suppmat1396.doc 238KB Jun 05 2011 09:30:52 PM

Supplementary Material for:
Molecular Mechanics (MM4) Calculations on Carbonyl Compounds
Part I: Aldehydes
Charles H. Langley, Jenn-Huei Lii, and Norman L. Allinger*

Computational Center for Molecular Structure and Design
Department of Chemistry, Chemistry Annex
The University of Georgia
Athens, GA 30602-2526

* author to whom correspondence should be addressed
office: (706) 542-2043

FAX: (706) 542-2673

1

S-1

Supplementary Material
Figs. 4 thru 8.

Tables X thru XII, XIX, XXIII and XXIV.

1

S-2

1

S-3

1

S-4

1

S-5

1

S-6

1

S-7

O1

Hald

C4

C2

2-methylpropanal

C3
Hiso
C5

Table X. 2-Methylpropanal Average‡ Rg Structure Results
Parameter
ED (rg)
MM3 (rg)
MM4 (rg)
ref. 17
rC2O1
1.206 (12)
1.209
1.209
rC2C3
1.521
1.524
rC3C4
1.533
1.532
rC3C5
1.541
1.536
rC-Cavg

1.528 (3)
1.532
1.531
rC2Hald
1.127 (35)
1.120
1.119
rC3Hiso
1.115
1.112
rCHMe
1.111
1.111

O1C2C3

C2C3C4

C2C3C5


C4C3C5

O1C2Hald

C2C3Hiso

123.3

124.7
111.9
110.5
110.4
118.9
107.2

124.4
111.8
109.2
111.3
120.1

105.9

‡ Rg structures are Boltzmann averages based on relative energies of
conformers: MM3: 85.8% eclipsed, 14.2% anti. MM4: 87.7% eclipsed,
12.3% anti.

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O1
Hald

C2

S-8

O1
C4
C3
C5

2-methylpropanal
(eclipsed)

Hald

C2

Hiso
C3

Hiso

C5

C4

Table XI. 2-Methylpropanal Rs Structure Results
Eclipsed
Bond
MW (rs) MM3 (rs) MM4 (rs) MW (rs)

ref. 22
ref. 22
rC2O1
1.209 (2)
1.205
1.205
1.209 (2)
rC2C3
1.509 (3)
1.516
1.519
1.507 (5)
rC3C4
1.525 (2)
1.526
1.527
1.526 (3)
rC3C5
1.525 (2)
1.535

1.530
1.526 (3)
rC3Hald
1.118 (2)
1.101
1.100
1.116 (2)
rC3Hiso
1.119 (2)
1.099
1.100
1.114 (4)
rCHMe
1.088*
1.094
1.091
1.088*
Angle‡

O1C2C3


C2C3C4

C2C3C5

C4C3C5

O1C2Hald

C2C3Hiso
Dihedral‡
C4C3C2Hiso
C5C3C2Hiso
C4C3C2C5
O1C2C3Hiso
O1C2C3C4
O1C2C3C5

2-methylpropanal
(anti, Cs symmetry)

Anti
MM3 (rs) MM4 (rs)
1.205
1.514
1.537
1.537
1.101
1.095
1.094

1.205
1.516
1.530
1.530
1.099
1.093
1.092

s

g

g

z

g

g

125.5 (3)
111.9 (3)
109.3 (3)
113.2*
121.4 (1)
100.9 (6)

124.9
111.9
110.3
110.4
118.7
107.4

124.5
112.1
109.2
111.3
120.1
105.8

125.7 (3)
109.3 (3)
109.3 (3)
111.8*
120.4 (1)
105.1 (5)

124.2
110.4
110.4
110.4
119.0
108.4

123.9
109.3
109.3
112.0
120.4
106.8

s

g

g

z

g

g

113.0 (14)
120.8 (14)
126.2 (3)

118.7
117.9
123.3
115.2
3.5
126.8

118.7
117.4
123.9
116.6
2.1
126.0

118.7 (3)
118.7 (3)
122.6 (4)
0.0†
118.7†
118.7†

117.6
117.6
124.7
0.0
117.6
117.6

118.6
118.6
122.9
0.0
118.6
118.6

* Fixed value by author. †Inferred from MW data. ‡Exp. bond angles and dihedrals compared
to MM3 and MM4 ED values.

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S-9
O1

Hald

C4

C2
C3

pivalaldehyde
(eclipsed, C s symmetry)

C6
C5

Table XII. Pivalaldehyde Structure Results
Parameter
ED (rg) MM3 (rg) MM4 (rg)
ref. 18
rC2O1
1.210 (2)
1.209
1.209
rC2C3
1.520 (2)
1.525
1.526
rC3C4
1.537 (2)
1.535
1.534
rC3C5,6
1.537 (2)
1.546
1.538
rC-Cavg
1.533
1.538
1.536
rC2Hald
1.119
1.119
rCHMe
1.111
1.110

O1C2C3

O1C2Hald

C2C3C4

C2C3C5,6
O1C2C3C4
O1C2C3C5,6

127.5 (12)
108.7 (11)
106.3 (11)
0.0

MW (rz)
ref. 23
1.206 (6)
1.516 (7)
1.537 (2)
1.537 (2)

1.207
1.523
1.534
1.545

1.205
1.524
1.531
1.535

1.130 (5)
1.118 (13)

1.108
1.101

1.101
1.092

0.0

0.0

124.9
118.7
111.1
109.4

124.6
120.0
111.1
107.7

126.0 (5)
121.0 (6)
110.5 (4)
107.4 (3)

0.0
120.4

0.0
120.6

0.0

1

MM3 (rz) MM4 (rz)

S-10

O
H

CH3

C'
C
CH3

CH3

pivalaldehyde
(Cs symmetry)

Table XIX. (CH3)3C—C' Rotational Barriers in Pivalaldehyde (in kcal mol-1).
MW
IR
B3LYP/
MM3
MM4
ref. 43
ref. 44
6-31G*
1.18

0.96

1.43

1.73

1

1.09

S-11
Table XXIII. 2-Methylpropanal (Eclipsed) Exp. and Calculated Frequencies (in cm-1).
Wgt. Mode
Assignment
Sym.
Exp.
MM3
dev. MM4
Ref. 42
1
1
A
2990
2990
0 2992
a CH3
1
2
A
2982
2990
8 2991
a CH3
1
3
A
2974
2989
15 2991
a CH3
1
4
A
2953
2987
34 2988
a CH3
1
5
A
2940
2921
-19 2937
CHiso
1
6
A
2885
2896
11 2899
s CH3
1
7
A
2876
2894
18 2898
s CH3
1
8
A
2810
2819
9 2814
C'Hald
1
9
A
1752
1759
7 1750
C'O
1
10
A
1474
1472
-2 1474
a CH3
1
11
A
1467
1464
-3 1462
a CH3
1
12
A
1452
1461
9 1450
a CH3
1
13
A
1449
1460
11 1444
a CH3
1
14
A
1437
1443
6 1432
s CH3
1
15
A
1399
1422
23 1383
s CH3
1
16
A
1381
1394
13 1382
HaldC'O
1
17
A
1329
1362
33 1347
CHiso
1
18
A
1290
1338
48 1295
CHiso
1
19
A
1182
1116
-66 1156
CH3
1
20
A
1138
1081
-57 1123
CH3
1
21
A
1109
1063
-46 1084
a CCC
1
22
A
965
968
3
960
CH3
1
23
A
942
946
4
942
CH3
1
24
A
922
921
-1
885
CC'
1
25
A
933
869
-64
860
C'Hald
1
26
A
800
775
-25
791
s CCC
1
27
A
632
587
-45
604
OC'C
1
28
A
395
417
22
399
CC2
1
29
A
351
369
18
365
CC2
1
30
A
272
290
18
254
CC2
1
31
A
227
241
14
220
CH3
1
32
A
212
215
3
202
CH3
1
33
A
75
107
32
87
C'—CH(CH3)2
rms
Hiso - isopropyl hydrogen, Hald - aldehydic hydrogen.
-in-plane rocking, -out-of-plane rocking/bending,  - torsion
Total Rms (in cm-1) for Formaldehyde, Acetaldehyde,

1

29

dev.
2
9
17
36
-3
14
22
4
-2
0
-5
-2
-5
-5
-16
1
18
5
-26
-15
-25
-5
0
-37
-73
-9
-28
4
14
-18
-7
-10
12
20

Propanal and 2-Methylpropanal (78 modes total):

MM3 -

1

36,

MM4 -

18.

S-12
Table XXIV. Low Frequencies for Aldehydes (in cm-1)
2-Methylpropanal (eclipsed conformer)
Wgt.
Assignment
Sym.
1
1
1
1

CC2 deform.
CH3 torsion
CH3 torsion
C(CH3)2 torsion

A
A
A
A

n-Butanal (cis/trans conformer)
Wgt.
Assignment
Sym.
1
1
1
1

CH3 torsion
C'CCC deform.
C'HO torsion
C'CCC torsion

A"
A'
A"
A"

IR (vap.)
Ref. 42
272
227
212
75

B3LYP/6-1G**

IR (liq.)
Ref. 48
270
210
145
-

B3LYP/6-1G**

Exp.
(N/A)
-

B3LYP/6-1G**

Exp.
(N/A)
-

B3LYP/6-1G**

IR (vap.)
Ref. 45
278
267
267
70

B3LYP/6-1G**

272
226
195
90

239
195
174
76

MM3

dev.

290
241
215
107
rms

18
14
3
32
19

MM4

dev.

254
220
202
87

-18
-7
-10
12
12

MM3

dev.

MM4

dev.

232
221
159
97
rms

-7
+26
-15
+21
19

229
218
160
92

-10
+23
-14
+16
16

MM3

dev.

MM4

dev.

326
252
216
201
115
104
rms

+27
-4
-10
-2
+1
+6
15

303
243
208
192
122
92

+4
-13
-18
-11
+8
-6
12

MM3

dev.

MM4

dev.

240
217
202
144
88
rms

-18
-17
+14
-17
+8
15

238
218
195
151
87

-20
-16
+7
-10
+7
13

MM3

dev.

MM4

dev.

291
260
241
218
94
rms

13
11
-7
18
24
16

254
241
227
208
65

-24
-8
-21
8
-5
15

2-Methylbutanal (C1)
Wgt.

Assignment

Sym.

1
1
1
1
1
1

skel. deform.
CH3 torsion
CH3 torsion
CCCC deform.
CCCC torsion
C'HO torsion

A
A
A
A
A
A

299
256
226
203
114
98

3-Methylbutanal (C1)
Wgt.

Assignment

Sym.

1
1
1
1
1

CH3 torsion
CH3 torsion
C'CCC deform.
C'CCC deform.
isopropyl rotation

A
A
A
A
A

258
234
188
161
80

Pivalaldehyde (Cs)
Wgt.

Assignment

Sym.

1
1
1
1
1

CeclCC' bending
CH3 torsion
CH3 torsion
CH3 torsion
C(CH3)3 torsion

A'
A"
A'
A"
A"

278
249
248
200
78

Total Rms (24 weighted modes):

1

17

14

R - Raman liquid, IR - IR vapour.

1