Article pubs.acs.org/crystal
S···π, π−π, and C−H···π Contacts Regulate Solid State Fluorescence in Regioisomeric Bisthiazolylpyrenes Shinaj K. Rajagopal,⊥ P. S. Salini,⊥ and Mahesh Hariharan* School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, CET Campus, Sreekaryam, Thiruvananthapuram, Kerala, India 695016 S Supporting Information *
ABSTRACT: The formation of well-defined packing motifs and control of π−π stacking by rationalizing the effects of molecular substitution in π-conjugated organic materials represent a significant challenge in supramolecular design. To explore the influence of the thiazolyl group in the solid state packing and photophysical properties of pyrene, a new class of three regioisomeric bisthiazolylpyrenes (2-2″TP) were designed and synthesized. Single crystal X-ray structure and quantum theory of atoms in molecules analysis revealed the presence of S···π interactions in 2′TP. Hirshfeld analysis showed the γ and β packing motif in 2TP and 2″TP, respectively, due to extensive π−π interactions, observed S···π interactions led to herringbone packing in 2′TP. The diverse packing arrangement of 2-2″TP led to a notable difference in the fluorescence behavior in the crystalline state. 2′TP possessing S···π interaction showed remarkable enhanced emission in the crystalline state compared to the amorphous state, in contrast to 2TP and 2″TP. Our results provide new insight for the rational design and regulation of intermolecular interactions of conjugated heterocyclic aromatics to achieve a diverse degree of orbital overlap between neighboring chromophore units and thereby favorable optoelectronic properties. explored in biomolecules.26,27 Among the chalcogens, noncovalent interactions involving sulfur atoms are prevalent in biological systems. Although sulfur is capable of forming a wide variety of noncovalent interactions mainly S···X (X = S, π, N, O, halogens) interactions,26,28−33 S···π interaction assisted supramolecular architecture has received less attention. Herein, we present our efforts to unravel the effect of regiochemistry of heterocyclic substituent, hence intermolecular interactions, in the generation of unique molecular architectures with distinct luminescent properties. In bisthiazolylpyrenes, the sulfur atom is ideally positioned to be involved in intermolecular interactions and can play a fundamental role in the interchromophoric association in the crystalline state. We took advantage of the well understood photophysics and of our own experience with the crystallization and regulation of intermolecular interactions of pyrene derivatives34−36 to achieve a diverse degree of orbital overlap between neighboring chromophore units.
1. INTRODUCTION Pyrene (P) based conjugated systems represent a burgeoning class of organic materials because of their potential applications in optoelectronics,1−4 biological probes,5,6 and liquid crystals.7,8 Albeit pyrene can be easily derivatized at 1, 3, 6, and 8positions,9 the regioselective preparation of disubstituted pyrene is highly challenging for the controlled synthesis of linear10 or cyclic oligomers11,12 as well as polymers.13,14 Recently, regioisomeric sulfur-bridged pyrene−thienoacenes have been synthesized as a new class of materials for organic field-effect transistor (OFET) applications.15 Functionalizing pyrene with heteroaromatics is particularly attractive since the abundance of electron-rich/-deficient atoms increases the number of noncovalent interactions in the solid state, creating fascinating and functional supramolecular architectures.16−18 There has been an increasing interest in the synthesis and investigation of the properties of heterocycle functionalized pyrene materials. Tuning the noncovalent interactions of π-conjugated materials is crucial to realize the structure−property relationships and to improve their design and function.1,19−23 The most explored interactions in this regard are hydrogen bonds, π−π stacking, and halogen interactions, which have earned immense attention across different realms of chemistry and biology.24,25 Besides, chalcogen interactions have been invoked as an intriguing class of noncovalent interactions and are well © 2016 American Chemical Society
2. EXPERIMENTAL SECTION 2.1. Materials and Methods. All reactions were carried out in oven-dried glassware prior to use and wherever necessary were Received: May 4, 2016 Revised: June 6, 2016 Published: June 16, 2016 4567
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Scheme 1. (a) Synthesis of 2-2″TP (b) Photographic Image of the Crystals in Daylight (above); and under UV Illumination (below) and (c) Molecular Structure of 2-2″TP
3026.31. Elemental analysis: calcd. value for C24H16N2S2: 72.70% C, 4.07% H, 7.06% N, 16.17% S; found: 72.90% C, 4.15% H, 7.01% N, 16.23% S. HRMS (EI) m/z calculated for C24H16N2S2 [M]+: 396.5272, found: 396.5290.
performed under dry nitrogen in dried, anhydrous solvents using standard gastight syringes, cannulae, and septa. Solvents were dried and distilled by standard procedures. Thin layer chromatography (TLC) analysis were performed on precoated aluminum plates of silica gel 60 F254 plates (0.25 mm, Merck), and developed TLC plates were visualized under short and long wavelength UV lamps. Flash column chromatography was performed using silica gel of 200−400 mesh employing a solvent polarity correlated with the TLC mobility observed for the substance of interest. Yields refer to chromatographically and spectroscopically homogeneous substances. Melting points were obtained using a capillary melting point apparatus and are uncorrected. IR spectra were recorded on a Shimadzu IRPrestige-21 FT-IR spectrometer as KBr pellets. 1H and 13C NMR spectra were measured on a 500 MHz Bruker advanced DPX spectrometer. The internal standard used for 1H and 13C NMR is 1,1,1,1-tetramethyl silane (TMS). All the elemental analyses were performed on an Elementar Vario MICRO Cube analyzer. All values recorded in elemental analyses are given in percentages. The reference standard used for elemental analysis is 4-aminobenzenesulfonic acid (sulphanilic acid). 2.2. Synthetic Procedure. Thioacetamide (42.5 mg; 0.57 mmol) and bromoacetylpyrene (BP) (100 mg; 0.23 mmol) were placed into a round bottomed flask. Ethanol (25 mL) was added, and the reaction was heated under reflux for 12 h. The residue was filtered under a vacuum and then washed with ethanol followed by diethyl ether. The residue was then suspended in ammonia (10 mL) for 20 h, filtered under a vacuum, and washed with water, ethanol, and diethyl ether and purified through column chromatography to give thiazolylpyrenes (22″TP). 2TP (Yield = 55%). Mp 159−161 °C. 1H NMR [500 MHz, DMSO, δ]: 8.59 (d, J = 9.25 Hz, 2H), 8.39 (s, 1H), 8.28 (d, J = 7.6 Hz, 2H), 8.19 (d, J = 9.30 Hz, 2H), 8.08 (m, 1H), 7.89 (s, 2H), 2.80 (s, 6H). 13 C NMR [125 MHz, DMSO, δ]: 165.86, 156.88, 131.95, 130.59, 129.98, 128.20, 127.85, 127.49, 125.38, 125.32, 125.25, 125.18, 117.95, 18.79. IR (KBr, cm−1): 3104.56, 3042.83. Elemental analysis: calcd. value for C24H16N2S2: 72.70% C, 4.07% H, 7.06% N, 16.17% S; found: 72.75% C, 4.20% H, 7.11% N, 16.30% S. HRMS (EI) m/z calculated for C24H16N2S2 [M]+: 396.5272, found: 396.5287. 2′TP (Yield = 64%). Mp 248−251 °C. 1H NMR [500 MHz, DMSO, δ]: 8.62 (d, J = 9.25, 2H), 8.31 (d, J = 7.95 Hz, 2H), 8.25 (d, J = 7.95 Hz, 2H), 8.19 (d, J = 7.9 Hz, 2H), 8.08 (s, 2H), 2.83 (s, 6H). 13C NMR [125 MHz, DMSO, δ]: 166.96, 156.48, 130.79, 130.02, 128.01, 127.45, 127.49, 125.69, 125.44, 125.31, 125.15, 117.65, 18.89. IR (KBr, cm−1): 3065.98, 2919.39. Elemental analysis: calcd. value for C24H16N2S2: 72.70% C, 4.07% H, 7.06% N, 16.17% S; found: 72.89% C, 4.17% H, 7.10% N, 16.27% S. HRMS (EI) m/z calculated for C24H16N2S2 [M]+: 396.5272, found: 396.5289. 2″TP (Yield = 68%). Mp 199−201.5 °C. 1H NMR [500 MHz, DMSO, δ]: 8.51 (s, 2H), 8.18 (d, J = 7.9 Hz, 2H), 8.15 (d, J = 7.9 Hz, 2H), 8.03 (s, 2H), 7.34 (s, 2H), 2.82 (s, 6H). 13C NMR [125 MHz, DMSO, δ]: 165.76, 154.68, 131.49, 130.02, 128.63, 127.76, 127.73, 125.59, 125.26, 125.11, 116.95, 19.38. IR (KBr, cm−1): 3109.25,
3. RESULTS AND DISCUSSION Hantzsch condensation37 of thioacetamide with corresponding bis(bromoacetyl)pyrene (Scheme 1a,c, Scheme S1 of the Supporting Information) rendered bisthiazolylpyrenes in 55% (2TP), 64% (2′TP), and 68% (2″TP) yield. 2-2″TP were characterized by spectroscopic and analytical techniques, and their structure was confirmed by single crystal X-ray diffraction analysis. Single crystals of 2TP and 2″TP suitable for X-ray diffraction were obtained through slow evaporation of chloroform/hexane mixtures, while that of 2′TP were obtained from dimethyl sulfoxide (Scheme 1b, Figure 1). 2TP, 2′TP, and 2″TP yielded solvent free monoclinic crystal system with space group P21/c, P21/n, and Cm, respectively (Table 1).
Figure 1. Single crystal X-ray structure of 2−2″TP.
In the single crystal X-ray structural analysis, varied twist angles are identified for the pyrene-thiazole planes of 2-2″TP. In 2TP, thiazole rings are found with torsional angles of 45.5° and 37.3° with respect to the pyrene plane, while the two thiazole rings in 2′TP and 2″TP exhibited the same torsional angle of 34° and 37.9°, respectively (Figure S1 of the Supporting Information). Compared to the C−H···π interactions mediated sandwich herringbone arrangement of P,38 22″TP generate three distinct packing arrangement utilizing the thiazole moiety including criss-cross, herringbone, and columnar arrangement (Figure 2). 2TP generates a selfassembled dimer associated via intermolecular C−H···π interactions involving C−H of the methyl group with the π electron cloud of the neighboring pyrene moiety between C−H of the methyl group and the π-electron cloud of the thiazole moiety (C−H···π: 2.9 Å and 136°) (Figure 3). Two types of 4568
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Table 1. Crystal Data and Structure Refinement for 2-2″TP formula formula wt color, shape dimens, mm crystal system space group, Z a, Å b, Å c, Å α, deg β, deg γ, deg V, Å3 temp, K dcalcd, g/cm−3 no. of reflections collected no. of unique reflections 2θmax, deg no. of parameters R1, wR2 (I > 2σ(I)) R1, wR2 (all data) goodness of fit
2TP
2′TP
2″TP
C24H16N2S2 396.51 brown 0.20 × 0.2 × 0.15 monoclinic P21/c, 4 17.9907 13.6508 7.4219 90 91.025 91.4730 1822.43 296 1.444 16108 3977 50 255 0.0420, 0.1146 0.0577,0.1282 1.027
C24H16N2S2 396.51 yellow 0.20 × 0.15 × 0.10 monoclinic P21/n, 2 9.0339 10.0371 11.1876 90 113.5140 90.0 930.19 296 1.415 14252 1830 50 128 0.0312, 0.0863 0.0357, 0.0907 1.037
C24H16N2S2 396.51 yellow 0.25 × 0.20 × 0.15 monoclinic Cm, 2 8.3153 27.633 3.9437 90.0 91.162 90.0 905.97 296 1.452 3850 1820 50 128 0.0243, 0.0676 0.0249, 0.0685 1.073
Figure 2. (a) Criss cross, (b) herringbone, and (c) columnar stacking of 2TP, 2′TP, and 2″TP, respectively. (d) Sandwich herringbone packing of P is given for comparison from ref 38.
pyrene units have an interplanar distance of 3.6 Å and a 72° rotation of each molecule along the stack axis, with the molecular long axes alternate nearly perpendicular to one another (Figure 2a). However, in 2′TP, unusual S···π interaction between thiazole unit and π electron cloud of neighboring pyrene moiety (S···π: 3.5 Å), mediated 2Dherringbone arrangement was observed with a molecular tilt angle and herringbone angle of 16° and 80.8°, respectively (Figure 2b). Each molecule can generate up to four S···π interactions with the neighboring molecules creating a pentamer cluster which is repeated along the bc-plane (Figure 5). In addition to the 2D assembly, 2′TP generates a 1-D array through C−H···π interaction, between neighboring pyrene units (C−H···π: 2.9 Å and 138°) and C−H···N interaction between the pyrene moiety of one molecule with the neighboring thiazole unit (C−H···N: 2.5 Å and 151°) (Figure S2 of the Supporting Information). Large transverse/ longitudinal displacement of 5.17 and 5.5 Å, respectively, of the vicinal pyrene units in the crystal structure of 2′TP prohibits the π-contacts between neighboring pyrene units. In sharp contrast, there is no significant hydrogen bonding (nonclassical C−H···π) interactions in the crystal packing of 2″TP, instead prefers face- to-face arrangement of pyrene units
Figure 3. Self-assembled dimer of 2TP formed by the intermolecular C−H···π interactions.
1D supramolecular arrays are generated by the intermolecular C−H···π interactions between (i) C−H of the methyl group and the π electron cloud of the thiazole moiety (C−H···π: 2.8 Å and 138°) and (ii) thiazole moieties in the neighboring molecules (C−H···π: 2.7 Å and 163°) (Figure 4) yielding a criss-crossed π-stacked arrangement. The π-stacks between 4569
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Figure 4. C−H···π interactions in 2TP between (a) C−H of the methyl group and the π electron cloud of the thiazole moiety and (b) thiazole moieties in the neighboring molecules.
Figure 5. Pentamer of 2′TP generated by the intermolecular S···π interactions between neighboring pyrene units and thiazole units.
whereas π−π interaction comprises 13.8%, 1.5%, and 15.2% (Figure 7). The ratio (ρ) of %C···H to %C···C interactions are determined to find out the packing motifs. A significantly higher value of 2′TP (ρ = 21.2) indicates the herringbone structure, while that of 2TP (ρ = 1.18) and 2″TP (ρ = 0.85) suggests the γ and the β-structures, respectively. In P, 36.4% of C−H···π and 10.6% of π−π interactions corresponds to a ρ value of 3.4 revealing a sandwich herringbone arrangement in the crystalline state (Figure 7 and Table 2). Intermolecular S···π interaction in 2′TP is further confirmed by QTAIM analysis (Figure 8).40,41 The accumulation of electron charge density [ρb(r)] of 0.045 e·Å−3 and a positive value of Laplacian [∇2ρb(r)] of 0.517 e·Å−5 at the (3, −1) bond critical point (BCP) with the interaction distance of 3.49 Å demonstrates the presence of extended S···π interaction along the bc-plane in 2′TP. The role of regio-effects of the thiazole moiety on the electronic properties of pyrene was investigated using frontier molecular orbital (FMO) analysis, cyclic voltammetric, UV−vis absorption, and fluorescence measurements. FMO analysis of 2-2″TP shows that the electron density of HOMO and LUMO orbitals is distributed throughout the whole molecule (Figure 9 and Table S1 of the Supporting Information). The relative position of the substituents does not influence the energy levels
exhibiting π−π stacking interaction with an interplanar distance of 3.9 Å leading to a 1-D columnar arrangement (Figures 6 and 2c). Similar to 2″TP, a columnar arrangement was also observed in 2,7-bisthiazolylpyrene reported by Zhu and coworkers.36
Figure 6. π−π interaction between pyrene moieties in 2″TP.
The effect of position of thiazole units for generating diverse packing arrangements in crystalline 2-2″TP is further investigated by Hirshfeld surface analysis.39 Intermolecular interactions in 2-2″TP are summarized in Table 2. The strong C−H···π interaction comprises 16.3%, 31.8%, and 12.9% of the total Hirshfeld surfaces for 2TP, 2′TP, and 2″TP, respectively, 4570
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Table 2. Shows the Percentage of Intermolecular Contacts of a Molecule in Crystalline 2-2″TP 2TP 2′TP 2″TP P
H···H
C···H
C···C
S···H
N···H
S···C
S···S
S···N
C···N
ρa
42.7 37.6 44.9 53.0
16.3 31.8 12.9 36.4
13.8 1.5 15.2 10.6
15.6 10.7 16.3
7.7 7.9 7.1
1.1 8.4 1.0
1.1 0.0 0.4
0.9 0.1 0.0
0.7 2.0 2.2
1.18 21.20 0.85 3.4
a
Total percentage of intermolecular contacts ca. 99.9% (2TP), 100% (2′TP), 100% (2″TP), and 100% (P). Herringbone (ρ > 4.5), sandwich herringbone (3.2 < ρ < 4.0), γ (1.2 < ρ < 2.7), β (0.46 < ρ < 1.0). ρ = (%C···H)/(%C···C).
Figure 7. Hirshfeld 2D fingerprint plot of (a) 2TP, (b) 2′TP, (c) 2″TP, and (d) P42 with the region of the plots corresponding to C···C interaction.
Figure 8. QTAIM electron density map of 2′TP with arrow indicating the existence of intermolecular S···π contacts.
of HOMO and LUMO orbitals as the substituents contribute to the molecular orbitals in a similar manner. The oxidation potentials of 2-2″TP were identified by cyclic voltammetric studies (0.1 M nBu4NPF6 in acetonitrile) (Figure S3 of the Supporting Information). A one-electron oxidation was observed at ∼1.1 V for 2-2″TP, while the reduction wave was not resolved before solvent decomposition. Steady-state absorption spectra of 2-2″TP in chloroform exhibit two distinct bands centered at 290 and 360 nm, respectively (Figure S4a and Table S2 of the Supporting Information). The higher and lower energy bands are attributed to a combination of several electronic transitions as evidenced from time dependent density functional theory (TDDFT)43,44 calculations. Tethering thiazole moiety in P resulted in considerable red shift (30 nm) in the UV−vis absorption maximum of 2-2″TP, when compared to P (λmax = 337 nm)35 in chloroform (Table S2 of the Supporting Information). Noticeably, 2-2″TP exhibited identical absorption spectra, which shows that the regiochemistry of thiazole unit has a negligible effect on the absorption wavelength. Upon excitation at 365 nm, the emission spectrum of 2-2″TP in chloroform exhibits red-shifted peaks compared to that of P (λmax = 390
Figure 9. Illustrations of the frontier molecular orbitals of (a) 2TP; (b) 2′TP; and (c) 2″TP evaluated at the B3LYP/6-311G**+ from the crystal structure.
nm)35 (Table S2 of the Supporting Information). For 2TP, a peak at 403 nm was observed with a shoulder at 419 nm (Φf = 47%), whereas 2′TP (Φf = 50%) and 2″TP (Φf = 58%) show an emission peak at 409 nm and shoulder at 429 nm, respectively (Figure S4b and Table S2 of the Supporting Information). Picosecond time-resolved fluorescence measurements of 2−2″TP in chloroform (λex = 375 nm) indicate short fluorescence lifetimes when monitored at the respective emission maximum (τf = 1.93 ns for 2TP τf = 0.72 ns for 2′TP and τf = 1.33 ns for 2″TP) (Figure S4c and Table S2 of the Supporting Information). In the crystalline state, it is noteworthy that there is a significant position dependent effect for both the absorption and emission properties of 2-2″TP (Figure 10a,b, Table S2 of the Supporting Information). Diffuse reflectance absorption spectra of crystalline 2-2″TP exhibit a band centered around 4571
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Figure 10. (a) Absorption, (b) emission spectra as compared to P, (c) schematic representation of close packing in crystalline 2-2″TP.
340−435 nm, with an additional absorption tail extending to 600 nm for 2TP. λmax of 2TP, 2′TP, and 2″TP were found to be red-shifted compared to P (Δλmax = 41 nm for 2TP, Δλmax = 4 nm for 2′TP, and Δλmax = 16 nm for 2″TP).35 The broad absorption spectra of crystalline 2TP and 2″TP indicate plausible formation of aggregates in the crystalline state, while that of 2′TP possesses vibronic features owing to the herringbone arrangement. The observed red-shifted tail for 2TP was due to the increased π−π overlap and a marked decrease in the interplanar distance compared to 2″TP (Table S3). Upon excitation at 380 nm, crystalline 2TP exhibits a peak centered at 528 nm while that of 2′TP and 2″TP is observed at 471 and 547 nm, respectively. A remarkable red shift is observed in the emission spectra of 2TP and 2″TP when compared to P (Δλmax = 56 nm for 2TP, and Δλmax = 27 nm for 2″TP), while the λmax value of 471 nm in 2′TP is comparable to that of P (λmax = 472 nm).35 Notably, a significant blue shift of 76 nm was observed in the emission maximum of 2′TP compared to 2″TP. The blue shift arises from the herringbone structure, where the contribution of π−π interactions is negligible compared to 2TP and 2″TP, imparting a monomer-like behavior in the crystalline state (Figures 10c and 11a). In the excitation spectra of crystalline 2-2″TP, an emission wavelength dependent red shift was observed compared to the corresponding steady state absorption spectra suggesting the possible ground state interaction between the vicinal pyrene units (Figure S5 of the Supporting Information).45
Upon excitation at 375 nm, picosecond time-resolved fluorescence measurements of crystalline 2-2″TP show triexponential decay having average lifetimes of 2.95, 2.01, and 12.99 ns, respectively, when monitored at their respective emission maximum (Figure 11b, Table S2 of the Supporting Information). Longer fluorescence lifetime (τf = 14.2 ns) observed for 2″TP when compared to 2TP and 2′TP could arise from an excited oligomer21 resulting from face to face columnar geometry in 2″TP. A major component of 2′TP shows a shorter lifetime comparable to the solution state, corroborating its monomer like behavior in the crystalline state due to a herringbone arrangement. Furthermore, 2-2″TP showed enhanced emission behavior in the crystalline state compared to the amorphous state as evidenced from quantum yield measurements. Intriguingly, 2′TP with minimum π−π stacking interaction, owing to the S···π interactions mediated herringbone structure, showed a 7-fold emission enhancement in the crystalline state when compared to the amorphous state, while π−π stacking interaction mediated 2TP and 2″TP exhibited 1.44 and 1.69 fold, respectively (Table S2 of the Supporting Information).
4. CONCLUSIONS In summary, three highly conjugated regioisomers of bisthiazolylpyrene are reported, and the effect of position of substituents in modulation of the crystal packing and luminescent properties is investigated. 2-2″TP shows distinct position dependent π-stacked arrangements in the crystalline state including criss-crossed, herringbone, and face-to-face arrangement. Among these regioisomeric bisthiazolylpyrenes, 2′TP showed remarkable properties compared to 2TP and 2″TP. The S···π interaction generated herringbone structure in 2′TP led to a monomer-like arrangement and showed a 7-fold enhancement in the quantum yield compared to the amorphous state. We believe that this fundamental research will provide new insight for the rational design and synthesis of conjugated heterocyclic aromatics for the applications of highperformance optoelectronic materials.
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ASSOCIATED CONTENT
S Supporting Information *
Figure 11. (a) CIE color diagram of fluorescence emission and (b) lifetime studies for crystalline 2-2″TP.
The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.cgd.6b00676. 4572
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(20) Jiang, L.; Gao, J.; Fu, Y.; Dong, H.; Zhao, H.; Li, H.; Tang, Q.; Chen, K.; Hu, W. Nanoscale 2010, 2, 2652. (21) Hinoue, T.; Shigenoi, Y.; Sugino, M.; Mizobe, Y.; Hisaki, I.; Miyata, M.; Tohnai, N. Chem. - Eur. J. 2012, 18, 4634. (22) Feng, Q.; Wang, M.; Dong, B.; He, J.; Xu, C. Cryst. Growth Des. 2013, 13, 4418. (23) Varughese, S. J. Mater. Chem. C 2014, 2, 3499. (24) Vargas Jentzsch, A.; Hennig, A.; Mareda, J.; Matile, S. Acc. Chem. Res. 2013, 46, 2791. (25) Cavallo, G.; Metrangolo, P.; Milani, R.; Pilati, T.; Priimagi, A.; Resnati, G.; Terraneo, G. Chem. Rev. 2016, 116, 2478. (26) Wang, W.; Ji, B.; Zhang, Y. J. Phys. Chem. A 2009, 113, 8132. (27) Lange, A.; Günther, M.; Büttner, F. M.; Zimmermann, M. O.; Heidrich, J.; Hennig, S.; Zahn, S.; Schall, C.; Sievers-Engler, A.; Ansideri, F.; Koch, P.; Laemmerhofer, M.; Stehle, T.; Laufer, S. A.; Boeckler, F. M. J. Am. Chem. Soc. 2015, 137, 14640. (28) Iwaoka, M.; Takemoto, S.; Tomoda, S. J. Am. Chem. Soc. 2002, 124, 10613. (29) Esparza-Ruiz, A.; Peña-Hueso, A.; Hernández-Díaz, J.; FloresParra, A.; Contreras, R. Cryst. Growth Des. 2007, 7, 2031. (30) González, F. V.; Jain, A.; Rodríguez, S.; Sáez, J. A.; Vicent, C.; Peris, G. J. Org. Chem. 2010, 75, 5888. (31) Chiu, C.-Y.; Kim, B.; Gorodetsky, A. A.; Sattler, W.; Wei, S.; Sattler, A.; Steigerwald, M.; Nuckolls, C. Chem. Sci. 2011, 2, 1480. (32) Daeffler, K. N. M.; Lester, H. A.; Dougherty, D. A. J. Am. Chem. Soc. 2012, 134, 14890. (33) Beno, B. R.; Yeung, K.-S.; Bartberger, M. D.; Pennington, L. D.; Meanwell, N. A. J. Med. Chem. 2015, 58, 4383. (34) Nagarajan, K.; Rajagopal, S. K.; Hariharan, M. CrystEngComm 2014, 16, 8946. (35) Rajagopal, S. K.; Philip, A. M.; Nagarajan, K.; Hariharan, M. Chem. Commun. 2014, 50, 8644. (36) Qiao, Y.; Zhang, J.; Xu, W.; Zhu, D. Tetrahedron 2011, 67, 3395. (37) Hantzsch, A.; Weber, J. H. Ber. Dtsch. Chem. Ges. 1887, 20, 3118. (38) Robertson, J. M.; White, J. G. J. Chem. Soc. 1947, 358−368. (39) CrystalExplorer 3.0, Wolff, S. K.; Grinwood, D. J.; McKinnon, J. J.; Turner, M. J.; Jayatilaka, D.; Spackman, M. A. University of Western Australia, Perth, Australia, 2012. (40) Volkov, A.; Macchi, P.; Farrugia, L. J.; Gatti, C.; Mallinson, P. R.; Richter, T.; Koritsanszky, T. A Computer Program Package for Multipole Refinement, Topological Analysis of Charge Densities and Evaluation of Intermolecular Energies from Experimental or Theoretical Structure Factors, User Manual; 2006; Vol. XD2006 (41) Bader, R. F. W. Atoms in Molecules: A Quantum Theory; Oxford University Press: Oxford, U.K., 1990. (42) Fabbiani, F. P.; Allan, D. R.; Parsons, S.; Pulham, C. R. Acta Crystallogr., Sect. B: Struct. Sci. 2006, 62, 826. (43) Lee, C.; Yang, W.; Parr, R. G. Phys. Rev. B: Condens. Matter Mater. Phys. 1988, 37, 785. (44) Becke, A. D. J. Chem. Phys. 1993, 98, 5648. (45) Lewis, F. D.; Yang, J.-S. J. Phys. Chem. B 1997, 101, 1775.
Detailed description of synthesis and characteristics of compounds, spectral measurements, X-ray crystallography, cyclic voltammetry, and computational methods of 2-2″TP (PDF) Accession Codes
CCDC 1469554−1469556 contain the supplementary crystallographic data for this paper. These data can be obtained free of charge via www.ccdc.cam.ac.uk/data_request/cif, or by emailing
[email protected], or by contacting The Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: +44 1223 336033.
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AUTHOR INFORMATION
Corresponding Author
*E-mail
[email protected]. Author Contributions ⊥
S.K.R. and P.S.S. contributed equally.
Notes
The authors declare no competing financial interest.
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ACKNOWLEDGMENTS M.H. acknowledges Kerala State Council for Science, Technology and Environment (KSCSTE) for the support of this work, 007/KSYSA-RG/2014/KSCSTE. The authors thank Alex P. Andrews, IISER-TVM for single crystal X-ray structure analyses.
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REFERENCES
(1) Sasaki, S.; Igawa, K.; Konishi, G.-i. J. Mater. Chem. C 2015, 3, 5940. (2) Figueira-Duarte, T. M.; Müllen, K. Chem. Rev. 2011, 111, 7260. (3) Chercka, D.; Yoo, S.-J.; Baumgarten, M.; Kim, J.-J.; Mullen, K. J. Mater. Chem. C 2014, 2, 9083. (4) Oniwa, K.; Kikuchi, H.; Shimotani, H.; Ikeda, S.; Asao, N.; Yamamoto, Y.; Tanigaki, K.; Jin, T. Chem. Commun. 2016, 52, 4800. (5) Fujimoto, K.; Yamada, S.; Inouye, M. Chem. Commun. 2009, 7164. (6) Wu, J.; Zou, Y.; Li, C.; Sicking, W.; Piantanida, I.; Yi, T.; Schmuck, C. J. Am. Chem. Soc. 2012, 134, 1958. (7) Sienkowska, M. J.; Monobe, H.; Kaszynski, P.; Shimizu, Y. J. Mater. Chem. 2007, 17, 1392. (8) Diring, S.; Camerel, F.; Donnio, B.; Dintzer, T.; Toffanin, S.; Capelli, R.; Muccini, M.; Ziessel, R. J. Am. Chem. Soc. 2009, 131, 18177. (9) Feng, X.; Tomiyasu, H.; Hu, J.-Y.; Wei, X.; Redshaw, C.; Elsegood, M. R. J.; Horsburgh, L.; Teat, S. J.; Yamato, T. J. Org. Chem. 2015, 80, 10973. (10) Qu, L.; Shi, G. Chem. Commun. 2004, 2800. (11) Bolink, H. J.; Barea, E.; Costa, R. D.; Coronado, E.; Sudhakar, S.; Zhen, C.; Sellinger, A. Org. Electron. 2008, 9, 155. (12) Iwamoto, T.; Kayahara, E.; Yasuda, N.; Suzuki, T.; Yamago, S. Angew. Chem., Int. Ed. 2014, 53, 6430. (13) Häner, R.; Samain, F.; Malinovskii, V. L. Chem. - Eur. J. 2009, 15, 5701. (14) Kim, J.-H.; Kim, H. U.; Kang, I.-N.; Lee, S. K.; Moon, S.-J.; Shin, W. S.; Hwang, D.-H. Macromolecules 2012, 45, 8628. (15) Zhang, S.; Qiao, X.; Chen, Y.; Wang, Y.; Edkins, R. M.; Liu, Z.; Li, H.; Fang, Q. Org. Lett. 2014, 16, 342. (16) Wang, Y.; Wang, H.; Liu, Y.; Di, C.-a.; Sun, Y.; Wu, W.; Yu, G.; Zhang, D.; Zhu, D. J. Am. Chem. Soc. 2006, 128, 13058. (17) Cho, H.; Lee, S.; Cho, N. S.; Jabbour, G. E.; Kwak, J.; Hwang, D.-H.; Lee, C. ACS Appl. Mater. Interfaces 2013, 5, 3855. (18) Mateo-Alonso, A. Chem. Soc. Rev. 2014, 43, 6311. (19) Foster, J. A.; Piepenbrock, M.-O. M.; Lloyd, G. O.; Clarke, N.; Howard, J. A. K.; Steed, J. W. Nat. Chem. 2010, 2, 1037. 4573
DOI: 10.1021/acs.cgd.6b00676 Cryst. Growth Des. 2016, 16, 4567−4573
