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

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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

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S-2

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S-4

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S-6

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C5

Table X._{2-Methylpropanal Average‡ Rg Structure Results} Parameter _{ED (rg)}

ref. 17

MM3 (rg) MM4 (rg)

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 123.3 124.7 124.4

C2C3C4 111.9 111.8

C2C3C5 110.5 109.2

C4C3C5 110.4 111.3

O1C2Hald 118.9 120.1

C2C3Hiso 107.2 105.9

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S-8 C2 O1 C3 Hiso C4 C5 Hald C2 O1 C3 C4 C5 Hiso Hald 2-methylpropanal (anti, C_s symmetry) 2-methylpropanal

(eclipsed)

Table XI._{2-Methylpropanal Rs Structure Results}

Eclipsed Anti

Bond _{MW (rs)}

ref. 22

MM3 (rs) MM4 (rs) MW (rs) ref. 22

MM3 (rs) MM4 (rs)

rC2O1 1.209 (2) 1.205 1.205 1.209 (2) 1.205 1.205

rC2C3 1.509 (3) 1.516 1.519 1.507 (5) 1.514 1.516

rC3C4 1.525 (2) 1.526 1.527 1.526 (3) 1.537 1.530

rC3C5 1.525 (2) 1.535 1.530 1.526 (3) 1.537 1.530

rC3Hald 1.118 (2) 1.101 1.100 1.116 (2) 1.101 1.099

rC3Hiso 1.119 (2) 1.099 1.100 1.114 (4) 1.095 1.093

rCHMe 1.088* 1.094 1.091 1.088* 1.094 1.092

Angle‡ s g g z g g

O1C2C3 125.5 (3) 124.9 124.5 125.7 (3) 124.2 123.9

C2C3C4 111.9 (3) 111.9 112.1 109.3 (3) 110.4 109.3

C2C3C5 109.3 (3) 110.3 109.2 109.3 (3) 110.4 109.3

C4C3C5 113.2* 110.4 111.3 111.8* 110.4 112.0

O1C2Hald 121.4 (1) 118.7 120.1 120.4 (1) 119.0 120.4

C2C3Hiso 100.9 (6) 107.4 105.8 105.1 (5) 108.4 106.8

Dihedral‡ s g g z g g

_C4C3C2Hiso _{113.0 (14)} _118.7 _118.7 _{118.7 (3)} _117.6 _118.6 _C5C3C2Hiso _{120.8 (14)} _117.9 _117.4 _{118.7 (3)} _117.6 _118.6 _C4C3C2C5 _{126.2 (3)} _123.3 _123.9 _{122.6 (4)} _124.7 _122.9

_O1C2C3Hiso _115.2 _116.6 _0.0† _0.0 _0.0

_O1C2C3C4 _3.5 _2.1 _118.7† _117.6 _118.6

_O1C2C3C5 _126.8 _126.0 _118.7† _117.6 _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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Table XII. Pivalaldehyde Structure Results Parameter _{ED (rg)}

ref. 18

MM3 (rg) MM4 (rg) MW (rz) ref. 23

MM3 (rz) MM4 (rz)

rC2O1 1.210 (2) 1.209 1.209 1.206 (6) 1.207 1.205

rC2C3 1.520 (2) 1.525 1.526 1.516 (7) 1.523 1.524

rC3C4 1.537 (2) 1.535 1.534 1.537 (2) 1.534 1.531

rC3C5,6 1.537 (2) 1.546 1.538 1.537 (2) 1.545 1.535

rC-Cavg 1.533 1.538 1.536

rC2Hald 1.119 1.119 1.130 (5) 1.108 1.101

rCHMe 1.111 1.110 1.118 (13) 1.101 1.092

O1C2C3 127.5 (12) 124.9 124.6 126.0 (5)

O1C2Hald 118.7 120.0 121.0 (6)

C2C3C4 108.7 (11) 111.1 111.1 110.5 (4)

C2C3C5,6 106.3 (11) 109.4 107.7 107.4 (3)

O1C2C3C4 0.0 0.0 0.0 0.0 0.0 0.0

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S-10

C' O

C

CH₃

CH₃ CH3 H

pivalaldehyde (Cs symmetry)

Table XIX._{(CH3)3C—C' Rotational Barriers in Pivalaldehyde (in kcal mol-1).} MW

ref. 43

IR ref. 44

B3LYP/ 6-31G*

MM3 MM4

1.18 0.96 1.43 1.73 1.09

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CHiso

1 6 _{s CH3} A 2885 2896 11 2899 14

1 7 _{s CH3} A 2876 2894 18 2898 22

1 8 __C'Hald A 2810 2819 9 2814 4

1 9 C'O A 1752 1759 7 1750 -2

1 10 __{a CH3} A 1474 1472 -2 1474 0

1 11 _{a CH3} A 1467 1464 -3 1462 -5

1 12 _{a CH3} A 1452 1461 9 1450 -2

1 13 __{a CH3} A 1449 1460 11 1444 -5

1 14 _{s CH3} A 1437 1443 6 1432 -5

1 15 _{s CH3} A 1399 1422 23 1383 -16 1 16 _HaldC'O A 1381 1394 13 1382 1 1 17 _CHiso A 1329 1362 33 1347 18

1 18 __CHiso A 1290 1338 48 1295 5

1 19 _CH3 A 1182 1116 -66 1156 -26 1 20 _CH3 A 1138 1081 -57 1123 -15 1 21 _a CCC A 1109 1063 -46 1084 -25

1 22 _CH3 A 965 968 3 960 -5

1 23 __CH3 A 942 946 4 942 0

1 24 CC' A 922 921 -1 885 -37

1 25 _C'Hald A 933 869 -64 860 -73

1 26 _s CCC A 800 775 -25 791 -9

1 27  OC'C A 632 587 -45 604 -28

1 28 __CC2 A 395 417 22 399 4

1 29 _CC2 A 351 369 18 365 14

1 30 _CC2 A 272 290 18 254 -18

1 31 __CH3 A 227 241 14 220 -7

1 32 _CH3 A 212 215 3 202 -10

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Propanal and 2-Methylpropanal (78 modes total): MM3 - 36, MM4 - 18.

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n-Butanal (cis/trans conformer)

Wgt. Assignment Sym. IR (liq.)

Ref. 48 B3LYP/6-1G** MM3 dev. MM4 dev.

1 _{CH3 torsion} A" 270 239 232 -7 229 -10

1 C'CCC deform. A' 210 195 221 +26 218 +23

1 C'HO torsion A" 145 174 159 -15 160 -14

1 C'CCC torsion A" - 76 97 +21 92 +16

rms 19 16

2-Methylbutanal (C1)

Wgt. Assignment Sym. Exp. (N/A)

B3LYP/6-1G** MM3 dev. MM4 dev.

1 skel. deform. A - 299 326 +27 303 +4

1 _{CH3 torsion} A - 256 252 -4 243 -13

1 _{CH3 torsion} A - 226 216 -10 208 -18

1 CCCC deform. A - 203 201 -2 192 -11

1 CCCC torsion A - 114 115 +1 122 +8

1 C'HO torsion A - 98 104 +6 92 -6

rms 15 12

3-Methylbutanal (C1)

Wgt. Assignment Sym. Exp.

(N/A) B3LYP/6-1G** MM3 dev. MM4 dev.

1 _{CH3 torsion} A - 258 240 -18 238 -20

1 _{CH3 torsion} A - 234 217 -17 218 -16

1 C'CCC deform. A - 188 202 +14 195 +7

1 C'CCC deform. A - 161 144 -17 151 -10

1 isopropyl rotation A - 80 88 +8 87 +7

rms 15 13

Pivalaldehyde (Cs)

Wgt. Assignment Sym. IR (vap.)

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R - Raman liquid, IR - IR vapour.