ACCEPTED MANUSCRIPT
As seen in Table 3, the most of the optimized bond lengths are slightly different from the
experimental results, since the molecular states are different during the experimental and theoretical
processes. Many packing molecules are treated in condensed phase during experimental (XRD)
measurements, while one isolated molecule is considered in gas phase during the theoretical (DFT)
calculation. By allowing the relaxation of all parameters, the calculations converge to optimized
geomentries, which correspond to true energy minima as revealed by the lack of imaginary frequencies in
the vibrational mode calculation. This molecule has twenty four C-C bond lengths, twenty two C-H bond
lengths, three C-O lengths, two C-N bond lengths, two S-O bond lengths and one C-Cl, C-S, N-S bond
lengths. The aromatic rings of the MFMSC are somewhat irregular and the spread of the C-C bond
distance is 1.387-1.406
Å
(DFT) and 1.365-1.391
(XRD) for sulfonyl-bound benzene(C8-C13) ring, 1.390-1.404
Å (XRD) for chlorophenyl (C18-C23)ring, which is similar to the spread reported by smith et
Å
(XRD) for formyl phenyl (C1-C6) ring, 1.390-1.400
Å
(DFT) and 1.368-1.326
Å
Å
(DFT) and
1.360-1.387
al.. [59]. Loughrey et al. [60] reported the bond lengths S31-O32= 1.4337, S32-O33=1.4256, S31-
N34=1.6051, S31-C28=1.7737 and C21-N20=1.4212
are 1.456, 1.457, 1.704, 1.796 and 1.439 . The above said bond lengths O2 –S1, O3-S1, N1-S1, C8-S1,
and C1-N1 are in good agreement with experimental values (1.428, 1.427, 1.650, 1.7600 and 1.437 ).
Å, whereas the corresponding values for MFMSC
Å
Å
Petrov et al. [61] and Panicker et al. [62] recorded the crystal structure and conformations of benzene
sulfonamide by gas electron diffraction and quantum chemical computations. According to their results,
the bond lengths C-S, S-N and S-O vary in the range of 1.7756-1.7930, 1.6630-16925 and 1.4284- 1.4450
Å, respectively. Binil et al. [63] reported the C=O bond length as 1.2145, 1.2146 Å (DFT), 1.2000, 1.23
Å (XRD). In the present case, the C=O bond length is 1.210, 1.208 Å (DFT) , 1.199(2), 1.201(2) Å
(XRD) and the C-O bond length is 1.441 Å ( DFT) and 1.437(2) Å (XRD) which was in agreement with
the reported values [64,65]. The C-Cl bond length 1.757
Å (DFT) and 1.737(2) Å (XRD) is in agreement
with the C-Cl bond length reported by Kumar et al. [66] and also in the C-F bond length reported by
murugavel et al. [23] is 1.351
than C-F bond length.
Å (DFT) and 1.360(2) Å (XRD). The C-Cl bond length is slightly greater
In MFMSC, 4-chloropheyl ring shows to be a little distorted on account of the electronegative
chlorine atom added to C21 position as seen from the bond angle C22- C21-C20 (119.13o by DFT
121.2(2)o by XRD) value, which is greater than typical hexagonal angle of (120o) at the point of
substitution. Because of SO2 group substitution at C8 position, the sulfonyl bound benzene ring also
shows slightly distortion as evidenced from the theoretical bond angle C9-C8-C13= 120.9o value, which
is greater than typical hexagonal angle of 120o and experimentally the above bond angle value is 119.7o.
The symmetry of benzene ring is distorted because of electron donating substituents on it and hence
benzene ring angles are smaller than 120o at the position of substitution [58]. Similarly due to N1 atom
attached at C1 position of 2-formylphenyl ring appears a little distorted. It is evident from the bond
angles C2-C1-C6 = 119.60o by DFT method which is smaller than typical hexagonal angle of 120o and
XRD by 120.3(2)o. The bond angles at C24 position are O4-C24-C16 = 123.4o, O5-C24-C16=113.3 o, 04-
o
C24-O5=123.3 and this asymmetry shows the repulsion between C=O and nearby atoms. At this
juncture, the value of C-S and S-N bond length is found to be high compared to other bond length values.
The computed torsion angle τ (C15-N1-S1-C8=81.7o) value falls within the expected range (70-120o).
The calculated DFT torsion angles τ1 (C9-C10-C11-C14= 178.4o) and τ2 (C14-C11-C12-C13=178.4 o) are
in good agreement with the XRD data. Further, the results of our calculations showed that S1-O2 and S1-
O3 bonds show typical double bond characteristics and all other bond lengths fall within the expected
range. The bond lengths obtained by XRD are slightly lower than that of theoretical values. When
comparing with the XRD data, theoretical bond lengths vary ± 0.85
due to intra molecular interaction in the solid state.
Å and these differences are probably
The difference between the XRD and DFT values for the bond lengths C8-C13, C10-C11 and
O3-S1 are 0.023, 0.031 and 0.035 Å, respectively, are seen from Table 3. Similarly, the difference in
bond angles N1-C15-C16, C1-N1-C15, C15-N1-S1 and O3-S1-O2 are 1.30, 1.21, 2.31 and 1.21o
respectively. This significant difference is due to intra molecular C13–H13...O2, C15–H15A...O3 and