Iraqi J. Chem., 28, 4, 2002
Quantum Mechanics Study of Crown Ethers by PM3
I. Conformational Analysis for Molecules of Very Small Cavity Sizes:
6-Crown–2 and their benzo and cyclo derivatives
Bahjat R. J. Muhyedeen
Department of Chemistry, College of Science
University of Baghdad, Jadriyah, Baghdad, Iraq.
‫الخالصة‬
‫ مددددل بددددال ب ددددط‬PM3 ‫ بو ددددطرة ر قددددة‬6-Crown-2 ‫دددد ل قددددة‬
‫الو ددددكو والسددددط و و ث ددددط‬
‫وان رط دددة شاادددط وال ماردددة‬
‫دددد ب ددددز ط ملدددداقطن الو ددددكو و ث ددددط‬
‫الز ادددوي بطا زدددط اهددد ط‬
‫ددد والقدددطك‬
‫ال‬
‫لقدددد رددددا شكا ددددة اللدددد‬
‫م‬
‫وحسددددط ثالثددددة علدددد ول هدددد‬
‫السدددط وق لقددد ال ددد ةددد مدددل ماردددة ال‬
‫ددد اةاددد ا ددداق اكا مدددل القدددطك ق رمدددط ال اردددطن اتبددد ل ل دددلي ال قدددة ا طاددد اهددد ط اااقطلادددةق ال ال ط دددطن‬
‫ددد ر سدددا شوكا ا ط ددداط اددد‬
‫ال‬
‫ال سدددواة الز سدددوبة ةطاددد مقطكبدددة مدددب مدددط ةددد اددد اتشبادددطن ق ةزدددط رل ماردددة ال‬
‫ا اق اك الز ةوطن الزلاقةق‬
Abstract
The conformational behavior of 6–Crown–2 rings has been studied
by using the PM3 method. A total of twenty-three geometrical structures
were studied including benzo, dibenzo, cyclohexyl and dicyclohexyl
derivatives. The 1,4-chair, 2,5-chair, 1,4-boat, 1,4- twist-boat, 2,4- half–
chair and 2,5- twist boat conformers show energy minima with the former
having lowest energy. The 2,5-boat, 2,5-sofa and 1,4-half- chair
conformers are transition state structures while 1,4-sofa and planar
conformer are not ground state structures. The relative energies are in good
agreement with literature values. The chair form of the crown moiety has
1
Bahjat R J Muhyedeen
the major role in affecting the stability of cyclohexyl and dicyclohexyl
derivatives.
Introduction
Studies of the molecular geometries of cyclohexane and some of its
derivatives, 1,4-dix-cyclohexane (x= CH2, O and NH), e.g., 6–Crown–2 (or
1,4 dioxane) and piperazine, have contributed considerably to the
elucidation of the stereochemistry and conformational behavior of these
substances. Besides that, cyclic oxygenated hydrocarbons are important
intermediates in chemical processes such as combustion, photochemical
oxidation and biological degradation of hydrocarbons. The conformational
analysis of cyclohexane has been extensively studied and is well
understood
[1-8]
, while there has been comparatively little work reported on
6-Crown-2. The earlier study of electron diffraction in 1963 shows that
when oxygen or nitrogen is replacing methylene carbon atoms of
cyclohexane, the CCX angle is nearly tetrahedral and the chair
conformation of 6–Crown–2 becomes slightly more puckered than
cyclohexane
[9].
The study of ring inversion from chair to boat or vice versa
is very important in the investigation of the polar character of such
molecules in solution. Of course, ring symmetry lessens the polarity of the
molecule, thus, 1,3 is more polar than 1,4 -dix-cyclohexane. This fact was
studied and proved by Reisse et al., [10]. Although 6–Crown–2 is described
as a non-polar solvent by many authors, but in some cases it behaves like a
polar liquid since it is a good solvent for many polar substances and is
miscible with water in all proportions. This dual behavior is reported in
many works and is interpreted via H-bonds or conformation polarization
(from non-polar chair toward a polar boat) under the influence of a dipole
field
[11]
. In 1970 Pickett and Strauss calculated theoretically the ΔG#C for
2
Iraqi J. Chem., 28, 4, 2002
chair to twist-boat to be 42.2 kJ/mol using a potential function derived from
vibrational and geometrical data [12].
Independently in 1971 the energy barrier of ring inversion of 6Crown-2 was measured experimentally by Jensen et al., [13] and Anet et
al.,[14]. Jensen observed the changes in 13C NMR spectra of a 100 MHz 1Hspectra while Anet measured the 1H NMR spectrum of hexadeuterio 6Crown-2 at low temperature. Both groups calculated ΔG#C for ring
inversion to be 40.6 kJ/mol. Hester and Chapman calculated the relative
energies for ten conformers using ab initio molecular orbital theory at
HF/6-31G* and BLYP/6-31G* levels
[15]
. They found the energy barrier for
chair to 2,5 twist-boat to be 29 kJ/mol.
To our knowledge no semiempirical study has been reported for 6Crown-2 conformers or its derivatives using PM3 method except chair
conformer[16]. In the present work we are interested in studying the
molecular geometries as well as the calculation of the relative energies and
thermodynamic properties of 6-Crown-2 (hereafter referred to as 6C2)
conformers and its derivatives of benzo and cyclo such as benzo-6C2,
dibenzo-6C2, cyclo-6C2 and dicyclo-6C2 (hereafter referred to as B6C2,
DB6C2, C6C2 and DC6C2 respectively) by the Quantum Mechanics (QM)
method. Also simple hybridization between Quantum Mechanics and
Molecular Mechanic (MM) is to be used through building and calculating
these structures. The vibrational analysis was used to identify the ground
state structures and the full data of fundamental frequencies will be
reported later.
3
Bahjat R J Muhyedeen
Calculation of Molecular Geometries
The optimized geometry of the molecule is found by minimization of
its total energy with respect to the full geometrical variables by RHF-SCF
treatment using PM3 method[17-19] in MOPAC2000 computer package[20].
The ring steric energy, ES, torsional strain energy, ETS, and the oxygen lone
pair energy, ELP, are estimated using a partial constrained routine work and
defined as follow:
ES =EUNCONS - ECONS(R,θ,φ)
ETS= EUNCONS - ECONS(φ)
ELP= EUNCONS - ECONS(2O)
Where:
EUNCONS
: The calculated energy with full optimization
ECONS(R,θ,φ): The calculated energy with constraint of bond distance, bond
angles and torsion angles of the crown ring only.
ECONS(φ)
: The calculated energy with constraint of torsion angles of the
crown ring only.
ECONS(2O) : The calculated energy with constraint of two oxygen atoms of
the crown ring only using internal coordinates and not xyz.
The relative energies are calculated as the difference between the
ECONS(φ) energies of eleven conformers because PM3 gives unacceptable
results in conformational energies when calculated in unconstraint routine.
Anderson et.al.[21] referred to this deficiency as an error when they
compared the results among PM3, AM1, AMBER and Ab initio methods.
4
Iraqi J. Chem., 28, 4, 2002
Building of Molecules
Twenty-three geometrical structures were built with the help of
plastic models to write down the torsional angles and were then redesigned
using Alchemy-II program. This program includes a minimization option
using a gradient technique or a molecular mechanics technique. This MM
technique performs a conjugate-gradient minimization on the selected
molecules and attempts to put the molecules into a minimal energy
conformation. The MM minimization was carried out for each structure and
the refined structure could then be used as starting coordinates for QM
minimization provided that it kept its torsional angles or point groups
unchanged through MM minimization.
Of course, the starting geometry is very important because it
determines the destiny of the final form. This point was frequently
examined in detail throughout the present work and it has been noticed that
any simple change in any starting geometrical parameter (r, θ, φ) would
result in a different final structure and an accurate building routine was
necessary for a comparative study of relative energies. Figures 1 & 2 show
their torsional angles. The adopted geometry parameters of the chair
structure of 6C2 were the average values of some references
[9,22]
, while the
adopted parameters of the two twist boat structures were approximately
similar to that mentioned by Chapman and Hester[15]. Other structures
parameters were suggested through this study due to the luck of knowledge
of their geometries. See Table-2 and Fig.-2.
I- 6-Crown-2
Eleven geometrical structures (I-XI) were built for 6C2, namely 1,4chair (C2h), 2,5-Chair (Ci), 1,4-boat (C2V), 2,5-boat (C2), 2,5-twist-boat
(C2), 1,4-twist-boat (D2), 1,4-sofa (CS), 2,5-sofa (C1), 1,4-half-chair (C2),
5
Bahjat R J Muhyedeen
2,5-half-chair (C2) and planar (D2h) conformers (see Fig-1). Among these
conformers only 1,4-chair and 1,4-boat remained unchanged through the
minimization process by MM method, while the other conformers showed
either slight deviation or completely converted to 1,4 chair or slightly
puckered 1,4 boat.
II- Benzo-6-Crown-2
One stable structure XII (CS) was built by addition of a benzo-ring
(*-C=C-*= 0o) to 1,4-boat moiety of 6C2 (*O-C-C-O*= -4o) (see Fig-1).
The addition of a benzo-ring to 1,4-chair moiety 6C2 (*O-C-C-O*= 54o)
lead to an unstable flat chair ring due to sp2-hybridization of a benzo-ring,
which could not fit to the chair form torsion ring phase of 54o difference to
benzo ring.
III- Dibenzo-6-Crown-2
Only one possible stable structure XIII C2V was built by addition of
two benzo-rings to 1,4-boat moiety of 6C2 in which the final appearance
looks like a bat-molecule (see Fig-1).
IV- Cyclo-6-Crown-2
In general, the cyclo–derivatives showed unusual flexibility and the
exact internal coordinates were required. Four structures (XIV-XVII) were
built by addition the two forms of cyclohexyl–moiety, viz., chair and boat,
to 1,4 chair–ring and 1,4 boat–ring of 6C2 to form C6C2 molecules of the
following
types:
CycloC+6C2C
(C1)
and
CycloC+6C2B
(C1),
CycloB+6C2C (C1), and CycloB+6C2B (CS). The capital bold subscript
letters C and B referred to chair and boat forms of both cyclohexyl and
crown molecules (see Fig-1). The cyclo–derivative structures of 6C2 were
6
Iraqi J. Chem., 28, 4, 2002
examined by QM as well as by MM method to investigate the structural
behavior of the crown ring when attached to the cyclohexyl–moiety.
V- Dicyclo-6-Crown-2
Six structures (XVIII-XXIII) were built by addition of the two forms
of cyclohexyl–moiety to 6C2C and 6C2B to form DC6C2 molecules (viz.,
Cyclomoiety+6C2ring+Cyclomoiety) of the following types:
CycloC–6C2C–CycloC (C-C-C, Cs) and CycloC–6C2C–CycloB(C-C-B, C1)
and CycloB–6C2C– CycloB (B-C-B, C1) and CycloC–6C2C–CycloC (C-B-C,
C1) and CycloC–6C2C–CycloB (C-B-B, C1) and CycloB– 6C2B–CycloC (BB-B, C2V). The bold letter refers to crown ring (see Fig-1).
Results and Discussion
The physical and thermodynamic properties of these molecules were
calculated. Table-1 shows the values of dipole moment, μ, heat of
formation, ΔH, entropy, ΔS, and heat capacity, ΔCp.
I- 6-Crown-2
Through full gradient optimization, only 2,5-chair, 1,4-sofa and 2,5sofa conformers were unstable and converted to 1,4- chair (C2h), but fixing
only one C-O-C angle the structure did not change its geometry. The
relative energies of eleven conformers were calculated by PM3 method
using a partial constrained routine. The lowest energy conformer was found
to be 2,5-chair (Ci) rather than 1,4-chair form of C2h symmetry. This Ci
symmetry could be regarded as a special configuration of chair form since
any small change in the internal coordinates will lead to conversion to C 2h
symmetry. The bond angles and torsion angles values are shown in Table-2
and Fig-2 respectively. The relative energies, ER, ES, ETS and ELP of these
eleven conformers are listed in Table-3 and shown in Fig.-4. The chair-boat
7
Bahjat R J Muhyedeen
energy difference is 2.799 Kcal/mol, which is in good agreement with
experimental value (2.6 Kcal/mol)[23]. Generally, the results show that the
2,5 structure is less stable than 1,4 structure except for chair conformer.
The most interesting point is that the 2,5-twist boat conformer is
more stable than 2,5-boat The energy components analysis showed that the
ETS and ELP for 2,5-twist-boat was less than that for 2,5-boat. Similar data
were found for 1,4-twist-boat comparing to 1,4-boat. The sofa conformers
have high relative energies even more than planar form. Among these
eleven conformers only the 1,4-twist-boat has a small value of ES.
The vibrational analysis of these conformers indicates that the 1,4sofa is not ground state but the 2,5-sofa is a transition state structure. Both
half-chair conformers have low relative energy but 1,4-half chair is a
transition state structure.
Most of the results obtained are in good agreement with the ab initio
study[15] reported by Hester and Chapman in 1997, but they found that 1,4
boat was a transition state and not an energy minimum which might be
related to starting torsional angles. Different starting parameters lead to
different results. They also found both sofa conformers were more stable
than planar.
II- Benzo–6–Crown–2
The crown moiety in BC62 molecule, XII, is found to be stable
through MM minimization and QM minimization, but the ring steric energy
is high (Ca. 38 Kcal/mole). The lone-pair energy (ELP=3.4 Kcal/mole) is
half of the ring torsional strain energy. Of course, this ring instability is
acquired form the sp2-sp3 bonds in the small size ring of the crown moiety
(see Fig.-3).
8
Iraqi J. Chem., 28, 4, 2002
III- Dibenzo–6–Crown–2
The crown moiety in DBC62 molecule XIII, C2V is unstable through
both MM and QM minimization when the gradient goes to 0.01, giving a
planar structure in which the crown moiety is transformed from boat to
planar structure with high strain structure (see Fig.-3). Nevertheless, the ES,
ETS and ELP values for C2V structure were smaller than that of benzo-boat,
which may refer to increased stability of crown ring moiety with two benzo
rings rather than with one benzo ring.
IV- Cyclo–6–Crown–2
The results of QM calculation of these structures show that the
crown-ring forms are stable through QM minimization.
One point worth noting is that the major contributors affecting the
stability of the structure are two factors:
First:
the priority to chair then to the boat forms of crown moiety.
Second: the similarity of the attached moieties of cyclohexyl to
crown moiety (i.e. like prefers like).
These results could be concluded from the comparison of structures
XVII, C-B, and XV, B-C. Fig.-4 shows the XIV, C-C is the lowest and XV,
B-C, is more stable than XVII, C-B, and XVI, B-B. The most unstable
structure is XVII, C-B, due to having two different moiety forms. Fig.-3
shows the torsional angles of these cyclo derivative structures and Table-3
shows ER, ES, ETS and ELP energies.
V- Dicyclo–6–Crown–2
The behavior of the crown ring when attached to two moieties of
cyclohexyl is similar to that when attached to one moiety of cyclohexyl,
9
Bahjat R J Muhyedeen
and the dominant contributors are the chair form and the similarity of the
attached moieties of cyclohexyl to crown moiety. The structures C-C-C,
C-C-B and B-C-B are more stable than B-B-B, C-B-B and C-B-C due to
the priority of the chair form of the crown ring in the first three structures.
The systematic increments in relative energies in these six structures are
due to dissimilarities of the moieties. Fig.-3 shows the torsional angles of
these dicyclo derivative structures and Table-3 shows ER, ES, ETS and ELP
energies. Fig.-4 shows the relative energies diagram for these structures.
The highest steric ring is C-B-C then C-B-B, even if the B-B-B has a
higher relative energy than C-C-C but it has a smaller ETS value.
Conclusion
The crown molecule 6C2 has six ground state conformers and three
transition state conformers with two non ground state conformers. The
lowest global energy was 2,5-chair. The crown moiety becomes more
strained when attached to benzo moiety and an sp2-sp3 hybridization arises
in the ring and this strain was decreased when attached to two benzo
moieties. In the cyclo and dicyclo derivative the chair form of crown
moiety is the major dominant contributor affecting the ring stability of the
molecule and the similarity of the attached moieties of cyclohexyl to crown
moiety is a minor contributor. The ES values of these 23 structures showed
consistent results and in general the ES values of the boat form were
smaller than the chair form. Both had systematic increments when there
was dissimilarity in the attached moieties.
The dicyclo 6-crown-2 looks like a cage molecule and it could be
postulated that in this form it may act as a specific reagent for molecules or
o
ions with 5 A diameter.
10
Iraqi J. Chem., 28, 4, 2002
Acknowledgements
The author wishes to express his gratitude to Prof. Dr. G.A. Derwish
for his valuable discussion. The financial support was from Al-Nawafith
Co. Ltd for sand and gravel filters.
References
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1990.
2- M. K. Leong, V. S. Mastryukov and J. E. Boggs, J. Phys. Chem., Vol.
98, pp.
6961, 1994.
3- L. Matyska and J. Koca, J. Comput. Chem. Vol. 15, pp. 937, 1994.
4- J. Koca, J. Mol. Struct. (THEOCHEM) Vol. 308, pp. 13, 1994.
5- D. M. Ferguson, I. R. Gould, W. A. Glauser, S. Schroeder and P. A.
Kollman, J. Comput. Chem. Vol. 13, pp. 525, 1992.
6- N.L. Allinger, J. A. Hirsch, M.A. Mille, I. J. Tyminsky, and F. A. Van
Catledge, J. Amer. Chem. Soc., Vol. 90,pp. 1199, 1968.
7- J. R. Hoyland, J. Chem. Phys., Vol.50, pp.2775, 1969.
8- J. E. Eilers, B. O’Leary, B. J. Duke, A. Liberles and D. R. Whitman, J.
Amer. Chem. Soc., Vo1.66, No.6, 1319-26, 1975.
9- M. Davis and O. Hassel, Acta Chem. Scand., Vol. 17, pp.1181, 1963.
10- J. Reisse, M. Claessens, O. Fabre, G. Michaus, M. L. Stien and
D. Zimmermann, Bull. Soc. Chim. Belg. Vol. 92, pp.819, 1983.
11- G. Perichet, R. Chapelan and B. Pouyet, J. Photochemistry.
12- H. Pickett and H. L. Strauss, J. Am. Chem. Soc. Vol. 92, pp. 7281,
1970.
13- F. R. Jensen and R. A. Neese, J. Am. Chem. Soc. Vol. 93, pp. 6329,
1971.
11
Bahjat R J Muhyedeen
14- F. A. L. Anet and J. Sandstrom, J. Chem. Soc. Chem. Comm., pp.
1558, 1971.
15- D. M. Chapman and R. E. Hester, J. Phys. Chem., A, Vol. 101, pp.
3382, 1997.
16- T. H. Lay, T. Yamada, P.-L. Tsai and J. W. Bozzelli, J. Phys. Chem.,
A, Vol. 101, pp. 2471, 1997.
17- J. J. P. Steward, J. Comput. Chem. Vol. 10, pp. 209, 1989.
18- J. J. P. Steward, J. Comput. Chem. Vol. 10, pp. 221, 1989.
19- E. Anders, R. Koch, and P. Freunscht, J. Comput. Chem. Vol. 14, pp.
1301, 1993.
20- J. J. P. Steward, MOPAC2000 V1.0 for Windows (Single), MO20-ASW, FUJITSU SYSTEM EUROPE
21- W. P. Anderson, P. Behm, and T. M. Glennon, J. Phys. Chem., A, Vol.
101, pp. 1920, 1997.
22- M. J. Bovill, D. J. Chadwick, and I. O. Sutherland, J. Chem. Soc. Chem
Perkin-Trans II, PP. 1529, 1980.
23- H. M. Niemeyer, J. Mol. Struct., Vol.57, pp. 241, 1979.
12
Iraqi J. Chem., 28, 4, 2002
TABLE-1 Heat of formation (Kcal/mol), ΔH, entropy (cal/K/mol), ΔS, and heat
capacity (cal/K/mol), ΔCp, dipole moment (debye), μ, ionization potential (eV), I.P.
and zero point energy (Kcal/mol), ZPE.
PG
C2h
Ci
C2v
C2
D2
C2
C2
C2
Cs
C1
D2h
nVib
0
0
0
1
0
0
1
0
2
1
3
μ
ΔH
ΔCp
ΔS
0.004
0.141
1.648
0.937
0.001
1.500
0.809
1.600
0.836
0.582
0.000
-83.205
-82.588
-80.384
-79.780
-79.675
-80.257
-79.740
-80.351
-65.737
-62.929
-72.967
22.380
21.7291
22.4082
22.7612
22.8737
22.7426
22.829
22.6037
22.4932
22.5990
22.4179
PG
Cs
nVib
2
1.333
-43.731
DIBENZO-BOAT
C2v
0
0.232
CYCLO- DERIVATIVE
nVib
CHAIR-CHAIR
PG
C1
0
BOAT -CHAIR
C1
BOAT -BOAT
CHAIR-BOAT
FREE CONFORMER
72.038
72.3188
73.1616
*
78.8488
77.4257
*
75.4738
*
*
*
I.P.
10.446
10.426
10.548
10.379
10.275
10.566
10.346
10.550
10.083
10.224
9.982
ZPE
73.974
75.099
74.064
*
73.353
73.509
*
73.720
*
*
*
32.4334
*
9.054
*
-9.546
41.8672
96.5379
8.657
105.56
9
0.221
-94.810
37.1151
89.3368
10.266
0
0.279
-92.049
37.3145
90.6997
10.279
Cs
C1
5
0
1.5244
1.200
-89.121
-92.522
29.136
*
90.1693
10.325
10.360
131.65
5
131.52
3
*
131.85
1
DICYCLODERIVATIVE
PG
nVib
CHAIR-CHAIRCHAIR
CHAIR-CHAIR-BOAT
Cs
0
0.391
-106.076
51.5973
104.2126
10.199
C1
0
0.337
-102.610
51.6493
104.3130
10.168
BOAT-CHAIR-BOAT
C1
0
0.095
-99.145
52.2162
108.8312
10.073
BOAT-BOAT-BOAT
CHAIR-BOAT-BOAT
CHAIR-BOAT-CHAIR
C2v
C1
C1
1
1
0
1.370
0.452
0.9050
-97.644
-99.653
-104.772
52.4929
51.9595
51.6756
*
*
105.8183
10.143
10.210
10.234
1,4-CHAIR
2,5-CHAIR
1,4-BOAT
2,5-BOAT
1,4-TWIST-BOAT
2,5-TWIST-BOAT
1,4-HALF-CHAIR
2,5-HALF-CHAIR
1,4-SOFA
2,5-SOFA
PLANAR
BENZO-DERIVATIVE
BENZO-BOAT
DIBENZODERIVATIVE
13
189.79
1
189.48
4
188.73
1
*
*
189.63
7
Bahjat R J Muhyedeen
Table 2 PM3 structural parameters for low-energy conformer of 6-Crown-2.
NAME
COMP.
BOND
ANGLE
O1-C2-C3
C2-C3-O4
C3-O4-C5
O4-C5-C6
C5-C6-O1
C6-O1-C2
NAME
COMP.
BOND
ANGLE
O1-C2-C3
C2-C3-O4
C3-O4-C5
O4-C5-C6
C5-C6-O1
C6-O1-C2
NAME
COMP.
BOND
ANGLE
O1-C2-C3
C2-C3-O4
C3-O4-C5
O4-C5-C6
C5-C6-O1
C6-O1-C2
1,4-Chair
2,5-Chair
1,4-Boat
2,5- Boat
BEFORE
AFTER
BEFORE
AFTER
BEFORE
AFTER
BEFORE
AFTER
108
112
112
113
112
112
113
117
117
112
113
113
109
109
114
114
112
112
113
113
109
102
113
114
114
113
113
113
114
113
113
114
111
114
114
113
113
114
113
113
114
118
114
108
115
109
109
115
1,4-Twist-boat
2,5-Twist-boat
1,4-Half-chair
2,5-Half-chair
BEFORE
AFTER
BEFORE
AFTER
BEFORE
AFTER
BEFORE
AFTER
112
112
112
112
115
112
115
112
112
115
112
115
112
114
112
110
111
112
114
112
112
114
113
114
109
112
116
108
108
115
113
114
115
113
114
115
108
115
109
112
116
108
114
113
114
114
113
114
1,4-Sofa
2,5-Sofa
PLANAR
BEFORE
AFTER
BEFORE
AFTER
BEFORE
AFTER
107
110
108
112
115
110
114
116
120
120
120
120
115
110
117
112
107
137
114
137
120
120
120
120
108
138
108
137
108
110
108
108
120
120
120
120
14
Iraqi J. Chem., 28, 4, 2002
Table 3 The energy components of 6C2 molecules (in Kcal/mole).
FREE CONFORMER
1,4-CHAIR
2,5-CHAIR
1,4-BOAT
2,5-BOAT
1,4-TWIST-BOAT
2,5-TWIST-BOAT
1,4-HALF-CHAIR
2,5-HALF-CHAIR
1,4-SOFA
2,5-SOFA
PLANAR
PG
C2h
Ci
C2v
C2
D2
C2
C2
C2
Cs
C1
D2h
nVib
0
0
0
1
0
0
1
0
2
1
3
ER
0.376
0.00
2.799
5.293
3.020
3.246
3.476
4.613
17.811
19.377
9.182
ES
7.2963
14.685
4.4075
6.8661
0.8346
8.0179
7.5361
17.7891
1.798
21.128
20.625
ETS
1.05
0.06
0.6589
3.036
0.1655
0.9775
0.692
2.399
1.3448
0.1432
0.0
ELP
1.353
0.609
1.559
0.971
0.175
0.432
0.905
1.822
0.066
0.295
0.010
BENZO-DERIVATIVE
PG
Cs
nVib
2
ER
***
ES
38.629
ETS
7.523
ELP
3.403
DIBENZO-BOAT
C2v
0
***
8.672
6.104
1.506
CYCLO- DERIVATIVE
PG
C1
C1
Cs
C1
nVib
0
0
5
0
ER
0.00
3.520
5.189
6.938
ES
4.1792
4.3251
3.4420
8.5733
ETS
1.04343
1.80259
0.5441
5.69362
ELP
1.058
0.728
0.756
5.529
PG
Cs
C1
C1
C2v
C1
C1
nVib
ER
0.00
3.757
4.571
6.569
8.334
20.252
ES
4.7126
3.7789
3.8698
3.039
7.1445
24.5963
ETS
2.201
2.493
-0.15
0.338
4.1122
21.149
ELP
0.162
1.330
1.118
3.553
3.686
20.178
BENZO-BOAT
DIBENZO-DERIVATIVE
CHAIR-CHAIR
BOAT -CHAIR
BOAT -BOAT
CHAIR-BOAT
DICYCLO- DERIVATIVE
CHAIR-CHAIR-CHAIR
CHAIR-CHAIR-BOAT
BOAT-CHAIR-BOAT
BOAT-BOAT-BOAT
CHAIR-BOAT-BOAT
CHAIR-BOAT-CHAIR
0
0
0
1
1
0
15