Experimental and computational insights into the nature of weak intermolecular interactions in trifluoromethyl-substituted isomeric crystalline N-methyl-N-phenylbenzamides

Article abstract of DOI:10.1039/c5nj01670c

The knowledge about the prevalence of weak interactions in terms of the nature and energetics associated with their formation is of significance in organic solids. In the present study, we have systematically explored the existence of different types of i

Full text of DOI:10.1039/c5nj01670c

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Experimental and computational insights into the
nature of weak intermolecular interactions in
trifluoromethyl-substituted isomeric crystalline
N-methyl-N-phenylbenzamides†
Cite this:DOI: 10.1039/c5nj01670c
Piyush Panini and Deepak Chopra*
The knowledge about the prevalence of weak interactions in terms of the nature and energetics
associated with their formation is of significance in organic solids. In the present study, we have
systematically explored the existence of different types of intermolecular interactions in ten out of the
fifteen newly synthesized trifluoromethyl derivatives of isomeric N-methyl-N-phenylbenzamides.
Detailed analyses of all the crystalline solids were performed with quantitative inputs from interaction
energy calculations using the PIXEL method. These studies revealed that in the absence of a strong
hydrogen bond, the crystal packing is mainly stabilized by a cooperative interplay of weak C–Hꢀ ꢀ ꢀOQC,
C–Hꢀ ꢀ ꢀp, and C(sp2)/(sp3)–Hꢀ ꢀ ꢀF–C(sp3) hydrogen bonds along with other related interactions, namely,
pꢀ ꢀ ꢀp and C(sp3)–Fꢀ ꢀ ꢀF–C(sp3). It is of interest to observe the presence of short and directional weak
C–Hꢀ ꢀ ꢀOQC hydrogen bonds in the packing, having a substantial electrostatic (coulombic + polarization)
contribution towards the total stabilization energy. The C(sp3)–F group was recognized in the formation of
different molecular motifs in the crystal packing as utilizing different intermolecular interactions. The con-
tribution from electrostatics among the different weak hydrogen bonds was observed in the decreasing
order: C–Hꢀ ꢀ ꢀOQC 4 C–Hꢀ ꢀ ꢀF–C(sp3) 4 C–Hꢀ ꢀ ꢀp. Furthermore, there was an increase in the electro-
static component with a concomitant decrease in the dispersion component for the shorter and direc-
tional hydrogen bonds.
Received (in Victoria, Australia)
28th June 2015,
Accepted 17th August 2015
DOI: 10.1039/c5nj01670c
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organic fluorine, and this number is still increasing.18 The
participation of organic fluorine in different intermolecular
Introduction
The study of intermolecular interactions, which link the molecules interactions was initially questioned by researchers.19 In the
in the solid state, has been crucial and of prime focus in crystal last decade, many studies on the participation of organic
engineering.1–6 In this regard, strong hydrogen bonds (e.g. N/O– fluorine in different intermolecular interactions have been
HꢀꢀꢀN/O) along with weak hydrogen bonds (like C–HꢀꢀꢀO/N/C) are studied and their role in the formation of different supra-
now well understood and recognized in chemistry and biology.7–11 molecular arrangements has been recognized.20–25 The signifi-
Recent emphasis in crystal engineering is focused on gaining a cance of these interactions has been very well summarized in a
greater understanding of weak intermolecular interactions, recent review,26 in a perspective27 and in a highlight.28 The
particularly those involving organic fluorine.12,13 The replace- significance of such weak intermolecular interactions involving
ment of hydrogen with a fluorine atom is recognized to affect organic fluorine was studied both in the presence and absence
the physicochemical properties of a compound but without of strong hydrogen bonds.29–35 However, the systematic study
much change in the molecular size.14,15 It also shows a greater of these interactions in terms of the electronic nature of the
increase in stability, which results in the increased resistance of participating fluorine atoms, i.e. fluorine atom connected to the
a compound towards metabolic degradation.16,17 20% of phar- C-atom of a different state of hybridization, was not reported.
maceuticals and 30% of agrochemicals are reported to possess Most of the past investigations involved the presence of a fluorine
atom present on the phenyl ring (C-atom in sp2 hybridized state).
Crystallography and Crystal Chemistry Laboratory, Department of Chemistry,
We recently investigated the capability of a fluorine atom con-
nected to an sp3 hybridized C-atom in the trifluoromethyl group
Indian Institute of Science Education and Research Bhopal, Madhya Pradesh,
462066 India. E-mail: dchopra@iiserb.ac.in; Fax: +91-0755-6692392
(–CF3 group) in the formation of different structural motifs and
† Electronic supplementary information (ESI) available. CCDC 1025677–1025685
their influence on the crystal packing in a series of isomeric
trifluoromethyl-substituted benzanilides.21 The presence of a –CF3
and 1027431. For ESI and crystallographic data in CIF or other electronic format
see DOI: 10.1039/c5nj01670c
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group on the molecule increases the acidity of the neighbouring H To gain a better insight into the different weak intermolecular
atoms and thus increases the possibility of its participation in the interactions present in the crystal packing, selected molecular
formation of a hydrogen bond. Furthermore, it was recently pairs (extracted from the crystal packing connected with different
experimentally established from charge density analysis per- intermolecular interactions) were analyzed. This is in contrast to
formed using high resolution X-ray data that there is an the routine practice of providing details on the crystal packing
intrinsic polarization of the electron density on the fluorine related to the arrangement of molecules50,51 on the basis of
atoms of the trifluoromethyl group.36 This further increases the pure geometry with no inputs from energetics. On the contrary,
possibility of its participation in different intermolecular inter- in reality, it is the latter that contributes immensely towards
actions, such as C–Hꢀ ꢀ ꢀF, C–Fꢀ ꢀ ꢀF–C, and C–Fꢀ ꢀ ꢀp, in the solid crystal formation.
state. The role of the presence of a –CF3 group in different fields
of chemistry and biology is very well recognized.37–40 The
influence of the presence of a –CF3 group has also been
Experimental section
observed in phase transitions41 and in crystal engineering.42
The starting materials, trifluoromethyl (–CF3)-substituted anilines
It is thus of interest to analyze the role and influence of the CF3
group [F–C(sp3)] in the participation of different intermolecular
and benzoyl chloride, were obtained from Sigma Aldrich and were
used directly as received. All the solvents and other reagents,
interactions in the absence of any strong hydrogen bonds. In
namely, dimethylaminopyridine (DMAP), methyl iodide (CH3I)
the crystal structure analysis of –CF3-substituted benzanilides,
and sodium hydride [(NaH) 60% solution in oil], were of analytical
grade. The solvents, dichloromethane (DCM) and tetrahydrofuran
(THF), were dried before use for the chemical reactions. The
intermediate compounds, namely, all the substituted N-phenyl-
these interactions were structurally analyzed in the presence of
a N–Hꢀ ꢀ ꢀOQC hydrogen bond. The focus is now on the removal
of the H-atom connected to the N-atom, which eliminates the
presence of any strong donor in the molecule, and hence
benzamides, were synthesized in accordance with the proce-
eliminates the possibility of the formation of the N–Hꢀ ꢀ ꢀOQC
dure already reported in our earlier work.21
H-bond.
In this regard, a library of trifluoromethyl-substituted
N-methyl-N-phenylbenzamides were synthesized (Scheme 1)
Synthesis of substituted N-methyl-N-phenylbenzamides
by replacing the H-atom connected to a N-atom with a methyl In a two-neck round bottom flask containing 1.2 equivalents of
group, and then their crystal structures were analyzed to NaH, 4 ml of dry THF was added with constant stirring using a
investigate the nature and role of the weak interactions (of the magnetic stirrer. Then, 1 equiv. of the substituted N-phenyl
type C–Hꢀ ꢀ ꢀF–Csp3, Csp3–Fꢀ ꢀ ꢀF–Csp3) in the crystal packing. Thus, benzamides was added slowly to the reaction mixture with
these compounds now eliminate the possibility of formation of constant stirring. Furthermore, 3–4 ml of dry THF was added
any strong H-bond. The substitution of the hydrogen atom with and the entire reaction mixture was refluxed for 2 h. The
the methyl group completely alters the molecular conformation reaction mixture was then allowed to cool to room temperature.
from a trans to cis geometry relative to that in benzanilides.43–45 Afterwards, cold methyl iodide, (excess amount, 0.6 ml added
The change in the fluorescence and luminescence behavior with in all reactions) was added slowly to the reaction mixture with
the change in its molecular conformation has been very well the whole flask kept over an ice bath with constant stirring.
studied by different research groups.46–48 To obtain a better After the addition, the reaction mixture was continuously
understanding of the nature of the different intermolecular stirred at room temperature for 1–2 h. The progress of the
interactions, the evaluation of the stabilization energy of these reaction was monitored with thin layer chromatography (TLC).
interactions is of prime focus in the present study. The con- After the completion of the reaction, it was quenched with 20 ml
tribution of the possible different interactions towards the crystal of 5% HCl and extracted with ethyl acetate and then washed with
packing was quantified by PIXEL.49 The PIXEL method provides brine solution three times. The organic extract was further
important insights towards understanding the crystal packing by washed with saturated solution of sodium sulphite to remove
partitioning the interaction energy or cohesive energy into their excess iodine. The organic extract was again washed with brine
coulombic, polarization, dispersion and repulsion contributions. solution and then dried with anhydrous sodium sulphate. The
Scheme 1 Synthetic route for all the compounds. ‘A’ and ‘B’ denote the two phenyl rings from the starting material, aniline and corresponding benzoyl
chloride. Compound code is denoted as ‘NMAB’ in this study. ‘NM’ refers to N-methyl substitution on N-phenylbenzamide, A or B = 0 [no substitution on
that ring] and A or B = 1, 2, 3 [o, m, p substitution of the –CF3 group on that ring, respectively].
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crude product thus obtained was finally purified by column Table 1 lists all the crystallographic and refinement data. Lists
chromatography with ethyl acetate and hexane as the eluant. of selected dihedral angles are presented in Tables 2 and 3.
The polarity of the eluant was increased slowly from 0% to 10%
Theoretical calculations
while performing the column. The yield was recorded after
evaporation of the solvent on completion of the column. Initially,
after the column, all the compounds were obtained as a thick oil
(Scheme 1). Compounds NM02, NM03, NM10, NM11, NM12,
NM22, NM23, NM31 and NM33 became solid after one day when
placed in the deep freeze section of the refrigerator or after
recrystallization from hexane on scratching the walls of the
container. Compound NM30 was observed as a low melting
solid (melting point = 39 1C). The remaining five synthesized
compounds (NM01, NM20, NM13, NM21, and NM32) remained
as a thick oil even at ꢁ20 1C.
The molecular geometry of each compound was optimized
by DFT/B3LYP calculation with 6-31G** basis set using TURBO-
MOLE.58 The experimentally obtained geometries were considered
as the starting coordinates for the calculation. The molecular
geometry thus obtained for the isolated molecule was compared
with the experimentally observed solid state geometry (Table 2).
The lattice energies (Table 4) of all the compounds were
calculated by the PIXELC module in the CLP computer program
package (version 10.2.2012), the total energy being partitioned
into their coulombic (Ecoub), polarization (Epol), dispersion (Edisp
)
All the synthesized compounds were characterized by FTIR
[Fig. S1(a)–(o), ESI†], 1H NMR [Fig. S2(a)–(o), ESI†] spectro-
scopy. The melting points were recorded using DSC for all the
solid compounds, and these are given in the ESI,† [Fig. S3(a)–( j)].
Powder X-ray diffraction (PXRD) data were recorded for all the
solid compounds and then compared with the simulated PXRD
patterns [Fig. S4(a)–(j), ESI†]. Details about the product yields,
melting points and spectroscopy data of all the synthesized
compounds are listed in Section S1 in the ESI.†
Details on all the crystallization experiments of all the solid
compounds from the different solvents and solvent mixtures
are presented in the ESI,† (Table S1). Single crystals of all the
solids except NM30 were obtained from a slow evaporation
method. Compound NM30 was observed to appear as a single
crystal in the sample vial at a temperature below 25 1C.
and repulsion (Erep) contributions. For the calculations, accurate
electron densities of the molecules were obtained at MP2/6-31G**
with GAUSSIAN0959 with H atoms at their neutron value. In the
case of disordered molecules, the molecular conformation with
the maximum population was considered for the calculation.
The interaction energy of the selected molecular pairs, extracted
from the crystal packing and related by the corresponding
symmetry element, was also calculated by the PIXEL method
(from the mlc file after the calculation). The total interaction
energy was partitioned into their coulombic (Ecoub), polarization
(Epol), dispersion (Edisp) and repulsion (Erep) contributions. These
are listed in Table 5 along with the selected intermolecular
interactions connecting the two molecules in the molecular pair.
The % dispersion energy contribution (% Edisp) towards the total
stabilization energy was calculated as follows:
Data collection, structure solution and refinement
%Edisp = [Edisp/(Ecoub + Epol + Edisp)] ꢂ 100;
Single crystal X-ray diffraction data were collected on a CrysAlis
CCD Xcalibur, Eos (Nova), Oxford Diffraction using Mo Ka
radiation (l = 0.71073 Å) for all the compounds except NM03,
NM30, NM22 and NM31. The single crystal X-ray diffraction
data of NM03, NM22 and NM31 were collected on a Bruker D8
Venture diffractometer with a CMOS detector using graphite
monochromated Mo Ka (l = 0.7107 Å) radiation, whereas data
for NM30 were collected on a Bruker APEX II three circle
diffractometer with a CCD detector. All the data except for
NM12 were collected at 120(2) K.
All the crystal structures were solved by direct methods
using SIR92.52 The non-hydrogen atoms were refined aniso-
tropically and the hydrogen atoms bonded to C atoms were
positioned geometrically and refined using a riding model with
Uiso(H) = 1.2Ueq [C(sp2)] and Uiso(H) = 1.5Ueq [C(sp3)]. Com-
pound NM30 was observed to be twinned in two orientations
Hence, % electrostatic contribution (coulombic + polarization),
%Eelec = 100 ꢁ %Edisp
These values are reported in Table 5.
The PIXEL interaction energy was further compared with the
interaction energies obtained from the theoretical calculations
at the DFT + Disp/B97D60–62 level at a higher aug-cc-pVTZ basis
set using TURBOMOLE.63 The hydrogen atoms were moved to
neutron values (1.083 Å for C–H) before the calculations. The
basis set superposition error (BSSE) for the interaction energies
was corrected using the counterpoise method.64 The final inter-
action energies are listed along with the PIXEL interaction
energies in Table 5.
Results and discussion
with the ratio for the BASF values being 0.59 : 0.41. The twin law ORTEP of NM10 and NM11 are presented in Fig. 1(a) and (b)
and the corresponding HKLF5 file were generated using the with the atom numbering scheme. The ORTEPs for the remain-
‘TwinRotMat’ tool in WinGx53 and the refinement was per- ing compounds are deposited in the ESI,† [Fig. S5(a)–( j)]. The
formed with the HKLF5 file using SHELXL2013.
Cambridge Structural Database search (CSD version 5.35
The disorder associated with the CF3 group was modelled updates Nov 2013) was performed for related structures to
with the PART command in two independent orientations (the compare the molecular conformation and crystal packing of
major component was labeled ‘A’) in SHELXL 2013.54 Molecular and related molecules with the present series of compounds. The
packing diagrams were generated using Mercury 3.3.55 Geometrical result gave only 8 hits [Fig. 1(d)]. The crystal structure of
calculations were carried out using PARST56 and PLATON.57 N-methyl-N-phenylbenzamide (labeled as ‘NM00’) is reported
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Table 1 Crystallographic and refinement data
DATA
NM02
NM03
NM10
NM30
NM11
Formula
Formula weight
C15H12NOF3
279.26
C15H12NOF3
279.26
C15H12NOF3
279.26
C15H12NOF3
279.26
C16H11NOF6
347.26
CCDC No.
Crystal system; space group
a (Å)
b (Å)
1025677
1025678
1025679
Orthorhombic; Pbca
9.6555(7)
13.7420(11)
19.3339(15)
90/90/90
2565.3(3)/1.446
8/1
1027431
Monoclinic; P21/c
23.731(5)
8.3394(15)
13.706(2)
90/106.707(12)/90
2597.9(8)/1.428
8/2
1025680
Monoclinic; P21/c
8.9803(4)
10.8526(4)
14.8181(5)
90/92.763(3)/90
1442.49(10)/1.599
4/1
Monoclinic; C2/c
35.8393(17)
10.6270(4)
Monoclinic; P21/c
15.1633(5)
9.9603(3)
17.7768(6)
90/97.269(2)/90
2663.27(15)/1.393
8/2
c (Å)
15.1660(7)
a (1)/b (1)/g (1)
90/114.399(5)/90
5260.3(4)/1.410
16/2
Volume (Å3)/density (g cmꢁ3
)
Z/Z0
F(000)/m (mmꢁ1
y (min, max)
)
2304/0.118
2.34, 25.00
ꢁ42, 42; ꢁ12, 12;
ꢁ18, 18
1152/0.116
1.35, 27.58
ꢁ18, 19; ꢁ12, 11;
ꢁ23, 18
1152/0.121
2.79, 25.00
ꢁ11, 11; ꢁ16, 16;
ꢁ22, 22
1152/0.119
0.90, 25.01
ꢁ28, 28; ꢁ9, 9;
ꢁ16, 16
704/0.153
2.75, 25.00
ꢁ10, 10; ꢁ12, 12;
ꢁ17, 17
hmin,max, kmin,max, lmin,max
No. of total ref./unique ref./obs. ref.
No. of parameters
25 157/4632/3475
391
22 406/6117/4629
395
12 605/2262/1743
211
4556/4556/3759
364
13 687/2534/2204
236
R_all, R_obs
0.0635, 0.0417
0.1008, 0.0888
ꢁ0.244, 0.215
1.050
0.0659, 0.0490
0.1356, 0.1259
ꢁ0.357, 0.381
1.061
0.0580, 0.0398
0.1028, 0.0901
ꢁ0.221, 0.207
1.055
0.0522, 0.0403
0.0897, 0.0854
ꢁ0.182, 0.223
1.063
0.0434, 0.0368
0.0982, 0.0933
ꢁ0.237, 0.308
1.043
wR2_all, wR2_obs
Drmin,max(e Åꢁ3
)
G. o. F
DATA
NM12
NM22
NM23
NM31
NM33
Formula
Formula weight
CCDC No.
Crystal system; space group
C16H11NOF6
347.26
1025681
C16H11NOF6
347.26
1025682
C16H11NOF6
347.26
1025683
C16H11NOF6
347.26
1025684
C16H11NOF6
347.26
1025685
%
Monoclinic; P21/c Monoclinic; P21/c Monoclinic; P21/c Monoclinic; P21/c Triclinic P1
a (Å)
b (Å)
c (Å)
9.0978(7)
22.1735(15)
7.9449(5)
8.3764(5)
23.2362(17)
7.9755(6)
11.2958(5)
14.0246(4)
10.4868(3)
12.3185(10)
7.9401(5)
15.4912(12)
8.9977(4)
10.8088(5)
16.6720(9)
a (1)/b (1)/g (1)
90/101.946(4)/90 90/103.567(2)/90 90/115.258(4)/90 90/90.168(4)/90
1568.02(19)/1.471 1509.00(18)/1.529 1502.48(9)/1.535 1515.19(19)/1.522 1486.36(12)/1.552
105.291(2)/98.901(2)/102.688(2)
Volume (Å3)/density (g cmꢁ3
)
Z/Z0
4/1
4/1
704/0.146
2.65/25.00
4/1
704/0.147
2.47/25.00
4/1
704/0.146
2.63/25.00
4/2
F(000)/m (mmꢁ1
y (min, max)
)
704/0.141
1.84, 25.00
704/0.149
1.30/30.67
ꢁ11, 12; ꢁ15, 15;
ꢁ23, 14
hmin,max, kmin,max, lmin,max
ꢁ10, 9; ꢁ22, 26; ꢁ9, 8; ꢁ27, 27;
ꢁ13, 13; ꢁ16, 16; ꢁ14, 13; ꢁ9, 9;
ꢁ9, 9 ꢁ9, 9
ꢁ12, 12 ꢁ18, 18
No. of total ref./unique ref./obs. ref. 13 654/2767/2117 21 987/2652/2199 14 260/2649/2238 11 173/2683/2044 30 219/9103/7006
No. of parameters
R_all, R_obs
247
246
250
246
491
0.0637, 0.0482
0.1388, 0.1285
ꢁ0.222, 0.363
1.066
0.0534, 0.0410
0.1059, 0.0993
ꢁ0.343, 0.497
1.033
0.0499, 0.0411
0.1065, 0.0993
ꢁ0.339, 0.398
1.066
0.0590, 0.0384
0.0930, 0.0865
ꢁ0.239, 0.215
1.034
0.0602/0.0430
0.1143/0.1040
ꢁ0.380, 0.446
1.039
wR2_all, wR2_obs
Drmin,max(e Åꢁ3
)
G. o. F
(ref. code: JAZJOJ10) in the CSD. The compounds in this series the phenyl ring (plane 2) on the nitrogen side (angle 3, the value
exist preferably in the cis-conformation [Fig. 1(c)]. Due to the being more than 561) from OQC–N–CH3 plane (plane 3) was
presence or substitution of H by a functional group ortho to observed to be more than for angle 2 (the value being less than 601
both the phenyl rings, the conformation may change to trans in most cases), which is the dihedral angle between plane 1
orientation on account of the role of sterics, as is observed in (phenyl ring on carbonyl side) and plane 3. No significant changes
the case of NM11, YEGJEY, DIBGIF and DIBGAX. It is of interest were observed between the solid state geometry and gaseous state
to note that the methyl substitution ortho to both of the phenyl geometry. The molecular conformation was observed to be stabi-
rings (YEGLAX) exhibits a cis-conformation, whereas substitu- lized by the presence of an intramolecular weak C(sp3)–HꢀꢀꢀOQC
tion by a trifluoromethyl (–CF3) group at the same position in hydrogen bond in both the solid state and the gas phase. In the
NM11 leads to a trans geometry [Fig. 1(b) and (d)]. The reason case of the molecules with the trans conformation, both the
for this observation may be the possibility of the formation of phenyl rings were nearly orthogonal to the central plane 3
two intramolecular weak C(sp3)–Hꢀ ꢀ ꢀOQC hydrogen bonds in (OQC–N–CH3 plane) in both the solid state and gas phase
the case of YEGLAX, which stabilizes the molecular conforma- geometry to minimize the sterics in the molecule.
tion in the cis-geometry. The dihedral angles between the
From the lattice energy calculations, using the PIXEL
planes formed by the two phenyl rings and the central part method for all the molecules (Table 4), it was observed that
(OQC–N–CH3) of the molecules for all the structures are the values lie between 102 kJ molꢁ1 and 115 kJ molꢁ1, with the
compared in Tables 2 and 3. The angle between the two phenyl dispersion energy being the major component. The lattice
rings for the molecule with the cis-geometry display similar values energy of the four related molecules in CSD was also calculated
(angle 1, value more than 601, Tables 2 and 3). The deviation of using the PIXEL method (Table 4). The result demonstrated
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Table 2 List of selected dihedral angles (1) and geometries of the intramolecular weak C(sp3)–Hꢀ ꢀ ꢀOQC hydrogen bond and their comparison with the
values obtained from the DFT/B3LYP calculations (in italic)
Angle 1 (1) plane1/2
Angle 2 (1) plane1/3
Angle 3 (1) plane2/3
Geometry of C(sp3)–Hꢀ ꢀ ꢀO (Å, 1)
NM00
NM02
NM03
NM10
NM30
NM11
NM12
NM22
NM23
NM31
NM33
67.4(1)
67.3
47.1(1)
32.9
62.5(1)
60.1
2.47, 93
2.42, 90
66.9(1)/64.9(1)0
70.3/69.90
58.6(1)/71.9(1)0
65.5/67.0
69.8(1)
46.0(1)/53.5(1)0
34.3/36.60
44.0(1)/43.5(1)0
39.2/38.8
39.2(1)
65.4(1)/62.6(1)0
70.9/62.10
59.8(1)/70.2(1)0
57.1/61.0
67.9(1)
2.32, 102/2.39, 970
2.50, 87/2.42, 910
2.31, 100/2.27, 1040
2.23, 106/2.51, 860
2.28, 102
76.3
38.9
77.1
2.33, 97
57.4(1)/55.5(1)0
68.0/65.5
1.7(1)
43.7(1)/43.4(1)0
36.4/32.7
84.9(1)
48.8(1)/53.6(1)0
58.4/54.8
85.6(1)
2.37, 94/2.65, 800
2.37, 96/2.46, 87
—
4.6
73.7(1)
76.1
62.3(1)
67.7
69.1(1)
66.3
61.4(1)
84.4
58.9(1)
39.4
65.4(1)
33.9
50.5(1)
34.6
61.2(1)
85.5
84.4(1)
77.5
64.8(1)
59.1
66.3(1)
58.5
61.5(1)
2.56, 87
2.32, 98
2.41, 97
2.42, 91
2.34, 102
2.43, 90
2.43, 92
2.24, 106
2.38, 94/2.40, 980
2.37, 97/2.42, 980
67.9
59.8
57.8
69.5(1)/72.9(1)0
65.9/68.6
34.1(1)/62.4(1)0
38.3/46.5
56.7(1)/65.5(1)0
57.6/62.3
(0) denotes the second molecule in the asymmetric unit.
Table 3 List of related structures, reported in CSD along with their space group, cell parameters and dihedral angles (as reported in Table 2)
Ref. code
Space group, Z
Cell parameters, a, b, c (Å)/a, b, g (1)
Angle 1 (1)
Angle 2 (1)
Angle 3 (1)
JAZJOJ1043 (NM00)
YEGKIE43
Pbca, Z = 8
12.5881, 12.3092, 14.6542/90, 90, 90
11.308(1), 15.878(2), 6.876(5)/90, 90, 90
—
—
—
P21nb, Z = 4
70.8
72.6
65.9
67.5
1.06
16.5
11.0
36.7
62.1
76.6
43.7
85.5
85.3
87.7
65.0
83.3
62.8
75.2
85.1
84.3
76.9
YEGLAX43
YEGKEA43
YEGKOK43
YEGJEY43
P1, Z = 2
11.602, 12.766(4), 7.372(1)/92.19(3), 104.93(2), 137.31(1)
13.257(7), 13.234(11), 8.005(1)/90, 98.01(1), 90
14.909(1), 6.795(2), 13.358(1)/90, 98.46(1), 90
15.250(3), 7.502(1), 13.733(3)/90, 106.77(2), 90
7.123(3), 16.792(8), 13.785(7)/90, 102.881, 90
11.1542(10), 8.4970(7), 31.528(3)/90, 95.122(2), 90
%
P21/a, Z = 4
P21/n, Z = 4
Cc, Z = 4
DIBGIF65
P21/n, Z = 4
DIBGAX65
Pc, Z = 8, Z0 = 4
43Azumaya et al., 1994; 65Cockroft et al., 2007.
Table 4 Lattice energy (kJ molꢁ1) partitioned into coulombic, polariza-
Molecular pairs and crystal packing analysis
tion, dispersion and repulsion contributions by the PIXEL method
It was of interest in this study to analyze the crystal packing of
N-methyl-N-phenyl benzamides (NM00) and to compare it with
that of its trifluoromethyl-substituted analogues (Table 1). The
molecular pairs extracted from the crystal packing of NM00 are
ECoul
EPol
EDisp
ERep
ETot
NM00
NM02
NM03
NM10
ꢁ30.3
ꢁ38.0
ꢁ42.3
ꢁ45.5
ꢁ35.5
ꢁ34.6
ꢁ36.4
ꢁ46.7
ꢁ40.8
ꢁ38.6
ꢁ45.7
ꢁ35.2
ꢁ30.3
ꢁ35.9
ꢁ32.8
ꢁ15.5
ꢁ14.8
ꢁ16.0
ꢁ16.4
ꢁ13.4
ꢁ13.9
ꢁ13.5
ꢁ19.7
ꢁ15.9
ꢁ12.8
ꢁ16.8
ꢁ13.5
ꢁ15.6
ꢁ14.8
ꢁ13.6
ꢁ123.0
ꢁ120.7
ꢁ119.6
ꢁ122.4
ꢁ122.9
ꢁ122.9
ꢁ97.9
65.5
66.3
75.1
69.4
66.4
64.3
46.0
77.2
70.9
57.2
78.8
67.0
61.8
71.9
78.5
ꢁ103.3
ꢁ107.2
ꢁ102.8 shown in Fig. 2(a), along with the associated interaction
ꢁ114.9
energies. The analysis of the molecular pairs revealed that the
NM30
ꢁ105.5
NM11a
NM12
ꢁ107.1
crystal packing in NM00 is mainly stabilized by the presence of
ꢁ101.9 weak C–Hꢀ ꢀ ꢀOQC and C–Hꢀ ꢀ ꢀp hydrogen bonds [Fig. 2(a) and
Table 5]. The most stabilized motif I (I.E = ꢁ24.5 kJ molꢁ1
)
NM22
NM23
NM31
NM33
YEGLAX
YEGKEA
YEGKOK
YEGJEYa
ꢁ119.6
ꢁ122.7
ꢁ111.2
ꢁ125.7
ꢁ129.2
ꢁ116.4
ꢁ127.4
ꢁ142.6
ꢁ108.7
ꢁ108.5
ꢁ105.4
consists of a short C–Hꢀ ꢀ ꢀOQC and a C–Hꢀ ꢀ ꢀp hydrogen bond,
ꢁ109.3 resulting in the formation of a molecular chain with the utiliza-
ꢁ117.8
tion of the b-glide plane perpendicular to the crystallographic
ꢁ100.4
a-axis [Fig. 2(b)]. Such chains are interconnected with the second
ꢁ106.2
ꢁ110.5 most stabilized molecular motif II (I.E = ꢁ19.6 kJ molꢁ1), which
consists of a pair of a C–Hꢀ ꢀ ꢀp hydrogen bond and a short Hꢀ ꢀ ꢀH
contact. The important fact observed here is that the motif I,
a
Molecules exist in trans conformation.
which consists of a short C–Hꢀ ꢀ ꢀO hydrogen bond (dHꢀ ꢀ ꢀO
=
that the substitution of the methyl group on N-methyl-N-phenyl 2.41 Å), has a 34% electrostatic (coulombic + polarization)
benzamide did not exhibit significant changes in the lattice and 66% dispersion contribution out of the total stabilization,
energy.
while the values corresponding to motif II are 22% and 78%,
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Table 5 List of interaction energies (kJ molꢁ1) of molecular pairs related by symmetry operation along with possible involved intermolecular interactions
DFT-D2/
B97-D
Geometry (Å/1)
D(Dꢀ ꢀ ꢀA),
Centroid-
centroid
distance (Å) ECoul EPol EDisp
Pair/
(BSSE
Possible involved
d(Hꢀ ꢀ ꢀA),
motif a
Symmetry code
ERep ETot corrected) interactionsc
+D–Hꢀ ꢀ ꢀA
b
NM00 (Pbca, Z0 = 1; ref. code: JAZJOJ10)
I
ꢁx + 3/2, y + 1/2, z
6.320
ꢁ9.1 ꢁ7.7 ꢁ33.1 (66) 25.4 ꢁ24.5 ꢁ28.4
ꢁ5.3 ꢁ2.1 ꢁ25.7 (78) 13.6 ꢁ19.6 ꢁ24.3
C6–H6ꢀ ꢀ ꢀO1
3.271(1)/2.41/136
3.757(1)/2.98/129
3.911(1)/2.96/147
3.664(1)/2.99/121
2.38
3.880(1)/2.98/140
3.787(1)/2.97/133
4.082(1)/3.14/147
3.361(1)/2.89/106
3.907(1)/2.86/163
3.936(1)/3.18/128
4.037(1)/3.11/144
3.836(1)/3.18/120
C14–H14Cꢀ ꢀ ꢀC5 (p)
C3–H3ꢀ ꢀ ꢀC9 (p)
C2–H2ꢀ ꢀ ꢀC11 (p)
H14Aꢀ ꢀ ꢀH9
II
ꢁx + 1/2, ꢁy + 1/2,
ꢁz + 1
6.877
III
IV
xꢁ1/2, y, ꢁz + 3/2
x, ꢁy + 1/2, zꢁ1/2
7.885
7.397
ꢁ5.0 ꢁ2.5 ꢁ19.6 (72) 9.8 ꢁ17.2 ꢁ19.7
ꢁ4.5 ꢁ2.5 ꢁ11.5 (62) 4.7 ꢁ13.9 ꢁ15.8
C12–H12ꢀ ꢀ ꢀC4 (p)
C14–H14Aꢀ ꢀ ꢀC3 (p)
C9–H9ꢀ ꢀ ꢀC2 (p)
C9–H9ꢀ ꢀ ꢀO1
V
VI
VII
ꢁx + 2, y + 1/2, ꢁz + 3/2
ꢁx + 2, ꢁy + 1, ꢁz + 1
ꢁx + 3/2, ꢁy + 1, zꢁ1/2
9.167
7.527
9.065
ꢁ3.7 ꢁ1.8 ꢁ8.8 (62) 4.2 ꢁ10.1 ꢁ11.3
0.6 ꢁ1.1 ꢁ15.4 (97) 5.8 ꢁ10.1 ꢁ11.2
ꢁ1.8 ꢁ0.6 ꢁ7.9 (77) 2.9 ꢁ7.3 ꢁ8.4
C4–H4ꢀ ꢀ ꢀO1
C10–H10ꢀ ꢀ ꢀC4 (p)
C10–H10ꢀ ꢀ ꢀC6 (p)
C10–H10ꢀ ꢀ ꢀC5 (p)
NM02 (C2/c, Z0 = 2)
I 1ꢀ ꢀ ꢀ1
ꢁx + 1/2, ꢁy + 1/2, ꢁz
7.800
5.505
ꢁ17.8 ꢁ5.4 ꢁ30.5 (57) 18.6 ꢁ35.1 ꢁ43.2
ꢁ8.8 ꢁ4.6 ꢁ44.2 (77) 26.1 ꢁ31.5 ꢁ31.0
C12–H12ꢀ ꢀ ꢀO1
C14–H14Bꢀ ꢀ ꢀO1
C40ꢀ ꢀ ꢀC40 (pꢀ ꢀ ꢀp)
C50ꢀ ꢀ ꢀC50 (pꢀ ꢀ ꢀp)
C50–H50ꢀ ꢀ ꢀC110 (p)
C8–H8ꢀ ꢀ ꢀO10
3.790(3)/2.77/158
3.610(3)/2.83/129
3.431(2)
II 2ꢀ ꢀ ꢀ2 ꢁx + 1, y, ꢁz + 1/2
3.393(2)
3.772(2)/2.78/153
3.393(2)/2.46/144
3.313(2)/2.43/138
3.400(3)/2.65/126
3.429(3)/2.67/127
3.670(2)/2.65/157
3.356(3)/2.45/141
2.823(2)/98(1)/158(1)
3.312(3)/2.58/125
3.428(2)/2.84/115
3.623(7)/2.68/146
3.300(3)/2.71/114
3.802(2)
3.609(2)/2.78/133
4.008(2)/2.99/157
3.541(8)/2.51/160
3.253(11)/2.58/120
3.797(9)/2.74/166
3.829(2)/2.86/149
3.800(2)/2.89/142
3.619(3)/2.66/147
3.306(3)/2.68/117
III 1ꢀ ꢀ ꢀ2 x, ꢁy, z + 1/2
6.175
ꢁ14.5 ꢁ6.0 ꢁ30.1 (59) 19.5 ꢁ31.1 ꢁ35.4
C60–H60ꢀ ꢀ ꢀF1
C80–H80ꢀ ꢀ ꢀF1
IV 1ꢀ ꢀ ꢀ1 ꢁx + 1/2, y + 1/2, ꢁz + 1/2 7.260
ꢁ11.4 ꢁ4.6 ꢁ36.2 (69) 22.2 ꢁ30.0 ꢁ35.3
ꢁ6.3 ꢁ4.8 ꢁ23.7 (68) 12.4 ꢁ22.4 ꢁ27.9
ꢁ8.3 ꢁ4.0 ꢁ14.9 (55) 9.5 ꢁ17.6 ꢁ18.2
C10–H10ꢀ ꢀ ꢀO1
C5–H5ꢀ ꢀ ꢀCg2 (p)
C20–H20ꢀ ꢀ ꢀO1
V 1ꢀ ꢀ ꢀ2 x, y, z
5.450
C15–F1ꢀ ꢀ ꢀF1A0–C150
C11–H11ꢀ ꢀ ꢀO10
C12–H12ꢀ ꢀ ꢀO10
C14–H14Bꢀ ꢀ ꢀF1A0
C90–H90ꢀ ꢀ ꢀF2
VI 1ꢀ ꢀ ꢀ2 ꢁx + 1/2, ꢁy + 1/2, ꢁz
8.499
VII 1ꢀ ꢀ ꢀ2 x, yꢁ1, z
VIII 2ꢀ ꢀ ꢀ2 x, ꢁy, z + 1/2
IX 2ꢀ ꢀ ꢀ2 x, yꢁ1, z
8.941
7.593
ꢁ4.6 ꢁ1.1 ꢁ14.4 (72) 5.4 ꢁ14.7 ꢁ18.4
ꢁ5.6 ꢁ2.2 ꢁ17.7 (69) 11.0 ꢁ14.5 ꢁ18.5
ꢁ5.4 ꢁ1.7 ꢁ10.2 (59) 7.3 ꢁ10.1 ꢁ10.7
C4ꢀ ꢀ ꢀC90 (pꢀ ꢀ ꢀp)
C100–H100ꢀ ꢀ ꢀC40 (p)
C110–H110ꢀ ꢀ ꢀC10 (p)
C140–H14Eꢀ ꢀ ꢀF1A0
C80–H80ꢀ ꢀ ꢀF2A0
C80–H80ꢀ ꢀ ꢀF3A0
C100–H100ꢀ ꢀ ꢀF3
C100–H100ꢀ ꢀ ꢀF2
C40–H40ꢀ ꢀ ꢀF2
10.627
X 1ꢀ ꢀ ꢀ2 ꢁx + 1, ꢁy, ꢁz + 1
XI 1ꢀ ꢀ ꢀ2 ꢁx + 1, y, ꢁz + 1/2
10.441
9.365
ꢁ2.3 ꢁ0.6 ꢁ6.2 (68) 2.0 ꢁ7.1 ꢁ8.3
ꢁ2.6 ꢁ1.0 ꢁ7.6 (68) 4.3 ꢁ7.0 ꢁ8.1
C40–H40ꢀ ꢀ ꢀF3
NM03 (P21/c, Z0 = 2)
I 1ꢀ ꢀ ꢀ2
x, y, z
5.173
ꢁ23.0 ꢁ8.0 ꢁ41.3 (57) 33.0 ꢁ39.3 ꢁ52.0
C12–H12ꢀ ꢀ ꢀO10
C14–H14Bꢀ ꢀ ꢀO10
C6ꢀ ꢀ ꢀC50 (pꢀ ꢀ ꢀp)
C6ꢀ ꢀ ꢀC60 (pꢀ ꢀ ꢀp)
C100–H100ꢀ ꢀ ꢀO10
C50–H50ꢀ ꢀ ꢀCg20 (p)
C80–H80ꢀ ꢀ ꢀC110 (p)
C10–H10ꢀ ꢀ ꢀCg1(p)
C9ꢀ ꢀ ꢀC9 (pꢀ ꢀ ꢀp)
C9ꢀ ꢀ ꢀC10 (pꢀ ꢀ ꢀp)
C30–H30ꢀ ꢀ ꢀC10 (p)
C120–H120ꢀ ꢀ ꢀO1
C90–H90ꢀ ꢀ ꢀO1
3.297(2)/2.26/161
3.448(2)/2.66/129
3.387(1)
3.481(1)
II 2ꢀ ꢀ ꢀ2 ꢁx, yꢁ1/2, ꢁz + 1/2
III 1ꢀ ꢀ ꢀ1 ꢁx + 1, ꢁy, ꢁz
6.506
6.565
ꢁ17.2 ꢁ7.3 ꢁ46.7 (65) 36.1 ꢁ35.1 ꢁ42.1
ꢁ9.7 ꢁ4.4 ꢁ41.5 (75) 27.9 ꢁ27.6 ꢁ33.4
3.340(2)/2.45/139
3.523(2)/2.49/159
3.799(2)/2.80/154
3.834(1)/2.89/146
3.245(1)
3.430(1)
IV 1ꢀ ꢀ ꢀ2 x, ꢁy + 1/2, z + 1/2
V 1ꢀ ꢀ ꢀ2 ꢁx, ꢁy, ꢁz
7.758
8.970
8.380
ꢁ8.3 ꢁ3.7 ꢁ28.6 (70) 17.0 ꢁ23.6 ꢁ28.6
ꢁ9.9 ꢁ4.7 ꢁ20.4 (58) 14.7 ꢁ20.3 ꢁ21.8
ꢁ7.8 ꢁ2.9 ꢁ16.1 (60) 10.9 ꢁ15.9 ꢁ18.6
3.860(1)/2.79/170
3.404(2)/2.33/173
3.614(2)/2.69/143
3.605(1)/2.71/139
3.393(2)/2.57/132
3.721(3)/2.69/160
3.111(3)/2.54/112
3.241(2)/2.81/104
3.527(4)/2.46/172
3.987(2)/2.96/159
3.259(3)/2.60/118
3.386(3)/2.89/109
3.555(3)/2.64/142
VI 1ꢀ ꢀ ꢀ2 ꢁx, y + 1/2, ꢁz + 1/2
C100–H100ꢀ ꢀ ꢀC3(p)
C3–H3ꢀ ꢀ ꢀO10
VII 1ꢀ ꢀ ꢀ2 x, yꢁ1, z
8.775
8.192
ꢁ8.0 ꢁ2.3 ꢁ8.8 (46) 4.6 ꢁ14.5 ꢁ16.7
ꢁ4.5 ꢁ1.4 ꢁ9.3 (61) 6.0 ꢁ9.2 ꢁ10.7
C20–H20ꢀ ꢀ ꢀF2A
C2–H2ꢀ ꢀ ꢀF1A0
VIII 1ꢀ ꢀ ꢀ2 x, ꢁyꢁ1/2, zꢁ1/2
C3–H3ꢀ ꢀ ꢀF1A0
IX 1ꢀ ꢀ ꢀ1 ꢁx + 1, y + 1/2, ꢁz + 1/2
X 1ꢀ ꢀ ꢀ1 ꢁx, ꢁy, ꢁz
8.594
10.564
9.340
ꢁ2.2 ꢁ0.9 ꢁ8.2 (73) 3.7 ꢁ7.6 ꢁ10.7
ꢁ2.6 ꢁ1.6 ꢁ4.1 (49) 1.0 ꢁ7.3 ꢁ8.8
ꢁ2.8 ꢁ0.7 ꢁ5.7 (62) 3.2 ꢁ6.0 ꢁ7.2
C5–H5ꢀ ꢀ ꢀF3A
C14–H14Cꢀ ꢀ ꢀO1
C9–H9ꢀ ꢀ ꢀF2A
XI 1ꢀ ꢀ ꢀ1 x, ꢁyꢁ1/2, zꢁ1/2
C8–H8ꢀ ꢀ ꢀF2A
XII 1ꢀ ꢀ ꢀ2 ꢁx + 1, y + 1/2, ꢁz + 1/2 10.943
ꢁ2.8 ꢁ0.4 ꢁ3.8 (54) 1.4 ꢁ5.6 ꢁ6.8
C11–H11ꢀ ꢀ ꢀF2A0
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Table 5 (continued)
DFT-D2/
B97-D
Geometry (Å/1)
Centroid-
centroid
distance (Å) ECoul EPol EDisp
D(Dꢀ ꢀ ꢀA),
d(Hꢀ ꢀ ꢀA),
+D–Hꢀ ꢀ ꢀA
Pair/
(BSSE
Possible involved
motif a
Symmetry code
ERep ETot corrected) interactionsc
b
NM10 (Pbca, Z0 = 1)
I
II
ꢁx + 1, ꢁy, ꢁz + 1
5.968
7.490
ꢁ16.2 ꢁ6.2 ꢁ34.2 (60) 20.2 ꢁ36.2 ꢁ41.3
ꢁ11.3 ꢁ5.8 ꢁ31.4 (65) 20.5 ꢁ28.1 ꢁ33.4
C11–H11ꢀ ꢀ ꢀC5 (p)
C14–H14Bꢀ ꢀ ꢀO1
C8–H8ꢀ ꢀ ꢀC6 (p)
C9–H9ꢀ ꢀ ꢀF3A
3.775(1)/2.74/161
3.382(2)/2.59/130
3.951(1)/2.90/164
3.378(15)/2.69/121
3.409(15)/2.76/119
3.974(2)/3.05/144
3.670(10)/2.72/146
3.335(11)/2.79/111
3.338(12)/2.79/112
3.310(2)/2.42/139
3.567(2)/2.50/169
3.839(2)/2.83/155
xꢁ1/2, y, ꢁz + 3/2
ꢁx + 1/2, yꢁ1/2, z
III
IV
7.881
ꢁ9.1 ꢁ2.6 ꢁ18.7 (62) 9.9 ꢁ20.6 ꢁ22.9
C10–H10ꢀ ꢀ ꢀF3A
C14–H14Cꢀ ꢀ ꢀC10 (p)
C14–H14Cꢀ ꢀ ꢀF2A
C2–H2ꢀ ꢀ ꢀF1A
xꢁ1/2, ꢁy + 1/2, ꢁz + 1
6.713
ꢁ4.8 ꢁ1.5 ꢁ16.5 (72) 5.4 ꢁ17.4 23.0
C3–H3ꢀ ꢀ ꢀF1A
V
VI
VII
ꢁx + 1, yꢁ1/2, ꢁz + 3/2
ꢁx + 3/2, yꢁ1/2, z
x + 1, y, z
8.997
8.989
9.655
ꢁ7.2 ꢁ3.7 ꢁ10.8 (50) 10.1 ꢁ11.7 ꢁ11.4
ꢁ4.4 ꢁ2.1 ꢁ8.0 (55) 4.9 ꢁ9.6 ꢁ11.2
ꢁ0.5 ꢁ1.7 ꢁ11.8 (84) 7.1 ꢁ6.9 ꢁ10.8
C5–H5ꢀ ꢀ ꢀO1
C4–H4ꢀ ꢀ ꢀO1
C3–H3ꢀ ꢀ ꢀC8 (p)
NM30 (P21/c, Z0 = 2)
I 1ꢀ ꢀ ꢀ2 x, y, z
7.321
ꢁ11.4 ꢁ5.4 ꢁ31.2 (65) 22.4 ꢁ25.6 ꢁ32.3
C30–H30ꢀ ꢀ ꢀO1
3.403(4)/2.65/127
3.727(3)/2.97/127
3.575(3)
3.359(3)/2.53/133
3.352(4)/2.49/136
3.385(3)/2.63/126
3.547(3)
3.408(3)
3.379(4)/2.62/127
3.346(3)
3.528(3)
3.758(3)/2.83/144
3.685(3)
3.713(3)/3.155(2)/104(1)
3.693(3)/3.161(2)/102
3.338(3)/2.52/132
C20–H20ꢀ ꢀ ꢀC1
C13ꢀ ꢀ ꢀC3 (pꢀ ꢀ ꢀp)
C80–H80ꢀ ꢀ ꢀO10
C12–H12ꢀ ꢀ ꢀO1
C120–H120ꢀ ꢀ ꢀF10
C40ꢀ ꢀ ꢀC90 (pꢀ ꢀ ꢀp)
C50ꢀ ꢀ ꢀC90 (pꢀ ꢀ ꢀp)
C8–H8ꢀ ꢀ ꢀF2
II 2ꢀ ꢀ ꢀ2 x, ꢁy + 1/2, z + 1/2
III 1ꢀ ꢀ ꢀ1 x, ꢁy + 3/2, z + 1/2
IV 2ꢀ ꢀ ꢀ2 x, ꢁy + 3/2, zꢁ1/2
8.623
8.686
7.524
ꢁ8.0 ꢁ4.1 ꢁ17.7 (59) 11.0 ꢁ18.8 ꢁ19.6
ꢁ8.4 ꢁ3.9 ꢁ17.0 (58) 11.0 ꢁ18.3 ꢁ19.6
ꢁ5.2 ꢁ2.0 ꢁ23.9 (77) 12.8 ꢁ18.3 ꢁ21.8
V 1ꢀ ꢀ ꢀ1 x, ꢁy + 1/2, zꢁ1/2
VI 1ꢀ ꢀ ꢀ2 x, ꢁy + 3/2, z + 1/2
7.482
ꢁ5.8 ꢁ2.3 ꢁ25.0 (76) 14.9 ꢁ18.2 ꢁ17.2
C3ꢀ ꢀ ꢀC11 (pꢀ ꢀ ꢀp)
C4ꢀ ꢀ ꢀC11 (pꢀ ꢀ ꢀp)
C40–H40ꢀ ꢀ ꢀC6 (p)
C40ꢀ ꢀ ꢀC13
8.400
ꢁ4.6 ꢁ3.4 ꢁ22.2 (74) 13.2 ꢁ17.0 ꢁ21.1
VII 2ꢀ ꢀ ꢀ2 ꢁx, ꢁy + 1, ꢁz + 1
7.998
8.078
6.529
ꢁ6.1 ꢁ1.6 ꢁ18.3 (70) 8.9 ꢁ17.0 ꢁ22.1
ꢁ5.9 ꢁ1.4 ꢁ18.2 (71) 9.2 ꢁ16.4 ꢁ21.3
ꢁ3.6 ꢁ1.8 ꢁ19.0 (78) 8.4 ꢁ16.0 ꢁ19.8
C150–F20ꢀ ꢀ ꢀC90 (p)
C15–F3ꢀ ꢀ ꢀC11 (p)
C120–H120ꢀ ꢀ ꢀF20
VIII 1ꢀ ꢀ ꢀ1 ꢁx + 1, ꢁy + 1, ꢁz + 2
1
2
IX 2ꢀ ꢀ ꢀ2 ꢁx, ꢁy + 1/2, ꢁz +
C150–F20ꢀ ꢀ ꢀC130QO10 4.517(3)/3.203(2)/166(1)
X 1ꢀ ꢀ ꢀ1 ꢁx + 1, ꢁy + 1/2,
ꢁz + 3/2
6.520
8.339
ꢁ3.4 ꢁ1.8 ꢁ18.1 (78) 7.8 ꢁ15.5 ꢁ19.3
ꢁ6.0 ꢁ2.1 ꢁ11.7 (59) 4.9 ꢁ14.9 ꢁ17.3
ꢁ6.2 ꢁ2.5 ꢁ12.3 (59) 6.4 ꢁ14.6 ꢁ17.2
ꢁ4.4 ꢁ3.1 ꢁ13.0 (63) 7.9 ꢁ12.6 ꢁ13.8
1.6 ꢁ0.3 ꢁ5.2 (95) 2.1 ꢁ1.8 ꢁ2.5
1.6 ꢁ0.3 ꢁ5.1 (94) 1.9 ꢁ1.8 ꢁ2.6
C8–H8ꢀ ꢀ ꢀF3
3.330(3)/2.54/129
4.473(3)/3.154(2)/166(1)
3.547(4)/2.73/132
3.637(3)/2.68/147
3.515(4)/2.66/135
3.495(4)/2.59/141
3.722(3)/2.73/152
3.499(5)/2.91/114
3.104(2)/90(1)/128(1)
3.002(2)/94(1)/94(1)
2.966(2)/94(1)/94(1)
C15–F3ꢀ ꢀ ꢀC13QO1
C4–H4ꢀ ꢀ ꢀO1
XI 1ꢀ ꢀ ꢀ1 x, y + 1, z
C14–H14Bꢀ ꢀ ꢀF1
C40–H40ꢀ ꢀ ꢀO10
XII 2ꢀ ꢀ ꢀ2 x, yꢁ1, z
8.339
C140–H14E0ꢀ ꢀ ꢀF30
C5–H5ꢀ ꢀ ꢀC60 (p)
C50–H50ꢀ ꢀ ꢀO10
XIII 1ꢀ ꢀ ꢀ2 x, ꢁy + 1/2, z + 1/2
XIV 2ꢀ ꢀ ꢀ2 ꢁx, ꢁy + 2, ꢁz + 1
XV 1ꢀ ꢀ ꢀ1 ꢁx + 1, ꢁy, ꢁz + 2
NM11 (P21/c, Z0 = 1)
8.349
10.740
10.759
C150–F20ꢀ ꢀ ꢀF30–C150
C150–F30ꢀ ꢀ ꢀF30–C150
C15–F1ꢀ ꢀ ꢀF1–C15
I
ꢁx + 1, ꢁy, ꢁz + 2
7.697
8.980
8.424
7.409
8.484
7.347
ꢁ27.0 ꢁ7.9 ꢁ29.4 (46) 23.4 ꢁ40.8 ꢁ43.4
ꢁ7.7 ꢁ2.6 ꢁ29.4 (74) 17.6 ꢁ22.0 ꢁ31.3
0.1 ꢁ1.6 ꢁ24.9 (94) 8.6 ꢁ17.8 ꢁ23.3
ꢁ4.6 ꢁ1.5 ꢁ17.4 (74) 6.7 ꢁ16.7 ꢁ21.0
ꢁ11.8 ꢁ3.9 ꢁ10.7 (41) 9.9 ꢁ16.6 ꢁ18.2
0.6 ꢁ2.5 ꢁ23.7 (93) 9.8 ꢁ15.8 ꢁ21.0
C9–H9ꢀ ꢀ ꢀO1
3.498(2)/2.46/160
3.296(2)/2.49/144
3.560(2)
3.579(2)
3.960(2)
C10–H10ꢀ ꢀ ꢀF6
C10ꢀ ꢀ ꢀC3 (pꢀ ꢀ ꢀp)
C11ꢀ ꢀ ꢀC4 (pꢀ ꢀ ꢀp)
C2ꢀ ꢀ ꢀC3 (pꢀ ꢀ ꢀp)
C16ꢀ ꢀ ꢀC4 (pꢀ ꢀ ꢀp)
C5–H5ꢀ ꢀ ꢀF6
II
xꢁ1, y, z
III
IV
V
ꢁx + 2, ꢁy + 1, ꢁz + 2
x, ꢁy + 1/2, zꢁ1/2
ꢁx + 2, y + 1/2, ꢁz + 3/2
ꢁx + 1, y + 1/2, ꢁz + 3/2
3.955(2)
3.543(2)/2.79/127
3.773(2)/2.82/148
3.287(2)/2.35/144
3.645(2)/2.65/154
3.305(2)/2.84/106
3.731(2)/2.87/137
3.871(2)/3.11/128
3.600(2)/2.58/156
3.727(2)/2.78/147
C6–H6ꢀ ꢀ ꢀF4
C5–H5ꢀ ꢀ ꢀO1
C4–H4ꢀ ꢀ ꢀF3
VI
C14–H14Aꢀ ꢀ ꢀF1
C14–H14Aꢀ ꢀ ꢀF3
C10–H10ꢀ ꢀ ꢀC5 (p)
C11–H11ꢀ ꢀ ꢀF5
C3–H3ꢀ ꢀ ꢀF1
VII
xꢁ1, ꢁy + 1/2, zꢁ1/2
11.364
5.674
ꢁ2.3 ꢁ0.5 ꢁ6.3 (69) 3.8 ꢁ5.3 ꢁ7.5
ꢁ6.7 ꢁ3.9 ꢁ41.4 (80) 15.7 ꢁ36.2 ꢁ45.0
NM12 (P21/c, Z0 = 1)
ꢁx + 2, ꢁy + 2, ꢁz
I
C10–H10ꢀ ꢀ ꢀC3 (p)
C9–H9ꢀ ꢀ ꢀC5 (p)
C9ꢀ ꢀ ꢀC9 (pꢀ ꢀ ꢀp)
3.821(2)/3.02/131
4.077(1)/3.04/160
3.624(2)
C15–F1ꢀ ꢀ ꢀF4A–C16
3.074(3)/140(1)/112(1)
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Table 5 (continued)
DFT-D2/
B97-D
Geometry (Å/1)
Centroid-
centroid
distance (Å) ECoul EPol EDisp
D(Dꢀ ꢀ ꢀA),
d(Hꢀ ꢀ ꢀA),
+D–Hꢀ ꢀ ꢀA
Pair/
(BSSE
Possible involved
motif a
II
Symmetry code
ERep ETot corrected) interactionsc
b
x, ꢁy + 3/2, zꢁ1/2
x, y, zꢁ1
7.061
7.945
9.098
ꢁ12.9 ꢁ7.1 ꢁ21.8 (52) 16.2 ꢁ25.6 ꢁ31.2
ꢁ8.9 ꢁ2.5 ꢁ16.5 (59) 5.7 ꢁ22.3 ꢁ25.9
ꢁ4.0 ꢁ1.6 ꢁ17.5 (76) 7.3 ꢁ15.8 ꢁ20.7
C12–H12ꢀ ꢀ ꢀO1
C6–H6ꢀ ꢀ ꢀO1
3.356(3)/2.32/160
3.562(3)/2.57/153
3.646(3)/2.66/152
3.446(3)/2.69/127
4.000(2)/2.96/162
3.751(3)/2.78/149
3.427(3)/2.63/130
3.814(9)/2.85/149
3.061(8)/166(2)/156(2)
III
IV
C11–H11ꢀ ꢀ ꢀO1
C10–H10ꢀ ꢀ ꢀF2
C14–H14Bꢀ ꢀ ꢀC3 (p)
C3–H3ꢀ ꢀ ꢀF1
xꢁ1, y, z
V
VI
ꢁx + 2, ꢁy + 2, ꢁz + 1
xꢁ1, y, zꢁ1
7.883
10.768
ꢁ3.1 ꢁ0.9 ꢁ12.1 (75) 4.1 ꢁ12.1 ꢁ16.0
0.2 ꢁ0.4 ꢁ4.9 (96) 1.3 ꢁ3.8 ꢁ6.1
C2–H2ꢀ ꢀ ꢀF1
C14–H14Aꢀ ꢀ ꢀF5A
C15–F3ꢀ ꢀ ꢀF4A–C16
NM22 (P21/c, Z0 = 1)
I
x, ꢁy + 1/2, z + 1/2
7.291
ꢁ24.7 ꢁ10.9 ꢁ32.9 (48) 31.5 ꢁ37.0 ꢁ40.5
C2–H2ꢀ ꢀ ꢀO1
3.500(2)/2.43/173
3.118(2)/2.21/140
3.679(3)/2.69/152
3.837(2)/2.79/163
3.500(1)
3.475(1)/2.51/148
3.583(14)/2.67/142
3.145(15)/2.25/139
3.352(2)/2.58/128
3.815(2)/2.91/142
3.882(2)/2.99/140
C8–H8ꢀ ꢀ ꢀO1
C6–H6ꢀ ꢀ ꢀO1
II
ꢁx + 1, ꢁy + 1, ꢁz
xꢁ1, y, z
5.937
8.376
7.976
8.023
ꢁ2.9 ꢁ4.7 ꢁ42.8 (85) 24.3 ꢁ26.0 ꢁ33.4
ꢁ10.2 ꢁ4.6 ꢁ30.0 (67) 20.6 ꢁ24.2 ꢁ30.3
ꢁ6.2 ꢁ2.6 ꢁ17.9 (67) 11.2 ꢁ15.6 ꢁ18.1
ꢁ3.1 ꢁ0.8 ꢁ7.7 (66) 1.4 ꢁ10.2 ꢁ14.6
C10–H10ꢀ ꢀ ꢀC5 (p)
C10ꢀ ꢀ ꢀC10 (pꢀ ꢀ ꢀp)
C4–H4ꢀ ꢀ ꢀCg2 (p)
C5–H5ꢀ ꢀ ꢀF2A
C12–H12ꢀ ꢀ ꢀF1A
C6–H6ꢀ ꢀ ꢀF6
III
IV
V
x, y, z + 1
ꢁx + 1, ꢁy + 1, ꢁz + 1
C11–H11ꢀ ꢀ ꢀF5
C11–H11ꢀ ꢀ ꢀF6
NM23 (P21/c, Z0 = 1)
I
ꢁx + 1, ꢁy + 1, ꢁz
5.065
7.982
ꢁ15.0 ꢁ9.3 ꢁ58.3 (71) 43.4 ꢁ39.1 ꢁ50.8
ꢁ18.4 ꢁ8.1 ꢁ37.1 (58) 25.0 ꢁ38.7 ꢁ42.4
ꢁ14.6 ꢁ5.6 ꢁ27.6 (58) 16.3 ꢁ31.4 ꢁ38.7
ꢁ4.6 ꢁ2.3 ꢁ18.6 (73) 11.3 ꢁ14.2 ꢁ19.0
ꢁ2.0 ꢁ0.7 ꢁ8.4 (76) 3.1 ꢁ8.0 ꢁ10.6
ꢁ2.1 ꢁ0.6 ꢁ6.7 (71) 3.9 ꢁ5.5 ꢁ6.6
C10–H10ꢀ ꢀ ꢀCg1 (p)
C10ꢀ ꢀ ꢀC11 (pꢀ ꢀ ꢀp)
C12–H12ꢀ ꢀ ꢀO1
C2–H2ꢀ ꢀ ꢀO1
3.652(2)/2.61/161
3.331(2)
II
ꢁx + 1, ꢁy + 1, ꢁz + 1
x, ꢁy + 1/2, zꢁ1/2
3.652(2)/2.58/172
3.552(2)/2.80/126
3.314(2)/2.62/121
3.302(2)/2.60/122
3.636(2)/2.62/157
3.457(2)
3.700(3)/2.64/166
2.948(2)/148(1)/96(1)
3.550(2)/2.48/173
3.004(2)/96(1)/145(1)
III
IV
V
6.205
C5–H5ꢀ ꢀ ꢀO1
C2–H6ꢀ ꢀ ꢀO1
ꢁx + 1, y + 1/2, ꢁz + 1/2
xꢁ1, ꢁy + 1/2, zꢁ1/2
x + 1, y, z + 1
7.260
C14–C14Cꢀ ꢀ ꢀF5A
C5ꢀ ꢀ ꢀC12 (pꢀ ꢀ ꢀp)
C8–C8ꢀ ꢀ ꢀF4A
10.749
11.682
C15–F3Aꢀ ꢀ ꢀF6A–C16
C3–H3ꢀ ꢀ ꢀF1A
VI
C15–F3Aꢀ ꢀ ꢀF4A–C16
NM31 (P21/c, Z0 = 1)
I
ꢁx + 1, yꢁ1/2, ꢁz + 1/2
7.187
7.940
ꢁ11.9 ꢁ4.9 ꢁ32.8 (66) 19.5 ꢁ30.1 ꢁ36.8
ꢁ12.5 ꢁ3.6 ꢁ17.2 (52) 11.3 ꢁ22.1 ꢁ26.0
C4–H4ꢀ ꢀ ꢀO1
3.410(2)/2.42/151
3.665(2)
3.656(2)
C4ꢀ ꢀ ꢀC1 (pꢀ ꢀ ꢀp)
C3ꢀ ꢀ ꢀC6 (pꢀ ꢀ ꢀp)
C9–H9ꢀ ꢀ ꢀO1
II
x, yꢁ1, z
3.508(2)/2.54/149
3.229(7)/2.38/135
3.699(6)/2.72/150
3.656(7)/2.74/143
3.595(2)
3.600(6)/2.90/123
3.692(2)/2.76/145
3.244(2)/2.52/123
3.280(2)/2.61/120
3.939(2)/3.05/139
3.614(5)/2.80/133
2.918(2)/134(1)/111(1)
C6–H6ꢀ ꢀ ꢀF3A
C12–H12ꢀ ꢀ ꢀF1A
C14–H14Aꢀ ꢀ ꢀF1A
C11ꢀ ꢀ ꢀC11 (pꢀ ꢀ ꢀp)
C14–H14Bꢀ ꢀ ꢀF2A
C11–H11ꢀ ꢀ ꢀO1
C5–H5ꢀ ꢀ ꢀF6
III
IV
ꢁx, ꢁy, ꢁz + 1
9.001
8.143
ꢁ5.5 ꢁ1.5 ꢁ18.7 (73) 6.2 ꢁ19.6 ꢁ24.9
ꢁ5.5 ꢁ3.3 ꢁ20.1 (70) 10.8 ꢁ18.2 ꢁ19.5
x, ꢁy + 1/2, z + ꢁ1/2
C6–H6ꢀ ꢀ ꢀF6
V
VI
VII
ꢁx, y + 1/2, ꢁz + 1/2
ꢁx + 1, ꢁy, ꢁz + 1
x, ꢁyꢁ1/2, zꢁ + 1/2
7.937
8.313
9.458
ꢁ6.5 ꢁ2.1 ꢁ15.2 (64) 9.6 ꢁ14.2 ꢁ19.4
ꢁ0.7 ꢁ0.8 ꢁ9.6 (86) 1.9 ꢁ9.2 ꢁ13.8
ꢁ0.0 ꢁ0.3 ꢁ6.3 (95) 1.7 ꢁ4.9 ꢁ7.6
C14–H14Cꢀ ꢀ ꢀCg2 (p)
C4–H4ꢀ ꢀ ꢀF2A
C15–F3Aꢀ ꢀ ꢀF6–C16
0
%
NM33 (P1, Z = 2)
I 1ꢀ ꢀ ꢀ1
ꢁx + 1, ꢁy + 1, ꢁz
7.358
4.361
ꢁ17.3 ꢁ8.1 ꢁ38.8 (60) 26.4 ꢁ37.8 ꢁ40.8
ꢁ10.6 ꢁ8.0 ꢁ57.2 (75) 40.6 ꢁ35.3 ꢁ49.8
C8–H8ꢀ ꢀ ꢀO1
3.562(1)/2.49/173
3.664(2)/2.63/159
3.648(1)/2.95/122
3.486(2)
II 1ꢀ ꢀ ꢀ2 ꢁx + 1, ꢁy + 1, ꢁz
C30–H30ꢀ ꢀ ꢀCg1 (p)
C9–H9ꢀ ꢀ ꢀC80 (p)
C8ꢀ ꢀ ꢀC30 (pꢀ ꢀ ꢀp)
C9ꢀ ꢀ ꢀC30 (pꢀ ꢀ ꢀp)
C60–H60ꢀ ꢀ ꢀF2A0
C60–H60ꢀ ꢀ ꢀF1A0
C50–H50ꢀ ꢀ ꢀF1A0
C110ꢀ ꢀ ꢀC110 (pꢀ ꢀ ꢀp)
C80–H80ꢀ ꢀ ꢀO1
3.311(2)
III 2ꢀ ꢀ ꢀ2 ꢁx + 1, ꢁy + 1, ꢁz + 1
IV 1ꢀ ꢀ ꢀ2 x, y, z
6.426
8.192
ꢁ12.7 ꢁ3.8 ꢁ32.5 (66) 16.0 ꢁ33.0 ꢁ37.1
ꢁ21.1 ꢁ6.9 ꢁ19.4 (41) 19.2 ꢁ28.2 ꢁ29.3
3.772(10)/2.72/166
3.475(7)/2.72/127
3.544(8)/2.88/120
3.547(2)
3.370(2)/2.30/169
3.285(2)/2.42/136
C20–H20ꢀ ꢀ ꢀO1
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Paper
Table 5 (continued)
DFT-D2/
B97-D
Geometry (Å/1)
Centroid-
centroid
distance (Å) ECoul EPol EDisp
D(Dꢀ ꢀ ꢀA),
d(Hꢀ ꢀ ꢀA),
+D–Hꢀ ꢀ ꢀA
Pair/
(BSSE
Possible involved
motif a Symmetry code
ERep ETot corrected) interactionsc
b
V 1ꢀ ꢀ ꢀ2 ꢁx, ꢁy + 1, ꢁz
8.726
ꢁ8.3 ꢁ4.7 ꢁ26.4 (67) 17.6 ꢁ21.9 ꢁ28.2
C14–H14Cꢀ ꢀ ꢀO10
C14–H14Bꢀ ꢀ ꢀC20(p)
C11ꢀ ꢀ ꢀC50 (pꢀ ꢀ ꢀp)
C4ꢀ ꢀ ꢀC5 (pꢀ ꢀ ꢀp)
C16ꢀ ꢀ ꢀC6 (pꢀ ꢀ ꢀp)
C3–H3ꢀ ꢀ ꢀO10
3.636(2)/2.80/134
3.502(2)/2.63/138
3.674(2)
3.541(1)
3.615(1)
3.167(1)/2.20/148
3.542(2)/2.81/125
3.275(11)/2.75/110
VI 1ꢀ ꢀ ꢀ1 ꢁx + 1, ꢁy, ꢁz
VII 1ꢀ ꢀ ꢀ2 x + 1, y, z
VIII 2ꢀ ꢀ ꢀ2 xꢁ1, y, z
7.963
10.529
8.998
ꢁ5.6 ꢁ2.4 ꢁ28.8 (78) 17.4 ꢁ19.4 ꢁ29.7
ꢁ14.9 ꢁ5.0 ꢁ10.5 (35) 15.5 ꢁ15.0 ꢁ14.6
ꢁ6.3 ꢁ1.1 ꢁ10.3 (58) 3.8 ꢁ14.0 ꢁ17.7
ꢁ3.1 ꢁ1.5 ꢁ11.6 (72) 6.1 ꢁ10.0 ꢁ13.1
ꢁ4.0 ꢁ0.7 ꢁ8.4 (64) 3.2 ꢁ10.0 ꢁ11.5
ꢁ4.4 ꢁ1.5 ꢁ11.9 (67) 7.9 ꢁ10.0 ꢁ13.8
ꢁ3.8 ꢁ1.1 ꢁ7.9 (62) 4.9 ꢁ8.0 ꢁ9.5
C140–H14Fꢀ ꢀ ꢀF5
C140–H14Dꢀ ꢀ ꢀF3A0
C150–F3A0ꢀ ꢀ ꢀC130QO10 3.179(10)/177
IX 1ꢀ ꢀ ꢀ1 xꢁ1, y, z
8.998
C12–H12ꢀ ꢀ ꢀF6
3.397(2)/2.43/148
3.311(2)/2.77/111
3.762(1)/2.78/151
3.009(1)/130(1)/99(1)
3.509(2)/2.48/160
3.654(2)/2.76/140
3.210(2)/2.54/119
3.262(2)/2.66/115
3.899(1)/2.90/153
3.682(7)/2.78/141
3.012(1)/139(1)/95(1)
2.889(1)/101(1)/101(1)
C14–H14Bꢀ ꢀ ꢀF6
C11–H11ꢀ ꢀ ꢀF6
X 1ꢀ ꢀ ꢀ1 ꢁx, ꢁy, ꢁzꢁ1
XI 1ꢀ ꢀ ꢀ2 ꢁx + 1, ꢁy, ꢁz
XII 1ꢀ ꢀ ꢀ2 x, y, zꢁ1
11.332
8.377
C15–F2ꢀ ꢀ ꢀF3–C15
C140–H14Fꢀ ꢀ ꢀF6
C140–H14Fꢀ ꢀ ꢀF4
C110–H110ꢀ ꢀ ꢀF1
C120–H120ꢀ ꢀ ꢀF1
C120–H120ꢀ ꢀ ꢀF2
C50–H50ꢀ ꢀ ꢀF5A0
C16–F5ꢀ ꢀ ꢀF6–C16
C16–F5ꢀ ꢀ ꢀF5–C16
10.301
XIII 2ꢀ ꢀ ꢀ2 ꢁx + 1, ꢁy + 2, ꢁz + 1
XIV 1ꢀ ꢀ ꢀ1 ꢁx + 2, ꢁy, ꢁz
9.320
13.180
ꢁ2.9 ꢁ0.4 ꢁ5.6 (63) 1.8 ꢁ7.2 ꢁ10.7
1.1 ꢁ0.2 ꢁ4.7 (96) 2.7 ꢁ1.2 ꢁ1.5
a
b
Arranged in descending order of energy. Values in parenthesis represent % dispersion energy contribution (%Edisp) towards the total
c
stabilization, % electrostatic contribution (%Eelec) = 100 ꢁ %Edisp
. Cg1 and Cg2 refer to the centre of gravity for the phenyl rings C1–C6 and
C7–C12, respectively.
Fig. 1 (a) and (b) ORTEP of NM10 and NM11 drawn with 50% ellipsoidal probability with an atom numbering scheme displaying two possible
conformations in this class of compounds. A similar numbering scheme was followed in all the structures. Only the major component of the disordered
part of the molecule is shown for clarity. The dotted lines indicates the presence of an intramolecular C(sp3)–Hꢀ ꢀ ꢀOQC hydrogen bond. ORTEPs of the
other molecules are shown in Fig. S5 in the ESI.† (c) Overlay of all the structures in cis-geometry, drawn with Mercury 3.0. (d) Molecular diagram of related
molecules reported in CSD with their reference code. Dotted lines indicate the presence of an intramolecular C–Hꢀ ꢀ ꢀOQC hydrogen bond.
respectively, which primarily involves C–Hꢀ ꢀ ꢀp hydrogen bonds. the van der Waals radii66 were observed. Furthermore, in the
Similar trends were observed in the other motifs as well. Motifs case of motifs IV and V, wherein weak C–Hꢀ ꢀ ꢀO hydrogen bonds
involving C–Hꢀ ꢀ ꢀp hydrogen bonds (III, VI, VII) display a disper- are present, the dispersion contribution decreases to 62%. Motif
sion contribution greater than 72%, the highest being in the case IV was observed to be utilized in the formation of a molecular
of motif VI (97%), wherein no interactions less than the sum of chain along the c-axis (using the c-glide plane perpendicular to
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among the top six most stabilized motifs, five consists (motifs
I, III–VI) of the presence of weak C–Hꢀ ꢀ ꢀOQC hydrogen bonds
with stabilization energies ranging from 17.6 kJ molꢁ1 to
35.1 kJ molꢁ1 with substantial electrostatic contributions
(in the range of 31 to 45%, Table 5). The highest stabilized
(with a 43% electrostatic contribution) molecular motif was I,
which included the presence of dimeric bifurcated weak
C–Hꢀ ꢀ ꢀOQC hydrogen bonds with donor atoms from two
different C–H bonds [C(sp2)–H and C(sp3)–H] in different electro-
nic environments. Motifs II, III and IV were observed to provide
similar stabilization (I.E: ꢁ31.5, ꢁ31.1 and ꢁ30.0 kJ molꢁ1
,
respectively) but differed in the nature of the participating inter-
actions. In the case of motif II, the molecules interact via the
Fig. 2 (a) Selected molecular pairs along with their PIXEL interaction
energy in NM00. Roman numbers in red indicate the molecular pairs (in
Table 5). (b) Packing of molecules via the utilization of weak C–Hꢀ ꢀ ꢀOQC
and C–Hꢀ ꢀ ꢀp hydrogen bonds in NM00. The molecular pairs in Table 5 are
indicated with Roman numbers in red in all the figures in this study. (c)
Weak C–Hꢀ ꢀ ꢀOQC and C–Hꢀ ꢀ ꢀp hydrogen bonds in the packing of
molecules in NM00 along the crystallographic c-axis.
the a-axis) and such chains are interconnected with motifs V and
VI [Fig. 2(c)].
N-Methyl-N-phenyl-3-(trifluoromethyl)benzamide (NM02)
Compound NM02 crystallizes in the monoclinic centro-
symmetric C2/c space group with two molecules in the asym-
metric unit. The asymmetric unit (motif V, I.E = ꢁ22.4 kJ molꢁ1
,
Table 5) is held via a short C(sp2)–HꢀꢀꢀOQC (2.45 Å/1411; invol-
ving acidic hydrogen, H20) and a short type II C(sp3)–FꢀꢀꢀF–C(sp3)
contact [2.823(2) Å, 98(1)1, 158(1)1]. The presence of a s-hole on
the fluorine atoms in the CF3 group has recently been revealed
and is responsible for the formation of such interactions in the
crystal packing.36 It was also well established that type II halogen–
halogen contacts may be considered as a halogen bond.67,68 It can
be noted here that the electrostatic contribution (coulombic +
polarization) towards the total stabilization energy is 32%
between the two interacting molecules in the asymmetric unit.
Furthermore, the analysis of the molecular pairs extracted
[Fig. 3(a)] from the crystal packing of NM02 revealed that
Fig. 3 (a) Selected molecular pairs, along with their PIXEL interaction
energy in NM02. C atoms are in purple and represent the second molecule
in the asymmetric unit. (b) Packing of molecules in NM02 with the
presence of weak C–Hꢀ ꢀ ꢀOQC, C–Hꢀ ꢀ ꢀF and C–Hꢀ ꢀ ꢀp hydrogen bonds.
(c) Part of the crystal packing down the ab plane in NM02, displaying the
presence of weak C–Hꢀ ꢀ ꢀOQC and C–Hꢀ ꢀ ꢀF–C(sp3) hydrogen bonds
along with C(sp3)–Fꢀ ꢀ ꢀF–C(sp3) interactions.
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existence of C–Hꢀ ꢀ ꢀp hydrogen bonds and pꢀ ꢀ ꢀp interactions,
with the % contribution from the dispersion being the highest
(77%) among all the motifs. Motif III involved one short
C(sp2)–Hꢀ ꢀ ꢀOQC (2.46 Å/1441) and two C(sp2)–Hꢀ ꢀ ꢀF–C(sp3)
hydrogen bonds (2.43 Å/1381; 2.65 Å/1261); the former being
significantly short. The dispersion contribution was 59% with
this being a significant contribution and comparable to related
weak H-bonds. Furthermore, motif IV, which involved one
C(sp2)–HꢀꢀꢀOQC and a short C–Hꢀꢀꢀp hydrogen bond (2.65 Å/
1571, Table 5), showed a dispersion contribution (69%) in between
that of motifs II and III. Two bifurcated C(sp2)–HꢀꢀꢀOQC along
with C(sp3)–HꢀꢀꢀF–C(sp3) were observed to hold the molecules in
motif VI (I.E = ꢁ18.2 kJ molꢁ1) with the highest (45%) electrostatic
contribution among all the motifs. Furthermore, in the case of
motif VII (I.E = ꢁ14.7 kJ molꢁ1) and VIII (I.E = ꢁ14.5 kJ molꢁ1),
wherein C–Hꢀꢀꢀp hydrogen bonds and pꢀꢀꢀp interactions are pre-
sent, the total stabilization was dominated from the contribution
due to the dispersion interactions (72 and 69%, respectively). It is to
be noted that the crystal packing in NM02 was also stabilized, albeit
less, by the presence of weak C(sp2/sp3)–HꢀꢀꢀF–C(sp3) hydrogen
bonds (motifs IX–XI). Motif IX (I.E = ꢁ10.1 kJ molꢁ1) showed the
presence of one bifurcated C(sp2)–HꢀꢀꢀF–C(sp3) and a short and
directional C(sp3)–HꢀꢀꢀF–C(sp3) (2.51 Å/1601) hydrogen bond with
the electrostatic contribution being 41% of the total stabilization.
Motifs X and XI [involving bifurcated C(sp2)–HꢀꢀꢀF–C(sp3) hydrogen
bonds], which were observed to contribute similar stabilization
(ꢁ7.1 and ꢁ7.0 kJ molꢁ1) towards the crystal packing, contain a
32% contribution from electrostatics. The stabilization energy for a
C–Hꢀ ꢀ ꢀF hydrogen bond was reported to be ꢁ0.40 kcal molꢁ1
(ꢁ1.6 kJ molꢁ1) by an ab initio theoretical calculation in the
molecular crystal.69 It was observed in the same study that the Fig. 4 (a) Selected molecular pairs, along with their PIXEL interaction
energy in NM03. C atoms are in purple and represent the second molecule
in the asymmetric unit. (b) Packing of molecules down the (101) plane in
stabilization energy for a C–Hꢀ ꢀ ꢀF hydrogen bond was mainly
dominated by electrostatic and dispersion components with the
NM03, displaying the presence of weak C–Hꢀ ꢀ ꢀOQC, C–Hꢀ ꢀ ꢀp and
latter being more prominent. Fig. 3(b) and (c) display the
packing of molecules in NM02 with the utilization of such weak
interactions.
C–Hꢀ ꢀ ꢀF–C(sp3) hydrogen bonds. (c) Part of the crystal packing displaying
motifs I and III (Table 5) connected via weak C(sp2)–Hꢀ ꢀ ꢀF–C(sp3) hydrogen
bonds down the (110) plane in NM03.
N-Methyl-N-phenyl-4-(trifluoromethyl)benzamide (NM03)
Compound NM03 crystallizes in the monoclinic centro- (2.49 Å, 1591; 2.80 Å, 1541) hydrogen bonds, the electrostatic
symmetric P21/c space group with Z0 = 2. A bifurcated weak contribution is 35% [Table 5]. It can be noted here that motif I
C(sp3)/(sp2)–Hꢀ ꢀ ꢀOQC hydrogen bond [this includes a short [consisting of highly short and directional C(sp2)–Hꢀ ꢀ ꢀO] has
and highly directional C(sp2)–Hꢀ ꢀ ꢀOQC; 2.26 Å, 1611, Table 5] approximately 6 kJ molꢁ1 more coulombic contribution than
along with pꢀ ꢀ ꢀp interactions were observed to link the mole- that in motif II, whereas the opposite situation was observed in
cules in the asymmetric unit. This molecular motif has the the case of the dispersion contribution with a similar magnitude
highest stability [motif I, I.E = ꢁ39.3 kJ molꢁ1, Fig. 4(a)] in the of approximately 6 kJ molꢁ1. Motif III (I.E = ꢁ27.6 kJ molꢁ1) and
crystal packing of NM03 [Fig. 4(b) and (c)] with the electrostatic IV (I.E = ꢁ23.6 kJ molꢁ1) are characterized by the presence of
contribution being 43%. Although motif I primarily consists of weak C(sp2)–Hꢀ ꢀ ꢀp and pꢀ ꢀ ꢀp interactions, and the dispersion
pꢀ ꢀ ꢀp interactions, a relatively high electrostatic contribution energy contribution in them exceeds 75% and 70% respectively.
towards the total stabilization (in comparison to related mole- Furthermore, a short and highly directional C(sp2)–Hꢀ ꢀ ꢀO
cular motifs, wherein C–Hꢀ ꢀ ꢀp or pꢀ ꢀ ꢀp are present, the electro- hydrogen bond (2.33 Å, 1731, motif V) was observed to provide
static contribution was observed to be less than 30%) is due to 20.3 kJ molꢁ1 stabilization towards the crystal packing in NM03
the presence of short C(sp3)/(sp2)–Hꢀ ꢀ ꢀOQC hydrogen bonds. with the contribution from electrostatics being 42%. Similar
Similarly, in the case of the second most stabilized molecular trends were observed in the case of motifs VI and VII [Fig. 4(a)],
pair (motif II, I.E = ꢁ35.1 kJ molꢁ1), wherein the molecules are wherein the molecules are held via the presence of C(sp2)–Hꢀ ꢀ ꢀO
linked with a short C(sp2)–Hꢀ ꢀ ꢀOQC (2.45 Å, 1391) and two hydrogen bonds, along with the other interactions (Table 5).
(including one at a short distance) directional C(sp2)–Hꢀ ꢀ ꢀp Moreover, the packing of molecules in NM03 were also observed
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to be stabilized by the presence of weak C(sp2)–Hꢀ ꢀ ꢀF–C(sp3) components of the total stabilization energy. In the case of III
hydrogen bonds (motifs VIII–XII, except X), which consists of and IV, this is of a dispersive origin (more than 62%), while
long C(sp2)–HꢀꢀꢀO (2.96 Å/1591) with stabilization energies ranging motif V (%Eelec = 50) and motif VI (%Eelec = 45) show a very
from 9.2 kJ molꢁ1 to 5.6 kJ molꢁ1 with %Eelec in the range from significant contribution from electrostatics. In the crystal pack-
27% to 46% (Table 5). Fig. 4(c) shows that the highly stabilized ing of NM10, a less stabilized molecular motif (motif VII,
motif I and III are interlinked via the presence of weak ꢁ6.9 kJ molꢁ1), involving weak C(sp2)–Hꢀ ꢀ ꢀp hydrogen bond,
C(sp2)–Hꢀ ꢀ ꢀF–C(sp3) hydrogen bonds down the (110) plane in was also observed, with %Edisp = 84.
the molecular packing of NM03.
N-Methyl-N-(4-(trifluoromethyl)phenyl)benzamide (NM30)
Compound NM30 crystallizes in the centrosymmetric mono-
N-Methyl-N-(2-(trifluoromethyl)phenyl)benzamide (NM10)
clinic space group P21/c with two molecules in the asymmetric
Compound NM10 crystallizes in the orthorhombic centro-
unit. The asymmetric unit was observed to be a highly stabi-
lized molecular pair (I.E = ꢁ25.6 kJ molꢁ1 with %Edisp = 65) in
symmetric Pbca space group with Z = 8. Molecular pairs
the crystal packing involving weak C(sp2)–Hꢀ ꢀ ꢀOQC and
extracted from the crystal packing in NM10 have been high-
C(sp2)–Hꢀ ꢀ ꢀp hydrogen bonds, along with the presence of a
lighted [Fig. 5(a)] along with their interaction energies. The
highest stabilized molecular motif I (I.E = ꢁ36.2 kJ molꢁ1) is
pꢀ ꢀ ꢀp interaction. The molecular motifs II to V were observed
similar to motif II in NM02 and motif III in NM03 [Fig. 5(a)]. As
to provide similar stabilization (Table 5, I.E of approximately
18.2 to 18.8 kJ molꢁ1) towards the crystal packing. Among
in the previous case, the molecules are linked via the presence
of a short C–Hꢀ ꢀ ꢀp with %Edisp = 60, which is 15–17% less than
these, motifs II and III were found to be involved in the
formation of a short C(sp2)–Hꢀ ꢀ ꢀOQC hydrogen bond (2.53 Å,
in the previous case (Table 5). This may be due to the absence
of Cꢀ ꢀ ꢀC (pꢀ ꢀ ꢀp) interactions, in the present case, at a distance
1331; 2.49 Å, 1361) with an electrostatic contribution of 41% and
less than 4 Å. It can be observed, on viewing down the crystallo-
42%, respectively. Motifs IV and V were involved in the forma-
tion of a weak C(sp2)–Hꢀ ꢀ ꢀF bond along with the pꢀ ꢀ ꢀp inter-
graphic bc plane [Fig. 5(b)], that the molecular chains formed
with the utilization of motif III (I.E = ꢁ20.6 kJ molꢁ1) and motif
action, and hence show a high dispersion contribution (77 and
VI (I.E = ꢁ9.6 kJ molꢁ1) along the b-axis are interconnected with
motifs II (I.E = ꢁ28.1 kJ molꢁ1) and V (I.E = ꢁ11.7 kJ molꢁ1).
Motif II, consists of a short C(sp3)–Hꢀ ꢀ ꢀOQC (2.59 Å, 1301) and
C(sp2)–Hꢀ ꢀ ꢀp at longer distances [%Edisp being 65%]. Further-
more, motifs III and IV, which involve weak C–Hꢀ ꢀ ꢀF–C(sp3)
hydrogen bonds at a distance greater than the sum of the van
der Waals radii of H and F (2.67 Å), were observed to provide
more stabilization in comparison to motifs V and VI, which
consist of a short C(sp2)–Hꢀ ꢀ ꢀOQC hydrogen bond (Table 5).
Differences among them appear in the nature of the individual
76%, respectively). The weak C(sp2)–Hꢀ ꢀ ꢀp hydrogen bond,
along with the pꢀ ꢀ ꢀp interactions, were observed to connect to
two symmetry independent molecules in the crystal packing in
motif VI (I.E = ꢁ17.0 kJ molꢁ1 with %Edisp of 74). Moreover, the
dimeric C(sp3)–Fꢀ ꢀ ꢀp interaction was found to link two molecules
in the crystal packing with motifs VII (I.E = ꢁ17.0 kJ molꢁ1) and
VIII of similar stabilization (Table 5), together with a substantial
dispersion contribution (more than 70%). The interaction energy
of the C(sp3)–Fꢀ ꢀ ꢀp interaction (for one interaction, the approx-
imate value will be ꢁ8.5 kJ molꢁ1; herein, a phenyl group, which
is involved in the interaction, is attached with an electron
withdrawing –CF3 group) is similar to the value for the C–Fꢀ ꢀ ꢀpF
interaction (ꢁ2.43 kcal molꢁ1 for the interaction of fluoro-
methane with hexafluorobenzene) by MP2/aug-cc-pVDZ calcula-
tion.70 In motifs IX and X (I.E being ꢁ16.0 and 15.5 kJ molꢁ1
,
respectively), a weak C(sp2)–Hꢀ ꢀ ꢀF hydrogen bond along with a
C(sp3)–FꢀꢀꢀCQO interaction were observed to connect the mole-
cules. Furthermore, weak C(sp2)–HꢀꢀꢀOQC and C(sp3)–HꢀꢀꢀF–C(sp3)
hydrogen bonds were observed to be involved in two similarly
stabilized molecular pairs (motifs XI and XII) in the crystal
packing. A short and directional C(sp2)–Hꢀ ꢀ ꢀp (2.73 Å, 1521)
along with weak C(sp2)–Hꢀ ꢀ ꢀOQC hydrogen bonds were recog-
nized to be involved in connecting the two symmetry indepen-
dent molecules in the crystal packing in motif XIII (I.E =
ꢁ12.6 kJ molꢁ1, with %Edisp = 63%). Moreover, type I C(sp3)–
Fꢀ ꢀ ꢀF–C(sp3) interactions were observed to connect the mole-
cules in the weakly stabilized molecular motifs XIV and XV with
a positive coulombic contribution. The stabilization in these
motifs is mainly of a dispersion origin (more than 94%, Table 5)
with the overall stabilization energy being 1.8 kJ molꢁ1. This
stabilization energy is comparable with the value reported in a
recent analysis (by an ab initio method and by symmetry-adapted
Fig. 5 (a) Molecular pairs, along with their interaction energies. extracted
from the crystal packing in NM10. (b) Packing of molecules down the bc
plane via weak C–Hꢀ ꢀ ꢀOQC, C–Hꢀ ꢀ ꢀp and C–Hꢀ ꢀ ꢀF–C(sp3) hydrogen
bonds in NM10.
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Fig. 6 (a) Selected molecular pairs in NM30 along with their interaction
energies. (b) Packing of molecules down the ac plane via weak C(sp2)–
Hꢀ ꢀ ꢀOQC, C(sp2)–Hꢀ ꢀ ꢀF–C(sp3), C(sp2)–Hꢀ ꢀ ꢀp hydrogen bonds and pꢀ ꢀ ꢀp
interactions in NM30.
perturbation theory (SAPT)) on the nature of C–Fꢀ ꢀ ꢀF–C for the
all unique dimers extracted from the crystal structure of CF4,
C2F4 and C6F6.71 From the SAPT analysis, it was observed that
the total stabilization energy was mainly dominated by the
dispersion energy component and the electrostatic component
can be stabilizing or destabilizing depending on the orientation
of the interacting dimers. Fig. 6(b) represents the packing of
molecules in NM30 down the crystallographic ac plane.
Fig. 7 (a) Selected molecular pairs extracted from the crystal packing in
NM11 along with their interaction energies. (b) Molecular network formed
with the utilization of weak C(sp2)–Hꢀ ꢀ ꢀOQC, C(sp2)–Hꢀ ꢀ ꢀF–C(sp3) hydro-
gen bonds and pꢀ ꢀ ꢀp interactions in NM11. (c) Packing of molecules via
C(sp2)/(sp3)–Hꢀ ꢀ ꢀF–C(sp3) hydrogen bonds in NM11.
(2.46 Å, 1601) and C(sp2)–Hꢀ ꢀ ꢀF–C(sp3) (2.49 Å, 1441) hydrogen
bonds along with offset pꢀ ꢀ ꢀp stacking interactions (motif I, I.E =
ꢁ40.8 kJ molꢁ1), was observed to provide the highest stabili-
zation towards the crystal packing. It is to be noted here that the
N-Methyl-2-(trifluoromethyl)-N-(2-(trifluoromethyl)phenyl)benz-
amide (NM11)
Compound NM11 crystallizes in a centrosymmetric monoclinic %Eelec contribution was 54% with a coulombic contribution of
space group P21/c with Z = 4. Unlike other molecules in this 42%. The next two stabilized motifs (II and III) were involved in
series, the molecular structure is observed to be in the trans the formation of pꢀ ꢀ ꢀp stacking interactions between pair of
conformation with CQO and N–C bonds oriented opposite to molecules, the I.E being ꢁ22.0 and ꢁ17.8 kJ molꢁ1, respectively,
each other. This may be due to the minimization of the steric with the stabilization being mainly dispersive in origin. It was
effect when two CF3 groups are present at the ortho position of observed that with an increase in the interacting distance of the
the two phenyl rings in the molecule. (CH3)N–CO was observed Ph-ring (from motif II to motif III), the dispersion contribution
to be disordered at two positions with the occupancy ratio of towards the total stabilization increased from 74% to 94% with
0.939(3): 0.061(3) [modeled with PART command in the no stabilization from coulombic (positive coulombic contribu-
SHELXL 2013 at two orientations: ‘A’ (for higher occupancy) tion, Table 5) in the case of the latter. Furthermore, motifs IV
and ‘B’]. Selected molecular pairs extracted from the crystal and V were observed to contribute similar stabilization towards
packing are given in Fig. 7(a). A dimeric molecular motif, the crystal packing (ꢁ16.7 kJ molꢁ1 and ꢁ16.6 kJ molꢁ1) but
consisting of a pair of short and directional C(sp2)–Hꢀ ꢀ ꢀOQC were different in the nature of the involved interactions. Motif IV
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appeared to be connected via a long C(sp2)–HꢀꢀꢀF–C(sp3) hydrogen
bond with %Eelec being 26%, whereas in motif V, the molecules
were connected with short C(sp2)–HꢀꢀꢀOQC (2.35 Å, 1441) and
C(sp2)–HꢀꢀꢀF–C(sp3) (2.65 Å, 1541) hydrogen bonds. As expected,
this results in the increase of the %Eelec contribution to 59% with
45% coulombic contribution (Table 5). The packing of molecules
in NM11 was recognized to involve the formation of mole-
cular networks wherein motif I was connected with motif V
[Fig. 7(b)]. Moreover, motif VI [consisting of the pair of weak
C(sp3)–Hꢀ ꢀ ꢀF–C(sp3) and a C–Hꢀ ꢀ ꢀp hydrogen bonds at dis-
tances longer than the sum of the van der Waals radii of the
involved atoms, I.E = ꢁ15.8 kJ molꢁ1, %Edisp = 93%] generate a
molecular chain with the utilization of a 21-screw along the b-axis
[Fig. 7(c)]. Such a chain was observed to be linked via the weakly
stabilized molecular motif VII (I.E = 5.3 kJ molꢁ1, %Edisp = 69%)
down the bc plane, which involved two weak C(sp2)–Hꢀ ꢀ ꢀF–C(sp3)
(2.58 Å, 1561; 2.78 Å, 1471) hydrogen bonds (Table 5).
N-Methyl-3-(trifluoromethyl)-N-(2-(trifluoromethyl)phenyl)benz-
amide (NM12)
Fig. 8 (a) Displaying molecular pairs extracted from molecular packing in
NM12. (b) Packing of molecules down the bc plane with the utilization of
weak C(sp2)–Hꢀ ꢀ ꢀOQC and C(sp2)–Hꢀ ꢀ ꢀF–C(sp3) hydrogen bonds in
NM12.
Compound NM12 crystallizes in the monoclinic P21/c space
group with Z = 4. The analysis of the molecular pairs extracted
from the crystal packing [Fig. 8(a)] showed that the highest
stabilized molecular motif I [ꢁ36.2 kJ molꢁ1 with %Edisp = 80%;
involves C(sp2)–Hꢀ ꢀ ꢀp hydrogen bonds and pꢀ ꢀ ꢀp interactions] involving the acidic hydrogen atoms, form the most stabilized
appears to be a robust motif in this series of compounds as also (I.E = ꢁ37.0 kJ molꢁ1) pair in the crystal packing with the total
previously recognized in NM02, NM03 and NM10. However, it stabilization being a 52% electrostatic (coulombic + polarization)
can also be noted here that this was not observed in the molecular contribution (Table 5). Motif II (I.E = 26 kJ molꢁ1), being the
packing of NM00. The packing of molecules down the bc plane in most common in this series of structures and consisting of a
NM12 displays the formation of a molecular chain along the weak C(sp2)–Hꢀ ꢀ ꢀp hydrogen bond and pꢀ ꢀ ꢀp interaction, was
crystallographic c-axis via motif III (I.E = 22.3 kJ molꢁ1), which was observed to provide stabilization to the crystal packing, which
observed to be interlinked with motif II (I.E = ꢁ25.6 kJ molꢁ1) and was primarily of a dispersive (85%) origin. The packing of mole-
motif V (I.E = ꢁ12.1 kJ molꢁ1) [Fig. 8(b)]. Motif II consists of two cules in NM22 was observed to form a zig-zag chain via motif I
short and directional C(sp2)–HꢀꢀꢀOQC hydrogen bonds (2.32 Å, with the utilization of a c-glide perpendicular to the b-axis. Such a
1601; 2.57 Å, 1531) with a 48% contribution from electrostatics chain is connected via the utilization of motifs III and IV [Fig. 9(b)]
(Table 5). In the case of motif III (I.E = ꢁ25.6 kJ molꢁ1; %Eelec = 41), down the bc plane. Motif III (I.E = ꢁ24.2 kJ molꢁ1) was found to
a weak C(sp2)–HꢀꢀꢀOQC along with a C(sp2)–HꢀꢀꢀF–C(sp3) hydro- involve a short C(sp2)–Hꢀꢀꢀp (2.51 Å, 1481) along with a weak
gen bond was observed to connect the molecules, displaying a C(sp2)–Hꢀ ꢀ ꢀF–C(sp3) hydrogen bond, whereas motif IV (I.E =
slightly less stabilization and electrostatic contribution than motif ꢁ15.6 kJ molꢁ1) consisted of two C(sp2)–Hꢀ ꢀ ꢀF–C(sp3) inter-
II (Table 5). Furthermore, dimeric C(sp2)–HꢀꢀꢀF–C(sp3) hydrogen actions. Both the motifs showed a similar contribution (67%)
bonds (2.63 Å, 1301) were recognized to link the molecules in motif from dispersion towards the total stabilization. Moreover, a pair
V (with %Edisp = 75%). Moreover, a weak C(sp2)–Hꢀ ꢀ ꢀp along with of bifurcated weak C(sp2)–HꢀꢀꢀF–C(sp3) hydrogen bonds were also
a weak C(sp2)–Hꢀ ꢀ ꢀF–C(sp3) hydrogen bond (2.78 Å, 1491) were recognized to stabilize (motif V, I.E being ꢁ10.2 kJ molꢁ1) the
also observed to stabilize the crystal packing in NM12 (motif IV, crystal packing in NM22.
ꢁ15.8 kJ molꢁ1; %Edisp = 76%). A weakly stabilized molecular
pair (motif VI, I.E = ꢁ3.8), involving weak C(sp2)–Hꢀ ꢀ ꢀF–C(sp3)
N-Methyl-4-(trifluoromethyl)-N-(3-(trifluoromethyl)phenyl)benz-
hydrogen bonds along with a type I C(sp3)–Fꢀ ꢀ ꢀF–C(sp3) inter-
amide (NM23)
action (Table 5), were also recognized in the crystal packing.
Compound NM23 crystallizes in the centrosymmetric mono-
clinic space group (P21/c) with Z = 4. Molecular pairs, extracted
from the crystal packing of NM23, along with their stabilization
energies are presented in Fig. 10(a). The analysis of the results
N-Methyl-3-(trifluoromethyl)-N-(3-(trifluoromethyl)phenyl)benz-
amide (NM22)
Compound NM22 crystallizes in the centrosymmetric mono- depicts the presence of two similar dimeric stabilizing pairs
clinic space group (P21/c) with Z = 4. The molecular pairs, [motif I (observed to be robust in this series) and motif II] in the
extracted from the crystal packing, are presented in Fig. 9(a). crystal packing. Motif I (I.E = ꢁ39.1 kJ molꢁ1, %Edisp of 71%)
Three possible short and/or directional C(sp2)–Hꢀ ꢀ ꢀOQC (2.21 Å, was recognized to involve a short C(sp2)–Hꢀ ꢀ ꢀp (2.61 Å, 1611)
1401; 2.43 Å, 1731; 2.69 Å, 1521) hydrogen bonds, with motif I, bond along with the presence of a weak offset pꢀ ꢀ ꢀp stacking
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Fig. 10 (a) Selected molecular pairs, along with their interaction energies,
in NM23. (b) Packing view down the bc plane in NM23, depicting network
of weak C(sp2)–Hꢀ ꢀ ꢀOQC, C(sp2)–Hꢀ ꢀ ꢀp and C(sp3)–Hꢀ ꢀ ꢀF–C(sp3) hydro-
gen bonds.
Fig. 9 (a) Selected molecular pairs extracted from the crystal packing in
NM22. (b) Network of weak C(sp2)–Hꢀ ꢀ ꢀOQC and C(sp2)–Hꢀ ꢀ ꢀF–C(sp3)
hydrogen bonds in the crystal packing down the bc plane in NM22.
packing [Fig. 11(b)]. The chain is further stabilized via motif II
(I.E = ꢁ22.1 kJ molꢁ1 with %Edisp being 52%), which involves a
short C(sp2)–Hꢀ ꢀ ꢀOQC (2.54 Å, 1491) bond along with a short
interactions, whereas
a
dimeric bifurcated weak C(sp2)– C(sp2)–Hꢀ ꢀ ꢀF–C(sp3) (2.38 Å, 1351) bond and a bifurcated
Hꢀ ꢀ ꢀOQC interaction was observed to stabilize (I.E = ꢁ38.7 kJ weak C(sp2)/(sp3)–Hꢀ ꢀ ꢀF–C(sp3) hydrogen bond. Furthermore,
molꢁ1 with %Edisp reduced to 58%) motif II in NM23 (Table 5). a weak C(sp2)–Hꢀ ꢀ ꢀOQC bond with support from a bifurcated
Both dimeric motifs I and II were found to be connected via C(sp2)–Hꢀ ꢀ ꢀF–C(sp3) hydrogen bond (motif IV, ꢁ18.2 kJ molꢁ1
)
motif III and IV in the formation of a molecular layer down the was involved in the formation of a molecular chain with the
bc plane [Fig. 10(b)]. Bifurcated weak C(sp2)–Hꢀ ꢀ ꢀOQC hydro- utilization of the c-glide perpendicular to the b-axis. The chain
gen bonds, involving acidic hydrogens, were recognized to link was observed to be connected with motif I and motif III down
the molecules in motif III (I.E = ꢁ31.4 kJ molꢁ1, %Edisp of 58%), the ac plane [Fig. 11(c)]. Motif III (I.E = ꢁ19.6 kJ molꢁ1, with
whereas in the case of motif IV (I.E = ꢁ14.2 kJ molꢁ1 with %Edisp of 73%) consists of a dimeric weak C(sp3)–Hꢀ ꢀ ꢀF–C(sp3)
%Edisp increased to 73%), a weak C(sp3)–Hꢀ ꢀ ꢀF–C(sp3) hydrogen hydrogen bond along with pꢀ ꢀ ꢀp stacking. The packing of
bond along with pꢀ ꢀ ꢀp stacking interaction were observed. molecules in NM31 was also observed to involve the formation
Furthermore, a weak C(sp2)–Hꢀ ꢀ ꢀF–C(sp3) hydrogen bond along of a molecular motif V with weak C(sp3)–Hꢀ ꢀ ꢀp interactions
with the type II C(sp3)–Fꢀ ꢀ ꢀF–C(sp3) interaction [in motif V [the stabilization energy is ꢁ14.2 kJ molꢁ1]. Furthermore,
(ꢁ8.0 kJ molꢁ1) and VI (ꢁ5.5 kJ molꢁ1)] were also found to weakly stabilized molecular motif VI [ꢁ9.2 kJ molꢁ1; involving
stabilize the crystal packing in NM23 [Fig. 10(a) and Table 5].
a dimeric C(sp2)–Hꢀ ꢀ ꢀF–C(sp3) hydrogen bonds] and motif VI
[ꢁ4.9 kJ molꢁ1; involving C(sp3)–Fꢀ ꢀ ꢀF–C(sp3) interactions] were
also recognized in the crystal packing of NM31.
N-Methyl-2-(trifluoromethyl)-N-(4-(trifluoromethyl)phenyl)benz-
amide (NM31)
N-Methyl-4-(trifluoromethyl)-N-(4-(trifluoromethyl)phenyl)benz-
amide (NM33)
Compound NM31 also crystallizes in the P21/c space group with
Z = 4. Fig. 11(a) depicts the extracted molecular pairs from the
crystal packing in NM31, along with their stabilizing energy. All Compound NM33 crystallizes in the centrosymmetric triclinic
0
%
the molecular motifs were observed to be stabilized by the space group P1 with Z = 4 (Z = 2). Selected molecular motifs,
presence of weak intermolecular interactions. The highest which contribute towards the stabilization of the crystal pack-
stabilized motif I (I.E = ꢁ30.1 kJ molꢁ1) was found to involve ing, are presented in Fig. 12(a). The two molecules in the
a short C(sp2)–Hꢀ ꢀ ꢀOQC (2.42 Å, 1511) hydrogen bond along asymmetric unit were observed to be connected via motif IV
with pꢀ ꢀ ꢀp stacking with the dispersion contribution being (I.E = ꢁ28.2 kJ molꢁ1), which involved the presence of a
66%. Motif I connects the molecule along the b-axis, utilizing bifurcated, short and directional C(sp2)–Hꢀ ꢀ ꢀOQC (2.30 Å,
a 21-screw in the formation of molecular chains in the crystal 1691; 2.42 Å, 1361) hydrogen bond with the stabilization energy
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Fig. 11 (a) Molecular pairs extracted from the crystal packing of NM31
along with their interaction energies. (b) Packing of molecules down the ab
plane in NM31 via weak C(sp2)–Hꢀ ꢀ ꢀOQC, C–Hꢀ ꢀ ꢀF–C(sp3) hydrogen
bonds and pꢀ ꢀ ꢀp interactions. (c) Packing of molecules down the ac plane
with the utilization of weak C(sp2)–Hꢀ ꢀ ꢀOQC, C–Hꢀ ꢀ ꢀF–C(sp3) hydrogen
bonds and pꢀ ꢀ ꢀp interactions in NM31.
Fig. 12 (a) Displaying selected molecular motifs connected with different
intermolecular interactions in the crystal packing of NM33. (b) Part of the
crystal packing down the bc plane in NM33, depicting the presence of
weak C(sp2)–Hꢀ ꢀ ꢀOQC, C–Hꢀ ꢀ ꢀp and C(sp2)–Hꢀ ꢀ ꢀF–C(sp3) hydrogen
bonds along with pꢀ ꢀ ꢀp interactions. (c) Packing of molecules in NM33
via the network of weak C–Hꢀ ꢀ ꢀOQC, C–Hꢀ ꢀ ꢀp and C–Hꢀ ꢀ ꢀF–C(sp3)
hydrogen bonds along with pꢀ ꢀ ꢀp and C(sp3)–Fꢀ ꢀ ꢀCQO interactions.
having a substantial electrostatic contribution of 59% (Table 5).
There are three more stabilized molecular pairs (motif I, II, III)
other than motif IV, which were recognized in the crystal
packing. The arrangements of the first four molecular motifs
in the crystal packing of NM33 are depicted in Fig. 12(b) down interactions were recognized to link the molecules in motif
the crystallographic bc plane. The highest stabilized molecular III with the %Edisp contribution being reduced to 66%. Further-
motif I (I.E = ꢁ37.8 kJ molꢁ1; %Eelec of 40%) consists of a short more, motif V (I.E = ꢁ21.9 kJ molꢁ1) and VI (I.E = ꢁ21.9 kJ molꢁ1
)
and highly directional dimeric C(sp2)–Hꢀ ꢀ ꢀOQC (2.49 Å, 1731) were observed to provide similar stabilization to the crystal
hydrogen bond. The stabilization of motif I is significantly packing; however, the involved interactions were recognized to
higher than motif IV, although both possess similar inter- be significantly different. A weak C(sp3)–HꢀꢀꢀOQC hydrogen bond
actions. The reason for this may be the presence of some along with a short C(sp3)–Hꢀꢀꢀp (2.63 Å, 1381) and pꢀꢀꢀp interac-
long-range dispersion interactions in motif I, as the net con- tions were found to stabilize motif V, whereas it was mainly the
tribution from the dispersion energy in motif I were observed latter which linked the molecules in motif VI. The differences
to be almost double than that in motif IV (Table 5). In motif II associated in the nature of interactions in the two motifs V and VI
(I.E = ꢁ35.3 kJ molꢁ1), the molecules were found to be linked are clearly reflected in the dispersion energy contribution, as this
via weak C–Hꢀ ꢀ ꢀp and pꢀ ꢀ ꢀp interactions with the contribution is 67% in the case of the former, but 78% in the latter. A very short
from dispersion being significantly high (75%), whereas three C(sp2)–HꢀꢀꢀOQC (2.20 Å, 1481) hydrogen bond, involving acidic
weak C(sp2)–Hꢀ ꢀ ꢀF–C(sp3) hydrogen bonds along with pꢀ ꢀ ꢀp hydrogen, along with a weak C(sp3)–HꢀꢀꢀF bond at higher distance
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(2.81 Å, 1251) were observed to stabilize the crystal packing (motif two crystal structures, termed as ‘supramolecular constructs
VII, I.E = ꢁ15.0 kJ molꢁ1), with a substantial electrostatic con- (SC)’. It can be 3D (exactly similar arrangement or isostructural),
tribution (65%). A weak C(sp3)–FꢀꢀꢀCQO interaction and C(sp3)– 2D (layers of molecules are similar), 1D (a row of molecules is
HꢀꢀꢀF hydrogen bond (motif VIII, I.E is ꢁ14.0 kJ molꢁ1) were similar) or 0D similarity (isolated unit-like dimers are identical
found to direct the molecular chain of molecule 2 along the in the packing). The measure of the extent with which the two
crystallographic a-axis [Fig. 12(c)]. Such chains were observed to crystal structures deviate from the perfect geometrical similarity
be linked with adjacent molecular chains, formed with the is defined as the ‘dissimilarity index (X)’.75 The lower the value of
utilization of a weak bifurcated C(sp2)/(sp3)–HꢀꢀꢀF hydrogen bond X, the better is the structural match. The analysis of the ten
along the a-axis (motif IX; I.E = ꢁ10 kJ molꢁ1) via the presence of crystal structures (Table S2, ESI†) revealed that the arrangement
the different intermolecular interactions involved in motifs II, IV, of the molecules match (regarding the presence of 2D SCs) in
V and VII [Fig. 12(c)].
the case of NM02 (packing of molecule 1) and NM03 (packing
It can be noted that weakly stabilized molecular motifs of molecule 2) with X = 6.7 (labeled as ‘C1’ Fig. 13 and Fig. S7,
possessing interactions involving organic fluorine were recog- Table S2, ESI†). There was also the presence of 1D SCs [the
nized in the crystal packing of NM33, with stabilization energies presence of a molecular chain (6 types, B1 to B6), Fig. 13 and
in the range from 10 kJ molꢁ1 to 1.2 kJ molꢁ1 [motif IX–XIV, Fig. S8, Table S2, ESI†] observed in the case of the pairs NM02_2/
Fig. 12(a)]. Motifs IX, X and XI were observed to provide similar NM03_1; NM02_2/NM10; NM03_1/NM10; NM12/NM22; NM22/
stabilization (ꢁ10 kJ molꢁ1) but involve interactions of a different NM23 and NM31/NM33_2. There were 6 different types (A1 to A6,
nature and geometry. Motif IX was found to involve bifurcated Fig. 13 and Fig. S9, ESI†) of similar molecular dimers (the presence
C(sp2)/(sp3)–Hꢀ ꢀ ꢀF hydrogen bonds (with one at a short distance of a 0D SC) also recognized in the different pairs of the crystal
of 2.43 Å, 1481), whereas a dimeric C(sp2)–Hꢀ ꢀ ꢀF bond and structure (Table S2, ESI†).
C(sp3)–Fꢀ ꢀ ꢀF–C(sp3) bond were observed in motif X. Further-
It was of further interest to compare all the present crystal
more, in the case of motif XI, bifurcated C(sp3)–Hꢀ ꢀ ꢀF hydrogen structures with related crystal structures reported in CSD
bonds (with one being short and directional; 2.48 Å, 1601) was [Fig. 1(d)]. Comparisons with structures with a cis-geometry
recognized. Unlike motif IX, it involves a bifurcated acceptor, (CSD ref. code: YEGJEY, YEGKEA, YEGKIE, YEGKOK and
wherein two fluorine atoms of one CF3 group are involved in YEGLAX) revealed no similarity with the unsubstituted com-
the formation of the hydrogen bond with a hydrogen atom of pound, NM00 (ref. code: JAZJOJ10) [Table S2, ESI†]. There was
the CH3 group. Moreover, motifs XII and XIII were observed to also the presence of a similar molecular chain (1D SCs) on
consist of weak C(sp2)–Hꢀ ꢀ ꢀF–C(sp3) hydrogen bonds, providing comparison of NM03_1, NM10, NM12 with YEGLAX [Fig. S10(a)
similar stabilization (8.0 and 7.2 kJ molꢁ1, respectively). A and Table S2, ESI†], which is analogous with the chain ‘B2’
dimeric C(sp3)–FꢀꢀꢀF–C(sp3) interaction (with one contact, Type I [in pair NM03_1/NM10; Fig. S8(b), ESI†]. In addition, the existence
geometry: 2.889(1) Å/101(1)1/101(1)1) was recognized in the for- of 1D SC (similar chain) was also recognized for NM22/YEGLAX.
mation of the molecular motif XIV [Fig. 11(a)], which provided Moreover, the pairs NM03_1/YEGKEA, NM10/YEGKEA, NM10/
the least stabilization (I.E = ꢁ1.2 kJ molꢁ1) to the crystal packing. YEGKOK, NM12/YEGKEA and NM23/YEGKEA display the
The partition of the interaction energy into different contribu- presence of a similar molecular robust dimer (equivalent with
tions indicated a positive coulombic contribution, with the net the dimer ‘A1’; 0D SCs) in their crystal packing [Fig. S11(a),
stabilization originating mainly from the dispersive contribution ESI†]. Furthermore, the presence of 0D SCs (similar molecular
(96%, Table 5).
pairs) was also observed for the pairs NM02_1/YEGKOK,
Comparison of the crystal structures
From the analysis of the crystal structures of 11 compounds
(ten derivatives of N-methyl-N-phenylbenzamide plus one
unsubstituted compound) in this study, it was observed that
seven molecules crystallized in the monoclinic space group
P21/c (including NM03 and NM30 with Z0 = 2 and NM11,
wherein the molecule preferred the trans geometry) and none
of them appeared to be isostructural.72 This also included
compounds NM10 and NM00, which crystallized in the same
space group: orthorhombic centrosymmetric Pbca. Furthermore,
except for NM11, all the compounds in this series appeared to
have a similar molecular conformation (cis-geometry) [Fig. 1(c)].
Hence, it was of interest to compare these crystal structures to
gain insights into the similarities and dissimilarities associated
with the crystal packing. Therefore, XPac 2.073,74 was used to
analyze the crystal packing of these structures, excluding NM11.
The details of this analysis are presented in Section S2 in the
ESI.† XPac identified the similar packing arrangements in the
Fig. 13 Relationship of all the crystal structures from the XPac analysis
(Section S2, ESI†). The compounds NM02, NM03, NM30 and NM33 have
two symmetry independent molecules, represented by the number in the
circle.
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NM02_1/YEGLAX NM22/YEGKOK, NM31/YEGLAX and NM22/ in the molecular motif. In future studies, it would be of interest
YEGKOK [Fig. S11(b)–(d), ESI†]. Furthermore, the comparison to extend this study to the investigation of interactions invol-
of the crystal structure of NM11 with the structure reported in ving organic fluorine in different electronic and chemical
CSD with the trans geometry (ref. code: YEGJEY, DIBGIF and environments.
DIBGAX) indicates the presence of similar chains in the case
of the pairs, NM11/DIBGAX_1 and NM11/DIBGAX_4, and sur-
prisingly, no similarity was observed for NM11/YEGJEY (having
Acknowledgements
four methyl substitution at ortho positions of both the phenyl
PP thanks UGC-India for research scholarship. We acknow-
rings in the molecule). Hence, from the overall comparison of
ledge the IISER Bhopal for research facilities and infrastruc-
the crystal structures, it can be observed that although none of
ture. The authors also thank Prof. T. N. Guru Row for SCXRD
these structures are isostructural, the presence of similar
and PXRD data collection on the CCD facility at IISc, Bangalore
structural motifs can be realized in their crystal packing.
under the IRHPA-DST Scheme. DC thanks DST-Fast Track
Scheme for research funding.
Conclusions
References
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