supplemental figure 1. rhf/6-31g**, mm3(94), and mm2(91...

18015012090603000.0

0.2

0.4

0.6

0.8 RHF/6-31G**

MM3(94)

MM2(91)

Torsion Angle (Degrees), (=C-N+-C-H)

Rel

ativ

e E

nerg

y (k

cal/m

ol)

Supplemental Figure 1. RHF/6-31G**, MM3(94), and MM2(91) Side Chain RotationalProfiles for N-methylpyridinium.

18015012090603000.0

0.5

1.0

1.5

2.0

2.5

3.0 RHF/6-31G**

MM3(94)

MM2(91)

Torsion Angle (Degrees), (=C-N+-C-C)

Rel

ativ

e E

nerg

y (k

cal/m

ol)

Supplemental Figure 2. RHF/6-31G**, MM3(94), and MM2(91) Side Chain RotationalProfiles for N-n-propylpyridinium.

18015012090603000

1

2

3

4

5

6

RHF/6-31G**

MM3(94)

MM2(91)


Rel

ativ

e E

nerg

y (k

cal/m

ol)

Supplemental Figure 3. RHF/6-31G**, MM3(94), and MM2(91) Side Chain RotationalProfiles for N-isopropylpyridinium.

18015012090603000

1

2

3

4

5

6

7

8

9

10

11RHF/6-31G**

MM3(94)

MM2(91)


Rel

ativ

e E

nerg

y (k

cal/m

ol)

Supplemental Figure 4. RHF/6-31G**, MM3(94), and MM2(91) Side Chain RotationalProfiles for s-trans-N-ethyl-N-vinylmethyleneammonium.

18015012090603000

2

4

6

8

10

12

RHF/6-31G**

MM3(94)

MM2(94)


Rel

ativ

e E

nerg

y (k

cal/m

ol)

Supplemental Figure 5. RHF/6-31G**, MM3(94), and MM2(91) Side Chain RotationalProfiles for s-trans-N-n-propyl-N-vinylmethyleneammonium.

18015012090603000

2

4

6

8

10

12

RHF/6-31G**

MM3(94)

MM2(91)


Rel

ativ

e E

nerg

y (k

cal/m

ol)

Supplemental Figure 6. RHF/6-31G**, MM3(94), and MM2(91) Side Chain RotationalProfiles for s-trans-N-isopropyl-N-vinylmethyleneammonium.

Supplemental Table 1. RHF/6-31G**, MM2(91), and MM3(94) Structural Results forPyridinium.

C4

C5 C6

N+1

C2C3

H7

H11

H12H10

H8

H9

Bond RHF/6-31G**a MM2 (91)b Difference MM3(94)b DifferenceN+(1) - C(2) 1.3638 1.3520 -0.0118 1.3546 -0.0092N+(1) - C(6) 1.3639 1.3521 -0.0118 1.3546 -0.0093N+(1) - H(11) 1.0121 1.0128 0.0007 1.0140 0.0019

RMS Diffc 0.0077 0.0065

Bond Angle RHF/6-31G**d MM2 (91)e Difference MM3(94)e DifferenceC(2) - N+(1) - C(6) 123.139 122.742 -0.397 124.048 0.909C(2) - N+(1) - H(11) 118.428 118.629 0.201 117.976 -0.452C(6) - N+(1) - H(11) 118.428 118.629 0.201 117.976 -0.452N+(1) - C(2) - C(3) 119.682 119.725 0.043 119.443 -1.239N+(1) - C(2) - H(7) 116.761 116.376 -0.385 116.091 -0.670N+(1) - C(6) - C(5) 119.682 119.727 0.045 118.443 -1.239N+(1) - C(6) - H(12) 116.761 116.375 -0.386 116.091 -0.670

RMS Diff 0.212 0.659

________________aRHF/6-31G** bond lengths are given in angstroms (Å) and are scaled to rg bond lengths based on MM3 (94)calculations of the pyridine and ethane structures.bMM2 (91) and MM3 (94) bond lengths are given in angstroms (Å) and are reported as rg bond lengths.cThe RMS difference in the calculated bond lengths reported in this Table represent the RMS difference of all thebonds and not just the RMS of those reported.dRHF/6-31G** bond angles are given in degrees (°) and are not scaled to the MM3 (94) structures of pyridine andethane.eMM2 (91) and MM3 (94) bond angles are given in degrees (°).

Supplemental Table 2. RHF/6-31G**, MM2(91), and MM3(94) Structural Results forN-ethylpyridinium

C4

C5 C6

N+1

C2C3

H7

C11

H15H10

H8

H9

C12

H14H13

H18

H16H17

Bond RHF/6-31G**a MM2(91)b Difference MM3(94)b DifferenceN+(1) - C(2) 1.3641 1.3650 0.0009 1.3646 0.0005N+(1) - C(6) 1.3641 1.3650 0.0009 1.3645 0.0004N+(1) - C(11) 1.5037 1.4989 -0.0048 1.5062 0.0025

RMS Diffc 0.0060 0.0043

Bond Angle RHF/6-31G**d MM2(91)e Difference MM3(94)e DifferenceC(2) - N+(1) - C(6) 120.610 120.391 -0.219 120.106 -0.504C(2) - N+(1) - C(11) 119.694 119.616 -0.078 119.944 0.250C(6) - N+ (1) - C(11) 119.667 119.490 -0.177 119.944 0.277N+(1) - C(2) - C(3) 121.198 120.743 -0.455 120.679 -0.519N+(1) - C(2) - H(7) 116.528 117.294 0.766 115.584 -0.944N+(1) - C(6) - C(5) 121.198 120.746 -0.452 120.679 -0.519N+(1) - C(6) - H(15) 116.521 117.274 0.753 115.584 -0.937N+(1) - C(11) - C(12) 111.709 111.426 -0.283 110.976 -0.733N+(1) - C(11) - H(13) 106.838 107.618 0.780 106.988 0.150N+(1) - C(11) - H(14) 106.795 107.538 0.743 106.988 0.193

RMS Diff 0.439 0.469

________________aRHF/6-31G** bond lengths are given in angstroms (Å) and are scaled to rg bond lengths based on MM3(94)calculations of the pyridine and ethane structures.bMM2(91) and MM3(94) bond lengths are given in angstroms (Å) and are reported as rg bond lengths.cThe RMS difference in the calculated bond lengths reported in this Table represent the RMS difference of all thebonds and not just the RMS of those reported.dRHF/6-31G** bond angles are given in degrees (°) and are not scaled to the MM3(94) structures of pyridine andethane.eMM2(91) and MM3(94) bond angles are given in degrees (°).

Supplemental Table 3. RHF/6-31G**, MM2(91), and MM3(94) Structural Results forN-n-propylpyridinium.

C4

C5 C6

N+1

C2C3

H7

C13

H11H10

H8

H9

C14

H16H12

C15

H18H17

H19

H20H21


RMS Diffc 0.0056 0.0051

Bond Angle RHF/6-31G**d MM2(91)e Difference MM3(94)e DifferenceC(2) - N+(1) - C(6) 120.585 120.395 -0.190 120.123 -0.462C(2) - N+(1) - C(13) 119.700 119.461 -0.239 119.936 0.236C(6) - N+(1) - C(13) 119.700 119.592 -0.108 119.936 0.236N+(1) - C(2) - C(3) 121.216 120.748 -0.468 120.672 -0.544N+(1) - C(2) - H(7) 116.500 117.280 0.780 115.570 -0.930N+(1) - C(6) - C(5) 121.216 120.740 -0.476 120.672 -0.544N+(1) - C(6) - H(11) 116.500 117.288 0.788 115.570 -0.930N+(1) - C(13) - H(12) 106.910 107.517 0.607 106.871 -0.039N+(1) - C(13) - C(14) 111.840 111.410 -0.430 111.011 -0.829N+(1) - C(13) - H(16) 106.900 107.457 0.557 106.871 -0.029

RMS Diff 0.435 0.488


Supplemental Table 4. RHF/6-31G**, MM2(91), and MM3(94) Structural Results forN-isopropylpyridinium

C4

C5 C6

N+1

C2C3

H7

C12

H11H10

H8

H9

C13

H15

C14

H18

H19

H16H17

H20

H21


RMS Diffc 0.0069 0.0042

Bond Angle RHF/6-31G**d MM2(91)e Difference MM3(94)e DifferenceC(2) - N+(1) - C(6) 120.178 120.120 -0.058 119.710 -0.468C(2) - N+(1) - C(12) 119.731 120.175 0.444 120.038 0.307C(6) - N+(1) - C(12) 120.091 119.705 -0.386 120.251 0.160N+(1) - C(2) - C(3) 121.483 120.836 -0.647 120.873 -0.610N+(1) - C(2) - H(7) 116.676 117.770 1.094 115.912 -0.764N+(1) - C(6) - C(5) 121.483 120.894 -0.589 120.907 -0.576N+(1) - C(6) - H(11) 116.789 117.573 0.784 115.817 -0.972N+(1) - C(12) - C(13) 110.377 111.471 1.094 110.633 0.256N+(1) - C(12) - C(14) 110.352 111.439 1.087 110.633 0.281N+(1) - C(12) - C(14) 104.112 107.023 2.911 105.585 1.473

RMS Diff 0.958 0.571


Supplemental Table 5. RHF/6-31G**, MM2(91), and MM3(94) Structural Results fors-trans- N-vinylmethyleneammonium

H5

C4

C3

N+2

H6H8

C1

H9

H10

H7

Bond RHF/6-31G**a MM2(91)b Difference MM3(94) DifferenceC(1) - N+(2) 1.3003 1.2892 -0.0111 1.2925 -0.0078N+(2) - C(3) 1.4506 1.4390 -0.0116 1.4450 -0.0056N+(2) - H(7) 1.0210 1.0130 -0.0080 1.0141 -0.0069

RMS Diffc 0.0082 0.0062

Bond Angle RHF/6-31G**d MM2(91)e Difference MM3(94) DifferenceN+(2) - C(1) - H(5) 119.988 118.943 -1.045 118.089 -1.899N+(2) - C(1) - H(6) 119.699 117.269 -2.430 117.606 -2.093C(1) - N+(2) - C(3) 126.019 126.305 0.286 127.437 1.418C(1) - N+(2) - H(7) 117.853 117.126 -0.727 116.203 -1.650C(3) - N+(2) - H(7) 116.128 116.569 0.441 116.361 0.233N+(2) - C(3) - C(4) 120.840 121.153 0.313 121.858 1.018N+(2) - C(3) - H(8) 114.206 116.695 2.489 114.703 0.497

RMS Diff 1.251 1.250


Supplemental Table 6. RHF/6-31G**, MM2(91), and MM3(94) Structural Results fors-trans- N-ethyl-N-vinylmethyleneammonium.

H12

C1

C2

N+3

H13H8

C5

H6

H7

C4

C9H10

H11

H16

H15H14

Bond RHF/6-31G**a MM2(91)b Difference MM3(94)b DifferenceC(2) - N+(3) 1.4607 1.4661 0.0054 1.4596 -0.0011N+(3) - C(4) 1.4995 1.5040 0.0045 1.5086 0.0091N+(3) - C(5) 1.3006 1.3015 0.0009 1.3011 0.0005

RMS Diffc 0.0067 0.0056

Bond Angle RHF/6-31G**d MM2(91)e Difference MM3(94)e DifferenceC(1) - C(2) - N+(3) 124.771 124.360 -0.411 124.772 0.001N+(3) - C(2) - H(8) 112.916 115.858 2.942 113.944 1.028C(2) - N+(3) - C(4) 120.379 120.038 -0.341 120.586 0.207C(2) - N+(3) - C(5) 119.470 121.277 1.807 120.110 0.640C(4) - N+(3) - C(5) 120.145 118.568 -1.577 119.303 -0.842N+(3) - C(4) - C(9) 111.840 111.923 0.083 111.415 -0.425N+(3) - C(4) - H(10) 106.385 108.359 1.974 107.268 0.883N+(3) - C(4) - H(11) 111.187 107.605 0.776 107.026 0.197N+(3) - C(5) - H(12) 120.363 118.802 -1.561 118.737 -1.626N+(3) - C(5) - H(13) 120.098 119.494 -0.604 118.387 -1.711

RMS Diff 1.354 0.856

________________aRHF/6-31G** bond lengths are given in angstroms (Å) and are scaled to rg bond lengths based on MM3(94)calculations of the N-vinyl-2-ethylidenimine (s-trans) and ethane structures.bMM2(91) and MM3(94) bond lengths are given in angstroms (Å) and are reported as rg bond lengths.cThe RMS difference in the calculated bond lengths reported in this Table represent the RMS difference of all thebonds and not just the RMS of those reported.dRHF/6-31G** bond angles are given in degrees (°) and are not scaled to the MM3(94) structures of N-vinyl-2-ethylidenimine (s-trans) and ethane.eMM2(91) and MM3(94) bond angles are given in degrees (°).

Supplemental Table 7. RHF/6-31G**, MM2(91), and MM3(94) Structural Results fors-trans-N-n-propyl-N-vinylmethyleneammonium.

H18

C1

C2

N+3

H19H10

C7

H8

H9

C4

C5H12

H11

C6

H13H14

H17H15

H16


RMS Diffc 0.0063 0.0063

Bond Angle RHF/6-31G**d MM2(91)e Difference MM3(94)e DifferenceC(1) - C(2) - N+(3) 124.807 124.363 -0.444 124.757 -0.050N+(3) - C(2) - H(10) 112.911 115.854 2.943 113.947 1.036C(2) - N+(3) - C(4) 120.471 120.037 -0.434 120.590 0.119C(2) - N+(3) - C(7) 119.420 121.297 1.877 120.140 0.720C(4) - N+(3) - C(7) 120.102 118.552 -1.550 119.269 -0.833N+(3) - C(4) - C(5) 112.011 111.966 -0.045 111.444 -0.567N+(3) - C(4) - H(11) 106.451 108.249 1.798 107.148 0.697N+(3) - C(4) - H(12) 106.917 107.502 0.585 106.916 -0.001N+(3) - C(7) - H(18) 120.054 119.474 -0.580 118.348 -1.706N+(3) - C(7) - H(19) 120.393 118.805 -1.588 118.747 -1.646

RMS Diff 1.283 0.819


Supplemental Table 8. RHF/6-31G**, MM2(91), and MM3(94) Structural Results fors-trans- N-isopropyl-N-vinylmethyleneammonium.

H12

C1

C2

N+3

H13H8

C5

H6

H7

C4

C9C11

H10

H16

H15H14

H19

H18H17

Bond RHF/6-31G**a MM2(91)b Difference MM3(94)b DifferenceC(2) - N+(3) 1.4624 1.4687 0.0063 1.4631 0.0007N+(3) - C(4) 1.5186 1.5074 -0.0112 1.5232 0.0046N+(3) - C(5) 1.3002 1.2975 -0.0027 1.2997 -0.0005

RMS Diffc 0.0078 0.0060

Bond Angle RHF/6-31G**d MM2(91)e Difference MM3(94)e DifferenceC(1) - C(2) - N+(3) 125.651 123.563 -2.088 124.494 -1.157N+(3) - C(2) - H(8) 112.642 115.680 3.038 113.852 1.210C(2) - N+(3) - C(4) 119.713 119.535 -0.178 120.387 0.674C(2) - N+(3) - C(5) 118.430 121.057 2.627 119.539 1.109C(4) - N+(3) - C(5) 121.838 119.394 -2.444 120.074 -1.764N+(3) - C(4) - C(9) 108.960 110.952 1.992 110.172 1.212N+(3) - C(4) - C(10) 112.196 112.872 0.676 111.722 -0.474N+(3) - C(4) - H(11) 103.910 106.480 2.570 105.401 1.491N+(3) - C(5) - H(12) 120.125 118.527 -1.598 118.487 -1.638N+(3) - C(5) - H(13) 120.658 119.545 -1.113 118.743 -1.915

RMS Diff 1.856 1.220


Supplemental Table 9. RHF/6-31G**, MM2(91), and MM3(94) Structural Results fors-trans-N-n-butyl-N-vinylmethyleneammonium.

H13

C1

C2

N+3

H12H11

C4

H10

H9

C5

C6H15

H14

C7

H17H16

C8H19

H18

H20

H22

H21


RMS Diffc 0.0062 0.0060

Bond Angle RHF/6-31G**d MM2(91)e Difference MM3(94)e DifferenceC(1) - C(2) - N+(3) 124.798 124.363 -0.435 124.754 -0.044N+(3) - C(2) - H(11) 112.920 115.854 2.934 113.948 1.028C(2) - N+(3) - C(4) 119.414 121.298 1.884 120.145 0.731C(2) - N+(3) - C(5) 120.472 120.042 -0.430 120.583 0.111C(4) - N+(3) - C(5) 120.108 118.545 -1.563 119.270 -0.838N+(3) - C(4) - H(12) 120.401 118.805 -1.596 118.747 -1.654N+(3) - C(4) - H(13) 120.040 119.474 -0.566 118.346 -1.694N+(3) - C(5) - C(6) 112.003 111.935 -0.068 111.414 -0.589N+(3) - C(5) - H(14) 106.393 108.227 1.834 107.146 0.753N+(3) - C(5) - H(15) 106.864 107.489 0.625 106.886 0.022

RMS Diff 1.242 0.794


Supplemental Table 10: RHF/6-31G** and MM3(94) Vibrational Frequency Resultsfor Pyridinium.

RHF/6-31G** MM3(94) Difference Assignment3432.4 3426.2 6.2 N+-H stretching3079.0 3081.3 -2.3 CH2 sym/sym stretch3077.7 3079.9 -2.2 CH2 sym/asym stretch3067.0 3068.9 -1.9 CH2 asym/sym stretch3065.6 3065.0 0.6 CH2 asym/asym stretch3048.0 3056.1 -8.1 CH2 sym str + N+-H str------- 1696.7 ------- Csp2-Csp2 asym stretch

1635.8 1638.5 -2.7 N+-Csp2 asym stretch1631.6 1656.1 -24.5 Csp2-Csp2 asym stretch1544.1 1509.8 34.3 CH2 asym wag1482.8 1455.4 27.4 Csp2-Csp2 asym stretch1378.4 1381.7 -3.3 CH2 sym wag1291.7 1223.8 67.9 CH2 asym wag + N+-H wag1197.6 1203.3 -5.7 CH2 asym wag1185.0 1150.3 34.7 CH2 sym wag1112.6 ------- ------- Csp2-Csp2 stretch1052.1 1147.7 -95.6 CH2 out-of-plane wag1044.4 978.9 65.5 N+-Csp2 symm stretch1041.5 995.8 45.7 Csp2-Csp2 asym stretch1016.6 1092.0 -75.4 CH2 out-of-plane wag1012.6 935.5 77.1 Skeletal bending1010.5 1026.7 -16.2 CH2 out-of-plane wag980.4 911.7 68.7 Ring Breathing883.4 818.6 64.8 CH2 out-of-plane wag842.0 851.5 -9.5 CH2 out-of-plane wag737.8 750.4 -12.6 CH2 out-of-plane bending652.5 632.4 20.1 CH2 out-of-plane bending621.2 581.5 39.7 Skeletal bending596.8 584.5 12.3 Skeletal bending395.4 397.4 -2.0 Ring twisting383.1 425.6 -42.5 Ring deformation

Total of 29 Vibrations RMS: 41.1

Supplemental Table 11: RHF/6-31G** and MM3(94) Vibrational Frequency Resultsfor N-methylpyridinium

RHF/6-31G** MM3(94) Difference Assignment3077.6 3079.2 -1.6 C-H sym/sym stretch3075.1 3075.2 -0.1 C-H sym/asym stretch3065.2 3067.3 -2.1 C-H asym/sym stretch3062.7 3062.0 0.7 C-H asym/asym stretch3048.5 3055.6 -7.1 C-H stretch3018.1 2981.8 36.3 CH3 asym stretch3004.9 2991.6 13.3 CH3 asym stretch2916.6 2869.5 47.1 CH3 sym stretch1649.0 1674.8 -25.8 Csp2=Csp2 sym stretch------- 1676.6 ------- Csp2=Csp2 + N+-Csp2 asym str

1602.6 1617.2 -14.6 Csp2=Csp2 + N+-Csp2 asym str1501.7 1510.9 -9.2 Csp2=Csp2 + N+-Csp2 sym str1491.0 1454.0 37.0 Csp2=Csp2 + N+-Csp2 asym str1455.7 1385.8 69.9 CH3 asym bend1448.6 1419.6 29.0 CH3 asym bend (C-H wagging)1428.3 1420.9 7.4 CH3 sym bend1361.6 1299.0 62.6 C-H sym wag (in-plane)1222.1 1226.1 -4.0 C-H asym + CH3 wag (in-plane)------- 1178.6 ------- CH3 wag + CH out-of-plane bend

1203.3 1177.5 25.8 C-H asym wag (in-plane)1177.5 1163.4 14.1 CH3 stretch + skeletal bend1134.7 ------- ------- C-H wag + CH3 rocking1127.9 1100.9 27.0 CH3 wagging (out-of-plane)1107.5 ------- ------- Csp2=Csp2 asym stretch1049.1 1112.8 -63.7 C-H asym wag (out-of-plane)1042.5 980.6 61.9 Csp2=Csp2-Csp2 bending1021.2 1044.4 -23.2 Csp2=Csp2 + N+-Csp2 asym str1014.9 1116.1 -101.2 C-H asym wag (out-of-plane)1008.2 931.4 76.8 Ring Breathing991.3 996.2 -4.9 C-H sym wag (out-of-plane)880.0 846.1 33.9 C-H asym wag (out-of-plane)779.6 747.3 32.3 C-H sym wag (out-of-plane)766.4 771.9 -5.5 Csp2=Csp2-Csp2 bending664.4 664.8 -0.4 Ring out-of-plane deformation636.6 581.1 55.5 Ring bending (in-plane)514.4 509.2 5.2 Ring bending (in-plane)438.8 447.8 -9.0 Ring bending (out-of-plane)395.6 374.5 21.1 Ring twisting373.9 406.1 -32.2 CH3 in-plane wag193.6 198.1 -4.5 CH3 out-of-plane wag18.7 ------- ------- CH3 torsion

------- -15.9 ------- CH3 torsion


Supplemental Table 12: RHF/6-31G** and MM3(94) Vibrational Frequency Resultsfor N-ethylpyridinium.

RHF/6-31G** MM3(94) Difference Assignment3076.3 3078.6 -2.3 C-H sym/sym stretch3073.9 3076.3 -2.4 C-H sym/asym stretch3064.4 3067.6 -3.2 C-H asym/sym stretch3061.8 3062.2 -0.4 C-H asym/asym stretch3048.0 3055.7 -7.7 C-H stretch2992.3 2948.1 44.2 CH2 asym stretch2961.6 2969.9 -8.3 CH3 asym stretch2950.6 2970.2 -19.6 CH3 asym stretch2938.6 2892.3 46.3 CH2 sym stretch2883.0 2874.0 9.0 CH3 sym stretch1647.4 1678.7 -31.3 Csp2=Csp2 stretch1603.4 1619.1 -15.7 Csp2=Csp2 + N+-Csp2 asym str1503.9 1485.7 18.2 Csp2=Csp2 + N+-Csp2 sym str1485.3 1676.6 -191.3 C-H wag (in-plane)1471.5 1556.5 -85.0 CH2 + CH3 asym bend1454.2 1433.0 21.2 CH2 + CH3 asym bend------- 1459.9 ------- CH3 asym bend

1452.4 1451.6 0.8 CH3 asym bend1404.7 1452.6 -47.9 CH3 sym bend1363.9 1353.2 10.7 C-H sym wag (in-plane)1355.8 1370.6 -14.8 CH3 + CH2 wag1283.9 ------- ------- C-H wag (in-plane) + CH2 wag1202.0 1234.1 -32.1 C-H wag (in-plane)1200.9 1176.7 24.2 C-H asym wag (in-plane)1161.8 1190.7 -28.9 N+-Csp3 stretch1141.6 1221.3 -79.7 C-H wag + CH2 wag (in-plane)1105.4 1062.5 42.9 Csp2=Csp2 stretch1081.6 1026.0 55.6 CH3 rock1048.5 1154.5 -106.0 C-H wag (out-of-plane)1042.7 ------- ------- Csp2=Csp2-Csp2(N+) asym bend------- 1036.6 ------- C-H asym wag (out-of-plane)

1038.8 1026.0 12.8 Csp2=Csp2 + N+-Csp2 sym str1015.1 1116.1 -101.0 C-H asym wag (out-of-plane)1008.3 931.0 77.3 Ring breathing993.1 1000.5 -7.4 C-H asym wag (out-of-plane)935.3 983.0 -47.7 Ring breathing + CH3 rock880.8 846.6 34.2 C-H asym wag (out-of-plane)787.1 787.8 -0.7 C-H sym wag (out-of-plane)773.7 838.0 -64.3 CH2 + CH3 wag739.8 754.4 -14.6 Ring bending (Csp2=Csp2-Csp2)672.8 665.0 7.8 Ring out-of-plane deformation636.6 581.2 55.4 Ring bending536.0 540.3 -4.3 Ring bending470.4 459.7 10.7 Ring bending (Csp2-N+=Csp2)396.4 375.3 21.1 Ring twisting379.2 406.2 -27.0 Ethyl in-plane bending310.2 329.1 -18.9 Ethyl bending + ring bending217.9 218.8 -0.9 CH3 torsion129.7 135.2 -5.5 Ethyl bending50.7 58.5 -7.8 Ethyl torsion


Supplemental Table 13: RHF/6-31G** and MM3(94) Vibrational Frequency Resultsfor N-n-propylpyridinium

RHF/6-31G** MM3(94) Difference Assignment3076.8 3078.7 -1.9 C-H sym/sym stretch3074.3 3076.5 -2.2 C-H sym/asym stretch3064.6 3067.6 -3.0 C-H asym/sym stretch3062.0 3062.3 -0.3 C-H asym/asym stretch3047.8 3055.7 -7.8 C-H stretch2985.0 2949.4 35.6 CH2 asym stretch2956.3 2968.6 -12.3 CH3 asym stretch2938.4 2970.2 -31.8 CH3 asym stretch2932.5 2891.3 41.2 CH2 sym stretch2909.6 2924.9 -15.3 CH2 asym stretch2876.6 2867.6 9.0 CH2 sym stretch2875.1 2881.3 -6.2 CH3 sym stretch1647.7 1679.5 -31.8 Csp2=Csp2 stretch1603.4 1619.2 -15.8 Csp2=Csp2 + N+-Csp2 asym str1503.5 1487.8 15.7 Csp2=Csp2 + N+-Csp2 sym str1485.0 1676.6 -191.6 Csp2=Csp2 + N+-Csp2 asym str1476.2 1458.3 17.9 CH2 + CH3 asym bend1463.0 1456.9 6.0 CH3 asym bend1462.9 1453.8 9.1 CH2 + CH3 asym bend1455.3 1439.1 16.2 CH2 + CH3 asym bend------- 1452.9 ------- CH2 + CH3 asym bend

1403.7 1395.4 8.3 CH3 wag1379.8 1569.1 -189.3 CH2 asym wag1363.6 1357.3 6.3 C-H sym wag (in-plane)1305.6 1351.6 -46.0 CH2 asym wag1299.6 1224.6 75.0 CH2 sym wag1261.3 1240.2 21.1 CH2 asym wag1200.9 1175.5 25.4 C-H wag (in-plane)1196.7 1221.9 -25.2 C-H asym wag (in-plane)1160.0 1185.2 -25.2 N+-Csp3 stretch1145.3 1033.7 111.6 C-H asym wag (in-plane)1104.7 ------- ------- C-H sym wag (in-plane)1098.9 1060.1 38.8 CH2-CH2 stretch1048.1 1155.0 -106.9 C-H asym bend (out-of-plane)1043.8 1058.8 -15.0 C-H sym wag (in-plane)1042.9 981.2 61.7 Ring bending (Csp2=Csp2-Csp2)1015.0 1116.2 -101.2 C-H wag (out-of-plane)1008.3 931.7 76.6 Ring breathing994.3 1015.4 -21.1 C-H wag (out-of-plane)993.7 993.0 0.7 Csp3-Csp3-Csp3 bending881.0 846.7 34.3 C-H sym wag (out-of-plane)876.6 899.7 -23.1 Csp3-Csp3-Csp3 bending860.3 902.6 -42.3 CH2 + CH3 bending794.2 762.8 31.4 Ring deformation (out-of-plane)------- 803.1 ------- Ring deformation (in-plane)771.6 665.2 106.4 C-H sym wag (out-of-plane)725.3 787.0 -61.7 CH2 twist673.2 ------- ------- N+ out-of-plane bend636.7 581.2 55.5 Ring deformation (in-plane)578.0 568.4 9.6 Ring deformation (in-plane)

Supplemental Table 13: RHF/6-31G** and MM3(94) Vibrational Frequency Resultsfor N-n-propylpyridinium (continued)

RHF/6-31G** MM3(94) Difference Assignment468.8 461.5 7.3 Ring deformation (out-of-plane)396.6 375.0 21.6 Ring twisting372.5 397.1 -24.6 CH2 wag301.8 300.3 1.5 CH3 wag266.3 295.3 -29.0 Propyl wag225.5 227.5 -2.0 CH3 twisting99.5 106.2 -6.8 CH2-CH2 bending83.7 50.3 33.4 CH2-CH2 torsion49.0 57.1 -8.1 Propyl torsion


Supplemental Table 14: RHF/6-31G** and MM3(94) Vibrational Frequency Resultsfor N-isopropylpyridinium

RHF/6-31G** MM3(94) Difference Assignment3090.8 3088.2 2.6 C-H sym/sym stretch3078.7 3079.5 -0.8 C-H sym/asym stretch3066.1 3068.7 -2.6 C-H asym/sym stretch3063.0 3062.7 0.3 C-H asym/asym stretch3047.8 3055.9 -8.1 C-H stretch2965.5 2977.0 -11.5 CH3 sym/asym stretch2962.2 2969.6 -7.4 CH3 sym/asym stretch2959.5 2968.1 -8.6 CH3 asym/asym stretch2950.4 2976.2 -25.8 CH3 asym/asym stretch2941.7 2930.7 11.0 C-H isopropyl stretch2885.5 2879.0 6.5 CH3 sym/sym stretch2882.2 2880.2 2.1 CH3 asym/sym stretch1645.7 1675.8 -30.1 Csp2=Csp2 stretch1603.4 1628.8 -25.4 Csp2=Csp2 + N+-Csp2 asym str------- 1680.9 ------- C-H wag (in-plane)

1500.2 1496.6 3.6 Csp2=Csp2 + N+-Csp2 sym str1485.9 1553.4 -67.5 Csp2=Csp2 + N+-Csp2 asym str1466.8 1471.6 -4.8 CH3 sym/asym bending1462.9 1469.4 -6.5 CH3 sym/asym bending1454.0 1459.3 -5.3 CH3 asym/asym bending1445.9 1457.0 -11.1 CH3 asym/asym bending1415.4 1409.0 6.4 CH3 sym/sym bending1397.6 1443.8 -46.2 CH3 asym/sym bending1380.7 1431.2 -50.5 C-H wag (in-plane)1338.5 1287.0 51.5 C-H isopropyl wag1326.9 1343.2 -16.3 C-H isopropyl wag1203.7 1184.7 19.0 C-H asym wag (in-plane)1201.7 1227.3 -25.6 C-H asym wag (in-plane)1175.7 1091.2 84.5 C-H asym wag (in-plane)1143.6 1211.3 -67.7 N+-Csp2 stretch1122.5 1092.1 30.4 CH3 asym stretch1108.8 1037.2 71.6 Ring bending (Csp2=Csp2-Csp2)1095.0 1032.5 62.5 Ring bending (Csp2=Csp2-Csp2)1048.4 1160.0 -111.6 C-H wag (out-of-plane)1046.7 974.1 72.6 Ring bending (Csp2=Csp2-Csp2)1039.3 930.1 109.2 Ring deformation (in-plane)1016.1 1116.3 -100.2 C-H wag (out-of-plane)1006.6 ------- ------- Ring breathing994.8 1009.5 -14.7 C-H wag (out-of-plane)926.1 940.7 -14.6 CH3 asym wag918.6 971.1 -52.5 CH3 asym wag879.7 847.6 32.1 C-H wag (out-of-plane)860.9 870.1 -9.2 CH3 sym wag790.0 782.0 8.0 C-H wag (out-of-plane)712.0 737.6 -25.6 Ring deformation (in-plane)675.4 665.9 9.5 C-H wag (out-of-plane)635.7 587.8 47.9 Ring deformation (in-plane)547.1 563.3 -16.2 Isopropyl deformation506.0 481.7 24.3 Ring deformation (out-of-plane)453.3 466.3 -13.0 H3C-CH-CH3 bending

Supplemental Table 14: RHF/6-31G** and MM3(94) Vibrational Frequency Resultsfor N-isopropylpyridinium (continued)

RHF/6-31G** MM3(94) Difference Assignment398.6 379.9 18.7 Ring twisting322.0 344.7 -22.7 CH3 asym twisting297.2 302.7 -5.5 CH3 sym twisting254.0 237.1 16.9 CH3 torsion (sym)226.1 255.5 -29.4 Isopropyl rocking222.8 233.5 -10.7 CH3 torsion (asym)121.1 125.6 -4.5 Isopropyl wag43.6 55.7 -12.1 Isopropyl torsion


Supplemental Table 15: RHF/6-31G** and MM3(94) Vibrational Frequency Resultsfor s-trans-N-vinylmethyleneammonium

RHF/6-31G** MM3(94) Difference Assignment3387.5 3422.4 -34.9 N+-H stretching3113.2 3135.0 -21.8 CH2 asym stretch3096.2 3112.7 -16.5 CH2 asym stretch3068.0 3069.4 -1.4 C-H stretch3002.8 3021.8 -19.0 CH2 sym stretch3001.8 3014.1 -12.3 CH2 sym stretch1724.9 1747.6 -22.7 N+-Csp2 stretch1663.4 1589.1 74.3 Csp2-Csp2 stretch1487.7 1426.7 61.0 CH2 scissor1409.4 1413.5 -4.1 N+-H wag1389.1 1241.2 147.9 CH2 wag1302.7 1195.4 107.3 C-H wag1213.5 1147.9 65.6 CH2 wag1137.2 1134.6 2.6 CH2 out-of-plane wag1039.7 997.1 42.6 CH2 in-plane wag1028.3 1071.2 -42.9 CH2 out-of-plane wag1021.0 1051.5 -30.5 CH2 out-of-plane wag940.5 994.0 -53.5 N+-H + CH2 out-of-plane wag848.4 864.5 -16.1 CH2 in-plane wag747.4 812.4 -65.0 Vinyl wag527.8 500.1 27.7 N+-Csp2=Csp2 bend510.5 581.3 -70.8 CH2 twist314.6 352.8 -38.3 Csp2-N+-Csp2 bend129.6 139.2 -9.6 Skeletal torsion


Supplemental Table 16: RHF/6-31G** and MM3(94) Vibrational Frequency Resultsfor s-trans-N-methyl-N-vinylmethyleneammonium

RHF/6-31G** MM3(94) Difference Assignment3115.3 3137.2 -21.9 CH2 asym stretch3105.2 3118.1 -12.9 CH2 asym stretch3065.0 3059.5 5.5 C-H stretch3023.3 3027.2 -3.9 CH2 sym + CH3 asym stretch3020.4 2990.2 30.2 CH2 sym str + CH3 asym str3010.7 2985.0 25.7 CH3 asym stretch3007.6 3017.9 -10.3 CH2 sym stretch2919.4 2870.5 48.9 CH3 sym stretch1720.4 1669.6 50.8 N+=Csp2 stretch1669.1 1553.5 115.6 Csp2=Csp2 stretch1487.8 1410.1 77.7 CH2 scissor + CH3 asym bend1446.7 1437.2 9.5 CH2 asym bend + CH2 scissor1444.1 1440.0 4.1 CH3 asym bend1427.8 ------- ------- CH3 sym bend1401.3 1471.9 -70.6 CH2 scissor1344.0 1294.9 49.1 C-H wag (in-plane) + N+-CH3 str------- 1285.7 ------- CH2 scissor

1300.4 1234.0 66.4 C-H wag (in-plane) + N+-CH3 str1137.5 1245.5 -108.0 CH3 rock + CH2 wag (out-of-

plane)1123.1 1142.8 -19.7 CH2 wag (out-of-plane) + CH3

rock1118.4 1099.4 19.0 CH3 wag1065.7 1047.7 18.0 CH2 asym wag (in-plane)1023.5 1124.4 -100.9 CH2 wag (out-of-plane)961.6 1069.4 -107.8 C-H wag (out-of-plane) + CH2

twist932.3 905.0 27.3 CH2 sym wag (in-plane)------- 968.4 ------- CH2 twist759.8 723.2 36.6 CH2 sym twist753.6 783.4 -29.8 N+-Csp2 + N+-CH3 stretch631.0 ------- ------- CH2 twist534.7 539.8 -5.1 Csp2=Csp2-N+ bend473.2 501.4 -28.2 Csp2-N+=Csp2 bend393.0 492.2 -99.2 N+ out-of-plane bend308.2 325.1 -16.9 Csp2=Csp2-N+ bend216.5 256.0 -39.5 CH3 torsion107.3 96.9 10.4 Skeletal torsion


Supplemental Table 17: RHF/6-31G** and MM3(94) Vibrational Frequency Resultsfor s-trans-N-ethyl-N-vinylmethyleneammonium

RHF/6-31G** MM3(94) Difference Assignment3112.1 3137.2 -25.1 CH2 asym stretch3105.9 3121.2 -15.3 CH2 asym stretch3061.5 3058.0 3.5 C-H stretch3022.7 3029.3 -6.7 CH2 sym stretch3006.9 3017.8 -10.9 CH2 sym str + Csp3-H asym str3002.2 2954.6 47.6 Csp3-H asym str2973.4 2977.2 -3.8 CH3 asym stretch2959.6 2969.3 -9.7 CH3 asym stretch2947.9 2897.5 50.4 Csp3-H sym stretch2891.2 2877.6 13.7 CH3 sym stretch1716.1 1672.9 43.2 N+-Csp2 + Csp2=Csp2 stretch1669.0 1586.9 82.1 Csp2=Csp2 + N+-Csp2 stretch1491.8 1468.7 23.1 CH2 scissor1462.8 1526.2 -63.4 CH3 asym bend + CH2 scissor1458.3 1456.1 2.2 CH3 asym bend + CH2 scissor1452.0 1460.2 -8.2 CH3 asym bend1405.7 1442.5 -36.8 CH3 sym bend + CH2 scissor1404.0 1387.1 16.9 CH3 sym bend + CH2 scissor1361.6 1314.1 47.5 CH2 (ethyl) asym bend1342.6 1370.3 -27.7 C-H wag + CH2 asym bend1305.3 1240.0 65.3 C-H wag + CH2 (ethyl) wag1248.9 1210.8 38.1 CH2 (ethyl) + CH2 wag (in-plane)1137.9 1065.0 72.9 CH3 rock1127.7 1232.4 -104.7 CH2 wag (out-of-plane)1085.0 1042.9 42.0 CH3 wag1067.3 1027.2 40.1 CH2 asym wag (in-plane)1021.3 1123.4 -102.1 CH2 wag (out-of-plane)967.0 1077.5 -110.5 C-H wag (out-of-plane) + CH2

twist961.1 996.3 -35.2 Csp3-Csp3 stretch890.4 897.6 -7.2 CH2 sym wag (in-plane)786.7 854.9 -68.2 Ethyl wag762.1 942.2 -180.1 CH2 twisting709.9 776.5 -66.6 Csp2-N+ str + CH3 rock655.9 728.8 -72.9 CH2 twist535.4 549.1 -13.7 Csp2=N+-Csp2 bend472.4 528.4 -56.0 N+ out-of-plane bend465.1 494.1 -29.0 CH2 wag (in-plane)330.1 352.8 -22.7 Csp2=Csp2-N+ bend241.0 272.1 -31.1 Csp3-Csp3-N+ bend200.0 210.5 -10.5 CH3 torsion119.8 134.4 -14.6 Ethyl torsion87.7 82.3 5.4 Skeletal torsion


Supplemental Table 18: RHF/6-31G** and MM3(94) Vibrational Frequency Resultsfor s-trans-N-n-propyl-N-vinylmethyleneammonium

RHF/6-31G** MM3(94) Difference Assignment3112.4 3137.4 -25.0 CH2 asymmetric stretch3106.2 3121.1 -14.9 CH2 asymmetric stretch3061.3 3058.1 3.2 C-H stretch3022.7 3029.2 -6.5 CH2 symmetric stretch3006.7 3017.9 -11.2 CH2 symmetric stretch2997.0 2956.1 40.9 CH2 asymmetric stretch2958.2 2968.6 -10.4 CH3 asymmetric stretch2945.3 2970.2 -24.9 CH3 asymmetric stretch2941.1 2883.4 57.7 CH2 asymmetric stretch2925.0 2930.8 -5.8 CH2 asymmetric stretch2887.5 2896.8 -9.3 CH2 symmetric stretch2875.6 2870.2 5.4 CH3 symmetric stretch1716.1 1672.9 43.2 N+-C stretch1669.2 1531.6 137.6 CH2 scissor1491.2 1595.3 -104.1 CH2 twist1473.7 1456.5 17.3 CH2 twist1463.0 1456.4 6.5 CH3 twist1458.5 1452.4 6.1 CH3 symmetric stretch------- 1476.0 ------- CH3 symmetric stretch

1457.5 1442.9 14.6 CH2 bend1404.5 1375.6 28.9 CH2 scissor1404.0 1408.4 -4.4 CH3 umbrella1380.0 1355.9 24.1 CH2 twist/CH3 umbrella1347.6 1315.6 32.0 CH2 scissor/CH wag1314.5 1240.8 73.7 C-H bend (out-of-plane)1297.2 ------- ------- C-H bend (out-of-plane)1290.0 1232.9 57.1 CH wag1228.8 1228.5 0.3 CH2, CH3 twist1145.4 1212.1 -66.7 CH2, CH3 rock1126.5 1123.4 3.1 C-H wag (out-of-plane)1099.1 1064.6 34.5 CH3 twist1067.9 1054.4 13.5 CH2 twist1020.2 1078.0 -57.8 CH2 twist (out-of-plane)------- 1039.6 ------- CH2 twist991.6 994.9 -3.3 C-C-C stretch965.5 979.9 -14.4 CH2 wag926.4 919.9 6.5 CH3 twist878.8 ------- ------- CH2 twist866.1 908.0 -41.9 CH2 twist766.8 895.3 -128.5 CH2 twist758.0 809.2 -51.2 CH2 twist728.2 794.6 -66.4 H-C-H bend648.4 730.9 -82.5 CH2 twist549.0 542.3 6.7 C-N+-C-C torison, CH2 wag

Supplemental Table 18: RHF/6-31G** and MM3(94) Vibrational Frequency Resultsfor s-trans-N-n-propyl-N-vinylmethyleneammonium (continued)

RHF/6-31G** MM3(94) Difference Assignment474.9 524.1 -49.2 CH2 wag454.8 506.4 -51.6 CH2 wag355.3 363.7 -8.4 CH2 wag285.9 301.0 -15.1 CH2 wag226.4 229.4 -3.0 CH3 twist186.9 217.7 -30.8 N+ bend (out-of-plane)113.3 128.1 -14.8 CH=CH2 wag

86.0 80.9 5.0 C-N+-C-C torsion75.4 45.8 29.6 C-N+-C-C torsion


Supplemental Table 19: RHF/6-31G** and MM3(94) Vibrational Frequency Resultsfor s-trans-N-isopropyl-N-vinylmethyleneammonium

RHF/6-31G** MM3(94) Difference Assignment3127.1 3146.9 -19.8 CH2 asymmetric stretch3107.0 3118.7 -11.7 CH2 asymmetric stretch3059.6 3057.3 2.2 C-H stretch3023.6 3027.5 -3.9 CH2 symmetric stretch3017.4 3025.6 -8.2 CH2 asymmetric stretch2985.7 2948.7 37.0 CH3 asymmetric stretch2970.5 2973.2 -2.7 CH3 asymmetric stretch2962.1 2970.8 -8.7 CH3 asymmetric stretch2953.9 2967.3 -13.4 CH3 asymmetric stretch2949.7 2978.7 -28.9 CH3 asymmetric stretch2887.6 2878.8 8.8 CH2 asymmetric stretch2882.0 2880.3 1.7 CH3 symmetric stretch1715.5 1673.1 42.4 N+-C stretch------- 1573.1 ------- C-H wag

1669.9 1544.7 125.2 CH wag, C-C stretch1478.2 1484.8 -6.6 CH2 scissor1470.6 1465.1 5.5 CH3 twist1461.9 ------- ------- CH3 twist1452.7 1461.1 -8.4 CH3 twist1448.4 1458.4 -10.0 CH3 twist1417.4 1452.7 -35.3 CH2 scissor1411.0 1442.1 -31.1 CH3 bend (out-of-plane)------- 1324.3 ------- CH3 bend (out-of-plane)

1395.5 1409.3 -13.8 CH3 umbrella1359.9 1347.0 12.9 C-H wag1343.7 1250.0 93.7 CH2 scissor1322.0 ------- ------- C-H wag1275.2 ------- ------- C-N+-C bend1171.5 1067.4 104.1 CH3 twist1130.3 1236.0 -105.7 CH wag, CH2 bend (out-of-plane)1124.5 1228.3 -103.8 CCC bend1101.8 1129.9 -28.1 CH3 twist1065.9 1069.8 -3.9 CH2 wag1018.5 1026.8 -8.3 CH2 twist967.3 1107.6 -140.3 CH wag, CH2 scissor929.9 935.4 -5.5 CH3 umbrella------- 978.6 ------- CH3 twist925.7 966.0 -40.3 CH3 twist902.5 903.3 -0.8 CH2 wag845.2 1091.4 -246.2 CH2 twist762.2 859.3 -97.1 CH2 twist694.2 757.2 -63.0 CCC bend656.4 723.0 -66.6 CH2 twist532.2 575.2 -43.0 CH2 wag511.2 538.9 -27.7 CH2 wag472.9 481.9 -9.0 CH2 wag395.8 410.6 -14.8 CH2 wag

Supplemental Table 19: RHF/6-31G** and MM3(94) Vibrational Frequency Resultsfor s-trans-N-isopropyl-N-vinylmethyleneammonium (continued)

RHF/6-31G** MM3(94) Difference Assignment337.2 334.0 3.2 C-C-N+-C torsion284.9 254.2 30.7 CH3 rotation266.5 289.5 -23.0 CH3 twist233.6 245.2 -11.6 C-N+-C-C torsion209.4 222.5 -13.1 CH3 twist101.3 104.5 -3.2 H-C-C-H bend61.3 50.5 10.8 CH3 bend

Total 48 Vibrations RMS: 59.6

supplemental figure 1. rhf/6-31g**, mm3(94), and mm2(91...

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