Supramolecular Design of Coordination Complexes of Silver(I) with

CRYSTAL GROWTH & DESIGN

Supramolecular Design of Coordination Complexes of Silver(I) with Polyimine Ligands: Synthesis, Materials Characterization, and Structure of New Polymeric and Oligomeric Materials

2003 VOL. 3, NO. 3 321-329

Goutam Kumar Patra and Israel Goldberg* School of Chemistry, Sackler Faculty of Exact Sciences, Tel Aviv University, 69978 Ramat Aviv, Tel Aviv, Israel Received January 27, 2003;

Revised Manuscript Received February 5, 2003

ABSTRACT: A series of new coordination polymers and oligomers of polyimine ligands with silver(I) ions have been synthesized and characterized by single-crystal X-ray diffraction studies, elemental analysis, IR, UV-Vis, and NMR spectroscopy. They represent discrete dinuclear Ag(I) complexes, one-dimensional polymers, and twodimensional polymeric assemblies, depending on the chosen type, functionality, and denticity of the bridging ligands. Trigonal, tetrahedral, and pseudo-tetrahedral, as well as the more common linear coordination motifs of the silver(I) ions, have been observed, demonstrating the high versatility in the supramolecular design of such hybrid organicinorganic materials. Introduction

Scheme 1

materials1

Crystal engineering of solid-state and designed construction of coordination polymers and oligomers, based on the interaction of metal ions with the organic ligands,2 is a popular area of current research3 that has grown tremendously in recent years. Such molecular assemblies include networks mimicking zeolites,4 materials exhibiting interesting properties of nonlinear optics,5 molecular recognition,6 and electrical conductivity,7 as well as new sensing devices.8 In hybrid organic-inorganic systems, the factors by which selfassembly is influenced mostly include coordination properties of the metal cations, functionality and denticity of the ligands,9 size and nature of the counterions,10 solvent system,11 the templates used,12 and acidity of the solution.12b To establish reliable synthetic and crystal engineering strategies for obtaining a desired species, a wide database of the experimental procedures and the preferred coordination motifs is required. It is of further interest to learn about how the molecular properties of the ligands affect the evolving supramolecular architectures. This study is part of our ongoing effort to design and characterize an extensive series of coordination polymers and oligomers, which consist of polyimine ligands and metal ion building blocks.13,14 Silver(I) ions play a central role in the formulation of such organicinorganic hydrid assemblies, since as soft acids they favor stable coordination to soft bases such as ligands containing sulfur and unsaturated nitrogen atoms.15 Here we describe a series of new coordination polymers and oligomers of Ag(I) with polyimine ligands of varying functionality and complexity, and evaluate the structural motifs that form in each case in relation to the molecular properties of the ligands. Some of the observed structures reveal unusual coordination modes. The ligands used, which were synthesized in this work, are shown in Scheme 1. * E-mail: [email protected]. Phone: +972-3-6409965. Fax: +972-3-6409293.

Ligands 1, 2, 5-8 are characterized by an approximate C2 symmetry. They were designed to contain readily accessible multiple (imino or amino) nitrogen donor sites on the periphery of the molecular framework. They thus provide excellent building blocks for the formulation of coordination polymers with the silver ions. Ligands 2, 3, 6 and 8 contain cyclohexyl or phenyl substituents on the central C-C bond, which constrain their possible conformation about this bond. Ligand 3 contains only inner ligating sites, while ligand 4 has C1 symmetry. Both are better suited for the construction of discrete entities. The coordination complexes referred to in this work include the polymeric arays [Ag(1)]n(NO3)n (1a), [Ag(2)]n(ClO4)n (2a), {[Ag3(5)2](ClO4)3}n (5a), [Ag(6)2]n(PF6)n (6a), [Ag(7)]n(ClO4)n (7a), and [Ag(8)2]n(ClO4)n (8a), as well as the oligomeric species [Ag(3)]2(BF4)2‚H2O (3a), and [Ag(4)]2(ClO4)2 (4a). Experimental Section General. All the reagents were procured commercially from Aldrich. Microanalyses were performed by Perkin-Elmer 2400II elemental analyzer and CE instruments. The melting point

10.1021/cg034011q CCC: $25.00 © 2003 American Chemical Society Published on Web 02/25/2003

322

Crystal Growth & Design, Vol. 3, No. 3, 2003

was determined by an electro-thermal IA9000 series digital melting point apparatus and is uncorrected. IR spectra (KBr disk) were recorded on a Nicolet Magna-IR spectrophotometer (series II), UV-Vis spectra on a Shimadzu UV-160A spectrophotometer, 1H and 13C NMR spectra by a Bruker DPX200 spectrometer. EI and CI mass spectra were on a VG Autospec M-250 instrument. Syntheses. [Ag(1)]n(NO3)n (1a). 0.21 g (1 mmol) of pyridine4-carbaldehyde azine (1), prepared by a reported literature procedure,16,17 was dissolved in 30 mL of methanol, and to this yellowish solution 0.170 g (1 mmol) of solid silver nitrate was added. The mixture was stirred at room temperature for 2 h to afford a yellow precipitate. It was filtered out, washed with few drops of methanol, and dried in vacuo over fused CaCl2. Yield was 0.23 g (60%). Single crystals suitable for X-ray analysis were grown by slow diffusion of methanol solution of the complex. Anal. found (calcd. for C12H10N4‚AgNO3): C, 38.02 (37.90); H, 2.61 (2.65); N, 18.53 (18.42)%. FTIR/cm-1 (KBr): 511s, 679s, 1240m, 1320vs. (NO3), 1425m, 1615vs. (CdN), 3446vb. 1H NMR [200 MHz, (CD3)2SO, TMS]: δ 8.75-8.72 (d, J ) 6 Hz, 4 H), 8.68 (s, 2 H), 7.82-7.79 (d, 4 H). UV-Vis λmax/ nm (CH3OH): 233. [Ag(2)]n(ClO4)n (2a). Benzil dihydrazone (0.24 g, 1 mmol), synthesized by a reported procedure,18 was dissolved in 40 mL of methanol. To this colorless solution, 0.21 g (1 mmol) of solid AgClO4 was added and dissolved with stirring. Stirring was continued for 1 h. Then the clear reaction mixture was kept in the refrigerator for 48 h. White crystalline solid, which were suitable for X-ray analysis, precipitated out. It was filtered off, washed with few drops of methanol, and dried in vacuo over fused CaCl2. Yield, 0.265 g (60%). Anal. found (calcd. for C14H14N4‚AgClO4): C, 37.68 (37.71); H, 3.22 (3.17); N, 12.68 (12.57)%. FTIR/cm-1 (KBr): 530m, 626s, 850ms, 948m, 1088vs. (ClO4), 1280m, 1334s, 1412s, 1556m, 1632vs. (CdN), 3353vb. 1H NMR [200 MHz, (CD ) SO, TMS]: δ 7.40-7.08 (m, 10 H), 3 2 6.65 (br, 2 H). UV-Vis λmax/nm (CH3OH): 398; 273. [Ag(3)]2(BF4)2‚H2O (3a). 0.445 g (1 mmol) of 2a was dissolved in 25 mL of methanol. To this solution, 5 mL water solution of 0.165 g (1.5 mmol) of sodium tetrafluoroborate was added dropwise with constant stirring. The reaction mixture was stirred at room temperature for 1 h then left in air for 2 h. White compound which was precipitated out was filtered, dried in vacuo over fused CaCl2, and recrystallized from acetonepetroleum ether (40-60 °C) to yield the white crystalline product. It was stored in vacuo over fused CaCl2. Yield, 0.275 g (27%). Single crystals suitable for X-ray analysis were grown by the direct diffusion of petroleum ether into the acetone solution of the complex. Anal. found (calcd. for 2C20H22AgN4BF4‚H2O): C, 45.95 (46.00); H, 4.53 (4.44); N, 10.68 (10.73)%. FTIR/cm-1 (KBr): 520m, 943s, 1085vs. (BF4), 1135m, 1335s, 1448s, 1581s, 1644vs. (CdN), 3335wb. 1H NMR [200 MHz, (CD3)2SO, TMS]: δ 7.65-7.60 (m, 5 H), 7.42-7.37 (m, 5 H), 1.94 (s, 12 H), 1.84 (s, 6 H). UV-Vis λmax/nm (/dm3 mol-1 cm-1)(CH3OH): 400 (250); 268 (11 600). N-(4-acetylpyridylidene)1,2-diamino 2-methylpropane (4). To 25 mL of anhydrous methanol 0.52 mL (5 mmol) of 1,2diamino 2-methyl propane and 1.1 mL (10 mmol) of 4-acetylpyridine was added. Then the reaction mixture was refluxed for 12 h maintaining dry condition. Then the solvent was evaporated to yield the light yellow liquid. Yield 0.72 g (75%). Anal. found (calcd. for C11H17N3): C, 69.15 (69.06); H, 8.81 (8.97); N, 22.05 (21.97)%. FTIR/cm-1 (KBr): 517m, 820s, 992m, 1320m, 1386vs, 1412s, 1556m, 1600vs (CdN), 1646m, 3390vb. 1H NMR [200 MHz, (CD ) SO, TMS]: δ 8.65-8.61 (d, 2 H), 3 2 7.66-7.61 (m, 2 H), 3.82 (s, methylene, 2 H), 1.31 (s, methyl, 6 H), 1.20 (s, methyl, 3 H). UV-Vis λmax/nm (/dm3 mol-1 cm-1) (CH3OH): 238 (12 660). [Ag(4)]2(ClO4)2 (4a). 0.19 g (1 mmol) of 4 was dissolved in 25 mL of acetonitrile. To this solution, 0.21 g (1 mmol) of solid AgClO4 was added and dissolved by stirring. Stirring was continued for another 1 h. Then it was left in air for 24 h. Colorless crystals separated out. It was filtered off and dried in vacuo over fused CaCl2. Yield 0.255 g (64%). Anal. found (calcd. for C11H17N3‚AgClO4): C, 33.21 (33.12); H, 4.26 (4.30); N, 10.63 (10.54)%. FTIR/cm-1 (KBr): 523m, 630s, 825s,

Patra and Goldberg 1093vs. (ClO4), 1328m, 1422s, 1608vs. (CdN), 1658m, 3400vb. 1 H NMR [200 MHz, (CD3)2SO, TMS]: δ 8.50-8.46 (d, J ) 8 Hz, 4 H), 7.80-7.74 (m, 4 H), 3.76 (s, methylene, 4 H), 1.32 (s, methyl, 6H) 1.20 (s, methyl, 3 H). UV-Vis λmax/nm (/dm3 mol-1 cm-1) (CH3OH): 235 (27 300). N,N’-bis(4-acetylpyridine)idene 1,3-diaminopropane (5). 4.20 mL (50 mmol) of 1,3-diaminopropane was taken in 75 mL of anhydrous methanol. To this methanol solution 11.02 mL (100 mmol) of freshly distilled 4-acetylpyridine was added dropwise with constant stirring. The reaction mixture was refluxed for 6 h in dry atmosphere. Then, the solvent was evaporated under reduced pressure to obtain yellow semisolid, which on recrystallization from diethyl ether gives light yellow solid. Yield, 8.40 g (60%); mp 56-58 °C. Anal. found (calc. for C17H20N4): C, 72.69 (72.82); H, 7.31 (7.20); N, 20.03 (19.99)%. CI-MS: m/z 281.2 (MH+, 98%). FTIR/cm-1 (KBr): 586m, 614w, 815s, 991m, 1054m, 1285s, 1317m, 1412s, 1544m, 1593vs, 1638vs, 1642vs (CdN), 2879w, 2933m, 3435wb. 1H NMR (200 MHz, CDCl3, TMS): δ 8.60 (d, 4 H), 7.61 (d, 4 H), 3.64 (t, 4 H), 2.21 (s, methyl, 6 H), 1.29 (t, 2H). 13C NMR (200 MHz, CDCl3, TMS): δ 163.48, 149.93, 146.63, 120.70, 50.05, 33.93, 15.18. UV-Vis λmax/nm (/dm3 mol-1 cm-1)(CH3OH): 264 (4 669); 232 (22 100). {[Ag3(5)2](ClO4)3}n (5a). To a methanol solution (20 mL) of 5 (0.28 g, 1 mmol) was added a methanol solution (5 mL) of AgClO4 (0.208 g, 1 mmol). The mixture was stirred at room temperature to afford a white precipitate. Stirring was continued for 1 h. Then, the off-white solid was collected by filtration and washed with a few drops of methanol and dried in vacuo over fused CaCl2. Yield: 0.250 g (42%). Anal. found (calc. for C17H20N4‚11/2AgClO4): C, 34.45 (34.50); H, 3.48 (3.41); N, 9.58 (9.47)%. Single crystals suitable for X-ray analysis were grown by direct diffusion of diethyl ether into a dilute acetonitrile solution of the complex. FTIR/cm-1 (KBr): 583w, 620s, 825vs, 1000m, 1078vs, 1113vs, 1143vs (ClO4), 1285m, 1411m, 1535m, 1590s, 1632vs (CdN); 3418vb. 1H NMR (200 MHz, (CD3)2SO, TMS): δ 8.63 (d, 4 H), 7.75 (d, 4 H), 3.62 (t, 4 H), 2.23 (s, methyl, 6 H), 1.24 (t, 2 H). UV-Vis λmax/nm (CH3OH): 266; 230. N,N’-bis(4-pyridyl)idene 1,2-diaminocyclohexane (6). Freshly distilled 1,2-diaminocyclohexane, 3.07 mL (25 mmol) and 4-pyridinecarboxaldehyde, 4.77 mL (50 mmol) were taken in 75 mL of anhydrous methanol. The reaction mixture was refluxed for 6 h maintaining dry condition. Then the solvent was evaporated under reduced pressure to obtain a light yellow semisolid, which on recrystallization from diethyl ether gives off-white solid. Yield, 4.75 g (65%); mp 132-134 °C. Anal. found (calc. for C18H20N4): C, 73.84 (73.93); H, 6.99 (6.90); N, 19.27 (19.17)%. EI-MS: m/z 292 (M+, 12%). FTIR/cm-1(KBr): 536m, 664m, split, 810vs, 868w, 991m, 1060m, 1230s, 1295w, 1320s, 1380s, 1405s, 1451 m, 1549vs, 1595vs, 1651vs (CdN), 2859m, 2923s, 3031w, 3417w. 1H NMR (200 MHz, CDCl3, TMS): δ 8.62 (d, 4 H), 8.15 (s, 2 H), 7.43 (d, 4 H), 3.46 (s, 2 H), 1.84 (br. 8 H). 13C NMR (200 MHz, CDCl3, TMS): δ 159.01, 150.20, 142.78, 121.65, 71.18, 32.45, 24.11. UV-Vis λmax/nm (/dm3 mol-1 cm-1)(CH3OH): 274 (5 775); 230 (35 090). [Ag(6)2]n(PF6)n (6a). 0.292 g (1 mmol) of 6 was dissolved in 50 mL of acetonitrile. To this solution 0.253 g (1 mmol) of solid AgPF6 was added and dissolved with stirring and the reaction mixture was stirred at room temperature for additional 1 h. The reaction mixture was kept in the refrigerator for overnight. White amorphous solid separated out. It was filtered off, washed with few drops of methanol, and dried in vacuo over fused CaCl2. Yield, 0.256 g (47%). Anal. Found (calc. for C18H20N4‚AgPF6): C, 39.56 (39.63); H, 3.59 (3.70); N, 10.39 (10.28)%. FTIR/cm-1 (KBr): 560s, 649m, 845vs (PF6) 994w, 1227m, 1404m, 1560s, 1601vs, 1643vs (CdN), 2862m, 2935s, 3434vb. 1H NMR (200 MHz, (CD3)2SO, TMS): δ 8.64 (d, 2 H), 8.58 (d, 2H), 8.47 (s, 1 H), 8.27 (s, 1 H), 7.68 (d, 2 H), 7.57 (d, 2H), 3.34 (s, 2 H), 1.68 (br. 8 H). UV-Vis λmax/nm (CH3OH): 270; 232. Single crystals suitable for X-ray analysis were grown (as an acetonitrile solvate) by the direct diffusion of diethyl ether into the acetonitrile solution of the complex. They were found to consist of the 2C18H20N4‚AgPF6 moieties. N,N’-bis(4-quinoline)idene ethylenediamine (7). 4.715 (30 mmol) 4-quinoline-carboxaldehyde was dissolved in 75 mL of

Coordination Complexes of Silver(I) with Polyimine Ligands

Crystal Growth & Design, Vol. 3, No. 3, 2003 323

Table 1. Crystal Data 1a

2a‚CH3OH

3a‚(CH3)2COa

4a

5ab

empirical formula

C12H10N4‚AgNO3

formula weight crystal system space group a/Å b/Å c/Å R/° β/° γ/° V/Å3 Z µ(MoKR)/mm-1 T/°K Dc/g cm-3 2θmax/° no. unique reflns no. reflns with I > 2σ no. refined parameters R1 (I > 2σ) R1 (all data) wR2 (all data) |∆F|max e Å-3

380.12 monoclinic P21/c 15.0250(2) 13.4340(3) 6.7420(5) 90.0 97.575(1) 90.0 1349.0(1) 4 1.51 110 1.872 55.7 2904 2430 190 0.026 0.037 0.062 0.63

C14H14N4‚AgClO4‚ CH4O 477.65 monoclinic P21/c 8.2730(2) 9.1150(2) 23.4830(7) 90.0 92.115(1) 90.0 1769.6(1) 4 1.33 110 1.793 55.8 3940 3188 241 0.052 0.068 0.135 1.20

2(C20H22N4‚AgBF4)‚ C3H6O‚H2O 1102.29 orthorhombic P212121 13.6890(1) 15.6240(1) 22.1470(2) 90.0 90.0 90.0 4736.7(1) 4 0.90 110 1.546 55.7 6202 6819 599 0.023 0.026 0.057 0.43

2(C11H17N3‚ AgClO4) 797.19 orthorhombic Pbca 11.4740(1) 15.1170(2) 33.8570(5) 90.0 90.0 90.0 5872.6(1) 8 1.57 110 1.803 55.7 6729 5505 367 0.030 0.043 0.071 0.72

C17H20N4‚ 1 1/2(AgClO4) 591.35 monoclinic C2/c 20.3610(5) 12.9980(4) 15.5010(7) 90.0 98.549(1) 90.0 4056.8(2) 8 1.70 110 1.936 55.8 4713 3258 276 0.074 0.114 0.179 1.74

compound

compound empirical formula formula weight crystal system space group a/Å b/Å c/Å R/° β/° γ/° V/Å3 Z µ(MoKR)/mm-1 T/°K Dc/g cm-3 2θ max/° no. unique reflns no. reflns with I > 2σ no. refined parameters R1 (I > 2σ) R1 (all data) wR2 (all data) |∆F|max e Å-3

6a‚CH3CNc

7a‚2/3CH3CNd

8a

2C18H20N4‚ AgPF6‚C2H3N 878.66 tetragonal P-4c2 10.5950(3) 10.5950 18.5580(4) 90.0 90.0 90.0 2083.2(1) 2 0.59 110 1.401 55.8 2286 1729 129 0.057 0.079 0.172 0.71

3(C22H18N4‚ AgClO4)‚2C2H3N 1719.28 monoclinic Cc 24.0940(3) 18.0610(2) 17.9020(3) 90.0 119.257(1) 90.0 6796.5(2) 4 1.05 110 1.680 55.8 14244 12361 906 0.039 0.052 0.094 0.95

2C34H24N6‚AgClO4

C34H24N6

1240.50 tetragonal I41a 11.4530(3) 11.4530 49.674(1) 90.0 90.0 90.0 6515.8(3) 4 0.41 110 1.265 55.8 3802 2818 212 0.066 0.094 0.216 1.10

516.59 monoclinic C2/c 26.3110(5) 9.3310(2) 11.7780(3) 90.0 115.072(1) 90.0 2619.1(1) 4 0.08 110 1.310 55.8 2984 2276 181 0.043 0.061 0.121 0.27

8

a Racemic twin; Flack’s absolute structure parameter ) 0.53(2). b This structure is severely disordered (including disorder of one of the silver ions around an inversion center) and is characterized by low precision. c Racemic twin; Flack’s absolute structure parameter ) 0.67(7). The anion and solvent species are disordered. d Racemic twin; Flack’s absolute structure parameter ) 0.49(2).

anhydrous methanol. To this solution 1 mL (15 mmol) of distilled ethylenediamine was added dropwise with constant stirring. Then the reaction mixture was refluxed for 6 h in dry atmosphere. Evaporating the solvent a slight yellow semisolid was obtained which on recrystallization from nhexane gave colorless needles. Yield, 3.65 g (72%); mp 97 °C. Anal. found (calc. for C22H18N4): C, 78.15 (78.07); H, 5.46 (5.36); N, 16.61 (16.56)%. EI-MS: m/z 338.1 (M+, 15%), 169.1 (M+/2, 95%). FTIR/cm-1 (KBr): 476s, 565m, 649s, 732vs, 763vs, 862s, 958s, 1007vs, 1060vs, 1137m, 1280s, 1351m, 1460s, 1500vs, 1577vs, 1643vs (CdN), 2904m, 3435vb. 1H NMR (200 MHz, CDCl3, TMS): δ 8.90 (d, 2 H), 8.86 (s, 2 H), 8.54 (d, 2 H), 8.09 (d, 2 H), 7.61 (q, 4 H), 7.37 (q, 2 H), 4.20 (s, methylene, 4 H). 13C NMR (200 MHz, CDCl3, TMS): δ 160.68, 150.12, 148.74, 138.77, 129.96, 129.42, 127.34, 125.52, 123.95, 120.78, 62.07. UV-Vis λmax/nm (/dm3 mol-1 cm-1)(CH3OH): 306 (27 300); 241 (30 130). [Ag(7)]n(ClO4)n (7a). 0.170 g (0.5 mmol) of 7 was dissolved in 20 mL of acetonitrile. To this solution 0.105 g (0.5 mmol) of solid AgClO4 was added and dissolved with stirring and stirring was continued for 30 min at room temperature. Then

the reaction mixture was kept in the refrigerator for overnight. Light yellow crystals, suitable for X-ray analysis were separated out. They were filtered off, washed with few drops of methanol, and dried in vacuo over fused CaCl2. Yield, 0.15 g (55%). Anal. Found (calc. for C22H18N4‚AgClO4): C, 48.38 (48.40); H, 3.40 (3.32); N, 10.22 (10.27)%. FTIR/cm-1 (KBr): 576m, 615s, 768vs, 840s, 1080vs, 1113vs, 1140vs (ClO4), 1238m, 1465s, 1512vs, 1584vs, 1637vs (CdN), 2907, 3446vb. 1 H NMR (200 MHz, (CD3)2SO, TMS): δ 8.50 (br, 4 H), 7.61 (d, 4 H), 3.58 (s, 4 H), 3.40 (br, 4 H), 2.31 (s, 6 H).UV-Vis λmax/ nm (CH3OH): 308; 238. N,N’-bis(4-quinoline)idene benzil dihydrazone (8). Benzil dihydrazone (1.90 g, 8 mmol), synthesized by a reported procedure,18 was dissolved in 60 mL of anhydrous methanol. To this colorless solution, 2.515 g (16 mmol) of solid 4-quinoline-carboxaldehyde was added and dissolved with stirring. Then the resulting yellowish solution was refluxed for 4 h, maintaining a dry atmosphere. Then it was slowly cooled to room temperature to yield yellowish crystalline solid, which was filtered off and dried in air. Crystals suitable for X-ray analysis were obtained by direct diffusion of n-hexane into its

324


dichloromethane solution. Yield, 2.80 g (68%); mp 183 °C. Anal. found (calc. for C34H24N6): C, 78.93 (79.04); H, 4.54 (4.69); N, 16.21 (16.27). CI-MS: m/z 517.2 (MH+, 20%). FTIR/cm-1 (KBr): 536w, 595m, 653s, 687vs, 761vs, 840s, 965s, split, 1045m, 1221m, 1437m, 1500s, 1530m, 1612vs (CdN), 3045m, 3425vb. 1H NMR (200 MHz, CDCl3, TMS): δ 8.98 (s, 2 H), 8.86 (d, 2 H), 8.11 (d, 2 H), 8.10-8.04 (m, 6H), 7.66 (t, 2 H), 7.54-7.48 (m, 8 H), 7.34-7.28 (m, 4 H). 13C NMR (200 MHz, CDCl3, TMS): δ 166.98, 158.61, 149.91, 148.77, 136.87, 133.56, 131.61, 129.92, 129.41, 128.97, 127.98, 127.54, 124.81, 122.22. UV-Vis λmax/nm (/dm3 mol-1 cm-1) (CH3OH): 335 (26 760); 254 (20 515). [Ag(8)2]n(ClO4)n (8a). 0.26 g (0.5 mmol) of 8 was dissolved in 25 mL of acetonitrile. To this solution 0.105 g (0.5 mmol) of solid AgClO4 was added and dissolved with stirring. The yellow reaction mixture was kept in the refrigerator for overnight. Yellow solid separated out. It was filtered off, washed with few drops of methanol, and dried in vacuo over fused CaCl2. Yield, 0.10 g (33%). Single crystals suitable for X-ray analysis were grown by the direct diffusion of n-hexane into the dichloromethane solution of the complex. Anal. Found (calc. for 2C34H24N6‚AgClO4): C, 65.86 (65.82); H, 3.82 (3.90); N, 13.51 (13.55)%. FTIR/cm-1 (KBr): 542w, 615s, 658m, 762s, 845m, 1098vs (ClO4), 1250m, 1446m, 1510s, 1545m, 1578s, 1602vs (CdN), 2855w, 2918s, 3476vb. 1H NMR (200 MHz, (CD3)2SO, TMS): δ 9.15 (s, 2 H), 8.94 (d, 2 H), 8.49 (d, 2 H), 8.05-7.92 (m, 6 H), 7.75 (t, 2 H), 7.58-7.52 (m, 8 H), 7.357.30 (m, 4 H). UV-Vis λmax/nm (CH3OH): 330, 253. Caution! Though we have not met with any incident while working with the perchlorate compounds described here, care should be taken in handling them as the perchlorates are potentially explosive. They should not be prepared and stored in large amounts. Crystallography. The diffraction measurements were carried out on a Nonius KappaCCD diffractometer, using graphite monochromated MoKR radiation (λ ) 0.7107 Å). The crystalline samples of the analyzed compounds were covered with a thin layer of light oil and freeze-cooled to 110 K to minimize solvent escape, structural disorder, and thermal motion effects, and increase the precision of the results. The crystal and experimental data for all the compounds are summarized in Table 1. These structures were solved by direct (SHELXS-86, SIR-92)19,20 and Patterson methods (DIRDIF-96),21 and refined by full-matrix least-squares on F2 (SHELXL-97).22 Intensity data of the silver complexes were routinely corrected for absorption effects. All non-hydrogen atoms were refined anisotropically. The hydrogens were located in idealized positions, and were refined using a riding model with fixed thermal parameters [Uij ) 1.2 Uij (eq.) for the atom to which they are bonded]. Crystals of 3a, 5a, and 6a are characterized by noncentrosymmetric space symmetry, but were refined as racemic twins. Compound 5a yielded crystals of poor quality, and its detailed structure could not be characterized by high precision, although the coordination motif has been reliably determined. Moreover, one of the silver ions in the asymmetric unit of this structure is disordered about the crystallographic center of inversion. The PF6 anions in 6a appear rotationally disordered about the 4-fold rotation symmetry axis as well.

Results and Discussion Syntheses of ligands 1-8 (Scheme 1), and their complexes with silver ions, along with spectral characterizations of all compounds, are described in Experimental Section. While numerous complexes have been obtained, the following discussion relates only to those compounds for which the crystal structures and coordination motifs have been reliably determined. The simple ligands 1 and 2, each with two terminal N-functional groups oriented in different directions, represent model compounds for the formation of linear coordination polymers with silver ions. The pyridyl

Patra and Goldberg

Figure 1. (a) Ortep view of the asymmetric unit of 1a (with 50% probability thermal displacement parameters), excluding the counterion. (b) The parallel arrangement of the linear coordination polymers in the crystal structure, which extend along the a+c axis of the crystal, is shown. The silver ions, depicted by pink spheres (as in all of the following color figures), are approached by the nitrate anions; H is not shown.

nitrogen donor atoms in 1 and the amino and imino N-sites in 2 may serve as effective binding and bridging sites for the construction of supramolecular arrays with the silver ion auxiliaries. The complex [Ag(1)]n(NO3)n (1a) has been prepared as a light yellow solid by reacting the ligand and silver nitrate in 1:1 molar ratio (Figure 1). The central CdN-NdC fragment in 1 is coplanar, dictating a linear conformation of the ligand. Correspondingly, 1a represents a typical nearly linear coordination polymer, with the silver ions connecting to the pyridyl groups of two adjacent ligands. The coordination bonding parameters are Ag-N(sp2) ) 2.177(2) and 2.180(2) Å, and N-Ag-N ) 173.59(7)°. The polymeric arrays consist of units displaced along the a+c axis of the crystal, and the four symmetry-related arrays run parallel to one another. The nitrate anions lie close to metal ions, the shortest Ag‚‚‚N(nitrate) distance being 3.318(2) Å. Benzil dihydrazone, 2, is a 1 + 2 condensate of benzil and hydrazine. Its white silver(I) polymeric complex, [Ag(2)]n(ClO4)n (2a), was synthesized by reacting silver(I) perchlorate with benzil dihydrazone at room temperature in methanol. 2a crystallizes with one molecule of methanol in the asymmetric unit. The polymeric complex (2a) is stable in solid state for about 3 weeks, and in solution for at least 6 h. Its structure is depicted in Figure 2. The conformational features of the ligand and the diversity of the nitrogen donor sites in this case (aminetype as well as imine-type), give rise to a helical (rather than linear) geometry of the polymer that forms. Due to the steric hindrance between the two phenyl groups substituted on the central C-C bond in 2, the NdCCdN and C(Ph)-C-C-C(Ph) torsion angles about this bond are 72.2 and 73.1°, respectively (nearly gauche). The N7 imine-type nitrogen and the N8 and N10 amine-



Figure 3. Ortep illustration of the dinuclear complex 3a with 50% probability thermal ellipsoids. Each of the silver ions coordinates to the nitrogen donor sites of two different ligands, Ag2 binds also a water molecule. The acetone solvent and the BF4 anion are omitted.

Figure 2. (a) Ortep view of the asymmetric unit of 2a, excluding the counterion and methanol solvent. (b) The arrangement of the helical coordination polymers aligned in the crystal structure parallel to each other. Note the trigonal coordination environment of the silver ions (pink spheres). The perchlorate counterions and molecules of the methanol solvent are arranged between the polymeric chains.

type sites of two different ligands provide a pseudotrigonal coordination environment around each silver ions (Figure 2b). The helical polymeric arrays, extend parallel to the b-axis of the crystal. Along the chains, neighboring molecules are related to each other by the screw axis, and every third species is related to the first one by a simple translation along b. Adjacent arrays are interrelated by inversion. The corresponding bond distances and angles of this interaction are Ag-N7(sp2) ) 2.229(4) Å, Ag-N8(sp3) ) 2.387(5) Å, Ag-N10(sp3) ) 2.380(4) Å, the inter-ligand N7-Ag-N10 ) 132.8(2)°, N7-Ag-N8 ) 144.6(2)°, and the intra-ligand N8-AgN10 ) 81.2(2)°. In 1a and 2a, the coordination polymers are aligned parallel to one another in the crystalline phase. The anions, as well as the methanol solvent in 2a, are located in voids between the polymeric chains. Reaction of 2a with sodium tetrafluoroborate in methanol and subsequent recrystallization from acetone, yielded a surprising product. In the given reaction conditions, condensation occurred between the acetone and the amine groups of 2, leading to a modified ligand 3, in which the access to the nitrogen sites is somewhat hindered. As a result, a dimeric rather than polymeric entity of composition [Ag(3)]2(BF4)2‚H2O (3a) was obtained. It is stable in the solid state for about one week, and in solution for only 2-3 h. 3a crystallizes with one molecule of acetone. It represents a dinuclear complex with all nitrogen sites turning inward and the aryl and

alkyl groups turning outward (Figure 3). Each of the two silver ions connects between two ligand molecules, binding to their two outer N-atoms. Around one silver, normal coordination parameters were observed: Ag1N(sp2) ) 2.169(2) and 2.179(2) Å and N-Ag1-N ) 167.05(8)°. The other silver ion holds an additional water molecule in its coordination sphere [at Ag2-O ) 2.304(2) Å], which weakens its coordination to the N-donor sites [Ag2-N(sp2) ) 2.237(2) and 2.316(2) Å], and considerably narrows the corresponding N-Ag2-N bond angles [116.22(8)°]. Ligand 4 was synthesized by condensation of 1,2diamino-2-methyl-propane and 4-acetylpyridine in anhydrous methanol in a 1:2 ratio. The resulting light yellow thick liquid product represents, however, a 1 + 1 condensate. It appears that due to steric hindrance, one side of the diamino reactant remains uncondensed even under a prolonged reflux. Subsequent 1:1 reaction of 4 with silver perchlorate in acetonitrile at room temperature, led to a dimeric complex assembly of composition [Ag(4)]2(ClO4)2 (4a). Although the potential coordination sites on both ends of 4 seem readily accessible by other species, the asymmetric nature of this ligand along with its higher flexibility, may have favored the formation of a discrete species rather than of a polymeric aggregate. This complex is fairly stable in air in solid state, but in solution its stability is solvent dependent. In acetonitrile, it is stable for at least 3 h. The structure of this compound is depicted in Figure 4. The molecules of 4 adopt a bent shape, and the terminal donor sites (an amine and a pyridyl) of two such moieties connect to each other through the silver ions in an almost linear fashion. The corresponding bond distances and angles that characterize these coordinations are Ag-N(sp3) ) 2.163(2) and 2.190(2) Å, AgN(sp2) ) 2.139(2) and 2.158(2) Å and N-Ag-N ) 163.50(8)° and 164.14(8)°. The dimeric complex formed is a macrocyclic entity, further stabilized by stacking interactions between the overlapping pyridyl rings of the two ligands within the complex (Figure 4). The dihedral angle between these two rings is 12.8(1)°, the distance between their mean planes being approximately 3.45 Å. Each of the next four ligands 5-8 has C2 symmetry, and three isolated sites for potential coordination of silver ions: two pyridyl-type sites at the two ends of the ligand, and one di-imino site in the central part of

326


Figure 4. (a) Ortep view of the asymmetric unit of 4a excluding the perchlorate anions. (b) The crystal structure of the discrete dimer complexes viewed approximately down the a-axis. The perchlorate anions are located between the discrete dimers, H not shown.

Figure 5. Illustration of the 1-D polymer of 5a with Ag(I), showing the trigonal and the linear modes of silver ion coordination. (a) Ortep view; the two disordered positions of Ag2 are shown. (b) Perspective view emphasizing the overlap between the pyridyl rings of adjacent ligands; Ag2 is represented here by an average position between its two disordered sites. The anions are omitted.

the molecule. The binding capacity of the latter is enhanced by the chelate effect, as the two inner N-atoms converge on the coordinating metal ion. Ligand 5 was synthesized by condensing 1,3-diamino propane and 4-acetylpyridine in anhydrous methanol in 1:2 molar ratio. Reaction between 5 and AgClO4, in 1:1 ligand-tometal ratio in methanol at room temperature gives offwhite complex of composition {[Ag3(5)2](ClO4)3}n (5a), verified by elemental analysis and X-ray crystallography. The high flexibility of the central propyl residue allows this ligand molecule to bend into a U-form, to optimize the metal ligand coordination (Figure 5). In the observed structure adjacent U-shaped units, related

Patra and Goldberg

by crystallographic inversion, entangle and link (through the Ag1 ions) to each other, the pyridyl end of one species penetrating the central part of the adjacent molecule. This pairing is sustained by two symmetryequivalent Ag1 coordination (of a nearly trigonal symmetry) centers. The coordination parameters are Ag1N1 ) 2.224(6) Å, Ag1-N9 ) 2.285(6) Å, Ag1-N13 ) 2.285(6) Å, and N-Ag1-N angles of 92.3(2), 130.3(2), and 130.8(2)°. Subsequent entities of this dimer are intercoordinated into a 1-D coordination polymer through the second silver ion center Ag2. Ag2 (which is disordered about crystallographic inversion) binds to the pyridyl ends of two adjacent and inversion related dimers at Ag2-N19 ) 2.34(1) Å and N-Ag2-N ) 158.8(2)°. The polymeric chains thus formed (Figure 5) propagate parallel to one another along either the a+b or the a-b directions of the crystal in an alternating manner. The differently oriented polymers arrange in layers perpendicular to the c-axis of the crystal, with the perchlorate anions being located between them. The less flexible bis bidentate Schiff base ligand 6 is readily preapared by reaction of 4-pyridine carboxaldehyde and cyclohexane-1,2-diamine. Upon reaction with AgPF6 in acetonitrile, it gives a white, moderately stable, polymeric complex [Ag(6)2]n(PF6)n (6a) in good yield. The cyclohexyl ring imposes steric strain on the ligand. In the observed structure of 6a, the ligand molecules are located on crystallographic C2 axes. The inner imino N-atoms are oriented in different directions (the nearly gauche N-C-C-N torsion angle is 72.2°), which make them inert to metal ion coordination. As a result, only the peripheral pyridyls coordinate to the silver ions (Figure 6a). In the tetragonal crystal that forms, the latter are located on axes of 4-fold rotation and associate with four surrounding ligand species. Every silver ion has a distorted tetrahedral coordination environment, and each ligand is bound to two metal centers; the Ag1-N4 distance is 2.358(5) Å, and the N-Ag1-N bond angles in this tetrahedral structure are 86.1(2), 107.8(2), and 139.6(2)° (twice each). This yields two-dimensional coordination polymers (Figure 6b,c) with corrugated surface, extending parallel to the ab plane, and centered at z ) 1/4 and z ) 3/4 of the unitcell. The concave parts of one such layer fit into the convex sections (lined by the cyclohexyl groups) of adjacent layers, yielding efficient interlayer packing in the crystal. Ligand 7 is a 1 + 2 condensate of ethylene-diamine (en) and 4-quinolinecarboxaldehyde. Its light-yellow silver(I) complex [Ag(7)]n(ClO4)n (7a) was synthesized by reacting silver(I) perchlorate with 7 at room temperature in acetonitrile. This polymeric complex is stable in the solid state for more than 2 weeks and in solution for at least 24 h. Replacement of the pyridine by a quinoline function imparts an additional element of molecular recognition to the ligand structure, i.e., tendency for an enhanced π-π stacking of the large flat aromatic fragments in the solid. The asymmetric unit of this structure includes (apart from the acetonitrile solvent and the perchlorate anions) a trimeric complex cation [Ag(7)]33+ (Figure 7). The central silver ion Ag3 coordinates to the diimine central fragment of one molecule and the peripheral quinoline N-sites of the two other molecules in the asymmetric unit. Moreover, the



Figure 6. (a) Ortep illustration of complex 6a, excluding the rotationally disordered PF6 anion and the acetonitrile solvent. The ligands reside in the crystal on axes of 2-fold rotation. (b) Edge-on view of the 2-D coordination polymer with corrugated surface. (c) Face-on view of the coordination polymer, showing the tetrahedral coordination mode around the silver ions. The disordered anions, residing in the concave sites of the polymeric network between the shown acetonitrile solvent species, are omitted in panels b and c.

Figure 7. Illustration of complex 7a. (a) Ortep drawing of the asymmetric unit, excluding the perchlorate anion. Ag1 and Ag2 are coordinated also to quinoline-N of adjacent species. (b) Fragment of the crystal structure, showing the relative disposition of two chain polymeric fragments.

Figure 8. (a) The molecular structure of the free ligand in 8. (b) Edge-on, and (c) face-on views of the 2-D polymers that form with silver ions in 8a. The efficient lock-and-key type crystal packing of adjacent polymeric layers is depicted in panel b. Note the tetrahedral coordination pattern around the silver ions. The anions are omitted.

quinoline rings of the central ligand overlap, and π-π stack with, the aryl groups of the neighboring species; the corresponding mean interplanar distance within the overlapping pairs are 3.42(3) and 3.46(3) Å. Each of the other ions Ag1 and Ag2 exhibits similar coordination patterns, bridging between three different ligands in a flattened tetrahedral motif, and associating with the N1and N53-quinoline groups of adjacent asymmetric units in the structure. This results in the formation of continuous linear coordination polymers propagating through the crystal, which are also stabilized by π-π stacking interaction within and between the [Ag(7)]33+ cations. Optimization of the aryl-aryl stacking effects a wide variation of the Ag-N coordination parameters. The corresponding bond lengths and bond angles vary within Ag1-N 2.235-2.579(4) Å, Ag2-N 2.245-2.508(4) Å, Ag3-N 2.193-2.680(4) Å, N-Ag1-N 73.0-145.2(1)°, N-Ag2-N 72.8-138.2(1)°, and N-Ag3-N 73.6155.5(1)°.

Ligand 8 is synthesized as yellow crystalline solid by reacting benzil dihydrazone with 4-quinolinecarboxaldehyde in anhydrous methanol. Reacting 8 with AgClO4 in 1:1 or 2:1 ratio in acetonitrile at room temperature leads to a 2-D coordination polymer [Ag(8)2]n(ClO4)n (8a). This yellow polymeric complex is fairly stable in air. 8 is a rather rigid ligand, due to the strain imposed by the phenyl groups substituted on the central C-C bond. It is characterized both in 8 and in 8a by a twisted conformation about this bond, which directs the inner nitrogen sites at nearly perpendicular directions and weakens the potential chelation features of this nitrogen pair (Figure 8a). The corresponding N-C-C-N and C(Ph)-C-C-C(Ph) torsion angles are 100.42 and 96.92°, and 105.57 and 98.29° in 8 and 8a, respectively. Evidently, the intermolecular coordination and interaction properties of 8 in reaction with silver(I) ions are similar to those exhibited by 6. Thus, although 8 bears six donor nitrogen sites, the four inner imino

328


Patra and Goldberg

Table 2. Coordination Geometry in Complexes 1a-8a complex

type of assembly

coordination geometry

Ag-N bond distance range (Å)

N-Ag-N bond angle range (°)

1a 2a 3a

1-D polymer 1-D polymer dimer

4a 5a

dimer 1-D polymer

6a 7a 8a

2-D polymer 1-D polymer 2-D polymer

linear trigonal linear & trigonal linear linear & trigonal tetrahedral pseudo-tetrahedral tetrahedral

2.177-2.180(2) 2.229-2.387(4) 2.169-2.179(2) 2.237-2.316(2) 2.139-2.190(2) 2.34(1) 2.224-2.285(6) 2.368(4) 2.193-2.680(4) 2.338(3)

173.6(1) 81.2-144.6(2) 167.1(1) 116.2(1) 163.5-164.1(1) 158.8(2) 92.3-130.8(2) 86.0-139.6(2) 72.8-155.5(1) 106.7-115.2(2)

nitrogens are inert and only the two peripheral sites are exposed to metal ion coordination. This yields, as in the previous example (shown in Figure 6), to the formation of tetrahedral coordination clusters around the silver nuclei located on 4-fold symmetry axes in a tetragonal crystal structure. Each ion is coordinated to four different ligands at Ag-N(quinoline) distance of 2.338(3) Å and N-Ag-N angles of 106.68(8) and 115.20(16)°. Correspondingly, every ligand links to two different silver ions, thus forming two-dimensional coordination polymeric arrays which expand parallel to the ab plane of the crystal. The phenyl groups line the layered arrays on both sides, forming corrugated surfaces. Adjacent symmetry-related layers fit into one another, a packing interaction enhanced by π-π overlap between the phenyl rings of one layer and the quinoline rings of another layer (Figure 8b,c). The geometric parameters of the Ag-N coordination in the complexes 1a-8a are summarized in Table 2. Conclusion The above observations illustrate some useful concepts of ligand design that can be applied in the solidstate synthesis of diverse coordination aggregates with Ag(I) ion auxiliaries. This includes incorporation of multiple N-donor sites within the ligand building blocks to allow simultaneous coordination to several metal ions and formation of stabilizing chelate rings. Then, variation of the ligand symmetry is an important factor in directing the size of the formed species. Ligands of lower symmetry tend to form discrete oligomeric compounds, while those of higher (e.g., C2) symmetry usually selfassemble as polymeric entities. Manipulation of the ligand flexibility and aromaticity by external substituents plays also an important role in directing the coordination geometries, by optimizing the secondary interactions (intramolecular strain, π-π stacking, etc.) within and between the complex constituents. Thus, for example, in the conformationally rigid 6 and 8 the inner N-sites are inert to coordination, which effects the formation of extended 2D networks through the peripheral ligation sites only. On the other hand, the less constrained ligands 5 and 7 can utilize their coordination potential to capacity. This results in the formulation of 1D polymeric arrays, associated with both silver chelation to the inner nitrogen sites of one ligand and its binding to the outer nitrogens of the neighboring species. Thus, while most studies of hybrid organicinorganic systems with silver(I) ions take advantage of the common linear coordination modes (where the silver is coordinated on opposite sides to two different moi-

eties), the above results demonstrate the facile construction of less known silver(I)-mediated trigonal23 as well as tetrahedral24,25 supramolecular architectures by suitably modified (functionally as well as structurally) organic ligands. This may enhance the utility of the silver ions in the designed formulation of more versatile hybrid materials. Acknowledgment. This research was partially supported by the Israel Science Foundation. Supporting Information Available: Crystallographic data for the coordination compounds 1a-8a, and the free ligand 8, in the crystallographic information file (CIF) format. This information is available free of charge via the Internet at http://pubs.acs.org.

References (1) Braga, D. Acc. Chem. Res. 2000, 33, 601-608. (2) Braga, D.; Grepioni, F.; Desiraju, G. R. Chem. Rev. 1998, 1375-1406. (3) Mareque Rivas, J. C.; Brammer, L. Coord. Chem. Rev. 1999, 183, 43-80. (4) Schwarz, P.; Siebel, E.; Fischer, R. D.; Apperley, D. C.; Davies, N. A.; Harris, R. K. Angew. Chem., Int. Ed. Engl. 1995, 34, 1197-1199. Li, H.; Eddaoudi, M.; Groy, T. L.; Yaghi, O. M. J. Am. Chem. Soc. 1998, 120, 8571-8572. (5) Lin, W.; Wang, Z.; Ma, L. J. Am. Chem. Soc. 1999, 121, 11249-11250. Chen, C.; Suslick, K. S. Coord. Chem. Rev. 1993, 128, 293-322 and references therein. (6) Kondo, M.; Yoshitomi, T.; Seki, K.; Matsuzaka, H.; Kitagawa, S. Angew. Chem., Int. Ed. 1997, 36, 1725-1727. (7) Singh, N.; Singh, R. K. Inorg. Chem. Commun. 2002, 5, 255258 and references therein. (8) Xiong, R. G.; Zuo, J. L.; You, X. Z.; Abrahams, B. F.; Bai, Z. P.; Che, C. M.; Fun, H. K. Chem. Commun. 2000, 20612062. (9) For examples of ligand control see (a) MacGillivray, L. R.; Subramanian, S.; Zaworotko, M. J. Chem. Commun. 1994, 1325-1326. (b) Blake, A. J.; Champness, N. R.; Chung, S. S. M.; Li, W.-S.; Schro¨der, M. Chem. Commun. 1997, 10051006. (c) Fujita, M.; Kwon, Y. J.; Sasaki, O.; Yamaguchi, K.; Ogura, K. J. Am. Chem. Soc. 1995, 117, 7287-7288. (10) For examples of anion control see (a) Withersby, M. A.; Blake, A. J.; Champness, N. R.; Hubbersty, P.; Li, W.-S.; Schro¨der, M. Angew. Chem., Int. Ed. Engl. 1997, 36, 23272329. (b) Hirsch, K. A.; Wilson, S. R.; Moore, J. S. Inorg. Chem. 1997, 36, 2960-2968. (c) Patra, G. K.; Mostafa, G.; Tocher, D. A.; Datta, D. Inorg. Chem. Commun. 2000, 3, 56-58. (d) Patra, G. K; Mostafa, G.; Drew, M. G. B.; Datta, D. Cryst. Eng. Comm. 2000, 2, 106-108. (e) Patra, G. K.; Goldberg, I. Polyhedron 2002, 21, 2195-2199. (11) For examples of solvent control see (a) Subramanian, S.; Zaworotko, M. J. Angew. Chem., Int. Ed. Engl. 1995, 34, 2127-2129. (b) Lu, J.; Paliwala, T.; Lim, S. C.; Yu, C.; Niu, T.; Jacobson, A. J. Inorg. Chem. 1997, 36, 923-929. (12) For examples of template control: (a) Gudbjarlson, H.; Poirier, K. M.; Zaworotko, M. J. J. Am. Chem. Soc. 1999, 121, 2599-2600. (b) Hennigar, T. L.; MacQuarrie, D. C.; Losier, P.; Rogers, R. D.; Zaworotko, M. J. Angew. Chem., Int. Ed. Engl. 1997, 36, 972-973.

Coordination Complexes of Silver(I) with Polyimine Ligands (13) Patra, G. K.; Goldberg, I. Dalton Trans. 2002, 1051-1057. (14) Patra, G. K.; Goldberg, I. Eur. J. Inorg. Chem. 2003, 969977. (15) Suenaga, Y.; Kuroda-Sowa, T.; Maekawa, M.; Munakata, M. Dalton Trans. 2000, 3620-3623. (16) Diskin-Posner, Y.; Patra, G. K.; Goldberg, I. Dalton Trans. 2001, 2775-2782. (17) Raj, S. S. S.; Fun, H.-K.; Zhang, J.; Xiong, R.-G.; You, X.-Z. Acta Crystallogr. Sect. C 2000, 56, e274-e276. (18) Busch, D. H.; Bailar, J. C. J. Am. Chem. Soc. 1956, 78, 1137-1142. (19) Sheldrick, G. M. SHELXS-86, Acta Crystallogr. Sect A 1990, 46, 467-473. (20) Altomare, A.; Burla, M. C.; Camalli, M.; Cascarano, M.; Giacovazzo, C.; Guagliardi, A.; Polidori, G. SIR-92, J. Appl. Crystallogr. 1994, 27, 435-436.

Crystal Growth & Design, Vol. 3, No. 3, 2003 329 (21) Beurskens, P. T.; Admiraal, G.; Beurskens, G.; Bosman, W. P.; Garcia-Granda, S.; Gould, R. O.; Smits, J. M. M.; Smykalla, C.; “The DIRDIF-96 Program System”. Technical Report of the Crystallography Laboratory, University of Nijmegen, The Netherlands, 1996. (22) Sheldrick, G. M. SHELXL-97. Program for the Refinement of Crystal Structures from Diffraction Data, University of Go¨ttingen, Germany, 1997. (23) Dong, Y.-B.; Ma, J.-P.; Huang, R.-Q. Inorg. Chem. 2003, 42, 294-300. (24) Bu, X.-H.; Hou, W.-F.; Du, M.; Chen, W.; Zhang, R.-H. Cryst. Growth Des. 2002, 303-307. (25) Tuna, F.; Hamblin, J.; Clarkson, G.; Errington, W.; Alcock, M. W.; Hannon, M. J. Chem. Eur. J. 2002, 8, 4957-4964.

CG034011Q

Supramolecular Design of Coordination Complexes of Silver(I) with

Recommend Documents