Experimental Section
Apparatus
Shimadzu Infinity FTIR-Spectrometer equipped with three
reflectional ATR unit was used for IR spectra. The C, H and
N analysis were performed on Elemantar Vario Micro Cube
instrument. The mass spectra were obtained by Shimadzu
2010 plus with a Direct Insertion probe and electron impact
ionizer. DI temperature was varied between 40 and 140 oC
and the ionization was achieved with 70 eV electrons. The
NMR spectra were recorded on Bruker Ultrashield 300 MHz
NMR spectrometer. d6-Dimethyl Sulfoxide was the solvent.
The thermogravimetric analyses were performed with
Shimadzu DTG-60H. In thermogravimetric analyses,
temperature was varied between 30 and 600 oC. These
analyses were performed at 10 oC min-1. rate, under N2
atmosphere and in Pt pans. Calibration of the instrument was
done with metallic In, Pb and Zn. Used reactives were of
analytical grade or higher produced by Merck or Fluka
brands and they were used without further purification.
X-ray Study
Single crystals
of
1-phenyl-1H-tetrazole, 1(2chlorophenyl)-1H-tetrazole,
1(4-hydroxyphenyl)-1Htetrazole,
1(4-metoxyphenyl)-1H-tetrazole and 1(4nitrophenyl)-1H-tetrazole were analyzed on an Oxford
Diffraction Xcalibur (TM) Single Crystal X-ray
Diffractometer with a sapphire CCD detector using MoKα
radiation (λ=0.71073 Å) operating in ω/2θ scan mode. The
unit-cell dimensions were determined and refined by using
the angular settings of 25 automatically centered reflections
in 3.2926.36 range for 1-phenyl-1H-tetrazole,
2.9226.37
for
1(2-chlorophenyl)-1H-tetrazole,
3.0226.37
for
1(4-hydroxyphenyl)-1H-tetrazole,
3.1126.36 for 1(4-metoxyphenyl)-1H-tetrazole and
2.7626.37 for 1(4-nitrophenyl)-1H-tetrazole. All data
were collected at 293 (2) K. The empirical absorption
corrections were applied by the semi-empirical method via
the CrysAlis CCD software [1]. Models were obtained from
the results of the cell refinement and the data reductions
were carried out using the solution software SHELXL97 [2].
The structure of compound I, II, IV, V and VI were solved
by direct methods using the SHELXS97 software
implemented in the WinGX package [3].
Theoretical calculations
All theoretical calculations were carried out using Gaussian
G09W (revision B.01) software package [4].The structure
and frequency calculations were performed with Becke’s B3
parameter hybrid functional by using the LYP correlation
functional (B3LYP) [5]. For all H, C, N and O atoms, a
correlation consistent polarized double-zeta basis set was
used (cc-pVDZ) [6].The enthalpies (H) and free energies (G)
were calculated using the complete basis set (CBS) method
of Petersson and coworkers in order to obtain accurate
energies. The CBS models use the known asymptotic
convergence of pair natural orbital expressions to extrapolate
from calculations using a finite basis set to the estimated
CBS limit. CBS-4M begins with an HF/3-21G(d) geometry
optimization; the zero point energy is computed at the same
level. It then uses a large basis set SCF calculation as a base
energy level, and a MP2/6-31+G calculation with a
CBS extrapolation to correct the energy through second
order.A MP4(SDQ)/6-31+(d,p) calculation is used to
approximate higher order contributions. In this study, we
applied the modified CBS-4M method (M referring to the
use of minimal population localization), which is a
reparametrized version of the original CBS-4M
methodand also includes some additional empirical
corrections [7,8].
Preparation of tetrazoles
All tetrazoles were prepared from aniline or substitutedanilines in acetic acid medium containing sodium azide
and triethyl orthoformate [9]. Triethyl orthoformate was
used as carbon donor. Preparation conditions and spectral
characterization of tetrazoles are given below.
1-phenyl-1H-tetrazole (I): Aniline (2.60g, 0.028 mol),
triethyl orthoformate (6.70 g, 0.045mol) and sodium
azide (2.73 g, 0.042mol) were put to react in 25 mL acetic
acid under reflux and N2 atmosphere at 75- 78 0C for
about 9 hours. All remaining solvent was evaporated. The
residual solid was rinsed with HCl and NaHCO3
consequently. Hexane was added to the organic residue
for crystallization. Melting point of C 7H6N4: 64.86 Yield:
50%
Elemental Analysis data:
Theoretical percentages: % C:57.53, H:4.13, N:38.32;
Experimental findings: % C:57.17, H:3.84, N:37.49.
IR data (cm-1): 3128, 3092, 3051, 1516, 1488, 1215,
1190, 1091, 996, 853, 827.
1
H NMR data: 10.12 (s, 1H), 7.86 (d, 2H, J= 9 Hz), 7.67
(d, 2H, J=8 Hz), 7.58 (t, 1H, J=9Hz)
13
C NMR data: 118.56, 121.59, 123.39, 129.08, 130.15,
134.23 (Ar), 142.71 (-CH)
m/z: 147 (M+1), 146 (MP), 118 (BP), 104, 91, 77
1(2-chlorophenyl)-1H-tetrazole (II): 2-chloroaniline
(3.44 g, 0.030 mol), triethyl orthoformate (11.8 g, 0.080
mol) and sodium azide (5.27 g, 0.080 mol) were put to
react in 100 mL acetic acid under reflux and N2
atmosphere at 75- 78 0C for about 14 hours. At the end of
this period, the solution was mixed with 200 mL ice
water mixture and white solid crystalline precipitate was
filtered, air dried and recrystallized in dioxane. Melting
point of C7H5N4Cl: 89.01 0C Yield: 70 %
Elemental Analysis data:
Theoretical percentages % C:46.56, H:2.79 , N:31.01;
Experimental findings: % C:46.37 , H:2.58, N:30.76.
IR data (cm-1): 3122, 3090, 1492, 1460, 1203,
1175, 1082, 758.
1
H NMR data: 9.95 (s, 1H), 7.83 (t,d, 1H, J= 10 Hz),
7.72 (t,d, 1H, J=10 Hz ), 7.65 (d,d, 2H, J=10Hz)
13
C NMR data: 129.08, 129.37, 131.07, 133.01 (Ar)
145.45 (-CH)
m/z: 181 (M+1), 180 (MP), 152(BP), 125, 117,111, 90
1(4-chlorophenyl)-1H-tetrazole (III): 4-chloroaniline
(3.60 g, 0.030 mol), triethyl orthoformate (11.8 g, 0.080
mol) and sodium azide (5.27 g, 0.080 mol) were mixed in
100 mL acetic acid under reflux and N2 atmosphere at 7578 0C for about 14 hours. At the end of this period,
mixture was mixed with 200 mL ice water and formed
white solid was filtered, air dried and was recrystallized
in acetonitrile. Melting point of C7H5N4Cl: 162.61 0C
Yield: 70 %.
Elemental Analysis data:
Theoretical percentages % C:46.56, H:2.79 , N:31.01;
Experimental findings: % C:46.19 , H:2.55, N:30.13.
IR data (cm-1): 3121, 3096, 3076, 1611, 1518, 1393, 1279,
1201, 1176, 1089, 830,721
1
H NMR data: 10.15(s, 1H), 7.96 (d, 2H, J= 12 Hz), 7.75
(d, 2H, J=12 Hz )
13
C NMR data: 123.29, 130.48, 133.04, 134.51 (Ar),
142.77 (-CH)
m/z: 180 (MP), 167, 152(BP), 125, 117,111, 90
1(4-hydroxyphenyl)-1H-tetrazole
(IV):
4hydroxyaniline (3.27 g, 0.030 mol), triethyl orthoformate
(11.8 g, 0.080 mol) and sodium azide (5.27 g, 0.080 mol)
were put to react in 50 mL acetic acid under reflux and N 2
atmosphere at 75- 78 0C for about 9 hours. At the end of
this period, the precipitate was filtered, air dried and was
recrystallized with MeCN:EtOH (V/V) (50/20) Melting
point of C7H6N4O: N/A (due to decomposition before
melting)
Yield: 80 %.
Elemental Analysis data:
Theoretical percentages % C:51.86, H:3.73 , N:34.54;
Experimental findings: % C:52.07 , H:3.58, N:33.94.
IR data (cm-1): 3117, 3091, 3074, 1600, 1517, 1460, 1276,
1209, 1170, 1087, 829, 719
1
H NMR data: 9.91 (s, 1H), 7.63 (d, 2H, J= 10 Hz), 6.89
(d, 2H, J=10 Hz )
13
C NMR data: 116.69, 123.54, 125.96, 159.08 (Ar),
142.52 (-CH)
m/z: 162 (MP), 134, 119(BP), 105,78
1(4-methoxyphenyl)-1H-tetrazole (V): methoxyaniline
(3.44 g, 0.030 mol), triethyl orthoformate (11.8 g, 0.080
mol) and sodium azide (5.27 g, 0.080 mol) were put to
react in 50 mL acetic acid under reflux and N2 atmosphere
at 75- 78 0C for about 17 hours. At the end of this period,
formed solid substance was filtered; air dried and
recrystallized in acetonitrile. Melting point of C8H8N4O:
119.29 0C
Yield: 70 %.
Elemental Analysis data:
Theoretical percentages % C:54.54, H:4.58 , N:31.79;
Experimental findings: % C:54.35 , H:4.50, N:30.61.
Significant IR data (cm-1): 3128, 3101, 3068, 3014, 1612,
1597, 1517, 1456, 1249, 1209, 1170, 1010, 823
1
H NMR data: 9.98 (s, 1H), 7.81 (d, 2H, J= 10 Hz), 7.19
(d, 2H, J=10 Hz), 3.85 (s, 3H)
13
C NMR data: 56.03 (OCH3), 115.42, 123.21, 127.34,
160.39 (Ar), 142.50 (-CH)
m/z: 176 (MP), 148, 133 (BP), 121, 105, 77
1(4-nitrophenyl)-1H-tetrazole (VI): 4-nitroaniline (4.14
g, 0.030 mol), triethyl orthoformate (11.8 g, 0.080 mol)
and sodium azide (5.27 g, 0.080 mol) were put to react in
200 mL acetic acid under reflux and N2 atmosphere at 7578 0C for about 15 hours. At the end of this period, the
precipitate was filtered; air dried and recrystallized in
acetonitrile. Melting point of C7H5N5O2: N/A (due to
decomposition before melting)
Yield: 45 %.
Elemental Analysis data:
Theoretical percentages % C:43.99, H:2.64 ,
N:36.63; Experimental findings: % C:43.57, H:2.51,
N:35.28.
IR data (cm-1): 3140, 3091, 3074, 3061, 1612, 1595,
1517, 1506, 1438, 1338, 1209, 1087, 750
1
H NMR data: 10.12 (s, 1H), 8.52 (d, 2H, J= 12 Hz),
8.24 (d, 2H, J=12Hz )
13
C NMR data: 122.75, 125.59, 138.63, 147.87 (Ar),
143.16 (-CH)
m/z: 207, 192, 191 (MP), 163, 133 (BP), 117,105, 90
1(2-pyridil)-1H-tetrazole (VII): 2-aminopyridine
(5.64 g, 0.060 mol), triethyl orthoformate (23.6 g,
0.160 mol) and sodium azide (10.40 g, 0.160 mol)
were put to react in 100 mL acetic acid under reflux
and N2 atmosphere at 75- 78 0C for about 14 hours.
At the end of this period, the white precipitate was
filtered; rinsed with water and air dried. Melting
point of C6H5N5:128.86 0C, Yield: 55 %
Elemental Analysis data:
Theoretical percentages % C:48.98, H:3.42 ,
N:47.58; Experimental findings: % C:48.73 , H:3.66,
N:45.97.
IR data (cm-1): 3128, 3092, 3051, 1512, 1488, 1215,
1190, 1091, 996, 853, 827
1
H NMR data: 10.20 (s, 1H), 8,65 (d, 1H, J=7Hz),
8.19 (t, 1H, J= 10 Hz), 8.08 (d, 1H, J= 12Hz), 7.65
(q, 1H, J= 7 Hz)
13
C NMR data: 115.40, 125.75, 141.32, 141.99,
146.94 (Pr), 149.66 (-CH)
m/z: 147 (MP), 119, 92, 78 (BP)
Bis-1,4-tetrazol-1-yl
benzene
(VIII):
1,4phenylenediamine (1.512 g, 0.015 mol), triethyl
orthoformate (11.8 g, 0.080 mol) and sodium azide
(5.27 g, 0.080 mol) were put to react in 100 mL
acetic acid under reflux and N2 atmosphere at 75- 78
0
C for about 72 hours. At the end of this period,
formed solid substance was filtered and air dried.
Melting point of C8H6N8: N/A (due to decomposition
before melting) Yield: 40 %
Elemental Analysis data:
Theoretical percentages % C:44.87, H:2.82 ,
N:52.30; Experimental findings: % C:44.71, H:2.53,
N:51.29
IR data (cm-1): 3128, 3093, 3053, 1527, 1485, 1213,
1188, 1089, 995, 852, 827
1
H NMR data: 10.10 (s, 2H), 8.25 (s, 4H)
13
C NMR data: 122.39, 134.65 (Ar), 142.95 (-CH)
m/z: 214 (MP), 203, 187, 158, 149,134, 104 (BP),
90, 77
References
[1] Oxford Diffraction, CrysAlis CCD and CrysAlis RED.
Version 1. 170. 14. Oxford Diffraction, Oxfordshire,
England (2002).
[2] G.M. Sheldrick, SHELXS97 and SHEXL97 Program
for Crystal Structure Solution and Refinement,
University of Gottingen, Germany (1997)
[3] L.J. Farrugia, WinGX Program for Crystallography
Package, J. Appl. Cryst. 32 (1999) 837.
[4] Gaussian 09, Revision B.01, Gaussian, Inc.,
Wallingford CT, USA, (2009)
[5] A.D. Becke, Correlation Energy of an Inhomogeneous
Electron Gas: A Coordinate‐space Model, J. Chem.
Phys. 88 (1988) 1053-62.
[6] D.E. Woon, T.H. Dunning Jr., TH. Gaussian Basis Sets
for Use in Correlated Molecular Calculations. III. The
Atoms Aluminum through Argon, J. Chem. Phys. 98
(1993) 1358 – 71.
[7] W.D. Ochterski, G.A. Petersson, J.A. Jr. Montgomery,
A Complete Basis Set Model Chemistry. V.
Extensions to Six or More Heavy Atoms, J. Chem.
Phys. 104 (1996) 2598 –2619.
[8] J.A. Jr Montgomery, M.J. Frisch, J.W. Ochterski, G.A.
Petersson, A Complete Basis Set Model Chemistry.
VII. Use of the Minimum Population Localization
Method, J. Chem. Phys. 112 (2000) 6532 - 42.
[9] Y. Satoh, N. Marcopulos, Application of 5Lithiotetrazoles in Organic Synthesis, Tetrahedron
Letters 36 (1995) 1759-62.