Synthesis, experimental and theoretical investigation of molecular structure, IR, Raman spectra and 1H NMR analyses of 4,4′-dihydroxydiphenyl ether and 4,4′-oxybis(1-methoxybenzene)

Article abstract of DOI:10.1016/j.molstruc.2012.11.002

4,4′-Dihydroxydiphenyl ether and 4,4′-oxybis(1-methoxybenzene) are synthesized. Experimental and theoretical studies on molecular structure, infrared spectra (IR), Raman spectra and nuclear magnetic resonance ( ¹H NMR) chemical shifts of the two synthesized compounds have been worked out. All the theoretical results, which are obtained with B3LYP/6-311G(d,p) method by using the Gaussian 09 program, have been applied to simulate molecular structure, infrared, Raman and NMR spectra of the compounds. The compared results reveal that the calculated geometric parameters match well with experimental values; the scaled theoretical vibrational frequencies are in good accordance with observed spectra; and computational chemical shifts are consistent with the experimental values in most part, except for some minor deviations. These great coincidences prove that the computational method B3LYP/6-311G(d,p) can be used to predict the properties of other similar materials where it is difficult to arrive at experimental results.

Full text of DOI:10.1016/j.molstruc.2012.11.002

Journal of Molecular Structure 1035 (2013) 285–294
Contents lists available at SciVerse ScienceDirect
Journal of Molecular Structure
journal homepage: www.elsevier.com/locate/molstruc
Synthesis, experimental and theoretical investigation of molecular structure, IR,
1
Raman spectra and H NMR analyses of 4,40-dihydroxydiphenyl ether and
4,40-oxybis(1-methoxybenzene)
⇑
Fu Liu, Zhongbo Wei, Liansheng Wang, Zunyao Wang
State Key Laboratory of Pollution Control and Resources, School of Environment, Nanjing University, Nanjing, Jiangsu 210046, PR China
h i g h l i g h t s
"
"
"
"
"
Theoretical geometrical parameters match with the X-ray analysis data.
Calculated IR and Raman spectra may reproduce the experimental results.
Description of the largest vibrational contributed to the normal modes are given.
Calculated 1H NMR chemical shifts mainly agree with the experimental values.
Theoretical B3LYP/6-311G(d,p) calculations are valid for the structural-similar compounds.
a r t i c l e i n f o
a b s t r a c t
4,40-Dihydroxydiphenyl ether and 4,40-oxybis(1-methoxybenzene) are synthesized. Experimental and
theoretical studies on molecular structure, infrared spectra (IR), Raman spectra and nuclear magnetic res-
onance (1H NMR) chemical shifts of the two synthesized compounds have been worked out. All the the-
oretical results, which are obtained with B3LYP/6-311G(d,p) method by using the Gaussian 09 program,
have been applied to simulate molecular structure, infrared, Raman and NMR spectra of the compounds.
The compared results reveal that the calculated geometric parameters match well with experimental val-
ues; the scaled theoretical vibrational frequencies are in good accordance with observed spectra; and
computational chemical shifts are consistent with the experimental values in most part, except for some
minor deviations. These great coincidences prove that the computational method B3LYP/6-311G(d,p) can
be used to predict the properties of other similar materials where it is difficult to arrive at experimental
results.
Article history:
Received 13 September 2012
Received in revised form 1 November 2012
Accepted 1 November 2012
Available online 23 November 2012
Keywords:
4,40-Dihydroxydiphenyl ether
4,40-Oxybis(1-methoxybenzene)
B3LYP/6-311G(d,p)
IR
Raman
1H NMR
Ó 2012 Elsevier B.V. All rights reserved.
1. Introduction
composition of polytriazole resins [5], the modification of 4,40-bis-
maleimidodiphenylmethane [6], the synthesis of 4,40-bis(4-nitro-
4,40-Dihydroxydiphenyl ether has been produced at low cost
with a high yield by simple methods and can be used as interme-
diate in the manufacture of agrochemicals and pharmaceuticals
[1]. Koga et al. [2] developed a method to prepare pure product
of 4,40-dihydroxydiphenyl ether with 87% yield. It is one of surface
bound products in heterogeneous light-induced ozone process [3].
The most extensive application of 4,40-dihydroxydiphenyl ether is
taking part in some polymer synthesis reactions, such as the prep-
aration of six different ionomers having various aromatic polymer
backbones with pendant 2-sulfobenzoyl side chains [4], the
2-trifluoromethylphenoxy) diphenyl ether (p-6FNPE) [7], and so
on. It is reported that polysulfonates gained by interfacial polycon-
densation from 4,40-dihydroxydiphenyl ether and disulfoxides
have good characteristics in chemical resistance to oils, acids and
alkali, and are resistant to hydrolysis and aminolysis [8]. Compared
with 4,40-dihydroxydiphenyl ether, 4,40-oxybis(1-methoxyben-
zene) draws less attention, on which the relevant studies are inad-
equate. Generally, it is regarded as the intermediate in synthetizing
4,40-dihydroxydiphenyl ether. Recently, many studies indicate that
methoxylated polybrominated diphenyl ethers (MeO-PBDEs) can
be demethoxylated to hydroxylated polybrominated diphenyl
ethers (OH-PBDEs) in vitro [9,10]. Moreover, the structures of
4,40-dihydroxydiphenyl ether and 4,40-oxybis(1-methoxybenzene)
are similar to 4,40-dibromodiphenyl ether (BDE-15) and
4,40-dichlorodiphenyl ethers (CDE-15), which have been detected
⇑
Corresponding author. Address: State Key Laboratory of Pollution Control and
Resources Reuse, School of the Environment, Xianlin Campus, Nanjing University,
Nanjing, Jiangsu 210046, PR China. Tel./fax: +86 25 89680358.
E-mail address: wangzun315cn@163.com (Z. Wang).
0022-2860/$ - see front matter Ó 2012 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.molstruc.2012.11.002

286
F. Liu et al. / Journal of Molecular Structure 1035 (2013) 285–294
extensively in environment. The extensive application and the typ-
ical structure of 4,40-dihydroxydiphenyl ether urge us to explore its
environmental behavior and potential environmental risk.
Vibrational spectroscopy and nuclear magnetic resonance
(NMR) techniques are widely used in the research of molecular
systems. Study on vibrational spectroscopy of compounds may
provide a convenient way to understand molecular properties of
theirs analogues and the degradation nature involving bond
cleavage [11]. Arguably NMR is one of the most sensitive and
versatile analytical probes of molecular structure and dynamics
of complex organic compounds [12]. Hence, experimental and
theoretical studies on the vibrational spectra and NMR chemical
shifts would be of significance for understanding their environ-
mental behavior and assessing their potential environmental risk
[13]. Furthermore, the density functional theory (DFT) method
has been one of the most frequently used calculated methods in
exploring molecular vibrational spectra in computational physics,
chemistry, and material science [14–16]. Some studies have
revealed that the DFT computations, combining the hybrid
exchange–correlation functional Becke-3–Lee–Yang–Parr (B3LYP)
with the standard 6-311G(d,p) basis set, yield good and consistent
results in molecular analyses [17–20]. The combination of DFT
calculations of chemical shifts and harmonic vibrational frequen-
cies with experimental NMR and IR parameters has become an
accepted technique to gather insight into the molecular structures
[21].
the mixture. And the solution was heated to 150 °C for 12 h
under nitrogen. After cooling to room temperature, the reac-
tion solution was diluted with 50 mL of water and extracted
four times with 20 mL of ethyl acetate. The extracted liquid
was absterged with saturated sodium chloride solution and
dried with anhydrous magnesium sulfate, and then filtered
and concentrated. The obtained crude product was further
eluted and purified by silica gel column chromatography
(300–400 mesh) with petroleum ether and ethyl acetate at
the ratio of 30:1–15:1. Thus, we got 4,40-oxybis(1-methoxy-
benzene) product and the purity was 95%. Then, the product
was recrystallized from n-hexane for spectroscopic studies.
1H NMR (CDCl3, 400 MHz) d: 3.81 (s, 6H), 6.86 (d,
J = 7.2 Hz, 4H), 6.93 (d, J = 7.2 Hz, 4H); IR (KBr)
2956, 1608, 1509, 1467, 1455, 1441, 1298, 1248, 1104,
835, 762 cmꢀ1; Raman (Ar+)
: 3066, 3009, 2953, 2903,
1604, 1452, 1242, 1164, 1029, 872, 837 cmꢀ1
t: 3062,
t
.
(2) 1 mmol of 4,40-oxybis(1-methoxybenzene) which was syn-
thesized according to the above method, mixed with 48%
HBr, and the solution was heated to reflux for 16 h at
160 °C. After cooling to room temperature, the reaction
liquid was evaporated to nearly dry in the rotary evaporator
and then extracted with dichloromethane. The obtained
crude product was further eluted and purified by silica gel
column chromatography (300–400 mesh) with petroleum
ether and ethyl acetate at the ratio of 15:1–10:1. Hence,
we gained the solid product, 4,40-dihydroxydiphenyl ether,
with 99% purity level. 1H NMR (CDCl3, 400 MHz) d: 6.70 (d,
J = 7.2 Hz, 4H), 6.75 (d, J = 7.2 Hz, 4H), 9.17 (s, 2H); IR
Thus, in the present study, we give experimental and computa-
tional descriptions and characteristics of 4,40-oxybis(1-methoxy-
benzene) and 4,40-dihydroxydiphenyl ether on geometrical
parameters, vibrational properties and hydrogen chemical shifts.
The structural parameters, vibrational frequencies and chemical
shifts are calculated using the DFT/B3LYP method with the 6-
311G(d,p) basis set. The aim is to check whether the B3LYP/6-
311G(d,p) method is reliable to forecast the characteristics of other
structural-similar compounds by comparing the agreement be-
tween experimental and calculated results.
(KBr)
844, 828 cmꢀ1; Raman (Ar+)
1190, 1151, 850, 819, 632 cmꢀ1
t
: 3602, 3035, 1601, 1502, 1463, 1285, 1211, 1157,
t: 3066, 1604, 1247, 1221,
.
Finally, the target products of high purity can be used for the
determination of molecular structure and spectral properties.
2. Synthesis and experimental methods
2.3. Experiments
The crystals of 4,40-dihydroxydiphenyl ether suitable for X-ray
analyses were grown from chloroform. A crystal was put on a glass
fiber. The X-ray diffraction measurements were carried on a Non-
ius CAD4 single-crystal diffractometer equipped with a graphite-
The two researched compounds were synthesized by ourselves.
The general synthetic route is shown in Fig. 1.
2.1. Materials
monochromated Mo K
a radiation (k = 0.71073 Å) by using an
4-Methoxyphenol (AR), cuprous iodide (CuI, AR), and tetra-
methylethylenediamine (TEMED, >98.0%) were purchased from
Sinopharm Group Co. Ltd. 4-Iodoanisole (99.5%) and cesium car-
bonate (Cs2CO3, 99.9%) were bought from Energy Chemistry Sa
En Group. N,N-dimethylformamide (DMF, 99.5%) and hydrobromic
acid (HBr, 48%) were supplied by Aladdin Chemistry Co. Ltd.
x/2h scan mode at 293 K. The structure was solved by the direct
method and refined by the full-matrix least squares procedure on
F2 using SHELXL-97 program [22]. The FT-IR spectra of the title
compounds diluted in the KBr pellets were measured on a Nicolet
Nexus 870 spectrophotometer in the range of 400–4000 cmꢀ1 at
room temperature. The Raman spectra were recorded on Renishaw
Invia Raman microscope spectrophotometer in the 100–4000 cmꢀ1
region. The excitation line at 514 nm was emitted by an Ar+ laser.
2.2. Synthetic steps
1
The H NMR measurements of 4,40-dihydroxydiphenyl ether and
(1) 5 mmol of 4-methoxyphenol and 5 mmol of 4-iodoanisole
were dissolved in 15 mL of DMF. Then, 0.5 mmol of TEMED
(serves as ligand), 12 mmol of Cs2CO3 (serves as base),
together with 0.5 mmol of CuI (as catalyst) were added into
4,40-oxybis(1-methoxybenzene) were carried out using a Bruker
DPX-300 NMR spectrometer at room temperature with tetrameth-
ylsilane (TMS) as an internal standard in dimethylsulfoxide-d6
(DMSO-d6) and deuterochloroform (CDCl3) respectively.
Fig. 1. The general synthetic route of 4,40-oxybis(1-methoxybenzene) and 4,40-dihydroxydiphenyl ether.

F. Liu et al. / Journal of Molecular Structure 1035 (2013) 285–294
287
Table 1
Optimized parameters of 4,40-oxybis(1-methoxybenzene) and 4,40-dihydroxydiphenyl ether.
Geometrical parameters
B3LYP/6-311G(d,p)
Exp.a
4,40-Oxybis(1-methoxybenzene)
4,40-Dihydroxydiphenyl ether
Bond length (Å)
c
c
c
c
c
c
c
c
c
c
c
c
c
C1–C2
C2–C3
C3–C4
C4–C5
C5–C6
C1–C6
C5–O7
C2–O14
O14–H24
C16–H26
C16–H27
C16–H28
C16–O14
1.397
1.401
1.388
1.397
1.389
1.397
1.395
1.373
1.395
1.397
1.391
1.395
1.391
1.393
1.395
1.378
0.966
1.386(4)
1.359(4)
1.383(4)
1.384(4)
1.380(4)
1.380(4)
1.395(4)
1.382(4)
1.093
1.094
1.088
1.430
Selected bond angle (°)
A C1–C2–C3
A C2–C3–C4
A C3–C4–C5
A C4–C5–C6
119.569
120.583
119.611
120.160
120.359
119.715
122.221
117.502
119.235
124.508
115.923
119.858
120.182
119.751
120.256
119.998
119.951
122.396
117.223
119.586
122.445
117.696
109.619
120.5(3)
120.9(3)
119.0(3)
120.0(3)
120.5(3)
119.0(3)
123.2(3)
116.7(3)
116.4(3)
121.4(3)
118.1(3)
116.0(2)
A C5–C6–C1
A C6–C1–C2
A C4–C5–O7
A C6–C5–O7
A C5–O7–C8
A C1–C2–O14
A C3–C2–O14
AC2–O14–H24
A C2–O14–C16
118.001
Selected dihedral angle (°)
D C4–C5–O7–C8
D C6–C5–O7–C8
ꢀ44.777
139.136
ꢀ44.708
ꢀ44.531
144.593
ꢀ42.891
ꢀ34.8(5)
149.2(3)
ꢀ73.3(5)
D C5–O7–C8–C9
a
The experimental X-ray diffraction values of 4,40-dihydroxydiphenyl ether.
of BDE-15. Thus, all the calculations were performed by using
DFT/B3LYP method with 6-311G(d,p) basis set in this study. There
are no imaginary frequencies in the results of vibrational analyses,
indicating that all the computations were converged on a true en-
ergy minimum. NMR chemical shifts were calculated with the
gauge including atomic orbital (GIAO) approach. Absolute isotropic
magnetic shielding constants were transformed into chemical
shifts (di = rTMS – ri) by referring to one of the standard com-
pounds, TMS [12,25,26]. The value of rTMS is 31.88 ppm for 1H
NMR spectra [17]. Detailed assignments of the signals for each
spectrum were made by employing the animate vibration function
of the Gaussview program [27]. The calculated vibrational wave-
numbers were scaled with the scale factors, as will be explained
in more detail in Section 4, yielding a good agreement between cal-
culated assignments and experimental data. The calculations of po-
tential energy distribution (PED) were done by Gaussian 09
software package with the key word: freq = intmodes. The Raman
intensities were calculated using Eq. (1), which is derived from
the basic theory of Raman scattering [28,29]:
4
fðv0
ꢀ
viÞ si
Ii ¼
ð1Þ
vi½1 ꢀ expðꢀhcvi=kTÞꢁ
Fig. 2. The molecular structure and atom numbering of 4,40-oxybis(1-methoxy-
benzene) (top) and 4,40-dihydroxydiphenyl ether (bottom).
where v0 is the laser exciting wavenumber in cmꢀ1 (in this work,
the excitation wavenumber v0 is 19455.3 cmꢀ1, which corresponds
to the wavelength of 514 nm of a Ar+ laser), vi is the vibrational
wavenumber of the ith normal mode (cmꢀ1); while Si is the Raman
3. Computational details
Gaussian 09 software [23] was used in the calculations of geo-
metrical parameters, vibrational frequencies and chemical shifts.
Qiu et al. [24] reported that DFT/B3LYP method was better than
Hartree–Fock (HF) method in the calculation on structural geometry
scattering activity of the normal mode vi; f (a constant equal to
10ꢀ12) is a suitably chosen common normalization factor for all
peak intensities; h, k, c and T are Planck and Boltzmann constants,
speed of light and temperature in Kelvin, respectively.

288
F. Liu et al. / Journal of Molecular Structure 1035 (2013) 285–294
100
80
60
40
20
0
1500
1000
500
0
4000 3500 3000 2500 2000 1500 1000
500
0
0
500
1000 1500 2000 2500 3000 3500 4000
Wavenumber (cm-1)
Wavenumber (cm-1)
(A)
(A)
100
80
60
40
20
0
1500
1000
500
0
4000 3500 3000 2500 2000 1500 1000
500
0
Wavenumber (cm-1)
0
500
1000 1500 2000 2500 3000 3500 4000
Wavenumber (cm-1)
(B)
(B)
100
1500
1000
500
0
80
60
40
20
0
4000 3500 3000 2500 2000 1500 1000
500
0
Wavenumber (cm-1)
0
500
1000 1500 2000 2500 3000 3500 4000
(C)
Wavenumber (cm-1)
(C)
100
80
60
40
20
0
2500
2000
1500
1000
500
4000 3500 3000 2500 2000 1500 1000
500
0
Wavenumber (cm-1)
0
0
500
1000 1500 2000 2500 3000 3500 4000
(D)
Wavenumber (cm-1)
Fig. 3. Calculated and experimental IR spectra of 4,40-oxybis(1-methoxybenzene)
and 4,40-dihydroxydiphenyl ether. (A) 4,40-oxybis(1-methoxybenzene) (Cal.); (B)
4,40-oxybis(1-methoxybenzene) (Exp.); (C) 4,40-dihydroxydiphenyl ether (Cal.); (D)
4,40-dihydroxydiphenyl ether (Exp.).
(D)
Fig. 4. Calculated and experimental Raman spectra of 4,40-oxybis(1-methoxyben-
zene) and 4,40-dihydroxydiphenyl ether. (A) 4,40-oxybis(1-methoxybenzene) (Cal.);
(B) 4,40-oxybis(1-methoxybenzene) (Exp.); (C) 4,40-dihydroxydiphenyl ether (Cal.);
(D) 4,40-dihydroxydiphenyl ether (Exp.).
4. Results and discussion
4.1. Optimized structures
As shown in Table 1, most of the calculated bond lengths and
bond angles are slightly larger than the corresponding experimen-
tal values. Differences between the calculated results and experi-
mental data are reasonable based on a fact that the theoretical
results are based on the gas phase, while the experimental data
are obtained in the solid phase. The ranges of C–C bond lengths
of 4,40-dihydroxydiphenyl ether and 4,40-oxybis(1-methoxyben-
zene) are 1.388–1.401 Å and 1.391–1.397 Å respectively. The ether
The optimized structural parameters of the two compounds,
which are calculated at the B3LYP/6-311G(d,p) level, are summa-
rized in Table 1, and shown in Fig. 2, using a consistent atom
numbering scheme. The experimental X-ray diffraction values of
4,40-dihydroxydiphenyl ether are also listed in Table
comparisons.
1 for

F. Liu et al. / Journal of Molecular Structure 1035 (2013) 285–294
289
Table 2
Comparison of the observed and calculated vibrational spectra of 4,40-oxybis(1-methoxybenzene).
Mode
Exp.a
IR
Freq.
Inte. (IR)
Acti. (Raman)
Assignments, PEDc (>10%)
Raman
3066vs
Unscaled
Scaledb
1
2
3
4
5
6
7
8
9
3209
3208
3200
3199
3190
3189
3185
3185
3131
3131
3053
3052
2997
2996
1662
1653
1629
1619
1543
1532
1507
1505
1491
1490
1478
1477
1454
1447
1344
1329
1324
1320
1290
1275
1243
1219
1205
1203
1180
1176
1171
1170
1127
1125
1065
1064
1023
1022
963
959
938
936
889
859
845
833
816
813
777
747
716
696
653
649
649
542
525
521
464
460
435
431
391
3074
3073
3066
3065
3056
3055
3055
3055
2999
2999
2925
2924
2901
2900
1609
1600
1577
1568
1494
1483
1457
1444
1443
1442
1430
1408
1401
1301
1287
1282
1278
1249
1234
1203
1180
1167
1165
1142
1139
1134
1133
1091
1089
1031
1030
990
990
932
929
908
906
861
832
818
807
790
787
752
723
693
674
632
628
628
525
508
504
449
445
421
3.1
12.1
2.0
4.7
2.5
573.8
151.4
163.5
512.5
347.8
253.5
145.0
103.6
174.2
252.7
148.4
175.1
614.8
27.9
351.5
91.3
114.6
15.2
6.8
t
t
t
t
t
t
t
t
t
t
t
t
t
t
t
t
t
t
C–H(79.6), bring(10.1)
C–H(79.9), bring(10.1)
C–H(82.4)
C–H(82.7)
C–H(79)
C–H(82.3)
C–H(83.3)
C–H(77.7)
asCH3(91.1)
asCH3(91.8)
asCH3(98.9)
asCH3(98.8)
sCH3(91.4)
3076w
3062w
5.6
4.8
19.7
18.5
35.7
46.6
43.8
7.8
123.0
1.1
2.6
3009m
2953m
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
2956m
2913m
2903s
2838m
1608w
1575w
sCH3(91.2)
1604m
ring(53.7),
qC–H(34.8)
ring(52),
qC–H(37.2)
3.9
ring(62.8),
ring(63.2),
q
q
C–H(29.0)
C–H(26.7)
1509vs
1466m
1441m
14.9
43.4
565.8
7.4
147.5
7.7
8.0
6.6
55.2
0.7
3.9
0.2
72.2
0.0
2.3
0.6
28.5
1111.1
7.4
0.6
55.3
4.3
0.4
0.7
1.1
15.6
13.1
149.5
4.5
4.6
0.5
0.1
0.3
0.5
0.2
39.3
33.7
81.2
11.5
2.8
1.9
49.5
1.4
q
q
C–H(49.4),
C–H(45.3),
x
x
CH3(12.2), bring(28.8)
CH3(13.8), bring(25.6)
1.9
1452s
25.1
15.4
40.9
21.9
9.8
29.4
1.5
2.1
r
r
r
r
x
x
CH3(81.9)
CH3(74.8),
CH3(96.1)
CH3(91.3)
CH3(63.9),
CH3(61.5),
q
C–H(10.6)
qC–H(17.6)
1419w
1298m
qC–H(21.2)
q
C–H(42.1),
x
CH3(12.6), bring(34.9)
t
t
t
ring(33.8),
ring(43.6),
ring(31.2),
qC–H(45.0)
qC–H(17.0),
qC–H(23.4),
1295s
15.6
4.3
5.3
x
x
CH3(14.3),
CH3(15.4),
q
q
C–O(17.1)
C–O(19.9)
q
C–H(65.5),
qC–O(12.3)
1248vs
4.3
t
t
t
t
t
ring(11.7),
q
C–H(57.5), qC–O(21.8)
1242m
1164s
25.4
130.6
1.9
74.8
79.5
14.3
4.4
9.1
2.5
70.2
1.6
1.1
0.6
32.9
0.1
1.1
0.3
0.0
1.7
0.1
22.5
34.4
0.3
168.9
0.4
3.4
7.7
14.6
3.3
3.0
31.6
11.6
3.5
5.7
0.6
3.0
1.1
13.7
3.6
0.1
asC–O(29.1),
asC–O(20.7),
asC–O(26.7),
t
t
t
ring(32.2),
ring(28.9),
ring(24.3),
q
q
q
C–H(21.0),
C–H(22.0),
C–H(26.1),
x
x
x
CH3(12.9)
CH3(22.1)
CH3(17.6)
1195s
1180s
sC–O(21.0), tring(33.3), qC–H(31.4)
1155m
q
q
C–H(13.0),
C–H(14.9),
x
x
CH3(62.5), bring(13.9)
CH3(60.4), bring(13.8)
bring(20.1),
bring(26.3),
q
q
C–H(64.9)
C–H(60.0)
q
q
CH3(75.8),
CH3(61.2),
x
x
C–O(12.6)
CH3(15.1), xC–O (13.7)
1104s
bring(25.3),
bring(25.8),
q
q
C–H(60.0)
C–H(59.0)
1032vs
1007m
1029w
t
t
C–O(36.9), bring(30.2),
C–O(38.3), bring(31.6),
q
q
C–H(16.2)
C–H(15.1)
q
q
C–H(33.6),
C–H(34.9),
s
s
ring(54.6)
ring(56.7)
x
x
x
x
C–H(82.7),
C-H(82.2),
C–H(73.3),
C–H(73.7),
s
ring(10.8)
sring(10.4)
s
s
ring(17.7)
ring(16.0)
878m
834vs
814s
872vs
837vs
815vs
tas C–O(16.4), bring(44.3), qC–H(30.1)
c
c
ring(17.2),
ring(22.8),
x
x
C–H(61.9), bC–O (13.0)
C–H(68.2)
bring(25.7), xC–H(48.3), qC–O(15.0)
x
x
C–H(88.2)
C–H(90.5)
762s
bring(30.8),
q
C–H(21.4),
q
q
x
C–O(33.1)
C–O(21.7)
C–O(17.7)
C–O(25.8)
C–O(18.5)
698w
693w
627w
s
s
s
ring(32.7),
ring(35.8),
ring(36.1),
x
x
x
q
q
C–H(38.8),
C–H(42.3),
C–H(28.8), q
C–H(26.2),
C–H(27.2)
5.4
9.2
2.6
0.3
bring(49.7),
bring(79.2),
q
524s
8.1
c
c
c
c
ring(24.9),
ring(28.8),
ring(52.8),
ring(22.1),
x
x
x
x
x
x
C–H(39.2),
C–H(22.1),
C–H(39.8)
C–H(33.6), xC–O (31.8)
C–H(21.6), xC–O (50.3)
C–H(21.9), C–O(43.0), xCH3(21.0)
q
C–O(30.1)
12.1
29.1
7.1
2.4
0.5
0.0
1.2
3.7
qC–O(32.3)
504m
501w
bring(21.7),
ring(17.0),
s
q
417
379
349
c
c
c
ring(65.2),
ring(64.1),
ring(19.4),
x
x
x
C–H(28.4)
C–H(25.2)
7.6
C–O60.1,
q
CH3(11.8)
(continued on next page)

290
F. Liu et al. / Journal of Molecular Structure 1035 (2013) 285–294
Table 2 (continued)
Mode
Exp.a
IR
Freq.
Inte. (IR)
Acti. (Raman)
Assignments, PEDc (>10%)
Raman
Unscaled
Scaledb
74
75
76
77
78
79
80
81
82
83
84
85
86
87
360
339
324
248
245
227
196
160
147
86
328
314
300
240
237
220
190
155
142
83
2.1
1.5
0.1
2.3
0.1
3.8
0.6
1.8
3.1
1.3
4.2
0.0
1.2
1.2
15.7
1.4
2.3
1.1
4.0
0.9
4.8
2.7
0.4
0.6
0.4
34.4
10.4
5.8
c
c
ring(12.3),
ring(14.9),
x
x
C–H(10.0), xC–O (51.9),
C–H(10.0), xC–O (48.9),
q
q
CH3(18.2)
CH3(19.2)
bring(21.4),
CH3(53.1),
ring(16.8),
CH3(34.0),
bring(35.1),
ring(34.9),
x
C–H(14.8), qC–O(42.9), xCH3(15.1)
q
c
q
x
q
C–O(27.8)
C–H(10.4),
C–O(41.7)
qCH3(62.9)
q
q
x
s
s
C–O(57.3)
C–O(33.3),
C–O(66.2)
C–O(52.8)
ring(10.0),
c
xC–H(26.4)
x
x
x
ring(28.6),
CH3(34.0),
CH3(25.2),
79
56
31
7
76
54
30
7
x
sC–O(59.9)
bC–O(60.0), bCH3(10.7),
bC–O(81.1)
bC–O(88.4)
xring(20.4)
a
b
c
vs, Very strong; s, strong; w, weak; m, medium.
With the scale factor of 0.958 for calculated wave numbers greater than 3000 cmꢀ1 and the scale factor of 0.9682 for other lower wavenumbers.
, Stretching; s, sym. stretching; as, asym. stretching; b, in-plane-bending; , out-of-plane bending; , torsion; , wagging; , rocking; , scissoring.
t
t
t
c
s
q
x
r
bonds C5–O7, C2–O14 and C16–O14 are 1.395 Å, 1.373 Å and 1.430 Å.
The range of C–H bond lengths of methyl is 1.088–1.094 Å. For both
compounds, the calculated values of the C–C–C angles in the aro-
matic rings are around the typical hexagonal angle of 120°. The cal-
culated values of the dihedral angles of C4–C5–O7–C8 (ꢀ44.777°/
139.136° for 4,40-oxybis(1-methoxybenzene), and ꢀ44.531°/
144.593° for 4,40-dihydroxydiphenyl ether), which are a critical
geometry parameter for conformers in the ground state, are closer
to the experiment results (ꢀ34.8(5)°/149.2(3)°). The phenomenon
demonstrates the non-planar nature of the two aromatic rings in
the two compounds, which is attributed to the steric interaction.
The calculation can be supported by the stereochemic study of Kurt
Mislow [30–32]. Qu et al. [13] reported that the sum of two dihe-
dral angles ðC0 —S—C1—C6; C1—S—C0 —C0 Þ for four types of TCDPSs
Theoretical (unscaled and scaled) and experimental vibrational fre-
quencies (cmꢀ1), peak intensities (km molꢀ1) and the correspond-
ing assignments for the vibrational modes are gathered in Tables
2 and 3. The tables also give PED values and the description of
the largest vibrational contributions to the normal modes. It is a
fact that the DFT method systematically overestimates the
vibrational wavenumbers because of the neglect of anharmonicity
effects in the real system [34]. So, we use generic frequency scale
factors to fit the theoretical results with experimental ones. More-
over, previous studies have revealed increasing frequency overesti-
mation of DFT in the high frequency regions (>3000 cmꢀ1) [35]. As
a result, the frequencies larger than 3000 cmꢀ1 are scaled down by
multiplying a factor of 0.958 [36], while other frequencies are
scaled down by a factor of 0.9682 [13, 37]. In addition, we use
linear regression method to analyze the consistency between
calculated and experimental frequencies. The results are given in
Table 4. The squared correlation coefficients R2 are all greater than
0.99, showing that good linearity exist between theoretical fre-
quencies and experimental values for the two compounds. In other
words, the calculated results with Gaussian package can be used to
predict vibrational frequencies.
1
1
6
(2,20,3,30-TCDPS, 2,20,3,40-TCDPS, 2,20,3,50-TCDPS, and 2,20,3,60-
TCDPS) is about equal to 90°, indicating that the plane of the
two benzene rings are almost vertical to each other. In the present
work, the same conclusion is reached based on the calculated re-
sults. Dihedral angle C4–C5–O7–C8 and C5–O7–C8–C9 of 4,40-oxy-
bis(1-methoxybenzene) is ꢀ44.777° and ꢀ44.708° separately,
and the corresponding value for 4,40-dihydroxydiphenyl ether is
ꢀ44.531° and ꢀ42.891°. The sum of the two angles is ꢀ89.485°
and ꢀ87.422°, close to ꢀ90°. However, the sum of the two exper-
imental data is ꢀ108.1(10)°, deviated from ꢀ90°. The existence
of extended hydrogen bonding in 4,40-dihydroxydiphenyl ether
and the stacking interaction may explain such results. For the
two dihedral angles, there are some slight deviations between
the two compounds and DPS (ꢀ50.1°/ꢀ49.5° (Cal.) and ꢀ49.6°/
ꢀ49.6° (Exp.)) [33], confirming that the steric effect of the substi-
tuted functional groups on the dihedral angles of C4–C5–O7–C8
and C5–O7–C8–C9.
4.2.1. Ring vibrations
The C–H and C–C related vibrations can help to determine the
existence of aromatic rings in a structure. The C–H stretching
vibrations of aromatic structures often occur in the range of
3000–3100 cmꢀ1. The nature of substituents has little influence
on the band in this region [38,39]. The C–H in-plane bending vibra-
tions often appear in the region 1000–1300 cmꢀ1. And 750–
1000 cmꢀ1 is the C–H out-of-plane bending vibrational region. It
is reported that the bands of the phenyl C–C stretching vibrations
generally appear at 1450 cmꢀ1
, , , and
1500 cmꢀ1 1580 cmꢀ1
4.2. Vibrational assignments
1600 cmꢀ1 in IR spectra with variable intensities [40].
For 4,40-oxybis(1-methoxybenzene), the aromatic C–H stretch-
ing vibrations appear at 3076 and 3062 cmꢀ1 in the IR spectrum
with weak peaks, while with very strong intensity at 3066 cmꢀ1
in Raman spectrum. Scaled theoretical C–H stretching modes are
found to be at 3073 and 3065 cmꢀ1. In IR spectrum, the frequencies
1298, 1248 and 1032 cmꢀ1 are assigned to the C–H in-plane bend-
ing vibrations, and two intensive bands at 814 cmꢀ1 and 762 cmꢀ1
are expected to be the C–H out-of-plane bending vibrations. The
wavenumbers at 698 cmꢀ1 in IR and 501 cmꢀ1 in Raman spectra
are ascribed to the C–H out-of-plane deformation. As shown in
Table 2, the IR wavenumbers 1466 cmꢀ1, 1509 cmꢀ1, 1575 cmꢀ1
Calculated and experimental IR and Raman spectra of the two
compounds are shown in Figs. 3 and 4, respectively. It is easy to
discover that the main absorption peaks of the calculated spectra
are mainly in accordance with those of the experimental spectra,
demonstrating that the calculated results are dependable. How-
ever, as to 4,40-dihydroxydiphenyl ether, there are some differ-
ences between the simulated spectra and the observed one,
because the fluorescence effect reduces the quality of the experi-
mental Raman spectra. 4,40-oxybis(1-methoxybenzene) has 31
atoms and 87 normal vibrational modes and 4,40-dihydroxydiphe-
nyl ether has 25 atoms and 69 normal vibrational modes.
and 1608 cmꢀ1
, in agreement with the calculated data, are

F. Liu et al. / Journal of Molecular Structure 1035 (2013) 285–294
291
Table 3
Comparison of the observed and calculated vibrational spectra of 4,40-dihydroxydiphenyl ether.
Mode
Exp.a
IR
Freq.
Inte. (IR)
Acti. (Raman)
Assignments, PEDc (>10%)
Raman
3066vs
Unscaled
Scaledb
1
2
3
4
5
6
7
8
9
3781
3779
3208
3206
3202
3201
3191
3191
3179
3179
1659
1651
1643
1637
1540
1528
1479
1470
1384
1380
1332
1314
1289
1264
1254
1224
1206
1202
1180
1178
1123
1120
1027
1025
957
949
940
932
892
860
844
841
816
811
798
755
716
706
654
652
589
3622
3620
3074
3071
3067
3066
3057
3057
3046
3045
1607
1598
1591
1585
1491
1479
1432
1423
1340
1336
1290
1272
1248
1224
1214
1185
1167
1163
1142
1140
1087
1085
994
993
927
919
910
903
864
833
817
814
790
785
773
731
693
683
633
139.8
152.3
4.7
4.6
10.0
7.7
14.9
15.7
17.0
19.2
0.0
267.2
249.6
367.4
453.2
309.9
355.4
191.0
168.6
248.9
232.2
185.4
70.6
151.4
29.5
4.8
1.3
0.5
0.1
6.0
7.5
2.1
1.5
35.6
59.6
3.8
65.5
142.8
19.2
11.1
30.6
1.1
1.1
1.5
1.1
0.2
0.1
1.1
0.6
25.7
76.8
97.4
41.1
2.0
t
t
t
t
t
t
t
t
t
t
t
t
t
t
t
t
t
t
t
t
t
t
O–H(91.4)
O–H(91.4)
C–H(75.4)
C–H(75.6)
C–H(59.0)
C–H(59.1)
C–H(74.5)
C–H(74.4)
3602s
3035w
C–H(64.3)
C–H(64.2)
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
1873w
1601w
1604m
1594m
ring(53.6), bC–H(39.3)
ring(54.7), bC–H(37.6)
ring(54.1), bC–H(29.4), bCOH(12.8)
ring(30), bC–H(41.6), bCOH(14.6)
ring(54.6), bC–H(55.2)
ring(34.8), bC–H(55.4)
ring(35.2), bC–H(41.6), bCOH(14)
ring(31.6), bC–H(43.2), bCOH(13.8)
ring(38), bC–H(37.6), bCOH(17.1)
ring(32.4), bC–H(44.4), bCOH(18.6)
0.5
8.1
13.1
101.3
732.3
55.8
117.4
82.4
115.5
1.8
8.4
233.9
2.0
252.7
54.3
280.7
838.1
6.0
1502vs
1463vs
1383s
1362m
1285w
1249s
ring(23.8),
ring(26.6),
q
q
C–H(56.6), bC–O(11.4)
C–H(51.6), bC–O(12.2)
1247m
1221w
tasC–O (17.6),
t
ring(31.2),
C–H(35.4), COH(16.3)
ring(25.4), C–H(35.4)
qC–H(24.6), bCOH(17.3)
t
t
t
ring(40.4),
asC–O(21.6),
sC–O(18.5),
q
t
1211vs
t
q
1190w
1151s
t
ring(33.3), bC–H(33.0)
ring(26.2), bC–H(30.2)
ring(29.2), bC–H(28.0)
bCOH(30.8),
bCOH(31.0),
bC–H(73.4),
bC–H(66.4),
t
t
1157s
t
t
ring(12.8)
ring(16.6)
1142m
3.2
29.2
44.9
10.6
10.2
0.2
0.4
2.3
1.0
30.2
45.9
94.8
126.9
3.8
2.9
165.7
6.1
bC–H(60.7), bring(26.3)
bC–H(59.6), bring(24.8)
1097vs
1009m
t
t
ring(55.6), bC–H(34.0)
ring(84.2), bC–H(34.4)
x
x
x
x
C–H(83.1),
C–H(82.8),
C–H(73.0),
C–H(75.3),
cring(11.1)
cring(10.8)
cring(17.2)
cring(17.4)
874w
844m
t
c
c
asC–O(13.8), bring(49.9), bC–H(34.6)
C–H(53.6), asC–O(18.5), COH(17.7), bring(25.0)
C–H(59.1), bC–O(17.9), COH(21.0), bring(14.5)
850s
819s
t
t
t
828vs
791s
x
x
C–H(78.2),
C–H(85.8)
c
ring(20.9)
2.3
6.5
7.1
2.0
c
C–H(47.4),
tCOH(15.7), bC–O(10.7), bring(18.5)
xC–H(80.3)
sring(32.2),
sring(38.6),
sring(37.4),
x
x
x
C–H(37.1), bC–O(17.7)
C–H(32.8), bC–O(11.0)
C–H(33.7), cCOH(10.6), tsC–O(12.4)
5.0
14.7
4.6
4.9
13.7
25.7
8.2
0.4
6.5
3.7
3.5
2.1
0.2
4.3
2.5
3.6
5.6
15.3
1.4
8.2
1.0
0.4
bring(53), bC–H(28.2)
bring(47.9), bC–H(24.3)
632w
584w
631
570
507
492
489
437
418
415
411
395
383
365
338
306
264
160
1.6
587m
507m
15.2
51.7
13.8
17.0
3.5
0.4
1.0
7.0
213.8
222.3
39.0
3.8
11.2
1.3
0.3
0.9
0.1
1.9
c
c
C–H(41.5), bC–O(17.9), bring(36.7)
ring(31.8), C–H(47.3), COH(14.8)
C–H(28.3)
ring(34.4),
C–O(38.7), bCOH(20.6)
523
508
505
451
432
429
425
408
396
377
349
316
272
165
145
63
c
x
c
c
492w
bring(65.2),
x
c
490m
C–H(41.8),
cCOH(17.0)
s
ring(40),
x
C–H(23.2)
C–H(24.2)
C–O(19.9)
sring(39.6), x
c
COH(33.2), x
s
C–O(29.8),
c
c
COH(28.4)
COH(35.4)
sC–O(25.8),
c
c
c
COH(69.2)
COH(76.6)
C–O(28.6),
357w
278w
c
COH(38.0)
bring(29.4),
sCOC(31.9)
c
c
ring(21.6),
C–O(37.9),
c
c
COH(27.8), bC–O(18.2)
COH(35.2), ring(37.6)
140
61
46
20
c
24.1
27.6
9.2
sC–O(42.5)
sC–O(77.5)
sC–O(88.4)
47
21
2.2
a
b
c
vs, Very strong; s, strong; w, weak; m, medium.
With the scale factor of 0.958 for calculated wave numbers greater than 3000 cmꢀ1 and the scale factor of 0.9682 for other lower wavenumbers.
, Stretching; s, sym. stretching; as, asym. stretching; b, in-plane-bending; , out-of-plane bending; , torsion; , wagging; , rocking.
t
t
t
c
s
q
x

292
F. Liu et al. / Journal of Molecular Structure 1035 (2013) 285–294
Table 4
explained by the different functional groups in the para-position.
And the associated dominated vibration mode is the coupling of
C–O asymmetric stretching and C–H in-plane bending vibrations.
Moreover, in the experimental Raman spectrum, the C–O
asymmetric stretching vibration appears at 1247 cmꢀ1, and the
symmetric stretching vibration wavenumber is 1190 cmꢀ1 for
4,40-dihydroxydiphenyl ether. For, 1242 cmꢀ1 is assigned to the
asymmetric stretching vibration, and the symmetric stretching
vibration is found at 1164 cmꢀ1. C–O in-plane bending vibrations
are observed at 850 cmꢀ1 for 4,40-dihydroxydiphenyl ether, and
at 837 cmꢀ1 and 693 cmꢀ1 for 4,40-oxybis(1-methoxybenzene).
The experimental values match well with the theoretical data in
Tables 2 and 3.
Correlation analysis of calculated and experimental vibrational frequencies.
Molecule
Correlation equations
R2
4,40-Oxybis(1-
methoxybenzene)
IR: kExp. = 0.9897kCal. + 15.824
0.9995
Raman: kExp. = 0.9983kCal. + 2.1141 0.9999
4,40-Dihydroxydiphenyl ether IR: kExp. = 0.9955kCal. ꢀ 0.4677
Raman: kExp. = 0.9922kCal. + 10.633
0.9982
0.9998
assigned as the aromatic C–C semicircle stretching vibrations. The
aromatic ring C–C stretching vibration in observed Raman spec-
trum is found at 1604 cmꢀ1. As shown in Table 2, the predicted
vibrations assigned to phenyl ring vibrations are in good accor-
dance with the experimental assignments.
For 4,40-dihydroxydiphenyl ether, the weak band observed at
3035 cmꢀ1 in IR spectrum and the strong band at 3066 cmꢀ1 in Ra-
man spectrum are assigned as the aromatic C–H stretching vibra-
tion. In IR spectrum, the C–H in-plane bending vibrations are
observed at 1211 cmꢀ1 and 1097 cmꢀ1, and two intensive bands
at 844 cmꢀ1 and 828 cmꢀ1 are expected to be the C–H out-of-plane
bending vibrations. The wavenumbers at 791 cmꢀ1 in IR and
492 cmꢀ1 in Raman spectra are ascribed to the C–H out-of-plane
deformation. 1463 cmꢀ1, 1502 cmꢀ1 and 1601 cmꢀ1 in IR spectrum
are assigned as the aromatic C–C semicircle stretching vibrations,
in agreement with the calculated data shown in Table 3.
1604 cmꢀ1 and 1594 cmꢀ1 are assigned as the aromatic ring C–C
stretching vibration in observed Raman spectrum. Comparisons
demonstrate that all the experimental values match with the the-
oretical frequencies.
4.2.3. O–H and –CH3 vibrations
For un-substituted phenol, the frequency of O–H stretching
vibration in the gas phase is 3657 cmꢀ1 [42]. Sundaraganesan
et al. [43] assigned a strong band in FT-IR spectrum at 3387 cmꢀ1
and a weak band in FT-Raman at 3390 cmꢀ1 to O–H stretching
vibration in 5-amino-O-cresol. In the present work, the strong
band observed at 3602 cmꢀ1 is assigned to O–H stretching mode,
and the calculated O–H band is at 3619 cmꢀ1. There is a small devi-
ation between the calculated and the experimental data. Although
the band is not observed in the experimental Raman spectrum, it is
calculated to be 3621 cmꢀ1. In addition, phenols have the in-plane
bending vibrations in the band region 1152–1250 cmꢀ1 [37]. The
weak band observed at 1285 cmꢀ1 and the strong band observed
at 1157 cmꢀ1 in IR spectrum are assigned as O–H in-plane bending
vibrations. The theoretically computed values at 1272 and
1167 cmꢀ1 have fine consistency with the experimental results.
The O–H out-of-plane bending vibrations for phenol lie in the
290–320 cmꢀ1 region for free O–H [41]. In the present work, the
scaled values of O–H out-of-plane deformation vibration are calcu-
lated to be 338 cmꢀ1 and 365 cmꢀ1, and the corresponding Raman
experimental value is 357 cmꢀ1, but not observed in the IR spectra.
The CH3 asymmetric stretching modes are found in the region of
2956–2913 cmꢀ1 in IR and 3099–2953 cmꢀ1 in Raman spectrum.
The symmetric stretching vibration of CH3 is found at 2838 cmꢀ1
in IR and 2903 cmꢀ1 in Raman spectrum. Peaks at 1441 cmꢀ1 in
IR and 1452 cmꢀ1 in Raman spectra, in accordance with predicted
frequencies at 1444 and 1457 cmꢀ1, are assigned to the scissoring
of CH3. The wagging vibrations are found at 1104 and 1155 cmꢀ1 in
IR spectrum, with the predicted frequencies at 1091 and
1165 cmꢀ1. In this range, the wagging vibrations of methyl group
mostly occur with aromatic ring vibrations.
The wavenumbers appearing at 1000 cmꢀ1 are usually assigned
as the trigonal ring breathing vibrations [41]. For 4,40-dihydroxydi-
phenyl ether, the band at 1009 cmꢀ1, which coincides with the
calculated value 994 cmꢀ1, is assigned to this mode. And for
4,40-oxybis(1-methoxybenzene), the experimental and calculated
value is 1007 cmꢀ1 and 990 cmꢀ1, respectively. The overtone of
aromatic ring is observed at 1875 cmꢀ1 in the IR spectrum of
4,40-oxybis(1-methoxybenzene), and for 4,40-dihydroxydiphenyl
ether, the band is at 1873 cmꢀ1. However, there is no correspond-
ing peak in the theoretical spectra. The mediumꢀp1eaks at 874 cmꢀ1
for 4,40-dihydroxydiphenyl ether and 834 cm
for 4,40-oxybis
(1-methoxybenzene) in experimental IR spectra are the contribu-
tion of the coupling of the skeleton vibration of the aromatic ring
and the C–O asymmetric stretching.
4.2.2. C–O vibrations
The frequencies around 1270–1230 cmꢀ1 in IR spectrum are re-
garded as the C–O stretching band of the aromatic ether.
1249 cmꢀ1 is assigned to C–O asymmetric strꢀet1ching vibrations
for 4,40-dihydroxydiphenyl ether and 1195 cm and 1180 cmꢀ1
for 4,40-oxybis(1-methoxybenzene). The small differences may be
4.3. 1H NMR chemical shifts
NMR is the most powerful method in analytical chemistry for
the identifications of structural groups and reactive ionic species.
Table 5
Comparison of theoretical and experimental values of 1H NMR chemical shifts.
Molecule
dH
Calc. (ppm)
Exp. (ppm)
Assignments
4,40-Oxybis(1-methoxybenzene)
7.137
6.861
6.700
6.491
3.449
6.945
6.927
6.874
6.856
3.805
H-21 (H-25)
H-19 (H-22)
H-20 (H-20)
H-18 (H-24)
H-26 (H-27, H-28, H-29, H-30, H-31)
4,40-Dihydroxydiphenyl ether
7.010
6.780
6.670
6.397
3.282
6.771
6.753
6.718
6.700
9.168
H-19 (H-23)
H-17 (H-21)
H-18 (H-20)
H-16 (H-22)
H-24 (H-25)

F. Liu et al. / Journal of Molecular Structure 1035 (2013) 285–294
293
1
Fig. 5. Observed H NMR spectra of 4,40-oxybis(1-methoxybenzene) (A) and 4,40-dihydroxydiphenyl ether (B).
dH;Expꢂ ¼ 0:7316 þ 0:9057dH;CalꢂðR2 ¼ 0:983Þ
ð2Þ
The experimental and calculated values together with the peak
assignments of 4,40-oxybis(1-methoxybenzene) and 4,40-
dihydroxydiphenyl ether for 1H NMR chemical shifts analyses are
shown in Table 5. The observed 1H NMR spectra are presented in
Fig. 5.
This indicates that the calculated chemical shifts may reproduce the
experimental data. However, for 4,40-dihydroxydiphenyl ether,
there is an obvious difference between the experimental and theo-
retical chemical shift values of H24 (25) in O–H. The possible expla-
nation is that the formation of hydrogen bond makes dH move to the
lower range [44,45].
The peaks with dH of 7.270 ppm in Fig. 5A and 2.500 ppm in
Fig. 5B are supposed to be related with the protons of the solvent
CDCl3 and DMSO-d6. The presence of other peaks suggests that
there are five distinct types of protons in the two compounds.
The peaks with dH of 3.805 ppm in Fig. 5A and 9.168 ppm in
Fig. 5B are assigned to the protons of substituents in the para-position,
methyl and hydroxyl, respectively. Normally, the protons on
phenyl ring are expected to yield NMR signals in the dH region of
6–8 ppm. The substitution of functional group atoms for proton
in biphenyl ether changes the chemical environment of the
remaining aryl protons. For 4,40-oxybis(1-methoxybenzene), the
correlation equation is
5. Conclusions
The theoretical and experimental investigation on molecular
structure, IR and Raman spectra and 1H NMR chemical shifts of
4,40-dihydroxydiphenyl ether and 4,40-oxybis(1-methoxybenzene)
have been given. In the current study, all the computations are
carried out with the Gaussian 09 program using DFT/B3LYP
method with 6-311G(d,p) level. The geometric parameters of

294
F. Liu et al. / Journal of Molecular Structure 1035 (2013) 285–294
4,40-dihydroxydiphenyl ether, gained by X-ray diffraction, match
well with the calculated data. The scaled theoretical vibration fre-
quencies show good agreement with the experimental results. The
1H NMR chemical shifts are found to have only minor deviations
from the experimental values. All these conclusions prove that
the B3LYP/6-311G(d,p) method is feasible to predict the parame-
ters and characteristics of structural-similar compounds.
[21] M. Szafran, A. Katrusiak, Z. Dega-Szafran, I. Kowalczyk, J. Mol. Struct. 996
(2011) 75.
[22] G.M. Sheldrick, Acta Crystallogr. A 64 (2008) 112.
[23] M.J. Frisch, G.W. Trucks, H.B. Schlegel, G.E. Scuseria, M.A. Robb, J.R. Cheeseman,
G. Scalmani, V. Barone, B. Mennucci, G.A. Petersson, H. Nakatsuji, M. Caricato,
X. Li, H.P. Hratchian, A.F. Izmaylov, J. Bloino, G. Zheng, J.L. Sonnenberg, M.
Hada, M. Ehara, K. Toyota, R. Fukuda, J. Hasegawa, M. Ishida, T. Nakajima, Y.
Honda, O. Kitao, H. Nakai, T. Vreven, J.A. Montgomery, J.E. Peralta, F. Ogliaro, M.
Bearpark, J.J. Heyd, E. Brothers, K.N. Kudin, V.N. Staroverov, R. Kobayashi, J.
Normand, K. Raghavachari, A. Rendell, J.C. Burant, S.S. Iyengar, J. Tomasi,
Gaussian 09, Revision A.02, Gaussian, Inc., Wallingford, CT, 2009.
[24] S.S. Qiu, X.H. Tan, K. Wu, A.Q. Zhang, S.K. Han, L.S. Wang, Spectrochim. Acta A
76 (2010) 429.
Acknowledgments
This research was financially supported by the National Natural
Science Foundation of China (Nos. 41071319 and 20977046), the
Fundamental Research Funds for the Central Universities of China
(No. 1112021101) and the Major Science and Technology Program
for Water Pollution Control and Treatment of China (No.
2012ZX07506-001).
[25] J.R. Cheeseman, G.W. Trucks, T.A. Keith, M.J. Frisch, J. Chem. Phys. 104 (1996)
5497.
[26] M.R. Bacon, G.E. Maciel, J. Am, Chem. Soc. 95 (1973) 2413.
[27] R. Dennington II, T. Keith, J. Millam, GaussView, Version 4.1, Semichem Inc.,
Shawnee Mission, KS, 2007.
[28] G. Keresztury, S. Holly, J. Varga, G. Besenyei, A.Y. Wang, J.R. Durig, Spectrochim.
Acta A 9 (1993) 2007.
[29] D. Michalska, R. Wysokimski, Chem. Phys. Lett. 403 (2005) 211.
[30] J.C. Barnes, J.D. Paton, J.R. Damewood Jr., K. Mislow, J. Org. Chem. 46 (1981)
4975.
References
[31] W. Weissensteiner, I.I. Schuster, J.F. Blount, K. Mislow, J. Am. Chem. Soc. 108
(1986) 6664.
[1] T. Katsurayama, A. Kanesho, JP2011057652-A, 2011.
[2] G. Koga, M. Yasaka, Y. Nakano, Org. Prep. Proced. 1 (1969) 205.
[3] S. Net, L. Nieto-Gligorovski, S. Gligorovski, B. Temime-Rousell, S. Barbati, Y.G.
Lazarou, H. Wortham, Atmos. Environ. 43 (2009) 1683.
[32] W. Egan, R. Tang, G. Zon, K. Mislow, J. Am. Chem. Soc. 93 (1971) 6205.
[33] B. Rozsondai, J.H. Moore, D.C. Gregory, I. Hargittai, Acta Chim. Acad. Sci. Hung
94 (1977) 321.
[4] E.P. Jutemar, P. Jannasch, ACS Appl. Mater. Interfaces 2 (2010) 3718.
[5] J.J. Tian, X.F. Wang, L.Q. Wang, High Perform. Polym. 22 (2010) 198.
[6] F.W. Huang, F.R. Huang, Y. Zhou, Polym. J. 42 (2010) 261.
[7] Y.H. Lu, Y.L. Gao, W. Li, Acta Polym. Sin. 1 (2010) 120.
[34] Y. Ye, M. Ruan, Y.Z. Song, Y.Y. Li, W. Xie, Spectrochim. Acta A 68 (2007) 85.
[35] D. Michalska, W. Zierkiewicz, D.C. Bienko, W. Wojciechowski, J. Phys. Chem. A
105 (2001) 8734.
[36] P.M. Wojciechowski, D. Michalska, Spectrochim. Acta A 68 (2007) 948.
[37] J.P. Merrick, D. Moran, L. Radom, J. Phys. Chem. A 111 (2007) 11683.
[38] G. Varsanyi, Assignments for Vibrational Spectra of Seven Hundred Benzene
Derivatives, vols. 1 & 2, Academic Kiado, Budapest, 1973.
[39] M. Jag, Organic Spectroscopy – Principles and Applications, second ed., Narosa
Publishing House, New Delhi, 2001.
[40] K. Nakanshi, P.H. Solomon, Infrared Absorption Spectroscopy, Holden-Day,
Inc., 1977 (Chapter 2).
[41] M.K. Subramanian, P.M. Anbarasan, S. Manimegalai, Spectrochim. Acta A 73
(2009) 642.
´
[8] W. Podkoscielny, D. Wdowicka, J. Appl. Polym. Sci. 35 (1988) 1779.
[9] Y. Wan, S. Wiseman, H. Chang, X. Zhang, P.D. Jones, M. Hecker, K. Kannan, S.
Tanabe, J. Hu, M.H.W. Lam, J.P. Giesy, Environ. Sci. Technol. 43 (2009) 7536.
[10] H. Hakk, R.J. Letcher, Environ. Int. 29 (2003) 801.
[11] S. Qiu, L. Liu, X. Jin, A.Q. Zhang, K. Wu, L.S. Wang, Spectrochim. Acta A 77
(2010) 572.
[12] J.H. Zhang, X. He, H.X. Gao, J. Mol. Struct. 1004 (2011) 109.
[13] R.J. Qu, X.S. Zhang, Q. Zhang, X. Yang, Z.Y. Wang, L.S. Wang, Spectrochim. Acta
A 81 (2011) 261.
[14] D.B. Chesnut, Annu. Rep. NMR Spectrosc. 21 (1989) 51.
[15] D.B. Chesnut, Annu. Rep. NMR Spectrosc. 29 (1994) 71.
[16] V. Barone, R. Improta, N. Rega, Acc. Chem. Res. 41 (2008) 605.
[17] M.T. Güllüoglu, Y. Erdogdu, J. Karpagam, N. Sundaraganesan, S. Yurdakul, J.
Mol. Struct. 990 (2011) 14.
[18] K.C. Gross, P.G. Seybold, Int. J. Quantum Chem. 85 (2001) 569.
[19] D. Sajan, I.H. Joe, V.S. Jayakumar, J. Raman Spectrosc. 37 (2006) 508.
[20] M.A. Tafipolsky, I.V. Tokmakov, V.A. Shlyapochnikov, J. Mol. Struct. 510 (1999)
149.
[42] G. Varsanyi, Assignments for Vibrational Spectra of Seven Hundred Benzene
Derivatives, vols. 1–2, Adam Hilger, 1974.
[43] N. Sundaraganesan, C. Meganathan, H. Saleem, B.D. Joshua, Spectrochim. Acta
A 68 (2007) 619.
[44] N. Suleymanoglu, R. Ustabas, Y.B. Alpaslan, F. Eyduran, C. Ozyurek, N.O.
Iskeleli, Spectrochim. Acta A 83 (2011) 427.
[45] B. Peng, Y. Nie, J.L. Miao, Z.W. Zhang, M.L. Xu, G.X. Sun, J. Mol. Struct. 1007
(2012) 214.