Spectroscopic, quantum chemical DFT/HF study and synthesis of [2.2.1] hept-2′-en-2′-amino-N-azatricyclo [3.2.1.02,4] octane

Article abstract of DOI:10.1016/j.saa.2008.06.043

The compound 4-N-bicyclo [2.2.1] hept-2′-en-2′-amino-N-azatricyclo [3.2.1.0^2,4] octane (2) has been synthesized and characterized by elemental analysis, IR, UV-vis, mass and NMR. Density functional theory (DFT) and Hartree-Fock (HF) calculations have been carried out for the title compound by using the standard 6-31G* basis set. The calculated results show that the predicted geometry can well reproduce the structural parameters. Predicted vibrational frequencies have been assigned and compared with experimental IR spectra and they complement each other. The theoretical electronic absorption spectra have been calculated by using CIS, TD-DFT and ZINDO methods. The ¹³C NMR and ¹H NMR of compound (2) have been calculated by means of Becke 3-Lee-Yang-Parr (B3LYP) density functional method with 6-31G* basis set. Comparison between the experimental and the theoretical results indicates that density functional B3LYP method is able to provide satisfactory results for predicting NMR properties. On the basis of vibrational analyses, the thermodynamic properties of the title compound at different temperatures have been calculated.

Full text of DOI:10.1016/j.saa.2008.06.043

Spectrochimica Acta Part A 71 (2009) 1749–1755
Contents lists available at ScienceDirect
Spectrochimica Acta Part A: Molecular and
Biomolecular Spectroscopy
journal homepage: www.elsevier.com/locate/saa
Spectroscopic, quantum chemical DFT/HF study and synthesis of [2.2.1]
hept-2ꢀ-en-2ꢀ-amino-N-azatricyclo [3.2.1.02,4] octane
Abbas Teimouria,∗, Mohammad Emamib, Alireza Najafi Chermahinic, Hossein A. Dabbaghd
a Payame Noor University (PNU), Isfahan, P.O. Box 81395-671, Iran
b Department of Chemistry, Shahid Beheshti University, Tehran, Iran
c Department of Chemistry, Yasouj University, Yasouj, Iran
d Department of Chemistry, Isfahan University of Technology, Isfahan, Iran
a r t i c l e i n f o
a b s t r a c t
The compound 4-N-bicyclo [2.2.1] hept-2ꢀ-en-2ꢀ-amino-N-azatricyclo [3.2.1.02,4] octane (2) has been syn-
thesized and characterized by elemental analysis, IR, UV–vis, mass and NMR. Density functional theory
(DFT) and Hartree-Fock (HF) calculations have been carried out for the title compound by using the stan-
dard 6-31G* basis set. The calculated results show that the predicted geometry can well reproduce the
structural parameters. Predicted vibrational frequencies have been assigned and compared with exper-
imental IR spectra and they complement each other. The theoretical electronic absorption spectra have
been calculated by using CIS, TD-DFT and ZINDO methods. The 13 C NMR and 1H NMR of compound (2)
have been calculated by means of Becke 3-Lee-Yang-Parr (B3LYP) density functional method with 6-31G*
basis set. Comparison between the experimental and the theoretical results indicates that density func-
tional B3LYP method is able to provide satisfactory results for predicting NMR properties. On the basis of
vibrational analyses, the thermodynamic properties of the title compound at different temperatures have
Article history:
Received 15 August 2007
Received in revised form 8 June 2008
Accepted 25 June 2008
Keywords:
Synthesis
Vibrational frequency
Electronic absorption spectra
NMR
DFT
Ab initio
been calculated.
© 2008 Elsevier B.V. All rights reserved.
1. Introduction
Norbornene has been subject to many different types of sci-
entific studies to this date. Fomine and co workers studied the
The rigid bicycle carbon skeleton of the three species has often
been employed to fix geometric variables in structure/reactivity
studies, as well as in the investigation of the relationship between
structural and spectroscopic properties [1]. They are also of interest
because, compared to acyclic species, the relatively rigid struc-
tures of the carbon skeleton lead to unambiguous orientations and
magnitudes of separation of substitutions. Norbornane is a key
compound in the structural chemistry and it demonstrates chal-
lenges to crystallographic structural determinations. Its derivatives
have held a prominent position in the investigation of phenomena
associated with non-classical ions [2], it is considered as one of the
prototype strained olefins, due to its extreme chemical reactivity,
undergoing elimination, dimerisation, addition and isomerisation
[3], as well as exo-selectivity [4]. Such properties of bicyclic com-
pounds wherein they differ from the corresponding acyclic alkane
are rationalized in terms of several types of ‘strain’ imposed by their
geometries.
reaction pathways for the ring-opening cross-metathesis of nor-
bornene with olefins using a variety of method density functional
theory (DFT) method [5].
The electronic structural information from core orbitals of
norbornadiene, norbornene and norbornane in their ground elec-
tronic states are studied by Wang using DFT studies [6]. Reaction
mechanisms of the cycloaddition between methyleneketene and
cyclopentadiene that was expected to yield a norbornene prod-
uct were theoretically studied by means of ab initio methods and
density functional theory by Sheng and Leszczynski [7]. Addition
of aryl azides to norbornene [8] and 1,3-dipolar cycloaddition of
phenyl azide to norbornene in aqueous solutions have been studied
[9]. The reaction of benzenesulfonyl azide with bridged ring com-
pounds [10], reaction of trimethylsilyl azide with bridged bicyclic
olefins [11] and reaction of benzenesulfonyl azides with different
substrates have been studied [12,13]. Recently we have reported
the DFT calculation of the 4-substituted aminoazo-benzenesulfonyl
azides [14] and a series of azo dyes derived from 2-hydroxy and
2,4-dihydroxy benzoic acids [15].
In the present work, 4-N-bicyclo [2.2.1] hept-2ꢀ-en-2ꢀ-amino-N-
azatricyclo [3.2.1.02,4] octane (2) was synthesized and the structural
properties were calculated by DFT and Hartree-Fock (HF) calcu-
∗
Corresponding author. Tel.: +98 311 7380003; fax: +98 311 7381002.
E-mail address: a teimouri@alumni.iut.ac.ir (A. Teimouri).
1386-1425/$ – see front matter © 2008 Elsevier B.V. All rights reserved.
doi:10.1016/j.saa.2008.06.043

1750
A. Teimouri et al. / Spectrochimica Acta Part A 71 (2009) 1749–1755
H5); 7.40 (1H, d, J = 8.10, H2, H6); 13C NMR (DMSO-d6): ı 146.85, 1C
(C1); 133.04, 1C (C4); 129.42, 2C (C2, C6); 120.57, 2C (C3, C5); m/z 224
(M+). Anal calc. for C6H4N6O2S: C, 32.14; H, 1.80; N, 37.48; found:
C, 32.06; H, 1.68; N, 37.26.
lations. The experimental spectra are compared with calculated
findings.
Literature survey also reveals that to the best of our knowledge
no HF/DFT frequency calculations and synthesis of compound (2)
have been reported to this date. Therefore, the present investigation
was undertaken to study the vibrational spectra of this molecule
and to identify the various normal modes with greater wave num-
ber accuracy. Ab initio and DFT calculations have been performed
to support our wave number assignments.
2.2.3. Reaction of [4-(sulfonyazide)phenyl]-1-azide (1) with
norbornene
Norbornene (0.84 g, 8.92 mmol) was dissolved in dry (with
P2O5) acetonitrile (15 ml) and mixed with a solution of [4-
(sulfonyazide)phenyl]-1-azide (1) (1 g, 4.46 mmol) in dry acetoni-
trile (15 ml). After stirring for 60 min, the reaction mixture was
refluxed for 120–180 min (under N2 atmosphere), after completion
of the reaction, the precipitate was filtered and chromatographed
on silica gel, the product was eluted with cyclohexane–ethyl acetate
80:20 to give white-yellow solid 4-N-bicyclo [2.2.1] hept-2ꢀ-en-2ꢀ-
amino-N-azatricyclo [3.2.1.02,4] octane (2) which was purified by
recrystallization using petroleum ether–dichloromethane. Yield:
52%; m.p. 86–88 ◦C; FTIR (KBr) 3372, 2968, 2873, 1569, 1521, 1384,
2. Experimental and theoretical methods
2.1. General method
4-Acetamidobenzenesulfonyl chloride was procured from
Merck. Norbornene and solvents were purchased from Merck. IR
spectra were recorded on a JASCO FT/IR-680 PLUS spectrometer
using KBr pellet technique. NMR spectra recorded on a Bruker 500
ultrasheild NMR and CDCl3 and DMSO-d6 used as solvent. Mass
spectra were determined on a Uk Fisons Trio 1000 spectrome-
ter using electron impact at 70 eV. UV spectra were recorded on
a JASCO V-570 UV/Vis/NIR spectrophotometer with some solvent.
The elemental analysis was determined at the central laboratory,
Isfahan University, Isfahan, Iran. The melting points were obtained
on a Gallenkamp apparatus and are not corrected. Analytical TLC
was performed on Silica Gel F254 plates (Merck) and column chro-
matography Merck silica gel 60 (40–63 ␮m 230–400 ASTM) was
used.
1147, 975, 932, 867, 591 cm−1 1H NMR (DMSO-d6): ı 7.44 (2H, d,
;
J = 8.83 Hz, Hq); 6.68 (1H, d, J = 5.84, Hi); 6.61 (2H, d, J = 8.84, Hp);
5.90 (1H, s, Hr); 2.88 (2H, s, Ho, n); 2.71 (2H, d, J = 6.5, Hg, h); 2.33
(2H, s, He, f); 1.88 (2H, d, J = 7.24, Hl); 1.37 (2H, d, J = 7.89, Hd); 1.17
(3H, d, J = 7.67, Hb, j, k); 0.92 (2H, m, Hm); 0.84 (2H, t, Hc); 0.68 (1H,
d, J = 9.5, Ha); 13C NMR (DMSO-d6): ı 152.78, 1C (C3 ); 143.72, 1C
ꢀ
(C8); 132.33, 1C (C11 ); 129.25, 1C (C10); 121.79, 1C (C9); 112.29, 1C
ꢀ
ꢀ
(C2 ); 69.40, 1C (C7 ); 44.71, 2C (C2, 3); 40.46, 2C (C1, 4 ); 35.23, 2C
ꢀ
ꢀ
ꢀ
(C6, 5); 30.88, 1C (C4 ); 27.73, 1C (C1 ); 25.09, 1C (C7); 22.87, 1C (C6 );
+
ꢀ
21.98, 1C (C5 ); m/z 356 (M ). Anal calc. for C6H24N2O2S: C, 67.38; H,
6.79; N, 7.86; found: C, 67.28; H, 6.57; N 7.68. Electronic absorption
spectra in dichloromethane (nm, log ε): ꢀmax = 210 (1.6), ꢀmax = 236
(0.92) and ꢀmax = 310 (1.12).
2.2. Synthesis
2.2.1. Synthesis of 4-acetamidobenzenesulfonyl azide
3. Computational details
4-Acetamidobenzenesulfonyl chloride (48.6 g, 208 mmol) was
dissolved in 500 ml acetone and the solution was cooled to tem-
perature of 0 ◦C over a period of 60 min. A chilled aqueous solution
of sodium azide (20 g, 312 mmol, 200 ml) was added dropwise
and the resultant solution allowed to stir for a further 60 min
at that temperature. The solution was then poured onto an
ice/water slurry (1.5 l) and the white precipitate was collected at
the pump, washed with ice-cold water and dried under vacuum,
4-acetamidobenzenesulfonyl azide could be used in the next step
directly, recrystallized from a solution of acetone and water giving
4-acetamidobenzenesulfonyl azide as white crystals, Yield: 75%;
m.p. 108–110 ◦C; FTIR (KBr) 2125, 1674, 1160 cm−1; 1H NMR (DMSO-
d6): ı 8.4 (1H, s, NH), 7.82 (4H, d, J = 8.3 Hz, phenyl), 2.23 (3H, s, CH3);
13C NMR (DMSO-d6): ı 169.5, 144.1, 132.3, 128.9, 119.6, 24.7; m/z
240 (M+).
The molecular structure of this compound in the ground state
is optimized by HF, Becke 3-Lee-Yang-Parr (B3LYP) functionals
[16,17] and by combining the results of the Gaussview program [18],
with symmetry considerations, vibrational frequency assignments
were made with a high degree of accuracy. There is always some
ambiguity in defining internal coordination. However, the defined
coordinate form complete set and matches quite well with the
motions observed using the Gaussview program. Finally, the calcu-
lated normal mode vibrational frequencies, the visible absorption
maxima, NMR and thermodynamic properties were also calcu-
lated with these methods. These calculations were performed at
Hartree-Fock (HF) and B3LYP levels on a Pentium IV/3.6 GHz per-
sonal computer using Gaussian 03 W [19] program package, Initial
geometries are obtained with PM3 method based on Hyperchem
7.02 package [20].
2.2.2. Synthesis of [4-(sulfonyazide)phenyl]-1-azide (1)
4-Acetamidobenzenesulfonyl azide (2.4 g, 10 mmol) and 10 ml
concentrated HCl was heated at reflux for 35 min, the resulting
solution was cooled in an ice/salt bath to 0 ◦C. The solution was
diazotized with a solution of sodium nitrite (0.76 g, 11 mmol) in
water (20 ml), with the temperature maintained below 5 ◦C, and
then stirred for a further 30 min in the cold. The solution was then
neutralized with a saturated sodium bicarbonate solution. Sodium
azide (15 mmol) in water (15 ml) was added slowly to a stirred
suspension of (10 mmol) diazonium salt. After stirring for an addi-
tional 30 min, the mixture was further neutralized with a saturated
sodium carbonate solution and then left to stir until precipita-
tion was deemed to be complete (2–3 h). The solid product was
filtered under suction, dried, and recrystallized from petroleum
ether–dichloromethane give white-yellow solid. Yield: 65%; m.p.
37–39 ◦C; FTIR (KBr) 3092, 2323, 2256, 2129, 1582, 1366, 1169, 830,
Initial geometry generated from standard geometrical param-
eters was minimized without any constraint in the potential
energy surface at Hartree-Fock level, adopting the standard 6-
31G* basis set. This geometry was then re-optimized again at
B3LYP level, using basis set 6-31G* for better description. The
optimized structural parameters were used in the vibrational fre-
quency calculations at the HF and DFT levels to characterize all
stationary points as minima. Then vibrationally averaged nuclear
positions of this compound were used for harmonic vibrational
frequency calculations resulting in IR frequency together with
intensities. Vibrational frequencies for these species are calculated
using these methods and then scaled by 0.8991 and 0.9663 for
HF/6-31G* and B3LYP/6-31G* [21]. CIS and the time-dependent
density functional theory (TD-DFT) calculations of electronic
absorption spectra were also performed on the optimized
structure.
750, 609 cm−1 1H NMR (DMSO-d6): ı 7.99 (2H, d, J = 8.12 Hz, H3,
;

A. Teimouri et al. / Spectrochimica Acta Part A 71 (2009) 1749–1755
1751
Scheme 1. Reaction pathway for the synthesis of compound (2).
Table 1
Selected calculated bond distances (Å), bond angles (◦) and torsional angles (◦) of optimized (2)
Parameters
HF/6-31G*
B3LYP/6-31G*
Parameters
HF/6-31G*
B3LYP/6-31G*
Bond lengths (Å)
C1–C2
C3–C4
C1–C7
C4–C7
C5–C6
C2–C3
C6–C1
C5–C4
1.505
1.506
1.540
1.536
1.560
2.369
1.549
1.545
1.521
1.526
1.537
1.540
1.508
1.510
1.553
1.541
1.566
2.405
1.560
1.551
1.521
1.528
1.545
1.548
C5ꢀ–C6ꢀ
C2ꢀ–C3ꢀ
C6ꢀ–C1ꢀ
C5ꢀ–C4ꢀ
Cring–N
Cring–S
(C–C)ring
C1–H
C2–H
C7–H
C6–Hexo
C6–Hendo
1.556
1.327
1.552
1.558
1.372
1.746
1.373
1.083
1.066
1.085
1.086
1.086
1.569
1.349
1.565
1.528
1.382
1.759
1.384
1.083
1.066
1.085
1.086
1.086
C1ꢀ–C2ꢀ
C4ꢀ–C3
C1ꢀ–C7ꢀ
C4ꢀ–C7ꢀ
Bond angles (◦)
C1–C6–C5
C1–C2–C3
C1–C7–C4
C2–C1–C6
C4–C5–C6
C4–C3–C2
C5–C4–C3
C1ꢀ–C6ꢀ–C5ꢀ
C1ꢀ–C2ꢀ–C3ꢀ
C1ꢀ–C7ꢀ–C4ꢀ
C2ꢀ–C1ꢀ–C6ꢀ
C4ꢀ–C5ꢀ–C6ꢀ
104.9
89.2
99.2
33.2
104.3
32.5
112.6
102.4
107.5
93.5
107.5
103.0
105.3
88.2
99.3
112.4
103.8
89.8
111.7
102.5
107.2
93.6
C4ꢀ–C3ꢀ–C2ꢀ
C5ꢀ–C4ꢀ–C3ꢀ
C7–C1–H
107.4
107.1
113.7
116.9
36.4
36.2
108.6
35.1
109.6
99.9
101.8
100.5
107.3
106.9
112.9
116.9
36.3
36.1
108.6
35.0
107.2
99.5
101.2
100.4
C7ꢀ–C1ꢀ–H
H–C6–Hꢀ
H–C6ꢀ–Hꢀ
H–C7–Hꢀ
H–C7ꢀ–Hꢀ
C2–C1–C7
C2ꢀ–C1ꢀ–C7ꢀ
C6–C1–C7
C6ꢀ–C1ꢀ–C7ꢀ
107.3
103.0
Dihedral angles (◦)
C3ꢀ–N–C8–C9
12.9
−167.9
0.6
−113.6
15.3
−165.9
0.1
N–S–C11–C10ꢀ
C1–C2–C3–C4
H–C2–C3–H
H–C1–C4–H
−96.0
−3.7
−101.2
−5.2
C3ꢀ–N–C8–C9ꢀ
C4ꢀ–C3ꢀ–C2ꢀ–C1ꢀ
N–S–C11–C10
−35.6
−177.6
−65.8
−140.5
77.7
4. Results and discussion
similar molecular structure (phenyl ring with arensulfonyl group)
1.385–1.400 Å [22]. The optimized Cring–N bond length by two
4.1. Molecular structure, optimized geometry
methods are 1.372 Å for HF/6-31G* method and 1.382 Å for B3LYP/6-
31G* method, which is slightly shorter than that in compound
The general route for the synthesis of 4-N-bicyclo [2.2.1]
hept-2ꢀ-en-2ꢀ-amino-N-azatricyclo [3.2.1.02,4] octane (2) is shown
in Scheme 1. The optimized structure parameters of this com-
pound calculated by ab initio and DFT/B3LYP levels with the
6-31G* basis set are listed in Table 1. The aim of this study is
to give optimal molecular geometry and vibrational modes of
compound (2).
The optimized configurations are shown in Fig. 1. Since the crys-
tal structure of this compound (2) is not available, the optimized
structure can be only being compared with other similar systems
for which the configurations have been optimized [22]. For exam-
ple, the optimized bond lengths of C–C in phenyl ring fall in the
range from 1.373–1.404 Å for HF/6-31G* method and 1.384–1.414 Å
for B3LYP/6-31G* method, which are in good agreement with a
Fig. 1. The optimized structure of (2) performed by B3LYP/6-31G* method.

1752
A. Teimouri et al. / Spectrochimica Acta Part A 71 (2009) 1749–1755
with a similar molecular structure [23]. For the bond of Cring–S,
the optimized lengths (see Table 1) are slightly shorter than that
in compound with a similar molecular structure (1.746 Å for HF/6-
31G* method and 1.759 Å for B3LYP/6-31G* method) [22]. Based on
above comparison, although there are some differences between
our values and the literature data, the optimized structural param-
eters can well reproduce the literature ones and they are the bases
for thereafter discussion.
There are three types of CC bonds involved in these species,
i.e.
C C double bonds (e.g. C(2)–C(3), strained C–C single
bonds (e.g. C(1)–C(7)) and –C–C single bonds (e.g. C(1)–C(2)),
which associates with three types of C–H bonds. The CC bond
lengths of norbornene are in the order: rC C < r–C–C < rC–C, e.g.
C(2)–C(3) < C(1)–C(2) < C(1)–C(7). The C(1)–H bond length is 1.083
and the C(7)–H bond length is 1.085. The bridge (C(1)C(7)C(4))
of the bicyclic carbon skeleton is known as the methano bridge
whereas the six-membered ring is the so-called ethano ring. In
the carbon skeleton, angle ∠C(1)C(7)C(4) is called the bridge angle,
which links to the single bonded carbon C(7) (methano carbon),
whereas ∠HC(7)H, together with angles ∠HC(5)H and ∠HC(6)H in
norbornene are called flap angles [1]. All those flap ∠HCH angles,
except for the ∠HC(7)H angle, are positioned on the ethano ring.
Hydrogen atoms of the flap angles in the bridge side are called
Hexo and those towards the other side of the bridge are called Hendo
[24]. The optimized bridge angles of ∠C(1)C(7)C(4) are 99.2◦ for
HF/6-31G* method and 99.4◦ for B3LYP/6-31G* method, which are
in good agreement with norbornene were given by 92.4◦ [25] and
95.4◦ [26].
Fig. 3. Predicted spectra of (2) at B3LYP/HF/6-31G* levels.
The calculated frequencies are slightly higher than the observed
values for the majority of the normal modes. Two factors may be
responsible for the discrepancies between the experimental and
computed spectra of this compound (2). The first is caused by the
environment and the second reason for these discrepancies is the
fact that the experimental value is an anharmonic frequency while
the calculated value is a harmonic frequency [27]. The benzene
ring modes predominantly involve C–C bonds and the vibrational
frequency is associated with C–C stretching modes of carbon skele-
ton. The C–C stretching modes, known as semi-circle stretching,
predicted at 1510–1660 cm−1 is in excellent agreement with exper-
imental observation of FT-IR value at 1520–1640 cm−1. The ring
breathing mode at 630 cm−1 coincides satisfactorily with a very
weak band at 670 cm−1 [28].
4.2. Vibrational frequency
The observed experimental FT-IR spectra and theoretically pre-
dicted IR spectra are shown in Figs. 2–3. The vibrational frequency
and approximate description of each normal modes obtained using
HF and DFT/B3LYP methods with 6-31G* basis set are given for this
compound in Table 2.
The aromatic structure shows the presence of C–H stretching
vibrations in the region 2900–3150 cm−1 which is the characteristic
In our study, vibrational frequencies calculated at B3LYP/6-31G*
level were scaled by 0.96 and those calculated at HF/6-31G* level
were scaled by 0.89 [21]. Gaussview program [18] was used to
assign the calculated harmonic frequencies. On the basis of the
comparison between calculated and experimental results, assign-
ments of fundamental modes were examined. The assignment
of the experimental frequencies are based on the observed band
frequencies in the infrared spectra of this species confirmed by
establishing one to one correlation between observed and theo-
retically calculated frequencies.
Table 2
Comparison of the observed and calculated vibrational spectra of (2)
HF (I)
B3LYP (I)
Exp.
Assignment
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
3448(36.4)
3095(14.2)
3020(14.1)
2953(29.0)
2934(41.1)
2931(122.3)
2928(40.4)
2926(60.2)
2915(41.3)
2910(56.3)
2904(7.7)
2874(56.7)
2873(36.4)
1657(265.1)
1595(597.9)
1579(26.2)
1509(257.2)
1490(0.0)
1488(15.0)
1481(27.0)
1307(50.2)
1113(100.3)
1070(152.7)
1014(26.2)
933(56.7)
892(16.4)
632(46.1)
526(166.3)
3453(24.7)
3134(1.9)
3372
3123
3097
–
–
3001
–
ꢁasym.(NH)
ꢁ(CH)
ꢁ(CH)
ꢁ(CH)
ꢁ(CH)
ꢁ(CH)
ꢁ(CH)
ꢁ(CH)
ꢁ(CH)
ꢁ(CH)
ꢁ(CH)
ꢁ(CH)
ꢁ(CH)
ꢁring
ꢁring
ꢁring
ꢁring
ꢁ(CH2)
ꢁ(CH2)
ꢁasym.(SO2)
ꢁ(CN)
ꢁsym.(SO2) + ꢁ(CN)
ꢂ(CH) + ꢂ(CN)
ꢂ(SN) + ꢂ(CH)
ꢂ(CS) + ꢂ(CN)
ꢂ, para
3089(13.6)
3022(19.5)
3004(37.1)
3002(67.9)
2998(52.01)
2997(43.8)
2987(29.4)
2980(36.7)
2974(16.0)
2943(44.2)
2939(67.8)
1624(247.7)
1587(554.5)
1560(12.0)
1495(154.9)
1484(0.3)
1480(7.8)
1472(32.8)
1286(1.2)
1103(314.5)
1050(68.5)
1011(16.5)
938(36.8)
885(29.2)
680(28.6)
521(86.1)
2993
–
2973
2968
2931
2873
1631
1569
1521
–
1472
1437
1384
–
1147
1010
975
928
893
669
591
ꢂ(CS) + ꢂ(CN) + ıring
ꢂring+ ω(SO2)
ꢁ, stretching; ı, in-plane bending; ꢂ, out of plane bending; ω, wagging. Subscript:
Fig. 2. FT-IR spectra of (2).
asym., asymmetric; sym., symmetric.

A. Teimouri et al. / Spectrochimica Acta Part A 71 (2009) 1749–1755
1753
Table 3
Experimental and theoretical electronic absorption spectra values
Exp.
Calculated, ꢀcal (nm) CIS
Wave length (nm)
Calculated, ꢀcal (nm) TD
Wave length (nm)
Calculated, ꢀcal (nm) ZNIDO
Oscillator strength
Oscillator strength
Wave length (nm)
Oscillator strength
210, 236, 310
187.69, 212.97, 309.06
0.0091, 0.3699, 0.0550
356.84, 476.11, 588.15
0.0136, 0.0057, 0.0233
385.57, 395.16, 790.43
0.1600, 0.2492, 0.0012
Table 4
region for the ready identification of the C–H stretching vibrations.
In this region, the bands are not affected, appreciably by the nature
Experimental and calculated 1H NMR chemical shifts (ppm) of (2)
of the substituents. The vibrations in this region (2900–3150 cm−1
)
Proton
B3LYP
HF
Exp.
are in agreement with experimental assignment 2870–3130 cm−1
[29,30]. The out-of-plane bending of C–H predicted region of
1040–1060 cm−1 at B3LYP/6-31G*, while the calculations at HF level
give the frequency values of 1050–1070 cm−1, slightly on the higher
side of expected region.
The calculations also show that the ꢂ(CH) vibrations are not
pure and contain significant contributions of other modes (ꢁ(SN)
and ꢂ(CN)). The stretching ꢁ(C–N) vibrations could be observed for
the compound studied in a broad energy range, depending on the
␲-bonding nature of the C–N bond. Single ꢃ(C–N) bonding appears,
for the example, in the azoaromatic compounds.
The S–N stretching vibration exhibits a moderate band in the
region 1010–1020 cm−1, the band observed at this region is not pure
ꢁ(SN) vibration and contains a significant contribution of ꢂ(CH)
mode. The observed bands 1320–1470 and 1100–1120 cm−1 were
assigned to the ꢁ(SO2)asym. and ꢁ(SO2)sym. modes, respectively.
The bands at 510–530 cm−1 was assigned to, the SO2 scissors and
SO2 wagging vibration, and has partly overlapped in this region,
calculations show that ω(SO2) vibration contains a considerable
contribution with ␲ ring [31]. The major bands (630–890 cm−1
region) relates to S–C stretch.
Hq
Hp
Hg
Hi
Hr
Hh
Hn
Ho
Hc
Hf
Hd
He
Hm
Hl
Hc
Hd
Hj
7.28
6.26
4.70
4.56
4.42
4.22
2.91
2.39
2.14
2.00
1.95
1.93
1.70
1.62
1.58
1.49
1.46
1.38
1.23
1.10
1.07
0.68
8.00
6.98
5.42
5.27
5.13
4.93
3.63
3.10
2.86
2.72
2.66
2.66
2.42
2.34
2.29
2.20
2.17
2.10
1.94
1.82
1.78
1.41
7.44
6.61
2.71
6.68
5.9
2.71
2.88
2.88
0.84
2.33
1.37
2.33
0.92
1.88
0.84
1.37
1.17
0.92
1.17
1.88
1.17
0.68
Hm
Hb
Hl
Hk
Ha
ular symmetry. Due to that fact, in Fig. 4, seven carbon peaks are
observed in 13C NMR spectrum of (2). The 1H NMR spectrum (Fig. 4)
of (2) shows that total the numbers of protons are in agreement with
the integrated experimental values. Chemical shifts were reported
in ppm relative to TMS for 1H and 13C NMR spectra. 1H and 13C NMR
spectra were obtained at a base frequency of 125.76 MHz for 13C
and 500.13 MHz for 1H nuclei. Relative chemical shifts were then
estimated by using the corresponding TMS shielding calculated in
advance at the same theoretical level as the reference.
4.3. Electronic absorption spectra
Experimental electronic spectra measured in dichloromethane
solution and the calculated (B3LYP/6-31G* level optimized struc-
ture) electronic absorption spectra are listed in Table 3. The
theoretical electronic spectra have a broad band from 304 to
308 nm, which is different from the experimental peak at 312 nm.
Molecular orbital coefficients analyses based on the optimized
geometry indicate that the frontier molecular orbitals are mainly
composed of p atomic orbitals, so electronic transitions cor-
responding to above electronic spectra are mainly LUMO and
HOMO–LUMO for the title compound. In the HOMO, electrons are
mainly delocalized on aziridine group, while in the LUMO, electrons
are delocalized on aziridine, phenyl ring and enamine moiety. So,
the electronic spectra are corresponding to electronic transition of
the phenyl ring (transition of ␲–␲* type). Absorption maximums
(ꢀmax) were calculated by the CIS, TD and ZINDO methods.
Calculated 1H and 13C isotropic chemical shielding for TMS at
the HF, B3LYP/6-31G* level in methanol were 31.87 and 183.97 ppm,
respectively.
Table 5
Experimental and calculated 13 C NMR chemical shifts (ppm) of (2)
Carbon
B3LYP
HF
Exp
C10ꢀ
C10
C11
C8
115.92
116.79
118.02
130.64
134.27
41.64
42.27
98.18
98.75
100.15
15.89
21.39
21.69
31.55
32.57
32.57
35.33
36.72
37.45
43.35
133.42
134.34
135.54
148.19
151.78
39.15
38.76
115.68
116.26
117.67
33.38
38.91
39.21
49.06
50.09
50.24
52.84
54.24
54.97
60.92
129.25
129.25
132.33
143.72
152.78
44.71
44.71
121.79
112.29
121.79
25.09
21.98
22.87
40.46
35.23
40.46
27.73
30.88
35.23
69.4
C3ꢀ
C3
C2
4.4. NMR spectra
The experimental and theoretical values for 1H, 13C NMR, and
calculated structural parameters of compound (2) are given in
Tables 4 and 5. The theoretical 1H and 13C NMR chemical shifts
of compound (2) have been compared with the experimental data.
According to these results, the calculated chemical shifts and cou-
pling constants are in compliance with the experimental findings.
The correlation values carbon and proton chemical shifts are found
to be 0.9913 and 0.9919 for HF and B3LYP with the 6-31G* basis set,
respectively.
C9
C2ꢀ
C9ꢀ
C7
C5ꢀ
C6ꢀ
C1
C6
C4
C1ꢀ
C4ꢀ
C5
As shown in Fig. 1, compound (2) shows seven different carbon
atoms, which is consistent with the structure on the basis of molec-
C7ꢀ

1754
A. Teimouri et al. / Spectrochimica Acta Part A 71 (2009) 1749–1755
Fig. 4. (a) 1H NMR spectra and (b) 13 C NMR spectra of 4-N-bicyclo [2.2.1] hept-2ꢀ-en-2ꢀ-amino-N-azatricyclo [3.2.1.02,4] octane (2).
The experimental values for 1H and 13C isotropic chemical
4.5. Thermodynamic properties
shifts for TMS were 30.84 and 188.1 ppm, respectively [32]. All the
calculations were performed by using Gaussview molecular visu-
alization program and Gaussian 03 program package on a personal
computer.
On the basis of vibrational analyses and statistical thermo-
dynamics, the standard thermodynamic functions: heat capacity
(Cp0,m), entropy Sm0 and enthalpy Hm0 were obtained and listed in

A. Teimouri et al. / Spectrochimica Acta Part A 71 (2009) 1749–1755
1755
Table 6
Thermodynamic properties at different temperatures at HF/B3LYP/6-31G* levels
T (◦C)
Method
Etot (kcal/mol)
Htot (kcal/mol)
Stot (cal/(mol K))
Cv (cal/(mol K))
Gtot (kcal/mol)
HF
B3LYP
−895595.257
−900172.599
290.199
272.159
152.073
156.772
79.917
87.385
244.860
255.418
298
Table 7
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Zero-point energy
Rotational constant
277.142
0.08395
0.46200
0.08909
258.143
0.08339
0.43501
0.08976
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152.073
43.504
35.785
72.784
6.770
156.772
43.504
35.844
77.424
6.697
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Vibrational
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5. Conclusions
4-N-Bicyclo
[2.2.1]
hept-2ꢀ-en-2ꢀ-amino-N-azatricyclo
[3.2.1.02,4] octane (2) has been synthesized and characterized
by elemental analysis, IR, UV–vis, 1H NMR, 13C NMR and mass
spectrometry. The calculated vibrational frequencies and the
experimental IR spectra complement each other. The predicted
electronic absorption spectra have some blue shifts compared
with the experimental data and molecular orbital coefficients
analyses suggest that the electronic spectra are assigned to ␲ → ␲*
electronic transitions. The experimental and the theoretical inves-
tigation of compound (2) have been performed successfully by
using NMR and quantum chemical calculations. The computation
analysis of (2) by HF and B3LYP methods are in excellent agreement
with all the experimental findings.
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