Yan
Li
,
Weiping
Yang
,
Yuanyin
Chen
and
Shuling
Gong
*
College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, PR China. E-mail: gongsl@whu.edu.cn; Fax: + 86 27 68754067; Tel: + 86 27 68752701
First published on 7th September 2010
Five 1,3-alternatethiacalix[4]arene derivatives bearing carboxylic acid and/or urea hydrogen-bonding groups were prepared and their crystal structures were determined by single-crystal X-ray diffraction methods. In compound 1, where the pendant arms are all adorned with carboxylic acid groups, the pendants all orientate along the base of the molecular axis. An interesting three-dimensional network of “endo-inclusion” aquatubes is formed by stacking the water contained cavities of 1 up and down. While concerning to the other four compounds to which the urea groups are introduced, their pendant arms either orientate towards the inner side of the cavities, or orientate towards the outside, depending on the types of hydrogen-bonding groups and the position of these groups. When the urea groups are in the same side (compounds 2, 4 and 5), the opposite chains in the molecule will locate away from each other which may be due to the steric repulsions. But when the urea group and carboxylic acid group are in the same side (compounds 3 and 4), the opposite chains all orientate inwards because of the intramolecular, inter-chain hydrogen bonds between the opposite chains. Although these four compounds can also self-assemble through the cavity stacking motif, the inwardly orientated pendant arms which protrude into the thiacalixarene cavity obstruct the channels.
Our early work reported such a one-dimensional channel formed by the self-assembly of 1,2-alternate p-tert-butylcalix[4]arene tetra-acetic acid.5d In the present contribution we have expanded our studies with the 1,3-alternate p-tert-butylthiacalix[4]arene framework mainly due to the following reasons: (1) the tubular shape of 1,3-alternate skeleton7 usually invokes the idea of forming the channels in the solid state by the cavity stacking motif;5a,5b (2) the presence of sulfur atoms in place of the usual CH2 bridges makes thiacalixarenes behaving many unique features compared with “classical” calixarenes, such as the larger cavity dimensions and metal complexation through the sulfur atoms which make these compounds good candidates for exploring the guest inclusion properties of cavity; and (3) the 1,3-alternate derivatives of p-tert-butylthiacalix[4]arene are easily accessible in multi-gram amounts without chromatographic purification, while the 1,3-alternate derivatives of p-tert-butylcalix[4]arene can only be obtained rarely by the trivial procedure.8
A variety of reversible intermolecular interactions such as coordination bonding, electrostatic, van der Waals forces or hydrogen and halogen bonding have been used, sometimes in combination, for the generation of solid state supramolecular architectures.9 For the formation of purely organic materials multiple hydrogen bonds are particularly attractive, since they are relatively strong, directional, and many of them can act simultaneously.9,10
Based upon the above conception, five 1,3-alternate thiacalix[4]arene derivatives bearing carboxylic acid and/or urea hydrogen-bonding groups at the lower rim have been synthesized (Scheme 1). Their molecular structures and self-assembly behaviour in the solid state are studied. Mainly, the orientation of the pendant arms and its influence on the formation of nanotubes formed by the cavity sacking motif are emphasized.
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Scheme 1 Syntheses of the compounds. |
Structure no. | Plane AR | Plane BR | Plane CR | Plane DR |
---|---|---|---|---|
1 | 103.94 | 102.43 | 102.58 | 100.25 |
2 | 107.87 | 121.56 | 104.38 | 112.54 |
3 | 116.47 | 104.17 | ||
4 | 102.96 | 108.17 | 116.38 | 115.49 |
5 | 112.90 | 109.28 | 110.58 | 119.51 |
Structure no. | Plane AC | Plane BD |
---|---|---|
1 | 26.53 | 22.69 |
2 | 32.25 | 54.13 |
3 | 40.68 | 40.68 |
4 | 39.44 | 43.72 |
5 | 43.49 | 48.86 |
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Fig. 1 Molecular structures of the five compounds. The hydrogen atoms connected to carbon atom and disordered atoms are all omitted for clarity. |
However, compared with the cavity shape, the most significant differences among these thiacalix[4]arenes are the spatial orientation of the pendant arms with respect to the calixarene cavity which can be established by examining the torsion angles related to the four chains reported in Table 3.
Chain A | Chain B | Chain C | Chain D | |
---|---|---|---|---|
1 | C6–O1–C11–C12 | C38–O4–C47–C48 | C30–O7–C35–C36 | C14–O10–C23–C24 |
−175.5(3) | −175.9(4) | −173.7(4) | −175.1(4) | |
O1–C11–C12–O2 | O4–C47–C48–O5 | O7–C35–C36–O9 | O10–C23–C24–O11 | |
−2.0(7) | −1.4(8) | −7.3(6) | −4.8(8) | |
O1–C11–C12–O3 | O4–C47–C48–O6 | O7–C35–C36–O8 | O10–C23–C24–O12 | |
178.3(4) | 178.5(5) | 174.4(4) | 177.0(5) | |
2 | C1–O1–C11–C12 | C15–O4–C24–C25 | C27–O7–C36–C37 | C40–O10–C49–C50 |
177.4(2) | 175.9(2) | 116.9(3) | 60.3(3) | |
O1–C11–C12–N2 | O4–C24–C25–O5 | O7–C36–C37–N1 | O10–C49–C50–O11 | |
6.7(4) | 8.5(4) | −4.7(3) | 93.3(3) | |
O1–C11–C12–O2 | O4–C24–C25–O6 | O7–C36–C37–O8 | O10–C49–C50–O12 | |
−172.2(3) | −171.2(3) | 176.4(2) | −88.1(4) | |
C11–C12–N2–C13 | C36–C37–N1–C38 | |||
−176.3(3) | −176.5(3) | |||
C12–N2–C13–O3 | C37–N1–C38–O9 | |||
171.7(3) | −176.7(3) | |||
C12–N2–C13–N4 | C37–N1–C38–N3 | |||
−7.8(5) | 5.1(4) | |||
3 | C1–O1–C11–C12 | C14–O4–C23–C24 | ||
171.9(4) | −167.1(5) | |||
O1–C11–C12–O3 | O4–C23–C24–N1 | |||
15.1(7) | −12.7(9) | |||
O1–C11–C12–O2 | O4–C23–C24–O5 | |||
−164.9(6) | 170.3(6) | |||
C23–C24–N1–C25 | ||||
−177.9(6) | ||||
C24–N1–C25–O6 | ||||
180.0(6) | ||||
C24–N1–C25–N2 | ||||
−0.1(9) | ||||
4 | C6–O1–C11–C12 | C19–O4–C24–C25 | C32–O7–C37–C38 | C45–O10–C50–C51 |
114.4(9) | 171.1(4) | 175.4(8) | 178.6(6) | |
O1–C11–C12–N1 | O4–C24–C25–N3 | O7–C37–C38–N5 | O10–C50–C51–O11 | |
−6.3(3) | 7.0(6) | −0.2(7) | 166.0(1) | |
O1–C11–C12–O2 | O4–C24–C25–O5 | O7–C37–C38–O8 | O10–C50–C51–O12 | |
170.1(9) | 171.0(5) | 179.9(0) | −18.2(4) | |
C11–C12–N1–C13 | C24–C25–N3–C26 | C37–C38–N5–C39 | ||
172.8(8) | 175.3(9) | 178.4(2) | ||
C12–N1–C13–O3 | C25–N3–C26–O6 | C38–N5–C39–O9 | ||
176.1(6) | 174.5(3) | 177.1(4) | ||
C12–N1–C13–N2 | C25–N3–C26–N4 | C38–N5–C39–N6 | ||
4.7(0) | −10.1(4) | 1.0(8) | ||
5 | C1–O1–C11–C12 | C19–O4–C24–C25 | C28–O7–C37–C38 | C45–O10–C50–C51 |
−177.4(3) | −79.0(3) | 81.0(3) | −167.0(2) | |
O1–C11–C12–N1 | O4–C24–C25–N3 | O7–C37–C38–N5 | O10–C50–C51–N7 | |
−9.5(4) | −76.7(3) | 79.9(3) | −7.6(4) | |
O1–C11–C12–O2 | O4–C24–C25–O5 | O7–C37–C38–O8 | O10–C50–C51–O11 | |
172.6(3) | 101.1(3) | −99.2(3) | 172.8(3) | |
C11–C12–N1–C13 | C24–C25–N3–C26 | C37–C38–N5–C39 | C50–C51–N7–C52 | |
−179.4(3) | 164.7(3) | −179.2(3) | −178.9(3) | |
C12–N1–C13–O3 | C25–N3–C26–O6 | C38–N5–C39–O9 | C51–N7–C52–O12 | |
172.8(3) | −172.8(3) | −179.3(3) | 170.5(3) | |
C12–N1–C13–N2 | C25–N3–C26–N4 | C38–N5–C39–N6 | C51–N7–C52–N8 | |
−5.6(5) | 6.7(5) | 0.3(5) | −11.4(4) |
The torsion angles of the four pendant arms of compound 1 show that the pendants' orientations are very similar. As illustrated in Fig. 1, the four pendant arms are all oriented along the base of the molecular axis. There is no intramolecular hydrogen bond between the two opposing pendant arms. But there are two water molecules, which occupy the cavity of compound 1. The intermolecular hydrogen bond between water and the methyleneoxycarboxylic acid group will be discussed in detail in the following.
In compound 2, two carboxyl groups are located on one side; two urea groups are located on the other side. The values of torsion angle in Table 3 show that the four pendant arms in compound 2 are oriented in pairs, one with chain B and chain A pointing towards the inner side of the calixarene cavity and the second with chain C and chain D pointing towards the outside, as illustrated in Fig. 1. The carboxyl group on chain B formed one intramolecular hydrogen bond O5⋯O10 (2.923 Å) with the opposing chain D, which leads to the burying of chain B in the cavity of the thiacalixarene and also the unusual large interplanar angles between the opposing aromatic rings B and D. There is no intramolecular, inter-chain hydrogen bond between the opposing chains A and C. But four intra-chain N–H⋯O hydrogen bonds exist in these two urea chains. Two are between NH2 group and CH2CO group, N3⋯O8 (2.705 Å) and N4⋯O2 (2.705 Å). The other two are between phenolic oxygen atom and NH group, N1⋯O7 (2.712 Å) and N2⋯O1 (2.627 Å).
Compound 3 also has two carboxyl groups and two urea groups as compound 2, the only difference is that the same groups are no longer located on the same side, but averagely on the two sides separated by the S1–S2–S3–S4 plane. And one half of the molecule is deduced from the other half by a twofold screw axis which located at (1/2, y, 1/4). The four pendant arms all orientate inwardly with respect to the calixarene cavity which may be due to the two intramolecular hydrogen bonds between the opposing pendant arms: O3⋯O6 (2.557 Å) and N1⋯O3 (3.170 Å) (Fig. 1). Besides, there are also four intra-chain N–H⋯O hydrogen bonds which is similar to compound 2.
There are three urea groups and one carboxyl group in compound 4 whose structure is comprised of two parts: (I) half part of compound 2 (the urea part) and (II) half part of compound 3. In part (I), one urea chain orientates outwardly (chain A) and one urea chain orientates inwardly (chain C). There is no intramolecular hydrogen bond between these two chains. In part (II), both chains (chain B and chain D) orientate inwardly because of the hydrogen bonds O12⋯O6 (2.504 Å) and N3⋯O12 (3.109 Å) (Fig. 1). The pendant orientation of the two parts is also consistent with the same parts in compound 2 and compound 3. There are six intra-chain N–H⋯O hydrogen bonds, three between NH2 group and CH2CO group and three between phenolic oxygen atom and NH group.
The spatial orientation of the four pendant arms of compound 5 is similar to compound 2 (Fig. 1). Two orientate inwardly (chain A and chain D) and two orientate outwardly (chain B and chain C). There is one intramolecular hydrogen bond N3⋯O12 (2.862 Å) between the opposing chains B and D and one N5⋯O3 (2.951 Å) between the opposing chains A and C. And like compounds 2, 3 and 4, the intra-chain N–H⋯O hydrogen bonds are also present in the four urea chains. Four are between NH2 group and CH2CO group, N2⋯O2 (2.691 Å), N4⋯O5 (2.737 Å), N6⋯O8 (2.675 Å) and N8⋯O11 (2.663 Å). Two are between phenolic oxygen atom and NH group, N1⋯O1 (2.607 Å), N7⋯O10 (2.654 Å).
From the above analysis we can see that in compound 1 where the pendant arms are all adorned with carboxylic acid groups, the pendants all orientate along the base of the molecular axis. Water molecules may also play a role in stabilizing the structure. While concerning to the other four compounds to which the urea groups are introduced, their pendant arms either orientate towards the inner side of the cavity, or orientate towards the outside. When the same substituted groups are in the same side, the opposite chains in the molecule will locate away from each other. That is, if one chain orientates towards the cavity, the relative opposite chain will orientate outwards, which is obvious in compounds 2, 4 and 5. This may be due to the steric repulsions between the substituted opposite chains. But when the carboxylic acid group and urea group are in the same side (compounds 3 and 4), i.e. the hydrogen-bond recognition sites are arranged in a complementary manner, the situation is different. The opposite chains all orientate inwards because of the intramolecular, inter-chain hydrogen bonds between the opposite chains. Besides, there is a common characteristic in the inwardly orientated urea chains, all the atoms on these chains are almost in the same plane, as can be seen from the torsion angles in Table 3. There are always two types of intra-chain N–H⋯O hydrogen bonds in these chains, the hydrogen bond between NH2 group and CH2CO group, and the hydrogen bond between phenolic oxygen atom and NH group.
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Fig. 2 Stacking diagrams of tapes of 1. Up: side view perpendicular to b axis; down: top view along the b axis. Hydrogen-bonded interactions are shown as broken lines. The hydrogen atoms connected to carbon atom, disordered atoms and water molecules are all omitted for clarity. |
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Fig. 3 The three-dimensional network of aquatubes of 1. The thiacalix[4]arene molecules in the same sheet are coloured with the same colour. |
In the crystal structure of compound 2, two molecules form a dimer through the cavity stacking motif viahydrogen bonds N4⋯O3 (3.091 Å) and N4⋯O8 (2.961 Å) (Fig. 4). Then neighbouring dimers connect each other side-by-side by the outwardly orientated chain C and chain D via a cyclic motif R22(8) which is formed by hydrogen bond N3⋯O12 (3.013 Å) and O11⋯O9 (2.622 Å). The buried chain B doesn't take part in the formation of the intermolecular hydrogen bond. The overall packing arrangement of 2 takes on a 1D double-stranded ladder-like chain form.
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Fig. 4 The 1D double-stranded ladder-like chain structures of 2. Hydrogen-bonded interactions are shown as broken lines. The hydrogen atoms connected to carbon atom and disordered atoms are all omitted for clarity. |
The self-assembly behaviour of compound 3 is the simplest among the five compounds. Neighbouring compounds connect to each other viahydrogen bond N2⋯O2 (3.154 Å) resulting in a 1D single-stranded linear chain parallel to the (101) plane (Fig. 5). In the 1D network, all the molecules are connected to each other through the cavity stacking motif.
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Fig. 5 The 1D single-stranded linear chain structures of 3. Hydrogen-bonded interactions are shown as broken lines. The hydrogen atoms connected to carbon atom are omitted for clarity. |
In the extended structure of compound 4 (Fig. 6), each molecule binds to three neighbouring molecules viahydrogen bond N4⋯O11 (3.053 Å), N2⋯O9 (2.928 Å) and N6⋯O3 (2.887 Å). The hydrogen bond motif in N4⋯O11 is the same as that in compound 3. The hydrogen bond between the urea groups, i.e. N2⋯O9 and N6⋯O3 is in a cyclic R22(8) motif.
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Fig. 6 The crystal structure of 4. Hydrogen-bonded interactions are shown as broken lines. The hydrogen atoms connected to carbon atom and disordered atoms are all omitted for clarity. |
In the crystal structure of compound 5, neighbouring molecules are linked by the inwardly orientated chains A and D viahydrogen bond N2⋯O6 (2.974 Å) and cyclic R22(8) motif hydrogen bond N2⋯O12 (2.978 Å), N8⋯O3 (3.012 Å) in a cavity stacking motif. A 1D polymeric chain is formed (Fig. 7). The overall 3D crystal architecture of 5 is characterized by the propagating of this chain system along two different directions directed by two outwardly orientated chains B and C. As shown in Fig. S1 (ESI),† neighbouring 1-D chains hydrogen-bond to each other via a cyclic R22(8) motif N4⋯O6 (2.942 Å), i.e. via the outwardly orientated chain B resulting the propagation of the infinite chain along [101] direction. Another outwardly orientated chain C leads to the propagation of the chain system perpendicular to (101) plane viahydrogen bond N6⋯O5 (2.976 Å) (Fig. S2 (ESI)).†
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Fig. 7 The 1D chain structure of 5 along b axis. Hydrogen-bonded interactions are shown as broken lines. The hydrogen atoms connected to carbon atom are omitted for clarity. |
Although various types of intermolecular organizations are formed by varying the type of hydrogen-bonding functionalities and the position of these interaction sites, there are some recurring hydrogen bond synthons in these supramolecular architectures. The hydrogen bond synthons that appear in compounds 2, 3, 4 and 5 are shown in Scheme 2. The participating carboxylic acid preferentially engages in heteromeric acid to amide hydrogen bond, either in a acid⋯amide discrete pattern II or in a acid⋯amide ring pattern I. This is consistent with the conclusion made by Seaton.12 The remaining urea groups tend to form amide⋯amide ring pattern III, which exists in most cases. These supramolecular synthons derived from the intermolecular hydrogen bond that are between the pendant arms of neighboring thiacalix[4]arene molecules play an important role in controlling the final crystalline form of each compound.
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Scheme 2 The hydrogen bond synthons that appear in compounds 2, 3, 4 and 5. |
In the solid state, all the compounds can self-assemble through the cavity stacking motif by the axis-orientated or the inwardly orientated pendant arms, the outwardly orientated pendant arms are not favorable for this packing motif. And only compound 1 forms the cavity stacking motif nanotubes. Although the assembly is formed with the assistance of solvent molecules, the formation of this kind of nanotubes involves the fully usage of the framework of 1,3-alternatethiacalix[4]arene, both the four pendant arms and the tubular cavity. For the other four compounds, although they can connect with the neighbouring molecules through the cavity stacking motif, the inwardly orientated pendant arms which protrude into the thiacalixarene cavity obstruct the passages in these assemblies. So they couldn't be deemed as nanotubes any more. In order to form the nanotubes that we expected, further efforts are being made to prevent the inward orientation of the pendant arms.
For compounds 2, 3 and 4, in the second step the solvent used was THF and a catalyzed amount of trifluoroacetic acid was also added. For compounds 5, in the second step the solvent used was acetonitrile.
Compound 2. Obtained as a white solid. Conversion: 11.5%, mp > 260 °C. 1H NMR (300 MHz, DMSO-d6): δ (ppm) 1.17 (s, 18 H, t-Bu), 1.21 (s, 18 H, t-Bu), 4.39 (s, 4 H, ArOCH2), 4.63 (s, 4 H, ArOCH2), 7.42 (s, 4 H, ArH), 7.46 (s, 4 H, ArH), 7.69 (s, 4 H, NH2), 8.79 (s, 2 H, NH), 11.02 (br, 2 H, COOH). ESI-MS: m/z 1037 [M + H] +, 1059 [M + Na]+, 1075 [M + K]+. Anal. calcd for C50H60N4O12S4: C 57.89, H 5.83, N 5.40, S 12.36. Found: C 57.59, H 5.66, N 5.15, S 12.03.
Compound 3. Obtained as a white solid. Conversion: 11.5%, mp > 300 °C. 1H NMR (300 MHz, CDCl3): δ (ppm) 1.20 (s, 18 H, t-Bu), 1.22 (s, 18 H, t-Bu), 4.36 (d, 2 H, J = 15.6 Hz, ArOCH2), 4.51 (s, 2 H, ArOCH2), 4.56 (s, 2 H, ArOCH2), 4.89 (d, 2 H, J = 15.9 Hz, ArOCH2), 5.39 (s, 2 H, NH), 7.15 (s, 2 H, ArH), 7.23 (s, 2 H, ArH), 7.44 (s, 2 H, ArH), 7.50 (s, 2 H, ArH), 8.54 (s, 2 H, NH2), 8.76 (s, 2 H, NH2), 11.20 (br, 2 H, COOH). ESI-MS: m/z 1037 [M + H] +, 1059 [M + Na]+, 1075 [M + K]+. Anal. calcd for C50H60N4O12S4: C 57.89, H 5.83, N 5.40, S 12.36. Found: C 57.63, H 5.72, N 5.11, S 12.09.
Compound 4. Obtained as a white solid. Conversion: 24.3%, mp: 219–222 °C. 1H NMR (300 MHz, CDCl3): δ (ppm) 1.20 (s, 18 H, t-Bu), 1.22 (s, 9 H, t-Bu), 1.25 (s, 9 H, t-Bu), 4.31 (s, 2 H, ArOCH2), 4.62 (d, 2 H, J = 14.7 Hz, ArOCH2), 4.71 (s, 2 H, ArOCH2), 4.75 (d, 2 H, J = 14.4 Hz, ArOCH2), 5.16 (s, 2 H, NH2), 5.39 (s, 1 H, NH), 7.29 (s, 2 H, ArH), 7.33 (s, 2 H, ArH), 7.35 (s, 2 H, ArH), 7.63 (s, 2 H, ArH), 8.12 (s, 2 H, NH2), 8.25 (s, 2 H, NH2), 8.59 (s, 1 H, NH), 9.57 (s, 1 H, NH), 11.24 (s, 1 H, COOH). ESI-MS: m/z 1079 [M + H] +, 1101 [M + Na]+, 1117 [M + K]+. Anal. calcd for C51H62N6O12S4: C 56.75, H 5.79, N 7.79, S 11.88. Found: C 56.38, H 5.68, N 7.52, S 11.53.
Compound 5. Obtained as a white solid. Conversion: 43%, mp > 300 °C. 1H NMR (300 MHz, DMSO-d6): δ (ppm) 1.19 (s, 36H, t-Bu), 4.53 (s, 8 H, CH2), 7.48 (s, 8 H, ArH), 7.64 (s, 4 H, NH2), 7.68 (s, 4 H, NH2), 7.99 (s, 4 H, NH). ESI-MS: m/z 1143 [M + Na]+; 1159 [M + K]+. Anal. calcd For C52H64N8O12S4: C 55.70, H 5.75, N 9.99, S 11.44. Found: C 55.47, H 5.51, N 9.61, S 11.06.
1 | 2 | 3 | 4 | 5 | |
---|---|---|---|---|---|
CCDC no. | 760511 | 760512 | 760513 | 773844 | 760514 |
Formula | C48H56O12S4·4(C2H5OH)·2(H2O) | C50H60N4O12S4·2(CH2Cl2) | C50H60N4O12S4 | C51H62N6O12S4·1.17(CH3OH)·0.67(CH2Cl2) | 2(C52H64N8O12S4)·H2O·2(C4H8O) |
M r/g mol−1 | 1173.47 | 1207.11 | 1037.26 | 1173.63 | 2404.92 |
Crystal system | Triclinic | Monoclinic | Monoclinic | Trigonal | Monoclinic |
Space group |
P![]() |
C2/c | C2/c |
R![]() |
P21/n |
a/Å | 10.5110(1) | 42.4396(7) | 24.5640(7) | 20.3779(1) | 14.9385(5) |
b/Å | 16.749(2) | 14.2832(3) | 20.0520(5) | 20.3779(1) | 25.0431(8) |
c/Å | 18.137(2) | 21.6031(5) | 10.7714(3) | 76.563(9) | 15.9995(5) |
α/° | 88.538(2) | 90.00 | 90.00 | 90 | 90.00 |
β/° | 77.585(2) | 117.638(4) | 93.394(2) | 90 | 91.281(2) |
γ/° | 87.949(2) | 90.00 | 90.00 | 120 | 90.00 |
V/Å3 | 3115.8(7) | 11601.0(6) | 5296.2(2) | 27534(4) | 5984.0(3) |
Z | 2 | 8 | 4 | 18 | 2 |
ρ c/g cm−3 | 1.251 | 1.382 | 1.301 | 1.172 | 1.255 |
μ/mm−1 | 0.219 | 0.410 | 0.242 | 0.213 | 0.223 |
F(000) | 1256 | 5056 | 2192 | 11131 | 2540 |
Crystal size/mm | 0.20 × 0.10 × 0.10 | 0.23 × 0.20 × 0.10 | 0.16 × 0.12 × 0.08 | 0.30 × 0.20 × 0.05 | 0.20 × 0.10 × 0.10 |
θ range/° | 1.15–25.00 | 1.53–25.10 | 2.34–25.04 | 1.76–25.00 | 1.59–25.00 |
Reflections collected/unique | 17![]() ![]() |
55![]() ![]() |
15![]() |
46![]() ![]() |
37![]() ![]() |
GOF | 1.037 | 1.015 | 1.102 | 0.809 | 0.981 |
Final R indices [I > 2σ(I)] | R 1 = 0.0831, wR2 = 0.2157 | R 1 = 0.0691, wR2 = 0.1764 | R 1 = 0.0920, wR2 = 0.2161 | R 1 = 0.0638, wR2 = 0.1450 | R 1 = 0.0600, wR2 = 0.1389 |
R indices (all data) | R 1 = 0.1092, wR2 = 0.2330 | R 1 = 0.0811, wR2 = 0.1832 | R 1 = 0.1201, wR2 = 0.2342 | R 1 = 0.1431, wR2 = 0.1634 | R 1 = 0.0821, wR2 = 0.1494 |
Footnote |
† Electronic supplementary information (ESI) available: Fig. S1 and S2: the propagated chain system of compound 5; Tables S3–S7: hydrogen bonds of compounds 1–5 [Å and °]; X-ray crystallographic information files (CIF) for compounds 1–5. CCDC reference numbers [CCDC NUMBER(S)]. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c0ce00129e |
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