Supporting Information

© Wiley-VCH 2008

69451 Weinheim, Germany

S1

Supporting Information Activation of the C-F bond: Transformation of CF3N=N- into azido-tetrazole Takashi Abe, Guo-Hong Tao, Young-Hyuk Joo, Yangen Huang, Brendan Twamley,

Jean’ne M. Shreeve *

[*] Department of Chemistry, University of Idaho, Moscow, Idaho 83844-2343, USA

E-mail: jshreeve@uidaho.edu CONTENTS General experimental methods S2 Typical example for the preparation of trifluoromethyl-azo-alkanes, representative example for the preparation of azo-tetrazoles and physical data for the compounds, 2a, 2b, 2d, 2e, 2f and 2g. S3–S4 NMR study on the isomerization of 1c, and 2c S5–S9 DSC data for the compounds, 2d and 2e S10 X-ray crystallography of 2c S11–S16 Computation details S17–S25 References S26

S2

General experimental methods.

Caution: For handling these energetic materials, small scale and best safety practices (leather gloves,

face shield) are strongly encouraged to be used in undertaking preparation of azido-tetrazoles (2a–g).

New azido-tetrazoles are very sensitive toward friction (spatula). Their impact sensitivities are around

1 J. We experienced an explosion in handling 2a when the stopcock with a ground joint was opened

after drying on the vacuum line.

1H, 19F and 13C NMR spectra were recorded on a 300 MHz Bruker Avance nuclear magnetic resonance

spectrometer operating at 300.1, 282.4 and 75.5 MHz, respectively, using CDCl3, CD3CN and

[D6]DMSO as solvent unless otherwise indicated. 15N NMR spectra were recorded on a 500 MHz

Bruker Avance nuclear magnetic resonance spectrometer operating at 50.7 MHz. Chemical shifts (1H

and 13C NMR) are reported relative to Me4Si. Chemical shifts (19F NMR) are reported relative to

CFCl3. Chemical shifts (15N NMR) are reported relative to external CH3NO2. The crystallization,

melting and decomposition points were obtained on a differential scanning calorimeter at a scan rate of

10°C/min, respectively. Densities of solid salts were obtained at room temperature by employing a

Micromeritics Accupyc 1330 gas pycnometer. Elemental analyses were determined using an Exeter

CE-440 elemental analyzer.

Representative example for the preparation of trifluoromethyl-azo-alkanes.[1]

1c: Into a 50 mL Schlenk tube with a Teflon stop cock which contained isopropylamine (0.270 g, 4.60

mmol) in methanol (0.75 mL), CF3NO (5.0 mmol) was condensed at −196 oC using vacuum line

techniques. The reaction mixture was allowed to warm slowly from −78 oC to room temperature with

stirring overnight. After the reaction was complete, the mixture was added to brine (2 mL) and a one

drop of aq. HCl. Two layers were separated. The upper layer which consisted of an oily yellow

greenish compound was separated. Yield 79%, 0.508 g. 1H NMR (CDCl3): δ = 1.38 (s, 3H; CH3), 1.40 (s, 3H; CH3), 4.10 (heptq, 3J(H,H) = 6.5 Hz, 5J(H,F) =

1.4 Hz, 1H; CH); 19F NMR (CDCl3): δ = −74.2 (s, CF3); 13C NMR (CDCl3): δ = 9.8, 70.3, 120.9 (q, 1J(C,F) = 273 Hz, CF3).

Representative example for the preparation of 5-azidotetrazoles, 2a–g.

2a: Into a 50 mL Schlenk tube with a Teflon stop cock which contained NaN3 (0.127 g, 2.00 mmol) in

CH3CN (5 mL), CF3N=NCH3 (2.00 mmol) was condensed by using vacuum line techniques. After

stirring the reaction mixture for 12 h at room temperature, the solvent was removed. The solid mixture

was extracted with CHCl3 (3 x 5 mL). The organic layer was concentrated in vacuo. Evaporation of

the CHCl3 left a colorless liquid. Yield 49%, 0.064 g.

IR (liq. Film): ~ν = 2163 (s; νas(N3)), 1545 (s; νas(N=C)), 1452, 1306, 1261, 1195, 1093, 1031; 1H NMR

(CDCl3): δ = 7.38 (d, 2J(H,H) = 9.7 Hz); 8.16 (d, 2J(H,H) = 9.7 Hz); 13C NMR (CDCl3): δ = 148.3,

148.9; HRMS (EI): m/z: calcd for C2H2N8: 139.0481; Found: 139.0477.

2b: Yield 78%, 0.088 g; colorless liquid; IR (liq. film): ~ν = 2982, 2942, 2231, 2160 (s; νas(N3)), 1632,

1546 (s; νas(N=C)), 1454, 1363, 1291, 1245, 1092; 1H NMR (CDCl3): δ = 1.27 (t, 3J(H,H) = 7.5 Hz,

3H; CH3), 2.61 (qd, 3J(H,H) = 7.5 Hz, 3J(H,H) = 5.0 Hz, 2H; CH2), 8.68 (t, 3J(H,H) = 5.0 Hz, 1H; CH); 13C NMR (CDCl3): δ = 10.0, 26.5, 148.9, 165.0; C,H,N analysis (%): calcd for C4H6N8 (166.18): C

28.91, H 3.65, N 67.44; Found C 27.87, H 3.44, N 66.53 (Exploded during analysis).

2d: Yield 98%, 0.119 g; colorless liquid; IR (liq. film): ~ν = 2793, 2156 (s; νas(N3)), 1628, 1545 (s;

νas(N=C)), 1361, 1244, 1173, 1094, 984; 1H NMR (CDCl3): δ = 1.26 (d, 3J(H,H) = 5.3 Hz, 6H; CH3),

S3

2.82 (heptd, 3J(H,H) = 6.9 Hz, 3J(H,H) = 5.3Hz, 1H; CH), 8.57 (d, 3J(H,H) = 5.3 Hz, 1H; CH); 13C

NMR (CDCl3): δ = 19.7, 33.1, 149.8, 169.1; MS (FAB; 3-nitrobenzyl alcohol matrix): 181.1249 (100)

[M++1] , 361.2460 (7) [2M++1]; C,H,N analysis (%): calcd for C5H8N8 (180.21): C 33.32, H 4.48, N

62.20; Found C 33.66, H 4.41, N 60.88.

2e: Yield 74%, 0.125 g; straw colored liquid; IR (liq. film): ~ν = 2928, 2858, 2155 (s; νas(N3)), 1631,

1545 (s; νas(N=C)), 1456, 1366, 1293, 1244, 1096; 1H NMR (CDCl3): δ = 0.9 (t, 3J(H,H) = 6.7 Hz, 3H;

CH3), 1.31–1.44 (m, 8H; CH2), 1.69 (m, 2H; CH2), 2.57 (td, 3J(H,H) = 7.4 Hz, 3J(H,H) = 5.6 Hz, 2H;

CH2), 8.65 (t, 3J(H,H) = 5.6 Hz, 1H; CH); 13C NMR (CDCl3): δ = 14.0, 22.5, 25.6, 28.8, 29.1, 31.5,

32.9, 148.8, 164.4; MS (FAB; 3-nitrobenzyl alcohol matrix): 237.1776 (100) [M++1], 473.3444 (5)

[2M++1]; C,H,N analysis (%): calcd for C9H16N8 (236.33): C 45.74, H 6.84, N 47.42; Found C 45.39,

H 6.81, N 47.16.

2f: Yield 89%, 0.110 g; colorless liquid; IR (liq. film): ~ν = 2970, 2156 (s; νas(N3)), 1645, 1535 (s;

νas(N=C)), 1451, 1318, 1287, 1240, 1092; 1H NMR (CDCl3): δ = 1.84–1.98 (m, 4H; CH2), 2.67–2.83

(m, 4H; CH2); 13C NMR (CDCl3): δ = 24.2, 25.2, 33.9, 35.6, 149.2, 185.9; C,H,N analysis (%): calcd

for C6H8N8 (192.22): C 37.49, H 4.20, N 58.31; Found C 37.04, H 4.12, N 57.22.

2g: Yield 93%, 0.139 g; colorless liquid; IR (liq. Film): ~ν = 2942, 2862, 2158 (s; νas(N3)), 1622, 1532

(s; νas(N=C)), 1449, 1292, 1233, 1092; 1H NMR (CDCl3): δ = 1.67–1.83 (m, 4H; CH2), 1.86–1.94 (m,

2H; CH2), 2.50–2.60 (m, 4H; CH2); 13C NMR (CDCl3): δ = 24.9, 26.8, 27.3, 31.1, 36.1, 148.8, 185.0;

C,H,N analysis (%): calcd for C7H10N8 (206.25): C 40.76, H 4.90, N 54.34; Found C 40.51, H 4.84, N

54.17.

S4

NMR study on the isomerization of trifluoromethyl-azo-alkanes. In a NMR tube which contained 0.50 g CD3CN, 14.5 mg (0.10 mmol) CF3N=N-i-C3H7, 1c, and 3.0 mg

(0.05 mmol) KF were dissolved. 1H and 19F spectra were measured at several intervals. The degree of

isomerization of 1c into dimethylcarboimino-trifluoromethylamine (1d) was determined by the

integration of the two peaks due to CF3N=N− and CF3NH− (Table S1). 1H and 19F NMR spectra taken

after 5 h, and 13C NMR of the mixture of 1c and 1d are shown in S6−S8.

Table S1 19F NMR study on the isomerization of trifluoromethylazopropane 1c

1c 1d

CF3 N N CCH3

CH3H CF3 N N C

CH3

CH3H[1,3]-proton shift

Ratio (%)

Entry Time (h)

1c

1d

1 0 100 0

2 5 66 34

3 10 10 90

4 45 4 96

5 72 2 98

S5

Star

1c

1H NMR CD3CN

KFt

F3C N N CCH3

CH3H

← δ/ppm

Figure S2.

1c

1H NMRCD3CN

KF+

5 h later

1c F3C N N CCH3

CH3H

F3C N N CCH3

CH3H

1d

← δ/ppm

S6

Figure S3.

Start

1c

19F NMRCD3CN

KFF3C N N C

CH3

CH3H

← δ/ppm

Figure S4.

S7

5

← δ/ppm

1d

19F NMRCD3CN

KF+

h later

H1cF3C N N C

CH3

CH3

H

1c

F3C N N CCH3

CH3

Figure S5.

S8

← δ/ppm

Figure S6.

← δ/ppm

Figure S7.

1c

CF3N N CHCH3

CH3

13C NMRCD3CN

KF1c +

1d

F3C NH

N CCH3

CH3

2c

1H NMRNN

NN

NN3

13C NMR

2c

NN

NN

NN3

← δ/ppm

Figure S8.

S9

DSC of 2d

Figure S9.

DSC of 2e

Figure S10.

S10

S11

X-ray Crystallography.

Crystals of compound 2c was removed from the flask, a suitable crystal was selected and attached to a

glass fiber, and data were collected at 90(2) K using a Bruker/Siemens SMART APEX instrument (Mo

Kα radiation, λ = 0.71073 Å) equipped with a Cryocool NeverIce low temperature device. 0.3 ° per

frame for 30 seconds, and a full sphere of data was collected. A total of 2400 frames were collected

with a final resolution of 0.83 Å. Cell parameters were retrieved using SMART software[2] and refined

using SAINT Plus[3]on all observed reflections. Data reduction and correction for Lp and decay were

performed using the SAINT Plus software. Absorption corrections were applied using SADABS.[4]

The structure was solved by direct methods and refined by least squares method on F2 using the

SHELXTL program package.[5] The structure was solved in the space group P2(1)/n (# 14) by analysis

of systematic absences. All non-hydrogen atoms were refined anisotropically. No decomposition was

observed during data collection. Details of the data collection and refinement are given in Tables

S2−S6.

(a)

(b) Figure S11. Thermal ellipsoid plot (a) and packing diagram (b) of 2c

S12

S13

Table S2. Crystal data and structure refinement for 2c. Identification code bt1168 Empirical formula C4 H6 N8 Formula weight 166.17 Temperature 90(2) K Wavelength 0.71073 Å Crystal system Monoclinic Space group P2(1)/n Unit cell dimensions a = 8.8038(3) Å α= 90°. b = 7.1821(2) Å β= 96.665(1)°. c = 11.8729(4) Å γ = 90°. Volume 745.65(4) Å3 Z 4 Density (calculated) 1.480 Mg/m3 Absorption coefficient 0.111 mm-1 F(000) 344 Crystal size 0.28 x 0.20 x 0.16 mm3 Crystal color and habit colorless rhomboid Diffractometer Bruker/Siemens SMART APEX Theta range for data collection 2.73 to 27.50°. Index ranges -11<=h<=11, -9<=k<=9, -15<=l<=15 Reflections collected 11014 Independent reflections 1715 [R(int) = 0.0192] Completeness to theta = 27.50° 100.0 % Absorption correction Semi-empirical from equivalents Max. and min. transmission 0.986 and 0.970 Solution method XS, SHELXTL v. 6.14 (Bruker, 2003) Refinement method Full-matrix least-squares on F2 Data / restraints / parameters 1715 / 0 / 134 Goodness-of-fit on F2 1.042 Final R indices [I>2sigma(I)] R1 = 0.0309, wR2 = 0.0790 R indices (all data) R1 = 0.0328, wR2 = 0.0807 Largest diff. peak and hole 0.261 and -0.227 e.Å-3

S14

Table S3. Atomic coordinates ( x 104) and equivalent isotropic displacement parameters (Å2x 103) for 2c. U(eq) is defined as one third of the trace of the orthogonalized Uij tensor. ________________________________________________________________________________ x y z U(eq) ________________________________________________________________________________ C(4) 7126(1) -98(1) 5884(1) 17(1) C(10) 6561(1) 3445(1) 3920(1) 18(1) C(11) 8183(1) 3735(1) 3709(1) 21(1) C(12) 5421(1) 4888(2) 3473(1) 23(1) N(1) 6352(1) -1042(1) 8427(1) 27(1) N(2) 6411(1) -310(1) 7601(1) 19(1) N(3) 6364(1) 690(1) 6727(1) 20(1) N(5) 8018(1) -1579(1) 5915(1) 20(1) N(6) 8450(1) -1695(1) 4847(1) 22(1) N(7) 7872(1) -353(1) 4201(1) 21(1) N(8) 7041(1) 695(1) 4860(1) 17(1) N(9) 6003(1) 2102(1) 4460(1) 19(1)

S15

Table S4. Bond lengths [Å] and angles [°] for 2c. _____________________________________________________ C(4)-N(5) 1.3200(12) C(4)-N(8) 1.3376(12) C(4)-N(3) 1.3881(12) C(10)-N(9) 1.2864(12) C(10)-C(11) 1.4932(13) C(10)-C(12) 1.4966(13) C(11)-H(11A) 0.952(14) C(11)-H(11B) 0.973(15) C(11)-H(11C) 0.962(14) C(12)-H(12A) 0.976(14) C(12)-H(12B) 0.976(14) C(12)-H(12C) 0.967(14) N(1)-N(2) 1.1191(12) N(2)-N(3) 1.2588(11) N(5)-N(6) 1.3683(12) N(6)-N(7) 1.2984(12) N(7)-N(8) 1.3591(11) N(8)-N(9) 1.4072(11) N(5)-C(4)-N(8) 109.80(8) N(5)-C(4)-N(3) 130.11(8) N(8)-C(4)-N(3) 120.07(8) N(9)-C(10)-C(11) 128.04(9) N(9)-C(10)-C(12) 114.66(8) C(11)-C(10)-C(12) 117.30(8) C(10)-C(11)-H(11A) 112.4(8) C(10)-C(11)-H(11B) 108.2(8) H(11A)-C(11)-H(11B) 110.5(11) C(10)-C(11)-H(11C) 109.6(8) H(11A)-C(11)-H(11C) 109.7(12) H(11B)-C(11)-H(11C) 106.2(12) C(10)-C(12)-H(12A) 111.2(8) C(10)-C(12)-H(12B) 108.3(8) H(12A)-C(12)-H(12B) 110.0(11) C(10)-C(12)-H(12C) 109.2(8) H(12A)-C(12)-H(12C) 109.9(11) H(12B)-C(12)-H(12C) 108.2(11) N(1)-N(2)-N(3) 171.85(10) N(2)-N(3)-C(4) 112.89(8) C(4)-N(5)-N(6) 104.61(8) N(7)-N(6)-N(5) 111.71(8) N(6)-N(7)-N(8) 105.77(7) C(4)-N(8)-N(7) 108.08(8) C(4)-N(8)-N(9) 125.32(8) N(7)-N(8)-N(9) 125.14(7) C(10)-N(9)-N(8) 115.84(8)

Table S5. Anisotropic displacement parameters (Å2x 103)for 2c. The anisotropic

displacement factor exponent takes the form: -2π2[ h2a*2U11 + ... + 2 h k a* b* U12

U11 U22 U33 U23 U13 U12

C(4) 17(1) 16(1) 18(1) 0(1) 1(1) -2(1) C(10) 19(1) 19(1) 16(1) -2(1) 1(1) 1(1) C(11) 20(1) 20(1) 23(1) 1(1) 4(1) 0(1) C(12) 23(1) 23(1) 25(1) 5(1) 3(1) 5(1) N(1) 28(1) 28(1) 26(1) 6(1) 9(1) 6(1) N(2) 17(1) 19(1) 22(1) 0(1) 4(1) 2(1) N(3) 24(1) 18(1) 18(1) 2(1) 4(1) 3(1) N(5) 21(1) 18(1) 22(1) -1(1) 2(1) 2(1) N(6) 25(1) 20(1) 22(1) -1(1) 3(1) 3(1) N(7) 23(1) 20(1) 21(1) -3(1) 4(1) 3(1) N(8) 18(1) 16(1) 18(1) -1(1) 2(1) 1(1) N(9) 18(1) 18(1) 20(1) 1(1) 0(1) 3(1)

Table S6. Hydrogen coordinates ( x 104) and isotropic displacement parameters (Å2x

103) for 2c.

x y z U(eq) H(11A) 8874(15) 2955(19) 4171(11) 29(3) H(11B) 8439(16) 5040(20) 3846(11) 37(4) H(11C) 8281(16) 3510(20) 2922(12) 33(3) H(12A) 4396(16) 4571(19) 3648(11) 32(3) H(12B) 5431(16) 4971(19) 2653(12) 34(3) H(12C) 5725(15) 6080(20) 3800(11) 31(3)

S16

S17

Theoretical study. Computations were performed by using the Gaussian03 (Revision D.01) suite

of programs.[6] The geometric optimization and the frequency analyses are carried out

at the level of Becke three Lee-Yan-Parr (B3LYP) parameters up to 6-31+G(d,p)

basis sets.[7] All of the optimized structures were characterized to be true local energy

minima on the potential energy surface without imaginary frequencies. The enthalpy

of reaction (ΔHro

298) is obtained by combining the MP2/6-311++G**[8] energy

difference for the reaction, the scaled zero point energies, and other thermal factors.

The heats of formation of the products were determined by using the method of

isodesmic reactions (Scheme S7).[9] The Ab Initio computational data are listed below

(Table S8, S9).

2a

(1)NN

NN

N3 NH

H CH4 2NH3+ +NHN

NN CH3N3 NH2NH2 NH=CH2+ + +

2b

(2)NN

NN

N3 NH

2CH4 2NH3+ +NHN

NN CH3N3 NH2NH2 NH=CH2+ + + CH3CH2CH3+

2c

(3)NN

NN

N3 N3CH4 2NH3+ +

NHN

NN CH3N3 NH2NH2 NH=CH2+ + + 2CH3CH3+

2d

(4)NN

NN

N3 NH

3CH4 2NH3+ +NHN

NN CH3N3 NH2NH2 NH=CH2+ + + CH3CH2CH3+

2CH3CH3+

2e

(5)NN

NN

N3 NH 5CH4 2NH3+ +

NHN

NN CH3N3 NH2NH2 NH=CH2+ + + 3CH3CH2CH3+

CH3CH3+

2f

(6)NN

NN

N3 N5CH4 2NH3+ +

NHN

NN CH3N3 NH2NH2 NH=CH2+ + + 2CH3CH2CH3+

CH3CH3+

2f

(7)NN

NN

N3 N5CH4 2NH3+ +

NHN

NN CH3N3 NH2NH2 NH=CH2+ + + 3CH3CH2CH3+

Scheme S7. Isodesmic reactions used for calculation of energetic materials.

S18

TABLE S8. Calculated (B3LYP/6-31+G**//MP2/6-311++G**) Total Energy (E0), Zero-Point

Energy (ZPE), Values of Thermal Correction (HT), and Heats of Formation (HOF) of the cations.

Name

E0(au)

ZPE(au)

HT(kJ/mol)

HOF(kJ/mol)

2a -514.0650615 0.070624 23.7 820.46

2b -592.4676237 0.127093 31.5 750.62

2c -592.4744486 0.126375 31.7 730.00

2d -631.6669392 0.155002 35.3 719.38

2e -788.4453017 0.269433 49.1 651.82

2f -669.6759062 0.163446 33.2 752.73

2g -708.8732098 0.192833 36.1 730.72

tetrazole -257.65387 0.04686 11.6 314.1

-74.6[10]CH4 -40.3796224 0.044793 10.0

CH3N3 -203.60768 0.05025 14.3 296.5

CH2=NH -94.3808863 0.039928 10.2 86.7

95.4[10]NH2NH2 -111.5836915 0.05331 11.0

-45.9[10]NH3 -56.4154647 0.034384 10.0

-84[10]CH3CH3 -79.571631 0.07461 11.6

-103.8[10]CH3CH2CH3 -118.76734 0.10328 14.4

Geometry Coordinates B3LYP/6-31+G(d,p) optimized geometries (Å) 2a C 1.121427 0.152191 -0.012733 C -2.360118 -0.491589 -0.054993 N 4.125516 -1.164250 0.084958 N 3.001792 -1.028368 0.059749 N 1.751863 -1.073254 0.038645 N 1.648588 1.363331 -0.042459 N 0.589790 2.220497 -0.089624 N -0.536409 1.594242 -0.089746 N -0.230124 0.261860 -0.040922 N -1.117331 -0.788751 -0.022842 H -2.743661 0.527217 -0.094384 H -3.047203 -1.331869 -0.039698

S19

2b C -1.311005 0.174577 -0.003440 C 2.217676 0.085268 -0.318548 N -4.069438 -1.599631 0.137959 N -2.983069 -1.288376 0.059842 N -1.746610 -1.135201 -0.040504 N -2.017554 1.285365 0.124309 N -1.108812 2.297803 0.101785 N 0.097357 1.857346 -0.031495 N 0.000260 0.496538 -0.101645 N 1.035144 -0.404934 -0.246620 H 2.393174 1.162595 -0.260766 C 3.392910 -0.827118 -0.471855 H 3.887628 -0.583757 -1.422875 H 3.036464 -1.859146 -0.539509 C 4.406070 -0.665555 0.676957 H 5.274521 -1.308913 0.507777 H 4.763664 0.366921 0.754389 H 3.959698 -0.943103 1.636878 2c C 1.109138 0.194714 -0.052750 C -2.343793 -0.544079 0.026036 C -2.942712 0.624882 0.762463 H -2.223456 1.105982 1.427861 H -3.812082 0.292219 1.335615 H -3.273698 1.389508 0.051228 C -3.255815 -1.696666 -0.291462 H -2.727473 -2.470488 -0.849786 H -4.112955 -1.345147 -0.878582 H -3.657782 -2.123376 0.635310 N 4.052125 -1.234128 0.243262 N 2.936337 -1.057563 0.153733 N 1.690206 -1.054079 0.066911 N 1.685280 1.384944 -0.058356 N 0.671493 2.276863 -0.212950 N -0.477349 1.691723 -0.283444 N -0.231418 0.347969 -0.162979 N -1.125741 -0.687415 -0.372943 2d C -1.677517 0.170968 -0.000106 C 1.866659 0.177855 0.000008 N -4.387734 -1.681910 -0.000243 N -3.307689 -1.340122 -0.000357

S20

N -2.072011 -1.152479 -0.000508 N -2.423137 1.263508 0.000501 N -1.544275 2.302138 0.000607 N -0.319240 1.894218 0.000400 N -0.372268 0.529448 -0.000056 N 0.696419 -0.345056 -0.000585 H 2.009499 1.262305 0.001114 C 3.081708 -0.702224 -0.000477 H 2.734222 -1.741431 -0.001727 C 3.912804 -0.449042 1.273737 H 4.799240 -1.091700 1.277266 H 4.254158 0.591621 1.325196 H 3.333811 -0.663268 2.177387 C 3.914116 -0.446333 -1.273220 H 4.254853 0.594632 -1.322414 H 4.800938 -1.088450 -1.276901 H 3.336207 -0.659266 -2.177893 2e C 3.805904 0.141616 -0.160769 C 0.443225 0.391032 0.930413 N 6.277256 -1.891659 -0.893644 N 5.271222 -1.476717 -0.578871 N 4.109290 -1.204847 -0.207438 N 4.571041 1.179662 -0.455035 N 3.792906 2.275362 -0.242408 N 2.609391 1.952653 0.160451 N 2.586916 0.588390 0.222415 N 1.528791 -0.210324 0.606651 H 0.363711 1.480515 0.896582 C -0.750433 -0.405969 1.346325 H -1.034150 -0.092735 2.361837 H -0.476476 -1.464950 1.390056 C -1.955292 -0.191780 0.404954 H -2.180246 0.880251 0.342720 H -1.677867 -0.512813 -0.607909 C -3.196096 -0.970328 0.866705 H -3.493291 -0.619883 1.865877 H -2.920312 -2.027118 0.983572 C -4.402257 -0.878184 -0.084346 H -5.153268 -1.604120 0.249920 H -4.093881 -1.200175 -1.090053 C -5.045567 0.514698 -0.173898 H -4.296563 1.243740 -0.508416 H -5.355414 0.833235 0.832863 C -6.255172 0.597068 -1.122270

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H -6.544780 1.650872 -1.224851 H -5.948547 0.268148 -2.125178 C -7.479710 -0.210453 -0.671535 H -8.320560 -0.062017 -1.357680 H -7.274380 -1.285541 -0.635704 H -7.809282 0.098751 0.328031 2f C 1.826746 0.176948 -0.011014 N 4.749176 -1.319562 0.059552 N 3.634247 -1.116699 0.047902 N 2.385518 -1.086000 0.043442 N 2.431846 1.351106 -0.052015 N 1.432686 2.272243 -0.100226 N 0.266388 1.718990 -0.086213 N 0.484402 0.364954 -0.024328 N -0.430292 -0.663096 -0.030396 C -1.687798 -0.411151 0.037677 C -2.656230 -1.579036 0.024672 C -2.463794 0.891397 0.112593 C -4.005341 -0.939447 -0.349261 H -2.703287 -1.997030 1.040682 H -2.319320 -2.379309 -0.638715 C -3.931803 0.454196 0.306264 H -2.323253 1.437953 -0.828695 H -2.080203 1.553177 0.893161 H -4.082937 -0.839142 -1.439182 H -4.862360 -1.528659 -0.011283 H -4.639542 1.169180 -0.122338 H -4.157571 0.372833 1.376761 2g C -2.068481 0.167141 -0.019616 N -4.785712 -1.613176 0.466074 N -3.714974 -1.301067 0.264510 N -2.497724 -1.146204 0.031439 N -2.763099 1.275747 0.168804 N -1.876039 2.291721 -0.002000 N -0.690234 1.855768 -0.267374 N -0.775936 0.485646 -0.272099 N 0.182843 -0.433842 -0.652320 C 1.432977 -0.141893 -0.526341 C 2.394767 -1.200221 -0.998704 C 3.384623 -1.628796 0.118019 H 2.963627 -0.767692 -1.833706 H 1.838528 -2.053467 -1.392546

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H 2.945058 -2.450753 0.692645 H 4.284077 -2.029937 -0.361656 C 2.058101 1.108843 0.054629 H 1.919598 1.940552 -0.645471 H 1.498522 1.398827 0.951980 C 3.547099 0.899575 0.391914 H 4.157527 0.963905 -0.518215 H 3.881087 1.713606 1.043879 C 3.757218 -0.462320 1.067688 H 4.791605 -0.569955 1.410792 H 3.128675 -0.501224 1.967521

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TABLE S9. Calculated (B3LYP/6-31+G**//MP2/6-311++G**) Total Energy

(E0), Zero-Point Energy (ZPE), Values of Gibbs Free Energy Correction (GT)

Name E0

(au)

ZPE

(au)

GT

(au)

1c –564.4303039 0.117862 –0.035964

1d –564.4433898 0.117775 –0.035402

CF3N N CHCH3

CH3

BaseCF3N N C

CH3

CH31c X

CF3N N CCH3

CH3

H

1d

ΔG(1c−1d)

ΔG(1c–1d)= –0.012607 au = –33.1 kJ/mol Geometry Coordinates B3LYP/6-31+G(d,p) optimized geometries (Å) 1c F -0.033639 -0.076327 0.268775 C 0.140722 -0.046492 1.603078 F 1.459285 0.036768 1.860206 N -0.340742 -1.322029 2.145393 F -0.450565 1.057517 2.079312 N -1.242647 -1.186788 2.981617 C -1.729040 -2.467811 3.528894 C -1.479174 -2.442850 5.042037 C -3.220112 -2.574946 3.185533 H -1.170317 -3.290018 3.063442 H -1.853816 -3.369302 5.488289 H -1.995662 -1.597648 5.507758 H -0.410973 -2.362647 5.264754 H -3.623630 -3.503582 3.601009 H -3.376200 -2.587655 2.102683 H -3.777931 -1.732877 3.607170

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1d F -2.443005 1.010738 -0.086813 C -1.563686 -0.017646 -0.010635 F -1.753077 -0.601132 1.207784 N -0.268042 0.500130 -0.221423 F -1.888350 -0.937808 -0.931045 N 0.732228 -0.460941 -0.115777 C 1.941537 -0.039825 -0.024938 C 3.026173 -1.078268 0.053177 C 2.332311 1.420367 0.000917 H -0.135844 1.371442 0.289630 H 3.606853 -0.962585 0.977073 H 3.728353 -0.965597 -0.782692 H 2.596147 -2.080997 0.025632 H 3.417012 1.536931 -0.043048 H 1.988652 1.914526 0.920820 H 1.891402 1.958003 -0.847482

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