Yb(1)-N(1) Yb(1)-N(2A) C(2)-Fe(1)-C(1) N(2A)-Yb(1)-N(1) C(1)-N(1)-Yb(1) C(2)-N(2)-Yb(1B) N(1)-C(1)-Fe(1) N(2)-C(2)-Fe(1)

2.201(2) 2.212(2) 2.268(2) 2.277(2) 2.319(2) 2.396(2) 2.370(2) 91.61(11) 116.24(8) 173.8(2) 169.2(2) 177.9(3) 177.5(3)

a Symmetry code: A, x - 1/2, - y + 1/2, z - 1/2; B, x + 1/2, - y + 1/2, z + 1/2

Figure 7. (a) Structure of 14 with hydrogen atoms omitted (symmetry code: A, x - 1/2, 1/2 - y, z - 1/2; B, x + 1/2, 1/2 - y, z + 1/2). (b) Local hydrogen-bonding linkages (symmetry code: A, 1 + x, y, z; B, 3/2 - x, 1/2 + y, 1/2 - z; C, 5/2 - x, 1/2 + y, 1/2 - z; D, 1/2 + x, 1/2 - y, z - 1/2; E, 1/2 + x, 1/2 - y, 1/2 + z). (c) 3D hydrogenbonded framework.

LnIII ions in a bend fashion with C1-N1-Ln1 and C2A-N2-Ln1 angles of 156.4(3)° and 161.7(3)° for 6, and 156.1(3)° and 162.9(3)° for 7. Six cyanide ligands coordinate the FeIII ion in

a distorted octahedral geometry, with normal Fe-C bond distances. Each Fe(CN)63- entity links two LnIII ions through two trans cyanide ligands, and each LnIII ion contacts two Fe(CN)63- fragments also in a trans fashion, giving rise to a helical chain associated by a 21 screw axis paralleling to the b axis. Two Fe(CN)63- and two Ln(H2O)(DMSO)43+ finish one whorl with a screw-pitch of 18.256(3) Å for 6 and 18.183(2) Å for 7. The intrachain distances between the two metal atoms along cyanide bridges are 5.300(2) Å (6) and 5.296(2) Å (7) for Ln1 · · · Fe1, and 5.356(3) Å (6) and 5.349(2) Å (7) for Ln1B · · · Fe1.TheanglesofFe1-Ln1-Fe1AandLn1-Fe1A-Ln1A are 157.85(3)° and 153.12(3)° for 6, 157.91(2)° and 153.05(2)° for 7. In the chain, the adjacent Ln · · · Ln distance across Fe(CN)63- fragments is 10.364(2) and 10.352(3) Å, and the Fe · · · Fe distance across Ln(H2O)(DMSO)43+ fragments is 10.458(2) and 10.448(2) Å for 6 and 7, respectively. It is interesting that in the crystal of 6 and 7 there exist both leftand right-handed helical chains with equal numbers and related by a n slip plane with each other for the neighboring two. These chains arrange in a parallel manner along the b axis and connect with each other by O-H · · · N hydrogen bonds to form a 3D framework. Thus, the molecule crystallizes in an achiral P21/n space group. The local hydrogen bond linkages are shown in Figure 4b for 7 and the 3D hydrogen-bonded structure is in Figure 4c. Hydrogen bond parameters are listed in Tables 6S and 7S in Supporting Information. [Fe(CN)6][La(H2O)6(DESO)3] (8). Complex 8 is an ionic compound without cyano-bridging, and the structure consists of Fe(CN)63- and La(H2O)6(DESO)33+ fragments (Figure 5a), which lie on a crystallographic center of inversion and a symmetry plane, respectively, and are linked together by O-H · · · N hydrogen bonds. The coordination geometry around the LaIII ion is slightly disordered tricapped trigonal prism, formed by six water and three DESO molecules. As listed in Table 8, the La-O distances range from 2.429(3) to 2.673(3) Å, with La-O(DESO) bonds being shorter than La-O(H2O). Three DESO molecules coordinate LaIII ion in a cis fashion,


Li et al. Table 11. Selected Bond Lengths (Å) and Angles (deg) for 15, 16, and 18 complex Ln(1)-O(1) Ln(1)-O(2) Ln(1)-O(3) Ln(1)-O(4) Ln(1)-O(1W) Ln(1)-O(2W) Ln(1)-O(3W) Ln(1)-N(1) C(1)-N(1)-Ln(1) N(1)-C(1)-Fe(1)

Figure 8. (a) Structure of 15 with hydrogen atoms omitted. (b) Local hydrogen-bonding linkages (symmetry code: A, 1 - x, 1/2 + y, 1/2 z; B, 1 - x, y - 1/2, 1/2 - z; C, x, -3/2 - y, 1/2 - z; D, x, y - 1, z; E, x, 3/2 - y, z - 1/2; F, x, 1 + y, z). (c) 3D hydrogen-bonded framework.

lying in the same side. Furthermore, in the crystal, a 3D supramolecular framework is formed by the hydrogen bond interactions between coordinated water and nitrogen atoms of cyanide ligand (Figure 5b and c); hydrogen bond parameters are listed in Table 8S in Supporting Information. trans-[Fe(CN)4(µ-CN)2Ln(H2O)4(DESO)2]n · 2nH2O [Ln ) NdIII (9), SmIII (10), GdIII (11), DyIII (12), ErIII (13)]. Complexes 9-13 are isostructural and have a zigzag chain structure (Figure 6a based on 9), being different from those of 1, 6, and 7 described above. Selected bond distances and angles are listed

15

16

18

2.425(7) 2.456(5) 2.487(5) 2.503(6) 2.553(7) 2.540(5) 2.553(5) 2.653(8) 167.2(7) 177.3(8)

2.370(5) 2.398(4) 2.438(4) 2.423(5) 2.493(5) 2.477(4) 2.490(4) 2.550(5) 167.7(5) 177.4(5)

2.317(6) 2.353(5) 2.399(5) 2.373(6) 2.423(6) 2.422(5) 2.444(6) 2.496(6) 168.3(6) 176.2(7)

in Table 9. The structure comprises 1D trans-[Fe(CN)4(µCN)2Ln(H2O)4(DESO)2]n entities and crystallization water molecules. The LnIII ion located on a 2-fold axis is eightcoordinated by two DESO, four water molecules, and two nitrogen atoms of the bridging cyanide ligands to give a distorted square antiprism geometry. Ln-O(H2O) bond distances are longer than that of Ln-(DESO) for each complex, with the similar situation found in that of 1. For the five complexes, the longest Ln-O and Ln-N distances correspond to the NdIII ion and the shortest ones to the ErIII, being in accordance with the variation of the radius of the LnIII ions. The FeIII ion resides in a centro-symmetric octahedral environment formed by six cyanide ligands. Each Fe(CN)63- entity links two Ln(H2O)4(DESO)2 fragments using two trans cyanide ligands, being different from that in 1 and similar to those in 6 and 7, and each LnIII ion bridges two Fe(CN)63- fragments also in a trans fashion with an N-Ln-N angle of 142.13(8)°, 141.93(7)°, 141.97(10)°, 141.98(9)°, and 142.12(13)°, for 9-13, respectively, giving a zigzag chain. The bridging cyanides coordinate to the LnIII ions in almost linear fashion with the C1-N1-Ln1 bond angle being 177.27(17)°, 177.54(15)°, 178.18(19)°, 178.41(18)°, and 178.5(3)° for 9-13, respectively. As in 1, FeIII and LnIII ions in the chain are coplanar, but different in the Fe-Ln-Fe and Ln-Fe-Ln angles, with the former being 142.97°, 142.82(2)°, 142.69(2)°, 142.61(2)°, and 142.54(3)o for 9-13, respectively, and the latter being all 180°. The intrachain Ln · · · Fe distance along cyanide bridges is 5.643(2), 5.618(2), 5.609(2), 5.578(2), and 5.569(3) Å, the Ln · · · Ln distance across one Fe(CN)63- fragment is 11.285(3), 11.235(2), 11.217(2), 11.156(2), and 11.137(3) Å, and the Fe · · · Fe distance across one Ln(H2O)4(DESO)23+ fragment is 10.701(3), 10.649(2), 10.628(2), 10.568(2), and 10.547(3) Å for 9-13, respectively. In the crystal structure, such 1D chains are parallel with each other and also linked by hydrogen bonds to form a 3D framework (Figure 6b and c for 9). Hydrogen bond parameters are given in Tables 9S-13S in Supporting Information. cis-[Fe(CN)4(µ-CN)2Yb(H2O)3(DESO)2]n · 2nH2O (14). Complex 14 has a 1D chain structure in which Fe(CN)63- and Yb(H2O)3(DESO)23+ entities are bridged by the cyanide ligands. The structure is shown in Figure 7, and the selected bond parameters are listed in Table 10. Different from those in 9-13, the two fragments locate on the normal positions, and the chain is distorted. The YbIII ion is seven-coordinated by two DESO molecules, three water molecules, and two nitrogen atoms of bridging cyanide ligands to give a highly distorted pentagonal bipyramid coordination geometry. Yb-O(DESO) lengths of 2.201(2) and 2.212(2) Å are shorter than those of Yb-O(H2O) (from 2.268(2) to 2.319(2) Å). Six cyanide coordination to FeIII ion is normal. Each Fe(CN)63- fragment links two YbIII ions using two cis cyanide ligands, whereas each YbIII ion contacts two Fe(CN)63- fragments in a trans fashion with the N-Yb-N


Crystal Growth & Design, Vol. 8, No. 8, 2008 2789 Table 12. Selected Bond Lengths (Å) and Angles (deg) for 17a Sm(1)-O(1) Sm(1)-O(1W) Sm(1)-O(2W) Sm(1)-N(1) Sm(1)-N(2B) N(1)-Sm(1)-N(2B) C(1)-Fe(1)-C(2) C(1)-N(1)-Sm(1) C(2)-N(2)-Sm(1C) N(1)-C(1)-Fe(1) N(2)-C(2)-Fe(1)

2.310(2) 2.508(2) 2.443(2) 2.497(3) 2.552(3) 117.3(1) 90.7(1) 169.1(3) 172.8(3) 176.3(3) 179.0(3)

a Symmetry code: A, x, -y + 1/2, z; B, x + 1/2, y, -z - 3/2; C, x - 1/2, y, -z - 3/2

Figure 9. (a) Structure of 17 with hydrogen atoms omitted (symmetry code: A, x + 1/2, y, 1/2 - z; B, x, 1/2 - y, z). (b) Local hydrogenbonding linkages (symmetry code: A, x, 1/2 - y, z; B, x + 1/2, y, -z - 3/2; C, x - 1/2, y, -3/2 - z; D, x - 1/2, 1/2 - y, -3/2 - z; E, x + 1/2, 1/2 - y, -3/2 - z; F, x, y, z - 1; G, x, 1/2 - y, z - 1; H, 1/2 - x, 1 - y, z - 1/2; J, x, y, 1 + z; K, 1/2 - x, 1 - y, 1/2 + z; L, 1/2 - x, y - 1/2, 1/2 + z). (c) 3D hydrogen-bonded framework.

angle of 116.24(8)°, giving a distorted 1D chain. The bridging cyanides coordinate to the YbIII ions in a basically linear fashion withaC(1)-N(1)-Yb(1)angleof173.8(2)°andC(2)-N(2)-Yb(1B) angle of 169.2(2)°. FeIII and YbIII ions in the chain are arranged

in two lines, respectively. The intrachain distances between the two metal atoms along cyanide bridges are 5.468(2) Å for Yb1 · · · Fe1 and 5.425(2) Å for Yb1B · · · Fe1. The adjacent Yb · · · Yb distance is 8.179(2) Å, the Fe · · · Fe distance is 8.792(2) Å, and the Fe1-Yb1-Fe1A and Yb1-Fe1-Yb1B angles are 107.61(2)° and 97.32(2)°, respectively. In the crystal structure, these chains are arranged parallelly and connected with each other by hydrogen bonds to form a 3D supramolecular framework (Figure 7b and c). The hydrogen bond parameters are given in Table 14S in Supporting Information. [Fe(CN)5(µ-CN)Ln(H2O)3(TMSO)4] · 1.5H2O [Ln ) LaIII (15), NdIII (16), GdIII (18)]. Complexes 15, 16, and 18 are isostructural, and the structure is composed of dinuclear [Fe(CN)5(µ-CN)Ln(H2O)3(TMSO)4] molecules and crystallization water molecules. The molecular structure of 15 is shown in Figure 8a, and the selected bond distances and angles for the three complexes are listed in Table 11. The LnIII ion eightcoordinates with four TMSO molecules, three water molecules, and one nitrogen atom of bridging cyanide ligand. The distances of Ln-O(TMSO) are shorter than those of Ln-O(H2O) for each complex. The bridging cyanides coordinate to the LnIII ions in a basically linear fashion with a C-N-Ln angle of 167.2(7)°, 167.7(5)°, and 168.3(6)°. The intramolecular Ln · · · Fe distance is 5.690(7), 5.597(5), and 5.556(6) Å for 15, 16, and 18, respectively. The shortening of Ln · · · Fe distances from 15 to 18 is also consistent with the variation of the radius of the lanthanide ions. Similarly, these dinuclear molecules and crystallization water are linked together by hydrogen bonds to form a 3D framework. The local hydrogen bond linkages are shown in Figure 8b for 15, and the 3D hydrogen-bonded structure is in Figure 8c. Hydrogen bond parameters are listed in Tables 15S, 16S, and 18S in Supporting Information. cis-[Fe(CN)4(µ-CN)2Sm(H2O)4(TMSO)2]n (17). The structure of 17 consists of a 1D chain polymer (Figure 9a) similar to a reported cyanide-bridged Sm-Cr complex,11 being made by the cyano-bridged alternating array of Fe(CN)63- and Sm(H2O)4(TMSO)23+ fragments. It is interesting that the chain lies in a symmetry plane, with all FeIII and SmIII ions being coplanar. The SmIII ion is eight-coordinated by two TMSO molecules, four water molecules, and two nitrogen atoms of bridging cyanide ligands, to give a slightly distorted square antiprism geometry. As listed in Table 12, Sm-O(TMSO) bond lengths are shorter than those of Sm-O(H2O). Each Fe(CN)63entity contacts two SmIII ions using two cis cyanide ligands; however, each SmIII ion contacts two Fe(CN)63- fragments in a trans fashion with a N-Sm-N angle of 117.3(1)°, giving an impulse-type chain. The intrachain distances between the two metal atoms across cyanide bridges are 5.540(1) Å for Sm1 · · · Fe1 and 5.632(1) Å for Sm1A · · · Fe1, and the Fe-Sm-Fe and Sm-Fe-Sm angles are 105.69(1)° and 94.08(1)°, respectively. The Sm · · · Sm separation by one Fe(CN)63- fragment is 8.176(1)


Li et al. Table 13. Selected Bond Lengths (Å) and Angles (deg) for 19, 20, and 21a complex Ln(1)-O(1) Ln(1)-O(1W) Ln(1)-O(2W) Ln(1)-N(1) Ln(1)-N(2B) C(1)-Fe(1)-C(2) N(1)-Ln(1)-N(2B) C(1)-N(1)-Ln(1) C(2)-N(2)-Ln(1C) N(1)-C(1)-Fe(1) N(2)-C(2)-Fe(1)

19

20

21

2.221(6) 2.323(8) 2.357(6) 2.439(9) 2.420(9) 88.9(4) 113.3(3) 173.7(9) 175.3(9) 178.1(10) 177.2(9)

2.196(2) 2.275(2) 2.313(2) 2.391(3) 2.401(3) 90.1(2) 113.7(1) 172.0(3) 177.2(3) 179.5(3) 179.9(3)

2.211(2) 2.241(2) 2.306(2) 2.375(4) 2.405(3) 90.4(2) 112.7(1) 172.0(3) 179.9(3) 179.8(3) 178.4(3)

a Symmetry code: A, x, -y + 1/2, z; B, x + 1/2, y, -z - 3/2; C, x - 1/2, y, - z - 3/2

Scheme 2

Figure 10. (a) Structure of 19 with hydrogen atoms omitted (symmetry code: A, 1/2 + x, y, -3/2 - z; B, x, 1/2 - y, z). (b) Local hydrogenbonding linkages (symmetry code: A, 1/2 + x, y, -3/2 - z; B, 1/2 + x, 1/2 - y, -3/2 - z; C, x - 1/2, y, -3/2 - z; D, x - 1/2, 1/2 - y, -3/2 - z; E, x, y, 1 + z; F, 1/2 - x, 1 - y, z - 1/2; H, 1/2 - x, 1 y, 1/2 + z; I, x, 1/2 - y, z; J, 1/2 - x, y - 1/2, 1/2 + z). (c) 3D hydrogen-bonded framework.

Å and the Fe · · · Fe distance is 8.904(1) Å. The bridging cyanides coordinate to the SmIII ions in a basically linear fashion with

the C(1)-N(1)-Sm(1) and C(2)-N(2)-Sm(1B) angles being 169.1(3)° and 172.8(3)°, respectively. Another interesting feature is that in the chain one cyanide nitrogen atom of Fe(CN)63hydrogen bonds to two coordinated water molecules of intervallic Sm(H2O)4(TMSO)23+ fragments to form a ladder-like structure. In addition, in 17, the chains are arranged in a parallel manner along the crystallographic a direction and linked by hydrogen bonds to form a 3D framework, as shown in Figure 9b and c, with hydrogen bond parameters given in Table 17S in Supporting Information. cis-[Fe(CN)4(µ-CN)2Ln(H2O)3(TMSO)2]n · nH2O [Ln ) DyIII (19), ErIII (20), YbIII (21)]. Complexes 19-21 are isostructural and also form a 1D chain structure similar to that of 17 with the only difference being the number of coordinated water molecules, and containing crystallization water. The structure of 19 is shown in Figure 10, and the selected bond distances and angles for the three complexes are listed in Table 13. The LnIII is coordinated to two TMSO molecules, three water molecules, and two nitrogen atoms of bridging cyanides to give distorted pentagonal bipyramid coordination geometry. Fe(CN)63- entities link LnIII ions using two cis cyanide ligands, but SmIII ions link Fe(CN)63- fragments in a trans fashion with the N-Ln-N angle being 113.3(3)°, 113.7(1)°, and 112.7(1)°, respectively, to give an impulse-type chain. The intrachain distances between two metal ions along the cyanide bridges are 5.504(9) (19), 5.477(3) (20), and 5.462(3) Å (21) for Ln1 · · · Fe1, and 5.526(8) (19), 5.500(3) (20), and 5.486(2) Å (21) for

8 7 4/3/1 2/3/2 dinuclear 1D / cis 5.56: 5.53 5.50 5.48; 5.50 5.46; 5.49 / 113.3 113.7 112.7 8 2/4/2 1D cis 5.54; 5.63 117.3 7 8 2/3/2 4/3/1 1D dinuclear cis / 5.47; 5.43 5.69 5.60 116.2 / 8 2/4/2 1D trans 5.62 5.58 5.57 142.0 142.0 142.1 9 3/6/0 ionic / / 5.64 5.62 / 142.1 141.9 7 4/1/2 1D trans 5.29; 5.35 169.7 C.N. for Ln 8 8 8 8 BL/H2O/CN- around Ln 3/3/2 4/3/1 3/4/1 4/3/1 structure 1D dinuclear cis or trans for µ-CN-Fe cis / Ln-Fe length across CN (Å) 5.77; 5.39 5.68 5.55 5.51 5.67; 5.36 5.30 ∠N-Ln-N (°) 145.3 / 167.0

Dy Gd La Yb Er Dy Gd Sm Nd La Yb Er Dy Gd Sm Nd La Ln

complex (BL)

8-14 (DESO) 1-7 (DMSO)

Table 14. Comparisons of Compositions and Structural Characteristics for 1-21

Nd

Sm

15-21 (TMSO)

Er

Yb



Ln1A · · · Fe1. The Fe-Ln-Fe and Ln-Fe-Ln angles are 107.41(8)° and 92.61(8)° for 19, 107.47(3)° and 92.80(2)° for 20, and 107.47(3)° and 92.91(3)° for 21, respectively. The Ln · · · Ln distance through one Fe(CN)63- fragment is 7.976(7), 7.949(2), and 7.935(2) Å, and the Fe · · · Fe distance across one Ln(H2O)3(TMSO)23+ is 8.890(7), 8.850(3), and 8.827(2) Å for 19-21, respectively. The bridging cyanides coordinate to the LnIII ionsalsoinabasicallylinearfashionwiththeC(1)-N(1)-Ln(1) and C(2)-N(2)-Ln(1B) angles being 173.7(9)° and 175.3(9)°, 172.0(3)° and 177.2(3)°, and 172.0(3)° and 179.9(3)° for 19-21, respectively. In the crystal structure, these chains arrange paralleling along the a axis and connect with each other by O-H · · · N and O-H · · · O hydrogen bonds to form a 3D framework. The local hydrogen bond linkages are shown in Figure 10b on 19, and the 3D hydrogen-bonded structure is in Figure 10c. Hydrogen bond parameters are listed in Tables 19S-21S in Supporting Information. Structural Comparison and Discussion. The 21 complexes described above perform 10 types of compositions and structures (seven kinds of linkage modes as represented in Scheme 2), owing to the different ratios of coordinated water and sulfoxide ligands, and different bridging fashions of cyanide ligands. Table 14 also lists some structural features and parameters. For this system, it seems to be difficult to deduce an underlying relationship between the composition and structure of complex and used blocking ligand and lanthanide ion because most of other factors also have great effects. Namely, no general rule that controls the crystal structures could be deduced. For each system with the same blocking ligand, with the decrease of the ionic radius of LnIII from LaIII to YbIII, the coordination number lower, can be attributed to the steric hindrance of coordination groups around the metal center. Actually, the steric hindrance of blocking ligands pays the most important contribution to the structural differences of such complexes. In addition, the extensive H-bonding interactions should also be responsible for the molecular structures. It should also be pointed out that a polymorph of 2 can also be obtained by a ball-milling method.8 However, using this synthetic method, by tuning the dosage of blocking ligand DMSO, two NdIII-FeIII and SmIII-FeIII complexes with a 2D stairlike layer structure have been obtained.6d This indicates that, to some extent, the synthetic methods have great effect on the structure of products in this system. Conclusions In summary, we have synthesized 21 cyano-bridged LnIII-FeIII complexes with three structurally closely related monosulfoxide compounds as blocking ligands. X-ray diffraction analysis shows that such complexes have different compositions and structures, which to some extent can be attributed to the different sizes and shapes of three blocking ligands and different lanthanide ions, although a general opinion cannot be deduced, considering the complicacy of the complex formations in the self-assembly system. This work provides a start for next detailed magnetic investigations of these complexes. To date, the understanding of the magnetic interactions involving rareearth ions in molecular magnets is still a challenge, particularly when the contribution of the first-order orbital momentum is involved. Magnetic experiments are in progress for better understanding the nature of the 4f-3d magnetic interactions in the above-mentioned complexes. Acknowledgment. The authors are thankful for financial support from the 973 Program of China (2007CB815305), NSF


Li et al.

of China (no. 5067304 and 20531040), and NSF of Tianjin, China (07JCZDJC00500). Supporting Information Available: Hydrogen bond parameters and detailed crystallographic information files in CIF format. This material is available free of charge via the Internet at http://pubs.acs.org.

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CG7010277

Cyano-Bridged Ln - American Chemical Society

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