Ligand-Induced Formation of Copper(I) Iodide Clusters: Exocyclic

Feb 17, 2016 - Sujin Seo , Eunji Lee , Huiyeong Ju , Seulgi Kim , In-Hyeok Park , Jong Hwa Jung , Shim Sung Lee. CrystEngComm 2017 19 (47), 7185-7190 ...
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Ligand-Induced Formation of Copper(I) Iodide Clusters: Exocyclic Coordination Polymers with Bis-dithiamacrocycle Isomers Seulgi Kim,† Arlette Deukam Siewe,† Eunji Lee,† Huiyeong Ju,† In-Hyeok Park,*,† Ki-Min Park,† Mari Ikeda,‡ Yoichi Habata,§ and Shim Sung Lee*,† †

Department of Chemistry and Research Institute of Natural Science, Gyeongsang National University, Jinju 660-701, South Korea Education Center, Faculty of Engineering, Chiba Institute of Technology, 2-1-1 Shibazono, Narashino, Chiba 275-0023, Japan § Department of Chemistry, Toho University, 2-2-1 Miyama, Funabashi, Chiba 274-8510, Japan ‡

S Supporting Information *

ABSTRACT: A comparative study on the formation of guest clusters induced by different shapes (or sizes) of exocyclic binding sites embedded in the bis-macrocyclic host isomers is reported. CuI reacts with two regioisomers of a bis-dithiamacrocycle, o-bis-L (W-shaped binding site) and m-bis-L (U-shaped binding site), to yield one-dimensional coordination polymers {[(μ4-Cu4I4)(o-bis-L)]·2CH3CN}n (1a) and [(μ4Cu2I2)(m-bis-L)]n (2). In 1a, the o-bis-L ligand isomer is linked by a spacious cubane [Cu4I4] cluster, while the m-bis-L ligand in 2 is linked by a smaller rhomboid [Cu2I2] cluster because of the different exocyclic binding sites. The results observed illustrate the possibility for the metal clusters including [CunIn] (n = 2 or 4) to adopt a controlled formation through the binding site alternation or design. Because of the adaptive cluster formations, the products show different photophysical properties. Additionally, sliding of the one-dimensional chains in 1a was observed upon loss of the lattice solvent molecules in ambient condition.

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INTRODUCTION Structural modification of existing receptor-type ligands is an interesting area because it can induce the formation of controlled coordinative compounds with physical properties.1 These include the family of sulfur-containing mixed-donor macrocycles providing various coordination modes to form discrete or infinite complexes with some thiaphilic metal ions.1,2 In particular, sulfur donors in the crown-type macrocycles have a tendency to lead metal coordination outside the macrocyclic cavity (exocoordination) because of the predominant repulsive forces between sulfur donors in the ring cavity.3 Exocyclic coordination in the thiamacrocyclic complexes could be synthetically attractive because it would generate a means of networking macrocyclic building units in a diverse arrangement. 3 Thus, one of the challenging tasks in thiamacrocyclic coordination is how to control endo- and exocoordination and to apply this unusual coordination mode to the design of new supramolecular coordination networks and to the applications. We have established several strategies to control the endo- or exocoordination modes by anion4 and ligand design including the conformation and interdonor (S··· S) distances in the ring cavity.5 Recently, we have also reported the regioisomers o-bis-L and m-bis-L of a bis-dithiamacrocycle (Scheme 1) as a versatile model system that leads to endo- and exocyclic coordination.6 Among the thiaphilic soft metal halides, the family of polynuclear copper(I) iodide clusters is particularly attractive © XXXX American Chemical Society

Scheme 1. Binding Models of [CunIn] Clusters toward the Regioisomers of a Bis-Dithiamacrocycle

because of its photoluminescence properties associated with an extraordinary structural diversity including two classical dinuclear [Cu2I2] and tetranuclear [Cu4I4] clusters (Scheme 1).7 Several coordination networks of thiamacrocycles with copper(I) iodide clusters have been reported by us.8 Recently, diverse sizes of CunIn (n = 2, 4, and 6) clusters in a threeReceived: October 7, 2015

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DOI: 10.1021/acs.inorgchem.5b02314 Inorg. Chem. XXXX, XXX, XXX−XXX

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Inorganic Chemistry dimensional (3D) framework by changing the CuI/dabco (dabco = 1,4-diazabicyclo[2.2.2]octane) ratio have been reported.9 The incorporation of a methyl group at the pC6H4 position of the flexible RS(CH2)8SR (R = phenyl or ptoluene) also resulted in structural changes in the coordination polymer (1D vs 2D) and cluster size ([Cu4I4] vs [Cu8I8]).10 However, a precise prediction of the copper(I) iodide clusters formed from the assembly reactions with the ligands remains challenging so far. So, we were motivated to employ o-bis-L and m-bis-L, which can serve the preorganized W- and U-shaped exocyclic binding sites (see the red parts in Scheme 1), respectively, to investigate the possibility of inductive tuning of polynuclear [CunIn] clusters. In connection with these reasons, we have proposed the size-fit binding models of the dithiamacrocycle isomers in which o-bis-L with the W-shaped binding site might lead to formation of a spacious cluster, while m-bis-L with the Ushaped binding site could induce formation of a smaller cluster. Furthermore, such a host dependence on the preferential formation of the clusters is found to induce different physical properties. On the basis of the above assumption, we performed a comparative experiment in the syntheses of copper(I) iodide complexes of o-bis-L and m-bis-L. Overall, we have been successful in isolating two copper(I) iodide coordination polymers [{[(μ4-Cu4I4)(o-bis-L)]·2CH3CN}n (1a) and [(μ4Cu2I2)(m-bis-L)]n(2)] with a similar connectivity pattern, but the size of the cluster-type guest being formed is induced by the host system, as depicted in Scheme 1. To the best of our knowledge, the observation of host-induced formation of the copper(I) iodide clusters has not been reported previously. In addition, displacement by sliding of the 1D chains of 1a was observed upon removal of the lattice solvent molecules in air via a single-crystal-to-single-crystal (SCSC) manner. The details of our investigations are described below.

Figure 1. Crystal structures of (a) a 1D polymeric chain linked by the cubane [Cu4I4] clusters in 1a, (b) a coordination environment around the cubane [Cu4I4] cluster, and (c) a side view. Noncoordinating solvent molecules are omitted. Symmetry operations for 1a: (A) −x + 1, −y + 2, −z + 1; (B) −x + 2, −y + 1, −z + 2.

product 1a is less symmetric than 2 probably because of the existence of two acetonitrile molecules in the lattice (not shown in Figures 1 and 2; see Figure 3a). So, the asymmetric unit in the complex part of 1a contains one o-bis-L ligand molecule (a half-molecule of one ligand and a half-molecule of the adjacent ligand) and one [Cu4I4] cluster. However, the asymmetric unit in 2 simply contains a quarter molecule of m-bis-L and half of the [Cu2I2] cluster.

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RESULTS AND DISCUSSION A mixture of two bis-dithiamacrocycle regioisomers (o-bis-L and m-bis-L) was prepared by a direct bis-cyclization reaction of 1,2,4,5-tetrakis(bromomethyl)benzene with 3,6-dioxa-1,8octanedithiol and separated by recrystallization and column chromatography, as reported by us previously.6 Synthesis and Structural Characterization of Copper(I) Iodide Complexes (1a and 2). Both of the colorless crystalline complexes 1a and 2 reported in this work were obtained by the reaction of 3 equiv of copper(I) iodide with 1 equiv of o-bis-L or m-bis-L. The solvent was chloroform/ acetonitrile, and all preparations were carried out at room temperature. The yields in crystalline materials were ca. 60− 70%. Single-crystal X-ray diffraction (SC-XRD) analysis (Table S1) revealed that both feature a 1D polymeric arrangement with similar connectivity patterns (Figure 1). The purity of each product was confirmed by comparing the simulated powder Xray diffraction (PXRD; Figure S1). Product 1a crystallizes in the triclinic space group P1̅ with the formula {[(μ4-Cu4I4)(o-bis-L)]·2CH3CN}n, whereas product 2 crystallizes in the monoclinic space group C2/m with the formula [(μ4-Cu2I2)(m-bis-L)]n. Indeed, o-bis-L isomers in 1a and m-bis-L isomers in 2 are linked by dinuclear [Cu2I2] and tetranuclear [Cu4I4] clusters, respectively, adopting an exocyclic 1D infinite chain structure. It is of interest to compare the structures of 1a and 2 even though both products share some common features. The

Figure 2. Crystal structures of (a) a 1D polymeric chain linked by the rhomboid [Cu2I2] cluster in 2, (b) the basic coordination environment around the rhomboid [Cu2I2] cluster, and (c) a side view. Symmetry operations for 2: (A) −x + 2, y, −z + 1; (B) −x + 1, y, −z; (C) −x + 1, −y, −z; (D) x, −y, z; (E) −x + 2, −y, −z + 1; (F) x + 1, −y, z + 1; (G) x + 1, y, z + 1. B

DOI: 10.1021/acs.inorgchem.5b02314 Inorg. Chem. XXXX, XXX, XXX−XXX

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Inorganic Chemistry

Figure 3. Matching of (a) the W-site/Cu4I4 cluster in 1a and (b) the U-site/Cu2I2 cluster in 2. In both structures, the ligands were omitted, except the binding sites. Symmetry operations for 2: (A) −x + 2, y, −z + 1; (D) x, −y, z; (E) −x + 2, −y, −z + 1.

In 1a, o-bis-L macrocycles are linked by classical cubane-type [Cu4I4] clusters, whose geometry resembles a distorted cube with alternating vertices of copper and iodine atoms. Accordingly, the spacious [Cu4I4] cluster is sandwiched by two o-bis-L macrocycles, resulting in a copolymeric chain structure with a −(o-bis-L)(Cu4I4)− pattern. All of the copper(I) atoms in 1a have a tetrahedral CuSI3 environment [Cu−I, 2.648(1)−2.757(1) Å; Cu−S, 2.302(1)−2.320(1) Å], while m-bis-L macrocycles in 2 are linked by the perfect rhomboid [Cu2I2] clusters, forming a copolymeric chain with a −(m-bis-L)(Cu2I2)− pattern. In the rhomboid cluster, the copper(I) atom has a tetrahedral CuS2I2 environment [Cu−I, 2.656(1) Å; Cu−S, 2.316(1) Å]. The bond distances of Cu−S and Cu−I in 2 are similar to those in 1a, and both are typical. Not surprisingly, given their hard nature, neither of the oxygen donors in both ligands participates in coordination. Both clusters act as a four-connected two-way node. Thus, for each product, two pairs of Cu−S bonds arising from two adjacent bis-dithiamacrocycles occupy well-separated positions, such that a couple of the ligand molecules are also arranged to adopt the cluster as a linker unit. Therefore, as proposed, the exocyclic sulfur-to-sulfur separations between two rigid macrocyclic rings in each bis-dithiamacrocycle are more important in association with the size of the binding sites. As expected, the exocyclic sulfur-to-sulfur separations in 1a [S1···S2, 6.012(2) Å; S3···S4, 6.106(2) Å], which forms the W-shaped binding site, are significantly larger than that in 2 [S1···S1D, 3.838(1) Å] with the U-shaped binding site (Figure 3). Consequently, the larger S···S separation due to the W-shaped binding site of the o-bis-L isomer is responsible for formation of the spacious [Cu4I4] cluster resulting in 1, whereas the m-bis-L isomer with a smaller S···S distance favors formation of the compact dinuclear [Cu2I2] cluster to generate 2. Sliding of 1D Chains upon Removal of Solvent Molecules [SCSC Transformation from 1a to {[(μ4Cu4I4)(o-bis-L)]}n (1b)]. When the crystals of 1a were kept in air, loss of the acetonitrile solvent molecules (an orange arrow in Figure 4a) within 7 days was confirmed by SC-XRD (termed 1b; see Figures 4b and S3 and S4). We also found that displacement by sliding of the 1D chains along the a axis occurred upon removal of the solvent molecules (a green arrow in Figure 4a). Such a sliding rearrangement is considered to stabilize the packing structure. Removal of the acetonitrile solvent molecules was also confirmed by 1H NMR spectra (Figure S5). The homogeneity of bulk samples for 1b was revealed by PXRD patterns (Figure S1). Exposure of 1b to the acetonitrile vapor shows no structure change, suggesting that the above transformation is irreversible.

Figure 4. (a) Removal of the acetonitrile molecules in 1a followed by sliding (a green arrow) of the 1D chain via an SCSC manner. (b) Acetonitrile-free structure of 1b after the sliding.

Photophysical Properties. As mentioned, 1a and 2 are colorless crystalline solids under ambient light. Under UV irradiation, 1a emits an intense yellow-green light at 554 nm (λex = 365 nm), whereas 2 is nonemissive (Figure 5). The absolute quantum yield for 1a in the solid state at 365 nm was determined to be Φ = 0.49. The major contribution to the luminescent origin of [Cu4I4] is believed to be the clustercentered excited states (*Cu4), which involve Cu···Cu

Figure 5. Solid-state photoluminescence spectra of o-bis-L, 1a, 1b, and 2 at room temperature (excitation at 365 nm). C

DOI: 10.1021/acs.inorgchem.5b02314 Inorg. Chem. XXXX, XXX, XXX−XXX

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Inorganic Chemistry interactions.7 The Cu···Cu distances in 1a are in the range of 2.624(8)−2.911(8) Å (av. 2.819 Å), similar to those reported,7 but some of them are shorter than that in 2 [2.876(8) Å]. The photophysical properties of the solvent-free sample 1b (λem = 551 nm) are not significantly different from those of 1a.

refinement data for the crystal structures of 1a, 1b, and 2 are summarized in Table S1.

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S Supporting Information *

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The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.inorgchem.5b02314. NMR spectra, PXRD patterns, TGA curves, and crystal structures (PDF) CCDC reference numbers 1419091 (1a), 1429218 (1b), and 1419092 (2) (CIF)

CONCLUSION In summary, we have introduced adaptive formations of the copper(I) iodide clusters, which are unpredictable under conventional conditions by employing the host system with different preorganized exocyclic binding sites. The regioisomers of the bis-dithiamacrocycle induce a profound structural change in the clusters formed as well as the related physical properties. A comparison of the two 1D polymeric products incorporating different sizes of the polynuclear [CunIn] clusters formed highlights the emissive property due to cuprophilic interactions. This result, as an example of the programmed self-assemblies, indicates that the proposed exocyclic interdonor distances (or binding sites), together with the cluster size, play decisive roles cooperatively in the selective synthesis of supramolecular materials with specific topology and function.

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ASSOCIATED CONTENT

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AUTHOR INFORMATION

Corresponding Authors

*E-mail: [email protected]. *E-mail: [email protected]. Notes

The authors declare no competing financial interest.

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ACKNOWLEDGMENTS This work was supported by the NRF (Grants 2012R1A4A1027750 and 2013R1A2A2A01067771).

EXPERIMENTAL SECTION

General Procedures. All chemicals and solvents used in the syntheses were of reagent grade and were used without further purification. NMR spectra were recorded on a Bruker 300 spectrometer (300 MHz). The Fourier transform infrared spectra were measured with a Nicolet iS10 spectrometer. Elemental analysis was carried out on a LECO CHNS-932 elemental analyzer. The absolute quantum yield was measured with a Hamamatsu Quantaurus QY-C11347-11 absolute photoluminescence quantum yield measurement system. Thermogravimetric analyses (TGA) were performed under a nitrogen atmosphere with a heating rate of 5 °C min−1 using a TA Q50 thermal analyzer. PXRD patterns were recorded on a D8 DISCOVER (Bruker AXS) with graphite-monochromatized Cu Kα radiation (λ = 1.54056 Å) at room temperature. Preparation of {[(Cu4I4)(o-bis-L)]·2CH3CN}n(1a). Copper(I) iodide (11.8 mg, 0.062 mmol) in acetonitrile (1 mL) was added to o-bis-L (10.0 mg, 0.020 mmol) in chloroform (1 mL). Slow evaporation of the solution afforded a colorless crystalline product, 1a, suitable for X-ray analysis. Mp: 256−257 °C (dec). IR (KBr pellet): 2954, 2912, 2857, 1473, 1399, 1367, 1350, 1287, 1241, 1195, 1140, 1115, 1067, 1032, 909, 801, 720 cm−1. Anal. Calcd for [C23.4H36.1Cu4I4N0.7O4S4]: C, 21.94; H, 2.84; N, 0.77. Found: C, 22.32; H, 2.92; N, 0.43. For elemental analysis, drying the product in air for 12 h led to the partial loss of acetonitrile molecules to yield {[(Cu4I4)(o-bis-L)]·0.7CH3CN}n. Preparation of [(Cu2I2)(m-bis-L)]n (2). Copper(I) iodide (11.6 mg, 0.061 mmol) in acetonitrile (1 mL) was added to m-bis-L (10.3 mg, 0.021 mmol) in chloroform (1 mL). Slow evaporation of the solution afforded a colorless crystalline product, 2, suitable for X-ray analysis. Mp: 261−262 °C (dec). IR (KBr pellet): 3032, 2902, 2859, 1637, 1509, 1438, 1384, 1352, 1292, 1240, 1127, 1094, 1025, 909, 861, 804 cm−1. Anal. Calcd for [C22H34Cu2I2O4S4]: C, 30.32; H, 3.93; S, 14.71. Found: C, 29.98; H, 3.91; S, 14.75. X-ray Crystallographic Analysis. Crystal data for 1a, 1b, and 2 were collected on a Bruker SMART APEX II ULTRA diffractometer equipped with graphite-monochromated Mo Kα radiation (λ = 0.71073 Å) generated by a rotating anode. Data collection, data reduction, and semiempirical absorption correction were carried out using the software package of APEX2.11 All of the calculations for structure determination were carried out using the SHELXTL package.12 In all cases, all non-hydrogen atoms were refined anisotropically and all hydrogen atoms were placed in idealized positions and refined isotropically in a riding manner along with their respective parent atoms. Relevant crystal data collection and

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REFERENCES

(1) (a) Lindoy, L. F. The Chemistry of Macrocyclic Complexes; Cambridge University Press: Cambridge, U.K., 1989. (b) Izatt, R. M.; Pawlak, K.; Bradshaw, J. S.; Bruening, R. L. Chem. Rev. 1991, 91, 1721. (c) Gokel, G. W. Crown Ethers and Cryptands; The Royal Society of Chemistry: Cambridge, U.K., 1994. (d) Izatt, R. M.; Pawlak, K.; Bradshaw, J. S.; Bruening, R. L. Chem. Rev. 1995, 95, 2529. (e) Lindoy, L. F. Coord. Chem. Rev. 1998, 174, 327. (f) Lindoy, L. F.; Park, K.-M.; Lee, S. S. Chem. Soc. Rev. 2013, 42, 1713. (2) (a) Wolf, R. E., Jr.; Hartman, J. R.; Storey, J. M. E.; Foxman, B. M.; Cooper, S. R. J. Am. Chem. Soc. 1987, 109, 4328. (b) Blake, A. G.; Schröder, M. Adv. Inorg. Chem. 1990, 35, 1. (c) Hill, S. E.; Feller, D. J. Phys. Chem. A 2000, 104, 652. (3) Park, S.; Lee, S. Y.; Park, K.-M.; Lee, S. S. Acc. Chem. Res. 2012, 45, 391. (4) (a) Lee, S. J.; Jung, J. H.; Seo, J.; Yoon, I.; Park, K.-M.; Lindoy, L. F.; Lee, S. S. Org. Lett. 2006, 8, 1641. (b) Kim, H. J.; Lee, S. S. Inorg. Chem. 2008, 47, 10807. (c) Lee, E.; Lee, S. S. Inorg. Chem. 2011, 50, 5803. (d) Lee, H.-H.; Park, I.-H.; Lee, S. S. Inorg. Chem. 2014, 53, 4763. (5) (a) Jo, M.; Seo, J.; Seo, M. L.; Choi, K. S.; Cha, S. K.; Lindoy, L. F.; Lee, S. S. Inorg. Chem. 2009, 48, 8186. (b) Kang, E.-J.; Lee, S. Y.; Lee, H.; Lee, S. S. Inorg. Chem. 2010, 49, 7510. (c) Kim, H. J.; Sultana, K. F.; Lee, J. Y.; Lee, S. S. CrystEngComm 2010, 12, 1494. (d) Lee, E.; Lee, S. S. Inorg. Chem. 2011, 50, 5803. (6) Siewe, A. D.; Kim, J.-Y.; Kim, S.; Park, I.-H.; Lee, S. S. Inorg. Chem. 2014, 53, 393. (7) (a) Ford, P. C.; Cariati, E.; Bourassa, J. Chem. Rev. 1999, 99, 3625. (b) Vitale, M.; Ford, P. C. Coord. Chem. Rev. 2001, 219−221, 3. (c) Kim, T. H.; Shin, Y. W.; Jung, J. H.; Kim, J. S.; Kim, J. Angew. Chem., Int. Ed. 2008, 47, 685. (d) Peng, R.; Li, M.; Li, D. Coord. Chem. Rev. 2010, 254, 1. (e) Harvey, P. D.; Bonnot, A.; Lapprand, A.; Strohmann, C.; Knorr, M. Macromol. Rapid Commun. 2015, 36, 654. (8) (a) Park, I.-H.; Lee, S. S. CrystEngComm 2011, 13, 6520. (b) Park, I.-H.; Kim, H. J.; Lee, S. S. CrystEngComm 2012, 14, 4589. (c) Kim, S.; Lee, E.; Park, K.-M.; Lee, S. S. CrystEngComm 2013, 15, 8544. (d) Ryu, H.; Park, K.-M.; Ikeda, M.; Habata, Y.; Lee, S. S. Inorg. Chem. 2014, 53, 4029. (9) Zhang, Y.; Wu, T.; Liu, R.; Dou, T.; Bu, X.; Feng, P. Cryst. Growth Des. 2010, 10, 2047. D

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Inorganic Chemistry (10) Knorr, M.; Bonnot, A.; Lapprand, A.; Khatyr, A.; Strohmann, C.; Kubicki, M. M.; Rousselin, Y.; Harvey, P. D. Inorg. Chem. 2015, 54, 4076. (11) APEX2: Data Collection and Processing Software, version 2009.10; Bruker AXS Inc.: Madison, WI, 2008. (12) SHELXTL-PC: Program for Solution and Refinement of Crystal Structures, version 6.22; Bruker AXS Inc.: Madison, WI, 2001.

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DOI: 10.1021/acs.inorgchem.5b02314 Inorg. Chem. XXXX, XXX, XXX−XXX