# Crystal Structures of Two Macrocyclic Bischalcones Possessing 26-Membered Rings

Authors: Rina Mondal; Nayim Sepay; Debajyoti Ghoshal; Asok K. Mallik
Journal: Journal of Crystallography
 (2015)

---

## Abstract

Single crystal X-ray diffraction of two macrocyclic bischalcones, namely, (2E,25E)-11,17,33,37-tetraoxapentacyclo[36.4.0.05,10.018,23.027,32]dotetraconta-1(42),2,5,7,9,18,20,22,25,27,29,31,38,40-tetradecaene-4,24-dione(1) and (2E,24E)-11,16,32,37-tetraoxapentacyclo[36.4.0.05,10.017,22.026,31]dotetraconta-1(42),2,5,7,9,17,19,21,24,26,28,30,38,40-tetradecaene-4,23-dione(2), each containing a 26-membered ring, has been studied. Compound 1 belongs to the monoclinic system, space group C2/c with a = 34.3615(9) Å, b = 12.7995(3) Å, c = 14.6231(3) Å, β = 96.912(2)°,  V = 6,384.6(3) Å3, and Z = 8. Compound 2 is triclinic, space group P-1 with a = 10.066(2) Å, b = 10.670(3) Å, c = 16.590(3) Å, α = 85.95(2), β = 89.244(14), γ = 62.211(13), V = 1572.0(6) Å3, and Z = 2. Intermolecular C–H⋯O hydrogen bonding interactions are present in both compounds.


---

## Body

## 1. Introduction

Compounds containing the chalcone (1,3-diphenyl-2-propen-1-one) moiety [1] are known to possess important biological activities such as antimicrobial [2], antiviral [3], antibacterial [4, 5], antihelminthic [5], antimalarial [6, 7], and antitumor [8] activities. Moreover, these compounds can be transformed in a number of ways into other biologically active heterocycles, for example, pyrimidines [9], isoxazole and pyrazole [10], and pyridines [11]. Macrocycles incorporating more than one chalcone moiety have great potential in generating new compounds suitable for molecular recognition [12–15] and photophysical [16, 17] studies. Recently, we reported the synthesis of a new family of 22- to 28-membered macrocycles containing two chalcone moieties. For structural confirmation, an X-ray crystallographic study of one compound of this family has been done [18]. The interesting aspects of that study arising out of the folded nature of the molecule encouraged us to record the X-ray crystallographic data of some other compounds of the family. In this paper, we report the X-ray crystallographic data of two other compounds, (2E,25E)-11,17,33,37-tetraoxapentacyclo[36.4.0.05,10.018,23.027,32]-dotetraconta-1(42),2,5,7,9,18,20,22,25,27,29,31,38,40-tetradecaene-4,24-dione (1) and (2E,24E)-11,16,32,37-tetraoxapentacyclo[36.4.0.05,10.017,22.026,31]dotetraconta-1(42),2,5,7,9,17,19,21,24,26,28,30,38,40-tetradecaene-4,23-dione (2), each having a 26-membered ring.


## 2. Experimental

### 2.1. Synthesis of1 and2

Synthesis of the macrocyclic bischalcones (2E,25E)-11,17,33,37-tetraoxapentacyclo-[36.4.0.05,10.018,23.027,32]dotetraconta-1(42),2,5,7,9,18,20,22,25,27,29,31,38,40-tetradecaene-4,24-dione (1) and (2E,24E)-11,16,32,37-tetraoxapentacyclo[36.4.0.05,10.017,22.026,31]-dotetraconta-1(42),2,5,7,9,17,19,21,24,26,28,30,38,40-tetradecaene-4,23-dione (2) (Scheme 1) was completed using the Claisen-Schmidt reaction in highly diluted aqueous methanol solution. The methods for the synthesis of1 and2 and their spectral data have been presented in our previous paper [18]. The light yellow single crystals of these compounds were obtained by slow evaporation of solvents from their solutions inn-hexane and acetone (1 : 3, v/v) (melting points:1, 182–184°C;2, 162–164°C).Scheme 1
Synthesis of1 and2.


### 2.2. Single Crystal X-Ray Crystallography

A summary of the crystallographic data and conditions is given in Table1. The selected bond lengths and bond angles of1 and2 are listed in Table 2. The structures of1 and2 as well as the packing arrangement in a unit cell of these compounds are shown in Figures 1 and 2, respectively. X-ray single crystal data collection and cell refinement were carried out at room temperature using a “Bruker SMART CCD-detector” diffractometer equipped with a normal focus, sealed tube X-ray source with graphite monochromated Mo-Kα radiation (λ = 0.71073 Å). The structures were solved by direct methods and refined by full-matrix least-squares based F
2 using SHELXS 97 set of programs [19]. ORTEP-3 for Windows [20] and PLATON [21] programs were used for molecular graphics. The structures were drawn with Mercury for Windows [22].Table 1
Crystallographic and experimental data for1 and 2.
Compounds
1
2
Empirical formula
C38H36O6
C38H36O6
Color/shape
Light yellow
Light yellow
Formula weight
588.67
588.67
Crystal system
Monoclinic
Triclinic
Space group
C2/c
P-1
Unit cell dimensions
a
=
34.3615
(
9
) Å,  α
=
90
a
=
10.066
(
2
) Å,  α
=
85.95
(
2
)
b
=
12.7995
(
3
) Å,  β
=
96.912
(
2
)
b
=
10.670
(
3
) Å,  β
=
89.244
(
14
)
c
=
14.6231
(
3
) Å,  γ
=
90
c
=
16.590
(
3
) Å,  γ
=
62.211
(
13
)
Volume
6384.6(3) Å3
1572.03(125) Å3
Z
8
4
Density (calculated)
1.225 g cm−3
1.24 g cm−3
Absorption coefficient
0.082 mm−1
0.083 mm−1
F(000)
2496
624
Crystal size
0.12 × 0.09 × 0.11 mm3
0.12 × 0.09 × 0.11 mm3
Theta range for data collection
1.2–27.6
2.2–27.7
Limiting indices
−44 ≤:h
≤
44
,
-
16
≤
:
k
≤
16
,
-
18
≤
:
l
≤
18
-
12
≤
:
h
≤
12
,
-
13
≤
:
k
≤
13
,
-
18
≤
:
l
≤
20
Reflections collected
50677
20993
Independent reflections
7,334[R(int) = 0.038]
5673[R(int) = 0.093]
Reflections observed (I
>
2∖σ
(
I
))
3677
1534
Refinement method
Full-matrix least-squares onF
2
Full-matrix least-squares onF
2
Data/restraints/parameters
7,334/1/413
5673/1/413
Goodness-of-fit onF
2
1.00
0.567
FinalR indices I
>
2
σ
I
a
R
1
=
0.047, w
R
2
b
=
0.105
R
1
=
0.0657, w
R
2 = 0.155
R indices (all data)
R
1
=
0.114, w
R
2
=
0.130
R
1
=
0.242, w
R
2
=
0.260
Weighting scheme
w
=
1/[σ
2(F
2
0)  + 0.0537P)2 + 0.8426P]
w
=
1/[σ
2(F
2
0) + 0.2000P)2  +  0.0000P]
Largest diff. peak and hole
0.13 and −0.17eÅ−3
0.17 and −0.15eÅ−3
a
R
=
(
∑
[
(
|
F
o
|
-
|
F
c
|
)
/
(
∑
|
F
o
|
]
); b
w
R
2
=
{
[
∑
(
w
[
F
o
2
-
F
c
2
2
]
/
[
∑
(
w
(
F
o
2
)
2
)
]
}
1
/
2.Table 2
Selected bond lengths (Å) and bond angles (°) of1 and 2.
Selected bond lengths for1
Selected bond lengths for2
C(15)–C(16)
1.458(3)
C(16)–C(17)
1.424(6)
C(16)–C(17)
1.324(3)
C(17)–C(18)
1.378(6)
C(17)–C(18)
1.458(3)
C(18)–C(19)
1.438(7)
C(18)–C(19)
1.359(3)
C(11)–O(2)
1.343(5)
O(1)–C(1)
1.359(13)
C(10)–O(2)
1.425(5)
O(1)–C(7)
1.426(11)
C(19)–O(3)
1.263(4)
Selected bond angles for1
Selected bond angles for2
C(6)–C(38)–C(37)
127.07(19)
C(1)–C(38)–C(37)
130.30(4)
C(15)–C(16)–C(17)
128.36(16)
C(36)–C(37)–C(38)
127.00(4)
C(17)–C(18)–C(17)
119.03(15)
C(16)–C(17)–C(18)
127.31(5)
C(35)–C(36)–C(37)
122.38(15)
C(17)–C(18)–C(19)
123.50(5)
C(7)–C(8)–C(9)
114.60(19)
C(7)–C(8)–C(9)
114.80(4)
C(25)–C(26)–C(27)
113.83(15)
C(8)–C(9)–C(10)
113.30(4)
C(26)–C(27)–C(28)
112.85(15)
C(26)–C(27)–C(28)
116.00(4)
C(27)–C(28)–C(29)
114.31(17)
C(27)–C(28)–C(29)
113.10(4)
C(29)–O(5)–C(30)
120.22(14)
C(6)–O(1)–C(7)
121.32(4)
C(24)–O(4)–C(25)
119.39(13)
C(10)–O(2)–C(11)
122.42(4)
C(9)–O(2)–C(10)
118.99(14)
C(30)–O(5)–C(29)
120.05(3)
C(1)–O(1)–C(7)
117.07(17)
C(25)–O(4)–C(26)
118.66(6)Figure 1
Molecular structure and atom numbering of compounds1 and2. (Displacement ellipsoids are drawn at the 50% probability level.)Figure 2
The packing arrangement in the unit cells of1 and2.


## 2.1. Synthesis of1 and2

Synthesis of the macrocyclic bischalcones (2E,25E)-11,17,33,37-tetraoxapentacyclo-[36.4.0.05,10.018,23.027,32]dotetraconta-1(42),2,5,7,9,18,20,22,25,27,29,31,38,40-tetradecaene-4,24-dione (1) and (2E,24E)-11,16,32,37-tetraoxapentacyclo[36.4.0.05,10.017,22.026,31]-dotetraconta-1(42),2,5,7,9,17,19,21,24,26,28,30,38,40-tetradecaene-4,23-dione (2) (Scheme 1) was completed using the Claisen-Schmidt reaction in highly diluted aqueous methanol solution. The methods for the synthesis of1 and2 and their spectral data have been presented in our previous paper [18]. The light yellow single crystals of these compounds were obtained by slow evaporation of solvents from their solutions inn-hexane and acetone (1 : 3, v/v) (melting points:1, 182–184°C;2, 162–164°C).Scheme 1
Synthesis of1 and2.


## 2.2. Single Crystal X-Ray Crystallography

A summary of the crystallographic data and conditions is given in Table1. The selected bond lengths and bond angles of1 and2 are listed in Table 2. The structures of1 and2 as well as the packing arrangement in a unit cell of these compounds are shown in Figures 1 and 2, respectively. X-ray single crystal data collection and cell refinement were carried out at room temperature using a “Bruker SMART CCD-detector” diffractometer equipped with a normal focus, sealed tube X-ray source with graphite monochromated Mo-Kα radiation (λ = 0.71073 Å). The structures were solved by direct methods and refined by full-matrix least-squares based F
2 using SHELXS 97 set of programs [19]. ORTEP-3 for Windows [20] and PLATON [21] programs were used for molecular graphics. The structures were drawn with Mercury for Windows [22].Table 1
Crystallographic and experimental data for1 and 2.
Compounds
1
2
Empirical formula
C38H36O6
C38H36O6
Color/shape
Light yellow
Light yellow
Formula weight
588.67
588.67
Crystal system
Monoclinic
Triclinic
Space group
C2/c
P-1
Unit cell dimensions
a
=
34.3615
(
9
) Å,  α
=
90
a
=
10.066
(
2
) Å,  α
=
85.95
(
2
)
b
=
12.7995
(
3
) Å,  β
=
96.912
(
2
)
b
=
10.670
(
3
) Å,  β
=
89.244
(
14
)
c
=
14.6231
(
3
) Å,  γ
=
90
c
=
16.590
(
3
) Å,  γ
=
62.211
(
13
)
Volume
6384.6(3) Å3
1572.03(125) Å3
Z
8
4
Density (calculated)
1.225 g cm−3
1.24 g cm−3
Absorption coefficient
0.082 mm−1
0.083 mm−1
F(000)
2496
624
Crystal size
0.12 × 0.09 × 0.11 mm3
0.12 × 0.09 × 0.11 mm3
Theta range for data collection
1.2–27.6
2.2–27.7
Limiting indices
−44 ≤:h
≤
44
,
-
16
≤
:
k
≤
16
,
-
18
≤
:
l
≤
18
-
12
≤
:
h
≤
12
,
-
13
≤
:
k
≤
13
,
-
18
≤
:
l
≤
20
Reflections collected
50677
20993
Independent reflections
7,334[R(int) = 0.038]
5673[R(int) = 0.093]
Reflections observed (I
>
2∖σ
(
I
))
3677
1534
Refinement method
Full-matrix least-squares onF
2
Full-matrix least-squares onF
2
Data/restraints/parameters
7,334/1/413
5673/1/413
Goodness-of-fit onF
2
1.00
0.567
FinalR indices I
>
2
σ
I
a
R
1
=
0.047, w
R
2
b
=
0.105
R
1
=
0.0657, w
R
2 = 0.155
R indices (all data)
R
1
=
0.114, w
R
2
=
0.130
R
1
=
0.242, w
R
2
=
0.260
Weighting scheme
w
=
1/[σ
2(F
2
0)  + 0.0537P)2 + 0.8426P]
w
=
1/[σ
2(F
2
0) + 0.2000P)2  +  0.0000P]
Largest diff. peak and hole
0.13 and −0.17eÅ−3
0.17 and −0.15eÅ−3
a
R
=
(
∑
[
(
|
F
o
|
-
|
F
c
|
)
/
(
∑
|
F
o
|
]
); b
w
R
2
=
{
[
∑
(
w
[
F
o
2
-
F
c
2
2
]
/
[
∑
(
w
(
F
o
2
)
2
)
]
}
1
/
2.Table 2
Selected bond lengths (Å) and bond angles (°) of1 and 2.
Selected bond lengths for1
Selected bond lengths for2
C(15)–C(16)
1.458(3)
C(16)–C(17)
1.424(6)
C(16)–C(17)
1.324(3)
C(17)–C(18)
1.378(6)
C(17)–C(18)
1.458(3)
C(18)–C(19)
1.438(7)
C(18)–C(19)
1.359(3)
C(11)–O(2)
1.343(5)
O(1)–C(1)
1.359(13)
C(10)–O(2)
1.425(5)
O(1)–C(7)
1.426(11)
C(19)–O(3)
1.263(4)
Selected bond angles for1
Selected bond angles for2
C(6)–C(38)–C(37)
127.07(19)
C(1)–C(38)–C(37)
130.30(4)
C(15)–C(16)–C(17)
128.36(16)
C(36)–C(37)–C(38)
127.00(4)
C(17)–C(18)–C(17)
119.03(15)
C(16)–C(17)–C(18)
127.31(5)
C(35)–C(36)–C(37)
122.38(15)
C(17)–C(18)–C(19)
123.50(5)
C(7)–C(8)–C(9)
114.60(19)
C(7)–C(8)–C(9)
114.80(4)
C(25)–C(26)–C(27)
113.83(15)
C(8)–C(9)–C(10)
113.30(4)
C(26)–C(27)–C(28)
112.85(15)
C(26)–C(27)–C(28)
116.00(4)
C(27)–C(28)–C(29)
114.31(17)
C(27)–C(28)–C(29)
113.10(4)
C(29)–O(5)–C(30)
120.22(14)
C(6)–O(1)–C(7)
121.32(4)
C(24)–O(4)–C(25)
119.39(13)
C(10)–O(2)–C(11)
122.42(4)
C(9)–O(2)–C(10)
118.99(14)
C(30)–O(5)–C(29)
120.05(3)
C(1)–O(1)–C(7)
117.07(17)
C(25)–O(4)–C(26)
118.66(6)Figure 1
Molecular structure and atom numbering of compounds1 and2. (Displacement ellipsoids are drawn at the 50% probability level.)Figure 2
The packing arrangement in the unit cells of1 and2.


## 3. Results and Discussion

The molecular structures of1 and2 are shown in Figure 1. Hydrogen bonding in the molecules is summarized in Table 2. For compound1, the distances C15–C16 (1.458(3) Å), C17–C18 (1.458(3) Å), and C18–C19 (1.359(13) Å) and, for compound2, the distances C16–C17 (1.424(6) Å), C18–C19 (1.438(7) Å), and C19–C20 (1.484(7) Å) are shorter than the normal C–C single bond (1.53 Å). However, the C16–C17 (1.324(3) Å) distance for compound1 is a bit shorter while C17–C18 (1.378(6) Å) distance for compound2 is somewhat longer than the normal C–C double bond (1.34 Å). Again, in the case of compound1, the C18–C19 bond length is very close to that of a C–C single bond. In both1 and2 each of the two phenyl rings attached to the >C=O is not coplanar with the α,β-unsaturated carbonyl moiety. All these may be due to accommodation of the polymethylene linkers in the molecules.In case of compound1, for the first chalcone moiety, the α,β-unsaturated carbonyl unit (C16–C17–C18) is almost coplanar with the phenyl ring C10–C11–C12–C13–C14–C15 (angle 3.69(5)°) but is not so with the phenyl ring C19–C20–C21–C22–C23–C24 (angle 69.69(12)°), while, for the second chalcone moiety, the α,β-unsaturated carbonyl unit (C36–C37–C38) is not coplanar with any of the two phenyl rings C30–C31–C32–C33–C34–C35 and C1–C2–C3–C4–C5–C6 (angles 16.82(9) and 22.90(11)°, resp.). On the other hand, in compound2, arrangement is the same in both chalcone moieties. In each case the α,β-unsaturated carbonyl unit is almost coplanar with one phenyl ring C1–C2–C3–C4–C5–C6 or C11–C12–C13–C14–C15–C16 (angle 1.20(3) or 3.33(4)°) while it makes an angle of nearly 67° with the other phenyl rings C30–C31–C32–C33–C34–C35 or C20–C21–C22–C23–C24–C25. It is therefore apparent that the extent of electron delocalization between the phenyl ring attached to carbonyl and the remaining part of the chalcone moiety is very poor for both compounds1 and2. The aliphatic chains O1–C7–C8–C9–O2 and O4–C25–C26–C27–C28–C29–O5 in1 and O1–C7–C8–C9–C10–O2 and O4–C26–C27–C28–C29–O5 in2 are mostly in staggered arrangement with the dihedral angles ranging from 57 to 64°. Antiarrangements were observed for C25–C26–C27–C28 and C26–C27–C28–C29 in1 and C7–C8–C9–C10 in2 (dihedral angles 177.32(17), 176.19(17), and 175.10(9)°, resp.). It is interesting to note that the arrangements for the apparently similar units C7–C8–C9–C10 and C26–C27–C28–C29 in2 are somewhat different in the crystalline state. For the first unit it is anti while for the second unit it is staggered. In the unit cell containing two molecules of2 (Figure 2), two anti units are much closer than two staggered ones.The salient feature of the crystal packing of1 and2 is that both of them form intermolecular hydrogen bonding networks (Figure 2). For the crystal of each compound there are two types of C–H⋯O intermolecular hydrogen bonds and one type of C–H⋯π supramolecular interactions (Table 3). In the crystal lattices, all the abovementioned hydrogen bonds and intermolecular interactions play a significant role in stabilizing the crystal structures. The intermolecular hydrogen bonds in1 and2 are summarized in Table 3.Table 3
Intermolecular hydrogen bonds, intramolecular C–H⋯O, and C–H⋯π supramolecular interactions in 1 and 2.
D–H⋯A
Symmetry
D–H(Å)
H⋯A (Å)
D⋯A(Å)
D–H⋯A (Å)
Compound1
C8–H8B⋯O2
3
/
2
-
x
,
1
/
2
-
y
,
1
-
z
0.9700
2.5400
3.469(3)
162
C14–H14⋯O6
x
,
1
-
y
,
-
1
/
2
+
z
0.9300
2.6000
3.411(2)
146
C16–H16⋯O2
—
0.931(15)
2.295(15)
2.717(2)
107
C29–H29B⋯O6
x
,
1
-
y
,
1
/
2
+
z
0.9700
2.4500
3.382(2)
161
C37–H37⋯O5
—
0.970(17)
2.243(17)
2.726(2)
109
C38–H38⋯O1
—
1.01(2)
2.323(19)
2.717(3)
101
C7–H7B⋯phenyl ring
x
,
-
y
,
-
1
/
2
+
z
0.9700
2.8500
3.708(2)
148
Compound2
C8–H8B⋯O2
—
0.9700
2.4800
2.852(11)
103
C9–H9B⋯O1
—
0.9700
2.4100
2.809(10)
104
C21–H21⋯O3
-
x
,
2
-
y
,
1
-
z
0.9300
2.5100
3.407(13)
161
C34–H34⋯O6
1
-
x
,
-
y
,
-
z
0.9300
2.4700
3.371(13)
164
C14–H14⋯phenyl ring
1
-
x
,
-
y
,
1
-
z
0.9300
2.8200
3.735
167Supplementary full crystallographic information for compounds1 (CCDC 999278) and2 (CCDC 999279) can be obtained via http://www.ccdc.cam.ac.uk/conts/retrieving.html or from the Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge, UK.


## 4. Conclusions

Several interesting structural aspects of two macrocyclic bischalcones1 and2, each containing a 26-membered ring, in the solid state were evident from their single crystal X-ray diffraction studies.



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*Source: 682534-2015-08-05.xml*