Structures of three new (phenylsulfonyl)indole derivatives

Article abstract of DOI:10.1007/s10870-009-9603-3

Three new 1-(phenylsulfonyl)indole derivatives, 3-acetyl-2-ethyl-1- (phenylsulfonyl)indole, (I), 2-benzyl-1-(phenylsulfonyl)indole, (II), and 3-trimethylsilylethynyl-1-(phenylsulfonyl)indole, (III), have been synthesized and their crystal structures determined by single crystal X-ray crystallography. (I), C₁₈H₁₇NO₃S, is triclinic with space group P-1 and cell constants: a = 8.6129(2) A, b = 8.8366(2) A, c = 11.0108(2) A, α = 72.7920(1)°, β = 75.0120(1)°, γ = 77.2550(1)°, V = 763.79(3) A³ and Z = 2. (II), C ₂₁H₁₇NO₂S, is monoclinic with space group P21/n and cell constants: a = 10.8355(18) A, b = 10.6987(19) A, c = 14.472(3) A, β = 75.0120(1), V = 1675.2(5) A³ and Z = 4. (III), C₁₉H₁₉NO₂SSi, is monoclinic with, space group P21/c and cell constants: a = 12.9596(1) A, b = 10.543(3) A, c = 13.543(2) A, β = 93.58°, V = 1846.8(6) A³ and Z = 4. All three have the same (phenylsulfonyl)indole skeleton with different ligands attached to the 2- and 3-sites of the indole ring. The angle between the mean planes of the indole and benzyl groups is 76.9(6)° (I), 82.9(3)° (II), 89.6(2)° (III) and between the sulfonyl group with the indole and benzyl rings is 61.2(9)° (I), 59.0((5)° (II), 51.5(6)°, 42.5(8)° (III) and 51.5(6)°(I), 44.3(8)° (II), 47.2(8)° (III), respectively. In addition to the ligand substitutions, weak intermolecular C-H???O hydrogen bond interactions and π stacking interactions between the π orbitals of nearby indole and phenyl rings influence these twist angles. Comparison to a MOPAC AM1 computational calculation supports these observations.

Full text of DOI:10.1007/s10870-009-9603-3

J Chem Crystallogr (2010) 40:40–47
DOI 10.1007/s10870-009-9603-3
ORIGINAL PAPER
Structures of Three New (Phenylsulfonyl)Indole Derivatives
Jerry P. Jasinski Æ Alison Rinderspacher Æ
Gordon W. Gribble
Received: 16 July 2008 / Accepted: 8 August 2009 / Published online: 18 August 2009
Ó Springer Science+Business Media, LLC 2009
Abstract Three new 1-(phenylsulfonyl)indole derivatives,
3-acetyl-2-ethyl-1-(phenylsulfonyl)indole, (I), 2-benzyl-1-
(phenylsulfonyl)indole, (II), and 3-trimethylsilylethynyl-1-
(phenylsulfonyl)indole, (III), have been synthesized and
their crystal structures determined by single crystal X-ray
crystallography. (I), C18H17NO3S, is triclinic with space
Comparison to a MOPAC AM1 computational calculation
supports these observations.
Keywords Crystal structure Á Hydrogen bonds Á
Indole Á Phenylsulfonyl Á MOPAC Á AM1
˚
group P-1 and cell constants: a = 8.6129(2) A, b =
˚
˚
8.8366(2) A, c = 11.0108(2) A, a = 72.7920(1)°, b =
Introduction
3
˚
75.0120(1)°, c = 77.2550(1)°, V = 763.79(3) A and
Z = 2. (II), C21H17NO2S, is monoclinic with space group
In connection with our interest in novel indole chemistry
[1], we have synthesized three new indole derivatives with
the 1-(phenylsulfonyl)indole skeleton and carried out the
X-ray structure determination of each of these molecules.
Derivatives of 1-(phenylsulfonyl)indole have proven to be
remarkably useful in the synthesis of biologically active
alkaloids and related analogues, including pyridocarbaz-
oles, such as the anticancer alkaloid ellipticine, carbazoles,
furoindoles, pyrroloindoles, indolocarbazoles, and other
substituted indoles [1]. Furthermore, we have used 2- and
3-nitro-1-(phenylsulfonyl)indoles in a variety of Diels–
Alder reactions, 1,3-dipolar cycloaddition reactions, and
nucleophilic addition reactions. The indole phenylsulfonyl
moiety is a protecting and activating group par excellence.
˚
P21/n and cell constants: a = 10.8355(18) A, b =
˚
˚
10.6987(19) A, c = 14.472(3) A, b = 75.0120(1), V =
3
1675.2(5) A and Z = 4. (III), C19H19NO2SSi, is monoclinic
˚
with, space group P21/c and cell constants: a = 12.9596(1)
˚
˚
˚
A, b = 10.543(3) A, c = 13.543(2) A, b = 93.58°, V =
3
1846.8(6)A and Z = 4. All three have the same (phenyl-
˚
sulfonyl)indole skeleton with different ligands attached to
the 2- and 3-sites of the indole ring. The angle between the
mean planes of the indole and benzyl groups is 76.9(6)° (I),
82.9(3)° (II), 89.6(2)° (III) and between the sulfonyl group
with the indole and benzyl rings is 61.2(9)° (I), 59.0((5)° (II),
51.5(6)°, 42.5(8)° (III) and 51.5(6)°(I), 44.3(8)° (II), 47.2(8)°
(III), respectively. In addition to the ligand substitutions,
weak intermolecular C–HÁÁÁO hydrogen bond interactions
and p stacking interactions between the p orbitals of nearby
indole and phenyl rings influence these twist angles.
Experimental
Synthesis of 3-Acetyl-2-Ethyl-1-(Phenylsulfonyl)
Indole (I)
J. P. Jasinski (&)
Department of Chemistry, Keene State College, Keene,
The synthesis of (I) was performed by stirring alumi-
num chloride (0.57 g, 4.3 mmol) and acetic anhydride
(0.20 mL, 2.1 mmol) in methylene chloride (20 mL) at
273 K (Fig. 1). After 20 min a solution of 2-ethyl-1-
(phenylsulfonyl)indole (0.19 g, 0.67 mmol) in methylene
NH 03435-2001, USA
e-mail: jjasinski@keene.edu
A. Rinderspacher Á G. W. Gribble
Department of Chemistry, Dartmouth College, Hanover,
NH 03755-3564, USA
123

J Chem Crystallogr (2010) 40:40–47
41
via syringe at 195 K. The reaction mixture was allowed to
warm up to room temperature. It was poured onto saturated
aqueous ammonium chloride (50 mL). The organic layer
was extracted with diethyl ether (3 9 50 mL), washed with
brine (2 9 50 mL), and dried with anhydrous magnesium
sulfate. The solvent was evaporated in vacuo, yielding a
dark-brown oil. The oil was purified via column chroma-
tography (1:1 hexanes: ethyl acetate). A tan-colored solid
1
(1.5 g, 4.4 mmol, 81%) was obtained: mp 371–373 K; H
NMR (CDCl3) d 8.18 (d, 1H, J = 8.7 Hz), 7.66 (d, 2H,
J = 8.4 Hz), 7.52 (t, 1H, J = 7.5 Hz), 7.38 (d, 3H,
J = 8.1 Hz), 7.34 (s, 1H), 7.31–7.26 (m, 3H), 7.22 (d, 3H,
J = 8.1 Hz), 6.13 (s, 1H), 4.37 (s, 2H); MS m/z 347, 205,
178, 128, 77.
Synthesis of 1-(Phenylsulfonyl)-3-
Trimethylsilylethynyl-Indole (III)
The synthesis of (III) was performed by stirring 3-iodo-1-
(phenylsulfonyl)indole (0.225 g, 0.588 mmol), copper
iodide (0.0050 g, 0.026 mmol), and (trimethylsilyl)acety-
lene (0.1 mL, 0.7 mmol) in triethylamine. The reaction
mixture was degassed and tetrakis(triphenylphosphine)
palladium was added quickly. The reaction mixture was
stirred overnight. Diethyl ether (25 mL) and 2 M HCl
(25 mL) were added to the yellowish reaction mixture. The
organic layer was extracted with diethyl ether (3 9 25 mL),
washed with brine (2 9 30 mL), and dried with anhydrous
magnesium sulfate. The solvent was evaporated in vacuo,
yielding a brown oil, which was purified via column chro-
matography (1:1 hexanes: methylene chloride). Colorless
crystals were obtained (0.0934 g, 0.264 mmol, 45%): mp
385–385.5 K; 1H NMR (CDCl3) d 7.99 (d, 1H, J =
7.5 Hz), 7.90 (d, 2H, J = 7.5 Hz), 7.78 (s, 1H), 7.65 (d, 1H,
J = 7.8 Hz), 7.56 (t, 1H, J = 7.8 Hz), 7.45 (t, 2H,
J = 6.6 Hz), 7.40–7.28 (m, 2H), 0.29 (s, 9H); MS m/z 353
(M?), 338, 212 (100%), 196, 168, 77.
Fig. 1 ORTEP drawing of C18H17NO3S, (I), showing the atom
numbering scheme and 50% probability displacement ellipsoids
chloride (3.5 mL) was added to the yellow suspension via
addition funnel. The solution was stirred for 2.5 h at
273 K, after which it was poured over crushed ice
(*100 mL). The organic layer was extracted with meth-
ylene chloride (3 9 20 mL). The combined organic
extracts were washed with brine (2 9 25 mL) and satu-
rated aqueous sodium bicarbonate (25 mL), and were dried
with anhydrous magnesium sulfate. The solvent was
evaporated in vacuo, yielding brown oil, which was stored
at 277 K. White crystals suitable for X-ray diffraction
studies were obtained after vacuum filtration (0.14 g,
1
0.44 mmol, 65%): mp 344–346 K; H NMR (CDCl3) d
8.30–8.28 (m, 1H), 7.90–7.88 (m, 1H), 7.81 (d, 2H, J =
8.5 Hz), 7.59 (t, 1H, J = 7.5 Hz), 7.47 (t, 2H, J = 7.5 Hz),
7.37–7.33 (m, 2H), 3.38 (q, 2H, J = 7.5 Hz), 2.66 (s, 3H),
1.37 (t, 3H, J = 7.5 Hz); 13C NMR (CDCl3) d195.9, 149.7,
139.2, 136.3, 134.5, 129.8 (2C), 127.4, 126.7 (2C), 125.0,
124.7, 121.0, 120.5, 115.2, 32.3, 21.1, 15.6; IR m(TCE)
3,394, 2,978, 2,471, 1,884, 1,801, 1,672, 1,533, 1,448,
Structure Determination and Refinement
X-ray data were collected with a Bruker Apex II CCD area
detector [2] using graphite-monochromated Cu–Ka (k =
˚
1.54178 A) at 100(2) K for (I) and Mo–Ka (k = 0.71073
1,385, 1,224, 1,182, 1,122, 1,093, 1,056 cm-1
.
˚
A) at 93(2)K for (II) and (III). The structure was solved by
direct methods using SHELXS97 [3]. All of the non-
hydrogen atoms were refined anisotropically by full-matrix
least-squares on F2 using SHELXL97 [3]. All H atoms
were placed in their calculated positions and included in
the refinement using the riding model. An absorption cor-
rection was performed on (I) and (II) using SADABS [4]
and all calculations were performed using SHELXTL [2].
Each structure was checked using PLATON [5]. Crystal
Synthesis of 2-Benzyl-1-(Phenylsulfonyl)Indole (II)
The synthesis of (II) was performed by adding sec-butyl-
lithium (1.4 M, 5.8 mL, 8.1 mmol) dropwise via syringe to
a solution of 1-(phenylsulfonyl)indole (1.4 g, 5.4 mmol) in
anhydrous THF (30 mL) at 195 K (Fig. 1). After 5 h
benzyl bromide (0.64 mL, 5.4 mmol) was added quickly
123

42
J Chem Crystallogr (2010) 40:40–47
O
and experimental data for (I), (II), and (III) is listed in
Table 1. Schemes 1, 2 and 3 show the molecular structures
of (I), (II) and (III), respectively. Ortep diagrams [6] of the
asymmetric unit and crystal packing of (I), (II), and (III)
are displayed in Figs. 1, 2, 3, 4, 5 and 6, respectively. The
short C(16)–C(17) triple bond in (III) is in the range of a
normal triple bond. Bond lengths and bond angles for each
structure are all within expected ranges [7]. Selected geo-
metric parameters for (I), (II), and (III) are listed in
Table 2.
Ac2O, AlCl3, CH2Cl2, 0 °C
65 %
N
N
SO2Ph
SO2Ph
II
Scheme 1 Synthesis of I
Ph
Results and Discussion
The dihedral angles between the mean planes of the indole
ring and the benzene ring of the phenylsulfonyl group are
76.9(6)° (I), 82.9(3)° (II), 89.6(2)° (III). The dihedral
angle in (I) is much lower than the 80–90° typically
observed (e.g. 86.80(6)° [8], 82.83(5)° [9], 85.6(1)° [10]
and 90.2(2)° and 94.0(2)° [11]) and closer to the 66.2(4)°
observed by Liu et al. [12] which presumably reflects
interaction of the ethyl group at C2 (Fig. 1).
N
SO2Ph
II
Scheme 2 Chemical structure of II
Table 1 Crystal and
Experimental Data
for (I), (II) and (III)
(I)
(II)
(III)
Formula
C18H17NO3S
327.39
C21H17NO2S
347.42
C19H19NO2SSi
353.50
Formula weight
Crystal color, habit
Crystal size (mm)
Crystal system
Colorless, block
0.29 9 0.28 9 0.25
Triclinic
Colorless, needle
0.90 9 0.35 9 0.20
Monoclinic
P 21/n, 4
93(2)
Colorless, needle
0.70 9 0.45 9 0.35
Monoclinic
P 21/c, 4
93(2)
Space group, Z
Temperature (K)
P - 1, 2
100(2)
˚
a (A)
8.6129(2)
8.8366(2)
11.0108(2)
72.7920(1)
75.0120(1)
77.2550(1)
763.79(3)
344
10.8355(18)
10.6987(19)
14.472(3)
90.000(0)
93.123(3)
90.000(0)
1,675.2(5)
728
12.9596(10)
10.543(3)
13.543(2)
90.000(0)
93.5(8)
˚
b (A)
˚
c (A)
a (°)
b (°)
c (°)
90.000(0)
1,846.8(6)
744
3
˚
Volume, A
F(000)
Absorption coeff (mm-1
Dcalc (Mg m-3
No. of reflections
)
2.012
0.207
0.251
)
1.424
1.378
1.271
2,414
4,062
4,562
2hmax/° with Cu Ka/Mo Ka
R, Rw [I [ 2r(I)]
130.2
56.6
56.5
0.0332/0.0864
0.69/-0.35
1.065
0.0382/0.0920
0.311/-0.463
1.039
0.0514/0.1167
0.466/-0.563
0.889
-3
˚
(Dq)max/min/e A
GOF on F2
Measurement
APEX2 [2]
SHELXTL
SHELXS97
Program system
Structure determination
Refinement
Full-matrix least-squares on F2 (SHELXL97)
123

J Chem Crystallogr (2010) 40:40–47
43
TMS
I
Pd(PPh3)4, CuI, Et3N
H
TMS
, r.t.
N
N
45 %
SO2Ph
SO2Ph
III
Scheme 3 Synthesis of III
Fig. 3 ORTEP drawing of C19H19NO2SSi, (III), showing the atom
numbering scheme and 50% probability displacement ellipsoids
Fig. 2 ORTEP drawing of C21H17NO2S, (II), showing the atom
numbering scheme and 50% probability displacement ellipsoids
The sulfonyl group in (I), (II), and (III) adopts the usual
nitrogen-sulfonyl geometry seen with other 1-(phenylsul-
fonyl)indoles wherein the N lone pair eclipses the sulfonyl
group [13]. Accordingly, the O1–S1–N1–C2 torsion angles
in (I), (II), and (III) are -38.8(15)°, -39.12(14)° and
-33.20(15)°. For comparison, the O1–S1–N1–C2 torsion
angle in 1-(phenylsulfonyl)indole is -37° and that in
(phenylsulfonyl)pyrrole is -35° [14]. The benzene ring of
the phenyl group at C2 in (II) is twisted by an angle of
68.4(8)° which would allow for minimal interaction with
the phenylsulfonyl group and thereby supporting its higher
torsion angle value (Fig. 2). The value of the twist angle
between the sulfonyl group with the indole and phenyl
rings is 61.2(9)° (I), 59.0(5)° (II), 42.5(8)° (III) and
51.5(6)°(I), 44.3(8)° (II), 47.2(8)° (III), respectively,
which actively supports the premise that a decrease in the
twist angle between the sulfonyl group and indole ring is
heavily influenced by the nature and bulk of the substituent
attached at C2. In (I) the separation between H10B with O1
Fig. 4 The molecular packing for (I) viewed down the a axis.
Dashed lines indicate weak C–HÁÁÁO intermolecular hydrogen bond
interactions
˚
in (III) is 2.59(6) A. There is no substituent attached to C2
in (III) (Fig. 3). Clearly, the proximity and bulk of the
substituent at C2 is a major influence in the value of this
twist angle. This along with crystalline packing effects
described below play a key role in the structural relation-
ships of the various groups on the geometry of the
molecular structures in (I), (II), and (III) (Fig. 2).
˚
measures 2.22(9) A while in (II) the separation between
˚
H10 and O1 is 2.35(5) A and the separation of H2A and O1
The sum of the angles around the indole N atom is
359.9(6)° (I), 357.8(6)° (II) and 356.4(4)° (III), indicating
123

44
J Chem Crystallogr (2010) 40:40–47
Fig. 5 The molecular packing
for (II) viewed down the c axis
Fig. 6 The molecular packing
for (III) viewed down the c axis.
Dashed lines indicate weak
C–HÁÁÁO intermolecular
hydrogen bond interactions
nearly ideal sp2 hybridization in each compound. The
˚
C2=C3 indole double-bond length is 1.375(3) A (I),
(II) (Fig. 5). Weak intermolecular hydrogen bonds in (III)
occur between the sulfonyl oxygen O1 and H11 from the
phenyl ring which help link the molecules into chains along
the 110 plane of the unit cell (Fig. 6).
˚
1.350(2) A (II) and 1.346(2) A (III) which is longer in (I)
˚
but similar in (II) and (III) to indole double-bond lengths
˚
˚
of 1.349(11) A [14] and 1.355(5) A [12] observed in
similarly related indole compounds. All of the other geo-
metric parameters are within expected ranges [7]. In (I)
there are weak intermolecular C–HÁÁÁO hydrogen bond
interactions between an oxygen atom (O2) from the sul-
fonyl group and hydrogen atoms from a nearby indole ring
(H6) and a 4-acetyl group (H13) as well as from an oxygen
atom (O3) from the acetyl group and a hydrogen atom
(H19) from a phenyl group (Table 3) which help link the
molecules into chains along the 011 plane of the unit cell
(Fig. 4). No intermolecular hydrogen bonds are evident in
Additional packing interactions are observed in the
crystalline environments of molecules (I) and (II) only. In
(I) intermolecular p stacking interactions occur between
Cg1/Cg1, Cg1/Cg2 and Cg3/Cg3-p orbitals of nearby
˚
indole rings [Cg1ÁÁÁCg1 = 3.9092(10) A (-x, -y, 1 - z);
˚
Cg1ÁÁÁCg2 = 3.5706(1) A (-x, -y, 1 - z); Cg3ÁÁÁCg3 =
˚
3.8373(1) A (1 - x, 1 - y, -z); where Cg1 (N1–C2–C3–
C8–C9), Cg2 (C4–C9) and Cg3 (C14–C19) = center of
gravity of the two groups within the indole ring and the
phenyl group, respectively]. In (II) there are weak intermo-
lecular C–HÁÁÁCg packing interactions between the Cg2-p
123

J Chem Crystallogr (2010) 40:40–47
45
˚
Table 2 Selected bond lengths (A), bond angles (°), and torsion angles (°) for (I), (II) and (III)
(I) C18H17NO3S
S(1)–O(1)
S(1)–N(1)
N(1)–C(2)
C(2)–C(3)
1.4287(14)
1.6941(14)
1.404(2)
S(1)–O(2)
S(1)–C(14)
N(1)–C(9)
C(12)–O(3)
1.4206(13)
1.7578(17)
1.423(2)
1.375(2)
1.220(2)
(II) C21H17NO2S
S–O(1)
1.4271(12)
1.6618(13)
1.4291(19)
1.350(2)
S–O(2)
1.4238(12)
1.7564(15)
1.419(2)
S–N(1)
S–C(17)
N(1)–C(2)
C(2)–C(3)
N(1)–C(9)
C(2)–C(10)
1.496(2)
(III) C19H19NO2SSi
S–O(1)
1.4174(13)
1.6555(15)
1.826(2)
1.840(2)
1.382(2)
1.346(3)
1.197(2)
S–O(2)
1.4120(13)
1.7412(18)
1.842(2)
1.843(2)
1.404(2)
1.419(3)
1.445(2)
S–N(1)
S–C(10)
Si–C(17)
Si–C(19)
N(1)–C(2)
C(2)–C(3)
C(16)–C(17
Si–C(18)
Si–C(20)
N(1)–C(9)
C(3)–C(16)
C(3)–C(8)
(I) C18H17NO3S
O(1)–S(1)–O(2)
O(1)–S(1)–C(14)
O(2)–S(1)–C(14)
S(1)–N(1)–C(2)
C(2)–N(1)–C(9)
C(3)–C(12)–C(3)
S(1)–C(14)–C(15)
119.17(7)
109.64(8)
109.74(8)
125.45(11)
109.05(13)
121.38(16)
119.54(13)
O(1)–S(1)–N(1)
O(2)–S(1)–N(1)
N(1)–S(1)–C(14)
S(1)–N(1)–C(9)
N(1)–C(2)–C(3)
O(3)–C(12)–C(13)
S(1)–C(14)–C(19)
107.88(7)
105.45(7)
103.77(7)
125.42(11)
108.52(14)
119.30(16)
118.30(15)
(II) C21H17NO2S
O(1)–S–O(2)
O(1)–S–C(17)
O(2)–S–C(17)
S–N(1)–C(2)
119.53(7)
108.54(8)
109.06(6)
125.49(11)
108.05(12)
119.54(12)
O(1)–S(1)–N(1)
O(2)–S–N(1)
107.57(7)
105.74(7)
105.51(6)
124.17(10)
108.23(14)
118.91(11)
N(1)–S–C(17)
S–N(1)–C(9)
C(2)–N(1)–C(9)
S–C(17)–C(22)
N(1)–C(2)–C(3)
S–C(17)–C(18)
(III) C19H19NO2SSi
O(1)–S–O(2)
O(1)–S–C(10)
O(2)–S–C(10)
S–N(1)–C(2)
120.65(8)
109.66(9)
109.73(8)
121.41(12)
108.23(14)
119.52(15)
O(1)–S–N(1)
O(2)–S–N(1)
N(1)–S–C(10)
S–N(1)–C(9)
N(1)–C(2)–C(3)
S–C(10)–C(11)
104.76(8)
106.24(8)
104.42(8)
126.80(12)
110.16(16)
118.57(14)
C(2)–N(1)–C(9)
S–C(10)–C(15)
(I) C18H17NO3S
O(1)–S(1)–N(1)–C(2)
O(1)–S(1)–C(14)–C(15)
O(2)–S(1)–N(1)–C(2)
-38.8(15)
O(1)–S(1)–N(1)–C(9)
O(1)–S(1)–C(14)–C(19)
O(2)–S(1)–N(1)–C(9)
137.43(14)
-174.20(12)
9.07(15)
4.31(16)
-167.24(13)
123

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J Chem Crystallogr (2010) 40:40–47
Table 2 continued
(I) C18H17NO3S
O(2)–S(1)–C(14)–C(15)
C(14)–S(1)–N(1)–C(2)
N(1)–S(1)–C(14)–C(15)
S(1)–N(1)–C(2)–C(3)
N(1)–C(2)–C(3)–C(8)
C(2)–C(3)–C(12)–O(3)
136.98(13)
77.39(15)
-110.73(14)
175.42(11)
0.17(18)
O(2)–S(1)–C(14)–C(19)
C(14)–S(1)–N(1)–C(9)
N(1)–S(1)–C(14)–C(19)
S(1)–N(1)–C(2)–C(10)
N(1)–C(2)–C(3)–C(12)
C(8)–C(3)–C(12)–O(3)
-41.52(15)
-106.30(14)
70.77(14)
-8.9(2)
-179.89(14)
-176.21(16)
3.9(3)
(II) C21H17NO2S
O(1)–S–N(1)–C(2)
O(1)–S–C(17)–C(18
O(2)–S–N(1)–C(2)
O(2)–S–C(17)–C(18)
C(17)–S–N(1)–C(2)
N(1)–S–C(17)–C(18)
S–N(1)–C(2)–C(3)
N(1)–C(2)–C(3)–C(8)
-39.12(14)
-179.7 3(11)
-167.90(11)
-47.19(13)
76.61(13)
O(1)–S–N(1)–C(9)
160.15(12)
-3.7(14)
O(1)–S–C(17)–C(22)
O(2)–S–N(1)–C(9)
31.37(13)
128.49(12)
-84.13(12)
-118.32(12)
14.7(2)
O(2)–S–C(17)–C(22)
C(17)–S–N(1)–C(9)
N(1)–S(1)–C(17)–C(22)
S–N(1)–C(2)–C(10)
N(1)–C(2)–C(10)–C(11)
65.21(13)
-165.94(10)
1.77(16)
170.00(13)
(III) C19H19NO2SSi
O(1)–S–N(1)–C(2)
O(1)–S–C(10)–C(11)
O(2)–S–N(1)–C(2)
O(2)–S–C(10)–C(11)
C(10)–S–N(1)–C(2)
N(1)–S–C(10)–C(11)
S–N(1)–C(2)–C(3)
N(1)–C(2)–C(3)–C(8)
-33.20(15)
-165.97(14)
-161.94(12)
-31.27(17)
82.08(14)
O(1)–S–N(1)–C(9)
170.64(14)
15.02(18)
O(1)–S–C(10)–C(15)
O(2)–S–N(1)–C(9)
41.91(16)
O(2)–S–C(10)–C(15)
C(10)–S–N(1)–C(9)
N(1)–S(1)–C(10)–C(15)
S–N(1)–C(9)–C(7)
149.72(15)
-74.07(16)
-96.77(16)
-21.6(3)
82.25(16)
-162.55(12)
1.58(19)
N(1)–C(2)–C(3)–C(16)
-176.80(15)
˚
˚
3.359(2) A; C22–H22AÁÁÁCg3 = 3.5833(19) A; Cg2 &
Cg3 = center of gravity of C4–C9; and C11–C16, respec-
tively; i = 1 - x, -y, 1 - z; ii = -1/2 - x, 1/2 - y,
-1/2 ? z; iii = 3/2 - x, 1/2 ? y, 1/2 - z]. In (III) the
closest intermolecular distance between rings occurs with
˚
Table 3 Weak hydrogen bond interactions for (I) and (III) (A and °)
D–HÁÁÁA
(I)
d(D–H)
d(HÁÁÁA)
d(DÁÁÁA) \(DHA)
C6–H6–O2#1
0.95
0.98
0.95
2.49
2.56
2.39
3.404(2)
3.514(2)
3.156(2)
160.3
164.5
137.4
˚
Cg1/Cg3 [Cg1ÁÁÁCg3 = 4.4482(17) A (x, y, z] which is too
C13–H13C–O2#2
C19–H19–O3#3
long for any appreciable p orbital interaction.
MOPAC calculations were performed on (I) and (II) with
MOPAC as implemented by WeMO Pro [15]. Compound
(III) would not converge with either AM1, PM3 or MNDO.
The AM1 (Austin Model 1) approximation together with
the Hartree-Fock closed-shell (restricted) wavefunction was
(III)
C11–H11A–O1#4
0.95
2.48
3.333(2)
149.4
Symmetry transformations used to generate equivalent atoms: #1 -x,
1 - y, 1 - z; #2 -x, -y, 1 - z; #3 x, 1 ? y, z; #4 1 - x, 1/2 ? y,
1/2 - z
used for (I) and (II) and minimizations were teminnated at
an r.m.s. gradient of less than 0.01 kJ mol-1
A
-1. When the
˚
orbitals of the indole [Cg2=C4–C9] and phenyl rings, Cg3
[Cg3=C11–C16], and hydrogen atoms from the benzyl ring
[C19–H19AÁÁÁCg3i; C22–H22AÁÁÁCg3iii and C20–H20AÁÁÁ
Cg2ii] and between Cg2-p orbitals of the indole ring and a
hydrogen atom from the benzyl ring, [C12–H12AÁÁÁCg2i],
refined atom coordinates in (I) are subjected to a MOPAC
calculation the angle between the mean planes of the indole
and benzyl ring becomes 78.6(9)8 and the angle between the
sulfonyl group and the mean planes of the indole and benzyl
rings are 49.6(5)° and 55.4(4)°, respectively. The increase
of nearly 2° in the angles between the indole and benzyl
rings in (I) coincides with the decrease and increase in
˚
respectively (Fig. 3). [C12–H12AÁÁÁCg2 = 3.5305(18) A;
˚
C19–H19AÁÁÁCg3 = 3.6437(19) A; C20–H20AÁÁÁCg2 =
123

J Chem Crystallogr (2010) 40:40–47
47
Acknowledgments The Dartmouth authors acknowledge the
Donors of the Petroleum Research Fund (PRF), administered by the
American Chemical Society, and Wyeth for support of this project.
JPJ thanks Bruker AXS, Inc., for their assistance with data collection.
This material is also based, in part, upon work supported by the
National Science Foundation under Grant No. CHE-0521047 (Bran-
deis University).
values of nearly 4° for the angles between the sulfonyl
group with the indole and benzyl rings, respectively. It is
clear that weak hydrogen bonding and p-ring interactions
influence this twist angle value for the various groups within
the molecule in this crystal.
When the refined atom coordinates in (II) are subjected
to a MOPAC calculation the angle between the mean planes
of the indole and the benzyl ring becomes 82.9(3)° and the
angle between the sulfonyl group and the mean planes of the
indole and benzyl rings are 48.0(9)° and 54.4(2)°, respec-
tively. The increase of just over 2° in the angles between the
indole and benzyl rings in (II) also coincides with the
decrease and increase in values of close to 4° for the angles
between the sulfonyl group with the indole and benzyl
rings, respectively. In relating these values to those in the
crystals themselves outlined earlier, it is clear that the weak
hydrogen bonding interactions, CgÁÁÁCg interactions and
intermolecular C–HÁÁÁCg packing interactions all have a
significant influence in concert on the twist angle values for
the comparitive groups in these molecules.
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Supporting Information Available
X-ray crystallographic files, in Cif format, for the structure
determinations of (I) (695250), (II) (695251) and (III)
(695252) have been deposited with the Cambridge Crys-
tallographic Date Center, CCDC: 26091. Copies of this
information may be obtained free of charge from the
Director, CCDC, 12 Union Road, Cambridge, CB2 1EZ
(fax: ?44-1223-336033; email: deposit@ccdc.cam.uk or at
www: http://www.ccdc.cam.ac.uk).
15. Schmidt JR, Polik WF (2007) WebMO Pro, version 8.0.010e.
WebMO, LLC: Holland. Available from http://www.webmo.net
123