Table S1. Calculated electronic energies/Hartree, zero-point energy/Hartree, geometrical parameters, relative energy/kJmol-1 and dipole moment (in Debye) for stereoisomers of twist-chair 1 (TC1).
B3LYP/cc-pVDZ//
B3LYP/cc-pVDZ / -666.133904 / -666.1287866 / -666.1319046 / -666.1151213
ZPE / 0.147023 / 0.146758 / 0.146859 / 0.146202
Ere / 0 / 12.748 / 4.824 / 47.177
µ / 2.7761 / 1.7254 / 1.9717 / 1.4279
N1-S r1/ / 1.709 / 1.695 / 1.733 / 1.781
S-N2 r2/ / 1.730 / 1.760 / 1.720 / 1.711
N2-C1 r3/ / 1.464 / 1.466 / 1.469 / 1.469
C1-C2 r4/ / 1.541 / 1.535 / 1.546 / 1.534
C2-C3 r5/ / 1.541 / 1.542 / 1.544 / 1.544
C3-C4 r6/ / 1.536 / 1.539 / 1.538 / 1.544
C4-N1 r7/ / 1.473 / 1.481 / 1.464 / 1.486
N1-N2 r8/ / 2.798 / 2.676 / 2.674 / 2.639
C2-C4 r9/ / 2.616 / 2.635 / 2.612 / 2.608
N1-S-N2 θ1/° / 108.89 / 101.52 / 101.51 / 98.16
S-N2-C1 θ2/° / 117.95 / 115.16 / 115.80 / 114.76
N2-C1-C2 θ3/° / 117.56 / 111.33 / 118.69 / 111.22
C1-C2-C3 θ4/° / 114.82 / 116.04 / 115.34 / 116.84
C2-C3-C4 θ5/° / 116.49 / 117.54 / 115.89 / 115.29
C3-C4-N1 θ6/° / 116.89 / 118.01 / 111.79 / 121.00
C4-N1-S θ7/° / 122.71 / 119.77 / 119.23 / 115.19
N1-S-N2-C1 φ1/° / -66.69 / -87.26 / -67.17 / -100.08
S-N2-C1-C2 φ2/° / 56..91 / 71.47 / 54.49 / 78.56
N2-C1-C2-C3 φ3/° / -68.95 / -67.05 / -69.97 / -52.37
C1-C2-C3-C4 φ4/° / 88.94 / 84.49 / 88.12 / 73.46
C2-C3-C4-N1 φ5/° / -52.66 / -57.95 / -37.91 / -81.44
C3-C4-N1-S φ6 /° / -22.68 / -16.33 / -48.62 / 17.11
C4-N1-S-N2 φ7/° / 70.66 / 72.85 / 93.25 / 54.78
Table S2. Calculated electronic energies/Hartree,zero-point energy/Hartree, geometrical parameters, relative energy/kJmol-1 and dipole moment (in Debye) for stereoisomers of twist -chair 2 (TC2).
Structure TC2aa TC2ae TC2ea TC2eeB3LYP/cc-pVDZ/// B3LYP/cc-pVDZ / -666.130937 / -666.1278733 / -666.116548 / -666.1052811
ZPE / 0.146846 / 0.146917 / 0.145570 / 0.145639
Erel / 0 / 8.228 / 34.465 / 64.226
µ / 2.7406 / 1.6642 / 1.8412 / 1.4456
N1-S r1/ / 1.733 / 1.707 / 1.776 / 1.750
S-N2 r2/ / 1.717 / 1.748 / 1.688 / 1.761
N2-C1 r3/ / 1.465 / 1.470 / 1.468 / 1.479
C1-C2 r4/ / 1.537 / 1.535 / 1.536 / 1.532
C2-C3 r5/ / 1.544 / 1.546 / 1.542 / 1.538
C3-C4 r6/ / 1.532 / 1.536 / 1.540 / 1.534
C4--N1 r7/ / 1.478 / 1.484 / 1.466 / 1.458
C2-C4 r8/ / 2.594 / 2.614 / 2.580 / 2.541
N1- N2 r9/ / 2.841 / 2.709 / 2.733 / 2.741
N1-S-N2 θ1/° / 110.86 / 103.23 / 104.14 / 102.61
S-N2-C1 θ2/° / 116.38 / 112.84 / 117.52 / 114.10
N2-C1-C2 θ3/° / 117.54 / 111.26 / 117.78 / 116.29
C1-C2-C3 θ4/° / 116.62 / 117.58 / 116.28 / 118.50
C2-C3-C4 θ5/° / 115.01 / 115.99 / 113.67 / 111.64
C3-C4-N1 θ6/° / 116.06 / 116.28 / 118.28 / 117.21
C4-N1-S θ7/° / 121.84 / 118.58 / 121.27 / 122.96
N1-S-N2-C1 φ1/° / 75.84 / 94.85 / 82.44 / 83.84
S-N2-C1-C2 φ2/° / -65.55 / -76.45 / -70.33 / -70.92
N2-C1-C2-C3 φ3 /° / 58.71 / 55.47 / 54.73 / 57.67
C1-C2-C3-C4 φ4/° / -80.84 / -75.38 / -75.83 / -77.29
C2-C3-C4-N1 φ5/° / 81.10 / 82.91 / 82.01 / 82.14
C3-C4-N1-S φ6/° / -22.68 / -22.68 / -22.68 / -22.68
C4-N1-S-N2 φ7/° / -43.16 / -49.28 / -46.23 / -48.46
Table S3.Calculated electronic energies/Hartree, zero-point energy/Hartree, geometrical parameters, relative energy/kJmol-1 and dipole moment (in Debye) for stereoisomers of twist-chair 3 (TC3).
Structure TC3aa TC3ae TC3ea / TC3eeB3LYP/cc-pVDZ/// B3LYP/cc-Pvdz / -666.1325829 / -666.1228404 / -666.1267683 / -666.1158924
ZPE / 0.147161 / 0.146529 / 0.146529 / 0.146037
Erel / 0 / 23.938 / 20.701 / 40.902
µ / 2.8202 / 1.6667 / 1.5459 / 0.8226
N1-S r1/ / 1.719 / 1.697 / 1.756 / 1.722
S-N2 r2/ / 1.728 / 1.772 / 1.704 / 1.757
N2-C1 r3/ / 1.468 / 1.472 / 1.470 / 1.474
C1-C2 r4/ / 1.544 / 1.539 / 1.544 / 1.541
C2-C3 r5/ / 1.546 / 1.545 / 1.549 / 1.551
C3-C4 r6/ / 1.547 / 1.551 / 1.544 / 1.548
C4- N1 r7/ / 1.464 / 1.466 / 1.469 / 1.467
N1-S-N2 θ1/° / 109.54 / 102.53 / 102.26 / 96.90
S-N2-C1 θ2/° / 117.58 / 115.12 / 116.39 / 113.05
N2-C1-C2 θ3/° / 115.01 / 109.71 / 116.33 / 111.09
C1-C2-C3 θ4/° / 118.61 / 118.90 / 119.92 / 120.47
C2-C3-C4 θ5/° / 118.33 / 119.42 / 118.20 / 119.13
C3-C4-N1 θ6/° / 117.93 / 119.24 / 111.87 / 112.66
C4-N1-S θ7/° / 116.92 / 116.78 / 113.69 / 114.30
N1-S-N2-C1 φ1/° / 50.95 / 68.15 / 70.86 / 72.15
S-N2-C1-C2 φ2/° / -71.50 / -83.94 / -72.44 / -82.74
N2-C1-C2-C3 φ3/° / 85.53 / 84.72 / 82.09 / 82.74
C1-C2-C3-C4 φ4/° / -39.44 / -39.44 / -39.44 / -39.44
C2-C3-C4-N1 φ5/° / -36.51 / -31.73 / -34.65 / -30.95
C3-C4-N1-S φ6/° / 82.92 / 81.37 / 93.02 / 90.86
C4-N1-S-N2 φ7/° / -66.51 / -74.61 / -83.80 / -89.27
Table S4. Calculated electronic energies/Hartree, zero-point energy/Hartree, geometrical parameters, relative energy/kJmol-1 and dipole moment (in Debye) for stereoisomers of twist- chair 4 (TC4).
Structure TC4aa TC4ae TC4ea / TC4eeB3LYP/cc-pVDZ//
B3LYP/cc-pVDZ / -666.1169828 / -666.1120756 / -666.1306823 / -666.1270157
ZPE / 0.146281 / 0.146850 / 0.146799 / 0.146930
Erel / 34.623 / 48.984 / 0 / 9.967
µ / 2.1206 / 1.9336 / 2.7359 / 1.7474
N1-S r1/ / 1.746 / 1.761 / 1.737 / 1.724
S-N2 r2/ / 1.686 / 1.714 / 1.715 / 1.741
N2-C1 r3/ / 1.466 / 1.475 / 1.465 / 1.469
C1-C2 r4/ / 1.534 / 1.538 / 1.537 / 1.534
C2-C3 r5/ / 1.538 / 1.546 / 1.543 / 1.545
C3-C4 r6/ / 1.542 / 1.543 / 1.532 / 1.538
C4- N1 r7/ / 1.477 / 1.483 / 1.478 / 1.482
N1-S-N2 θ1/° / 106.42 / 100.66 / 110.90 / 103.57
S-N2-C1 θ2/° / 118.98 / 114.07 / 116.40 / 113.44
N2-C1-C2 θ3/° / 117.02 / 111.83 / 117.53 / 110.99
C1-C2-C3 θ4/° / 115.38 / 116.82 / 116.64 / 117.07
C2-C3-C4 θ5/° / 114.02 / 112.83 / 114.89 / 115.69
C3-C4-N1 θ6/° / 120.21 / 119.67 / 116.00 / 115.52
C4-N1-S θ7/° / 118.83 / 111.55 / 121.47 / 117.31
N1-S-N2-C1 φ 1/° / -81.77 / -99.78 / -76.06 / -94.64
S-N2-C1-C2 φ2/° / 72.39 / 80.72 / 66.19 / 79.55
N2-C1-C2-C3 φ3 /° / -55.02 / -47.41 / -58.15 / -53..10
C1-C2-C3-C4 φ 4/° / 73.59 / 64.98 / 79.99 / 71.71
C2-C3-C4-N1 φ5/° / -85.06 / -94.90 / -82.62 / -89.41
C3-C4-N1-S φ6/° / 30.09 / 41.47 / 25.52 / 35.29
C4-N1-S-N2 φ7/° / 38.85 / 38.84 / 41.10 / 38.84
Table S5. Calculated electronic energies/Hartree, zero-point energy/Hartree, geometrical parameters, relative energy/kJmol-1and dipole moment (in Debye) for stereoisomers of twist-chair 5 (TC5).
Structure TC5aa TC5ae TC5ea TC5eeB3LYP/cc-pVDZ//
B3LYP/cc-pVDZ / -666.1315934 / -666.1190786 / -666.1216384 / -666.1079371
ZPE / 0.147977 / 0.145973 / 0.146717 / 0.145993
Erel / 0 / 27.653 / 22.865 / 56.957
µ / 2.9167 / 2.1917 / 2.3612 / 0.4661
N1-S r1/ / 1.736 / 1.742 / 1.835 / 1.772
S-N2 r2/ / 1.736 / 1.737 / 1.689 / 1.772
N2-C1 r3/ / 1.466 / 1.460 / 1.468 / 1.479
C1-C2 r4/ / 1.541 / 1.538 / 1.535 / 1.538
C2-C3 r5/ / 1.538 / 1.540 / 1.536 / 1.538
C3-C4 r6/ / 1.541 / 1.547 / 1.539 / 1.538
C4—N r7/ / 1.466 / 1.472 / 1.471 / 1.479
N1-S-N2 θ1/° / 108.58 / 101.10 / 106.25 / 95.21
S-N2-C1 θ2/° / 118.76 / 119.81 / 120.10 / 116.21
N2-C1-C2 θ3/° / 114.05 / 108.89 / 113.43 / 108.84
C1-C2-C3 θ4/° / 117.85 / 115.97 / 116.48 / 116.31
C2-C3-C4 θ5/° / 117.85 / 118.58 / 116.97 / 116.31
C3-C4-N1 θ6/° / 114.05 / 114.29 / 111.82 / 108.83
C4-N1-S θ7/° / 118.76 / 117.87 / 114.65 / 116.21
N1-S-N2-C1 φ1/° / 38.85 / 62.49 / 54.71 / 47.89
S-N2-C1-C2 φ2/° / -84.86 / -99.46 / -90.17 / -103.02
N2-C1-C2-C3 φ3/° / 71.78 / 62.63 / 64.26 / 70.02
C1-C2-C3-C4 φ4/° / -54.32 / -50.70 / -56.91 / -45.36
C2-C3-C4-N1 φ5/° / 71.78 / 77.94 / 85.05 / 70.05
C3-C4-N1-S φ6/° / -84.86 / -84.65 / -84.60 / -103.03
C4-N1-S-N2 φ7/° / 38.84 / 25.49 / 25.49 / 47.87
Table S6. Calculated electronic energies/Hartree, zero-point energy/Hartree, geometrical parameters, relative energy/kJmol-1and dipole moment (in Debye) for stereoisomers of twist-boat 1 (TB1).
Structure TB1aa TB1 ea TB1ae / TB1eeB3LYP/cc-pVDZ//
B3LYP/cc-pVDZ / -666.1268317 / -666.1161705 / -666.1149616 / -666.1056539
ZPE / 0.147617 / 0.146877 / 0.147138 / 0.146399
Erel / 0 / 26.07 / 29.922 / 52.441
µ / 2.8250 / 1.9805 / 2.0927 / 0.2865
N1-S r1/ / 1.734 / 1.794 / 1.718 / 1.766
S-N2 r2/ / 1.734 / 1.707 / 1.799 / 1.766
N2-C1 r3/ / 1.463 / 1.467 / 1.471 / 1.471
C1-C2 r4/ / 1.564 / 1.559 / 1.550 / 1.557
C2-C3 r5/ / 1.539 / 1.539 / 1.541 / 1.539
C3-C4 r6/ / 1.564 / 1.561 / 1.566 / 1.557
C4-N1 r7/ / 1.463 / 1.467 / 1.466 / 1.471
C4-N2 r8/ / 3.179 / 3.094 / 2.994 / 2.931
C3-N2 r9/ / 2.902 / 2.894 / 2.770 / 2.737
N1-S-N2 θ1/° / 107.77 / 101.46 / 102.85 / 94.28
S-N2-C1 θ2/° / 118.13 / 118.88 / 116.02 / 116.00
N2-C1-C2 θ3/° / 116.65 / 116.38 / 111.11 / 111.52
C1-C2-C3 θ4/° / 114.55 / 114.38 / 113.19 / 113.92
C2-C3-C4 θ5/° / 114.55 / 114.29 / 114.71 / 113.92
C3-C4-N1 θ6/° / 116.65 / 111.46 / 116.21 / 111.52
C4-N1-S θ7/° / 118.13 / 114.81 / 118.48 / 116.00
N1-S-N2-C1 φ1/° / -45.06 / -44.46 / -62.17 / -54.10
S-N2-C1-C2 φ2/° / 61.88 / 64.59 / 66.74 / 80.72
N2-C1-C2-C3 φ3/° / 20.68 / 21.89 / 27.91 / 12.49
C1-C2-C3-C4 φ4/° / -80.25 / -77.09 / -81.69 / -73.43
C2-C3-C4-N1 φ5/° / 20.69 / 10.79 / 10.79 / 12.52
C3-C4-N1-S φ6/° / 61.87 / 77.71 / 66.73 / 80.71
C4-N1-S-N2 φ7/° / -45.07 / -55.00 / -34.91 / -54.13
Table S7. Calculated electronic energies/Hartree, zero-point energy/Hartree, geometrical parameters, relative energy/kJmol-1 and dipole moment (in Debye) for stereoisomers of twist-boat 2 (TB2).
Structure TB2aa TB2ea TB2ae TB2eeB3LYP/cc-pVDZ//
B3LYP/cc-pVDZ / -666.116696 / -666.104154 / -666.122806 / -666.1162433
ZPE / 0.146884 / 0.146227 / 0.147186 / 0.146911
Erel / 15.258 / 46.481 / 0 / 16.516
μ / 2.5862 / 1.8972 / 2.6294 / 1.6055
N1-S r1/ / 1.833 / 1.785 / 1.780 / 1.730
S-N2 r2/ / 1.687 / 1.745 / 1.708 / 1.769
N2-C1 r3/ / 1.480 / 1.498 / 1.489 / 1.497
C1-C2 r4/ / 1.528 / 1.526 / 1.535 / 1.530
C2-C3 r5/ / 1.547 / 1.550 / 1.546 / 1.552
C3-C4 r6/ / 1.540 / 1.553 / 1.533 / 1.539
C4-N1 r7/ / 1.469 / 1.471 / 1.470 / 1.476
C1-C4 r8/ / 3.038 / 3.018 / 3.053 / 3.025
N2-C4 r9/ / 2.927 / 2.874 / 2.967 / 2.889
S-C2 r10/ / 3.116 / 2.916 / 2.976 / 2.896
N1-C3 r11/ / 2.557 / 2.639 / 2.544 / 2.572
N1-S-N2 θ1/° / 107.17 / 96.50 / 107.05 / 101.42
S-N2-C1 θ2/° / 124.74 / 116.32 / 118.86 / 114.93
N2-C1-C2 θ3/° / 115.73 / 113.80 / 115.00 / 114.05
C1-C2-C3 θ4/° / 116.20 / 113.77 / 116.99 / 114.50
C2-C3-C4 θ5/° / 117.10 / 118.28 / 117.08 / 118.03
C3-C4-N1 θ6/° / 116.38 / 121.51 / 115.79 / 117.12
C4-N1-S θ7/° / 112.85 / 114.19 / 114.55 / 114.47
N1-S-N2-C1 φ1/° / -64.07 / -87.82 / -71.74 / -83.77
S-N2-C1-C2 φ2/° / 11.16 / 14.46 / 11.16 / 13.66
N2-C1-C2-C3 φ3/° / 64.32 / 65.90 / 65.88 / 65.30
C1-C2-C3-C4 φ4/° / -35.00 / -35.00 / -35.00 / -35.00
C2-C3-C4-N1 φ5/° / -61.61 / -52.90 / -59.51 / -57.73
C3-C4-N1-S φ6/° / 68.83 / 38.61 / 60.21 / 49.24
C4-N1-S-N2 φ7/° / 11.17 / 46.01 / 23.35 / 37.25
Table S8.Calculated electronic energies/Hartree, zero-point energy/Hartree, geometrical parameters, relative energy/kJmol-1 and dipole moment (in Debye) for stereoisomers of twist- boat 3 (TB3).
Structure TB3aa TB3ae TB3ea TB3eeB3LYP/cc-pVDZ//
B3LYP/cc-pVDZ / -666.1127645 / -666.1002679 / -666.1244648 / -666.1143314
ZPE / 0.147084 / 0.146093 / 0.147199 / 0.146317
Erel / 30.421 / 60.658 / 0 / 24.315
μ / 2.1014 / 2.2590 / 2.6339 / 1.7019
N1-S r1/ / 1.750 / 1.805 / 1.754 / 1.727
S-N2 r2/ / 1.687 / 1.745 / 1.704 / 1.755
N2-C1 r3/ / 1.485 / 1.488 / 1.481 / 1.483
C1-C2 r4/ / 1.527 / 1.531 / 1.531 / 1.537
C2-C3 r5/ / 1.553 / 1.563 / 1.557 / 1.567
C3-C4 r6/ / 1.543 / 1.547 / 1.534 / 1.536
C4--N1 r7/ / 1.470 / 1.471 / 1.471 / 1.475
C1-C4 r8/ / 2.933 / 2.834 / 2.996 / 2.880
N2-C4 r9/ / 2.954 / 2.902 / 3.037 / 2.946
S-C2 r10/ / 3.00 / 3.00 / 2.968 / 2.952
N1-C3 r11/ / 2.597 / 2.591 / 2.532 / 2.519
N1-S-N2 θ1/° / 104.40 / 101.20 / 108.02 / 103.58
S-N2-C1 θ2/° / 122.52 / 119.00 / 120.45 / 117.35
N2-C1-C2 θ3/° / 113.43 / 115.43 / 113.75 / 115.13
C1-C2-C3 θ4/° / 114.49 / 111.68 / 116.61 / 113.94
C2-C3-C4 θ5/° / 116.26 / 115.07 / 117.75 / 115.54
C3-C4-N1 θ6/° / 119.03 / 118.29 / 114.79 / 113.54
C4-N1-S θ7/° / 114.11 / 111.57 / 114.47 / 113.59
N1-S-N2-C1 φ1/° / 66.46 / 70.90 / 65.45 / 70.72
S-N2-C1-C2 φ2/° / 7.13 / 7.13 / 7.13 / 7.13
N2-C1-C2-C3 φ3/° / -72.63 / -73.45 / -69.85 / -69.90
C1-C2-C3-C4 φ4/° / 25.34 / 21.71 / 20.35 / 16.34
C2-C3-C4-N1 φ5/° / 65.33 / 72.09 / 68.93 / 74.70
C3-C4-N1-S φ6/° / -49.15 / -50.37 / -50.37 / -50.37
C4-N1-S-N2 φ7/° / -35.96 / -40.03 / -35.00 / -40.46
Table S9. Calculated electronic energies/Hartree, zero-point energy/Hartree, geometrical parameters, relative energy/kJmol-1 and dipole moment (in Debye) for stereoisomers of twist-boat 4 (TB4).
Structure TB4aa TB4ea TB4ae TB4eeB3LYP/cc-pVDZ//
B3LYP/cc-pVDZ / -666.1239418 / -666.1085277 / -666.1185711 / -666.1028583
ZPE / 0.147215 / 0.146903 / 0.147033 / 0.146547
Erel / 0 / 39.66 / 13.628 / 53.62
μ / 2.8388 / 2.5142 / 2.4688 / 1.1588
N1-S r1/ / 1.703 / 1.805 / 1.692 / 1.787
S-N2 r2/ / 1.798 / 1.752 / 1.859 / 1.821
N2-C1 r3/ / 1.467 / 1.471 / 1.473 / 1.479
C1-C2 r4/ / 2.628 / 1.547 / 1.544 / 1.543
C2-C3 r5/ / 1.537 / 1.541 / 1.535 / 1.535
C3-C4 r6/ / 1.536 / 1.524 / 1.531 / 1.521
C4--N r7/ / 1.471 / 1.487 / 1.475 / 1.488
S-C3 r8/ / 3.158 / 3.146 / 3.099 / 3.085
N2-C3 r9/ / 2.987 / 2.913 / 2.925 / 2.858
N1-S-N2 θ1/° / 107.63 / 104.02 / 106.91 / 103.83
S-N2-C1 θ2/° / 113.92 / 115.30 / 111.97 / 113.40
N2-C1-C2 θ3/° / 117.19 / 113.27 / 113.59 / 110.04
C1-C2-C3 θ4/° / 116.29 / 114.85 / 115.94 / 114.73
C2-C3-C4 θ5/° / 116.36 / 114.74 / 115.83 / 114.10
C3-C4-N1 θ6/° / 115.45 / 115.37 / 115.08 / 115.09
C4-N1-S θ7/° / 120.52 / 118.55 / 119.41 / 117.28
N1-S-N2-C1 φ1/° / -15.00 / -15.00 / -15.00 / -15.00
S-N2-C1-C2 φ2/° / 75.43 / 82.94 / 79.60 / 84.74
N2-C1-C2-C3 φ3/° / -29.43 / -37.42 / -35.41 / 40.30
C1-C2-C3-C4 φ4/° / -61.64 / -59.68 / -61.10 / -60.45
C2-C3-C4-N1 φ5/° / 50.30 / 55.66 / 54.92 / 59.45
C3-C4-N1-S φ6/° / 40.88 / 36.12 / 37.94 / 34.27
C4-N1-S-N2 φ7/° / -64.19 / -64.19 / -64.19 / -64.19
Table S10. Calculated electronic energies/Hartree, zero-point energy/Hartree, geometrical parameters, relative energy/kJmol-1and dipole moment (in Debye) for stereoisomers of twist- boat 5 (TB5).
Structure TB5aa TB5ea TB5ae / TB5eeB3LYP/cc-pVDZ//
B3LYP/cc-pVDZ / -666.1155493 / -666.1126249 / -666.1205977 / -666.1182064
ZPE / 0.146969 / 0.146820 / 0.147129 / 0.146733
Erel / 12.839 / 20.13 / 0 / 5.25
μ / 2.4817 / 2.1255 / 2.5779 / 1.9723
N1-S r1/ / 1.687 / 1.718 / 1.700 / 1.716
S-N2 r2/ / 1.762 / 1.752 / 1.752 / 1.783
N2-C1 r3/ / 1.470 / 1.474 / 1.472 / 1.476
C1-C2 r4/ / 1.547 / 1.551 / 1.538 / 1.543
C2-C3 r5/ / 1.538 / 1.543 / 1.539 / 1.543
C3-C4 r6/ / 1.529 / 1.530 / 1.532 / 1.532
C4-N1 r7/ / 1.483 / 1.473 / 1.487 / 1.475
C3-N2 r8/ / 3.134 / 3.147 / 3.080 / 3.124
S-C3 r9/ / 3.017 / 3.013 / 2.950 / 2.933
N1-S-N2 θ1/° / 106.40 / 100.28 / 107.79 / 101.68
S-N2-C1 θ2/° / 115.55 / 114.98 / 115.67 / 113.76
N2-C1-C2 θ3/° / 119.99 / 119.31 / 116.89 / 117.23
C1-C2-C3 θ4/° / 116.55 / 117.93 / 116.49 / 118.15
C2-C3-C4 θ5/° / 115.02 / 115.77 / 114.67 / 115.39
C3-C4-N1 θ6/° / 113.42 / 110.12 / 113.11 / 109.98
C4-N1-S θ7/° / 121.51 / 118.40 / 119.28 / 117.27
N1-S-N2-C1 φ1/° / -15.00 / -15.00 / -15.00 / -17.64
S-N2-C1-C2 φ2/° / -60.52 / -60.43 / -62.31 / -60.26
N2-C1-C2-C3 φ3/° / 44.28 / 42.48 / 46.58 / 45.66
C1-C2-C3-C4 φ4/° / 50.30 / 50.30 / 50.30 / 50.30
C2-C3-C4-N1 φ5/° / -65.40 / -52.03 / -69.04 / -56.98
C3-C4-N1-S φ6/° / -20.94 / -42.56 / -16.42 / -36.11
C4-N1-S- φ7/° / 73.15 / 90.09 / 71.14 / 88.47
Table S11. Calculated electronic energies/Haetree, zero-point energy/Hartree, geometrical parameters, relative energy/kJmol-1 and dipole moment (in Debye) for stereoisomers of boat (B).
B3LYP/cc-pVDZ//
B3LYP/cc-pVDZ / -666.1248174 / -666.1158056 / -666.1032441
ZPE / 0.147561 / 0.146554 / 0.145656
Erel / 0 / 21.045 / 51.694
μ / 2.6489 / 1.6763 / 2.6489
N1-S r1/ / 1.722 / 1.707 / 1.744
S-N2 r2/ / 1.722 / 1.775 / 1.744
N2-C1 r3/ / 1.477 / 1.489 / 1.482
C1-C2 r4/ / 1.533 / 1.535 / 1.540
C2-C3 r5/ / 1.564 / 1.563 / 1.563
C3-C4 r6/ / 1.533 / 1.536 / 1.540
C4--N1 r7/ / 1.477 / 1.479 / 1.482
N1-S-N2 θ1/° / 108.57 / 101.33 / 95.22
S-N2-C1 θ2/° / 117.58 / 114.91 / 115.14
N2-C1-C2 θ3/° / 113.91 / 116.72 / 117.08
C1-C2-C3 θ4/° / 117.89 / 116.42 / 117.96
C2-C3-C4 θ5/° / 117.89 / 118.13 / 117.99
C3-C4-N1 θ6/° / 113.91 / 114.55 / 117.15
C4-N1-S θ7/° / 117.58 / 115.60 / 115.10
N1-S-N2-C φ1/° / -53.52 / -75.15 / -74.05
S-N2-C1-C2 φ2/° / -29.03 / -5.61 / -11.64
N2-C1-C2-C3 φ3/° / 71.40 / 64.45 / 62.87
C1-C2-C3-C4 φ4/° / -0.01 / -9.68 / -0.13
C2-C3-C4-N1 φ5/° / -71.40 / -70.07 / -62.70
C3-C4-N1-S φ6/° / 29.05 / 35.10 / 11.60
C4-N1-S-N φ7/° / 53.50 / 53.82 / 74.04
Table S12. NBO stabilization energies/kJmol-1 for TC1.
Donor NBO (i) Acceptor NBO (j) TC1aa TC1ae TC1ea TC1ee
LP (1) N2 / BD*(1) C1-He / 2.97 / - / 2.76 / -LP (1) N2 / BD*(1) C1-Ha / 10.97 / 40.60 / 10.21 / 35.58
LP (1) N2 / BD*(1) C1-C2 / 45.29 / 10.26 / 45.59 / 16.20
LP (1) N1 / BD*(1) C4-Ha / 3.22 / 3.56 / 7.24 / 10.50
LP (1) N1 / BD*(1) C4-He / 29.34 / 26.12 / 45.04 / -
LP (1) N1 / BD*(1) C3-C4 / 22.65 / 21.26 / 5.73 / 28.34
LP (1) N1 / BD*(1) S-N2 / 67.19 / 56.80 / 40.14 / 4.98
LP (1) N2 / BD*(1) S-N1 / 55.72 / 25.79 / 47.09 / 42.36
LP (1) S / BD*(1) N1-H / 7.45 / 9.38 / - / -
LP (2) S / BD*(1) N1-H / 18.80 / 14.57 / 9.59 / -
LP (1) S / BD*(1) N2-H / 7.12 / - / 8.00 / 3.39
LP (2) S / BD*(1) N2-H / 15.66 / 3.98 / 13.23 / 9.96
LP (1) S / BD*(1) N1-C4 / 13.06 / 8.83 / 6.99 / 6.32
LP (2) S / BD*(1) N1-C4 / 23.40 / 26.20 / 22.52 / 16.41
LP (1) S / BD*(1) N2-C1 / 11.80 / 6.45 / 9.25 / 4.02
LP (2) S / BD*(1) N2-C1 / 16.33 / 17.54 / 16.83 / 19.67
Table S13. NBO stabilization energies/kJmol-1 for TC2.
Donor NBO (i) Acceptor NBO (j) TC2aa TC2ae TC2ea TC2ee
LP (1) N2 / BD*(1) C1-He / 4.77 / - / 6.57 / 2.30LP (1) N2 / BD*(1) C1-Ha / 9.54 / 37.42 / 8.20 / 36.96
LP (1) N2 / BD*(1) C1-C2 / 46.13 / 12.43 / 46.67 / 5.07
LP (1) N1 / BD*(1) C4-Ha / 25.62 / 23.48 / 29.93 / 31.02
LP (1) N1 / BD*(1) C4-He / 18.63 / 17.54 / 3.01 / 2.72
LP (1) N1 / BD*(1) C3-C4 / - / - / 28.42 / 28.80
LP (1) N1 / BD*(1) S-N2 / 56.09 / 53.58 / 7.07 / 2.13
LP (1) N2 / BD*(1) S-N1 / 64.21 / 31.19 / 63.75 / 18.29
LP (1) S / BD*(1) N1-H / 3.98 / 6.40 / - / -
LP (2) S / BD*(1) N1-H / 16.70 / 17.16 / - / -
LP (1) S / BD*(1) N2-H / 9.25 / - / 12.18 / -
LP (2) S / BD*(1) N2-H / 18.29 / 6.95 / 16.37 / -
LP (1) S / BD*(1) N1-C4 / 16.53 / 11.93 / 11.13 / 5.86
LP (2) S / BD*(1) N1-C4 / 14.65 / 19.09 / 14.73 / 22.56
LP (1) S / BD*(1) N2-C1 / 10.63 / 5.90 / 7.74 / 2.13
LP (2) S / BD*(1) N2-C1 / 16.37 / 14.99 / 22.48 / 20.43
Table S14. NBO stabilization energies/kJmol-1 for TC3.
Donor NBO (i) Acceptor NBO (j) TC3aa TC3ae TC3ea
/TC3ee
LP (1) N2 / BD*(1) C1-He / 7.49 / - / - / -LP (1) N2 / BD*(1) C1-Ha / 4.40 / 36.25 / 4.23 / 36.29
LP (1) N2 / BD*(1) C1-C2 / 40.98 / 12.35 / 42.27 / 11.22
LP (1) N1 / BD*(1) C4-Ha / 2.55 / 2.89 / 26.91 / 26.96
LP (1) N1 / BD*(1) C4-He / 12.89 / 12.56 / - / -
LP (1) N1 / BD*(1) C3-C4 / 45.84 / 47.80 / 19.21 / 21.85
LP (1) N1 / BD*(1) S-N2 / 62.12 / 58.39 / 25.20 / 34.16
LP (1) N2 / BD*(1) S-N1 / 56.51 / 14.19 / 53.62 / 15.70
LP (1) S / BD*(1) N1-H / 6.66 / 10.38 / - / 2.43
LP (2) S / BD*(1) N1-H / 20.89 / 16.12 / 3.85 / 6.32
LP (1) S / BD*(1) N2-H / 4.73 / - / 7.95 / -
LP (2) S / BD*(1) N2-H / 20.89 / - / 17.12 / -
LP (1) S / BD*(1) N1-C4 / 13.23 / 8.71 / 6.82 / 4.27
LP (2) S / BD*(1) N1-C4 / 13.52 / 19.97 / 15.19 / 19.46
LP (1) S / BD*(1) N2-C1 / 14.99 / 7.79 / 10.55 / 5.02
LP (2) S / BD*(1) N2-C1 / 10.97 / 15.45 / 16.45 / 16.58
Table S15. NBO stabilization energies/kJmol-1 for TC4.
Donor NBO (i) Acceptor NBO (j) TC4aa TC4ae TC4ea
/TC4ee
LP (1) N2 / BD*(1) C1-He / 7.12 / - / 4.94 / -LP (1) N2 / BD*(1) C1-Ha / 8.37 / 33.03 / 9.46 / 35.75
LP (1) N2 / BD*(1) C1-C2 / 46.30 / 15.86 / 46.13 / 14.69
LP (1) N1 / BD*(1) C4-Ha / 17.25 / 6.61 / 27.08 / 29.30
LP (1) N1 / BD*(1) C4-He / - / - / 17.41 / 12.52
LP (1) N1 / BD*(1) C3-C4 / 39.81 / 39.39 / - / -
LP (1) N1 / BD*(1) S-N2 / - / - / 54.17 / 45.29
LP (1) N2 / BD*(1) S-N1 / 65.34 / 41.69 / 65.13 / 34.58
LP (1) S / BD*(1) N1-H / - / - / 3.73 / 5.07
LP (2) S / BD*(1) N1-H / - / - / 16.41 / 16.03
LP (1) S / BD*(1) N2-H / 12.73 / 3.14 / 9.25 / -
LP (2) S / BD*(1) N2-H / 16.58 / 8.58 / 18.80 / 8.12
LP (1) S / BD*(1) N1-C4 / 12.77 / 7.95 / 16.62 / 12.31
LP (2) S / BD*(1) N1-C4 / 12.39 / 10.00 / 13.44 / 13.40
LP (1) S / BD*(1) N2-C1 / 7.58 / 3.47 / 10.72 / 5.99
LP (2) S / BD*(1) N2-C1 / 25.20 / 20.43 / 16.28 / 15.40
Table S16. NBO stabilization energies/kJmol-1 for TC5.
Donor NBO (i) Acceptor NBO (j) TC5aa TC5ae TC5ea
/TC5ee
LP (1) N2 / BD*(1) C1-He / 13.69 / 5.32 / 15.53 / -LP (1) N2 / BD*(1) C1-Ha / - / 20.22 / - / 22.35
LP (1) N2 / BD*(1) C1-C2 / 34.70 / 26.04 / 33.86 / 15.91
LP (1) N1 / BD*(1) C4-Ha / - / - / 39.01 / 22.35
LP (1) N1 / BD*(1) C4-He / 13.69 / 12.77 / - / -
LP (1) N1 / BD*(1) C3-C4 / 34.70 / 32.27 / 9.54 / 15.91
LP (1) N1 / BD*(1) S-N2 / 50.82 / 33.82 / - / 5.27
LP (1) N2 / BD*(1) S-N1 / 50.78 / 26.87 / 74.01 / 5.27
LP (1) S / BD*(1) N1-H / 3.89 / - / - / -
LP (2) S / BD*(1) N1-H / 16.58 / 15.49 / 2. 30 / -
LP (1) S / BD*(1) N2-H / 3.89 / - / 4.48 / -
LP (2) S / BD*(1) N2-H / 16.58 / - / 26.12 / -
LP (1) S / BD*(1) N1-C4 / 15.11 / 17.79 / - / 10.21
LP (2) S / BD*(1) N1-C4 / 9.92 / - / 2.76 / 9.67
LP (1) S / BD*(1) N2-C1 / 15.11 / 6.24 / 16.91 / 10.21
LP (2) S / BD*(1) N2-C1 / 9.92 / 24.11 / 12.85 / 9.67
Table S17. NBO stabilization energies/kJmol-1 for TB1.
Donor NBO (i) Acceptor NBO (j) TB1aa TB1ea TB1ae
/TB1ee
LP (1) N2 / BD*(1) C1-He / 4.69 / 5.61 / 3.77 / -LP (1) N2 / BD*(1) C1-Ha / 7.37 / 6.24 / 39.39 / 34.95
LP (1) N2 / BD*(1) C1-C2 / 48.47 / 45.67 / 5.65 / 14.02
LP (1) N1 / BD*(1) C4-Ha / 7.37 / 38.64 / 4.81 / 34.95
LP (1) N1 / BD*(1) C4-He / 4.69 / - / 6.53 / -
LP (1) N1 / BD*(1) C3-C4 / 48.47 / 12.89 / 45.75 / 14.02
LP (1) N1 / BD*(1) S-N2 / 50.99 / 6.11 / 46.05 / 8.20
LP (1) N2 / BD*(1) S-N1 / 50.99 / 51.66 / 7.66 / 8.16
LP (1) S / BD*(1) N1-H / 4.56 / - / - / -
LP (2) S / BD*(1) N1-H / 16.49 / - / 19.42 / -
LP (1) S / BD*(1) N2-H / 4.56 / 2.47 / - / -
LP (2) S / BD*(1) N2-H / 16.49 / 21.31 / - / -
LP (1) S / BD*(1) N1-C4 / 14.23 / 7.41 / 18.33 / 10.13
LP (2) S / BD*(1) N1-C4 / 10.72 / 12.77 / 4.10 / 10.93
LP (1) S / BD*(1) N2-C1 / 14.23 / 17.54 / 6.40 / 10.13
LP (2) S / BD*(1) N2-C1 / 10.72 / 7.79 / 16.53 / 10.93
Table S18. NBO stabilization energies/kJmol-1 for TB2.
Donor NBO (i) Acceptor NBO (j) TB2aa TB2ae TB2ea TB2ee
LP (1) N2 / BD*(1) C1-He / 28.34 / 25.20 / 14.65 / 14.82LP (1) N2 / BD*(1) C1-Ha / 7.74 / 6.28 / 18.46 / 18.67
LP (1) N2 / BD*(1) C1-C2 / 12.31 / 13.73 / 4.40 / 4.73
LP (1) N1 / BD*(1) C4-Ha / - / 39.60 / 14.82 / 33.70
LP (1) N1 / BD*(1) C4-He / 6.74 / 4.19 / - / 7.33
LP (1) N1 / BD*(1) C3-C4 / 38.47 / 3.56 / 44.04 / -
LP (1) N1 / BD*(1) S-N2 / 6.74 / 29.30 / 2.47 / 39.47
LP (1) N2 / BD*(1) S-N1 / 82.59 / 66.26 / 27.54 / 22.81
LP (1) S / BD*(1) N1-H / - / 2.13 / - / 4.90
LP (2) S / BD*(1) N1-H / 4.60 / 12.26 / - / 16.03
LP (1) S / BD*(1) N2-H / 9.38 / 7.33 / - / -
LP (2) S / BD*(1) N2-H / 17.33 / 18.71 / - / -
LP (1) S / BD*(1) N1-C4 / 10.17 / 12.81 / 6.28 / 11.09
LP (2) S / BD*(1) N1-C4 / - / 3.68 / 11.68 / 9.92
LP (1) S / BD*(1) N2-C1 / 10.84 / 11.64 / 2.76 / 5.86
LP (2) S / BD*(1) N2-C1 / 33.24 / 22.94 / 29.68 / 22.73
Table S19. NBO stabilization energies/kJmol-1 for TB3.
Donor NBO (i) Acceptor NBO (j) TB3aa TB3ea TB3ae TB3ee
LP (1) N2 / BD*(1) C1-He / 24.45 / 24.95 / 5.73 / 8.46LP (1) N2 / BD*(1) C1-Ha / 19.72 / 20.34 / 23.78 / 25.95
LP (1) N2 / BD*(1) C1-C2 / 2.64 / 2.64 / 16.07 / 13.94
LP (1) N1 / BD*(1) C4-Ha / 9.21 / 37.67 / 7.12 / 34.91
LP (1) N1 / BD*(1) C4-He / 2.13 / 7.33 / - / 7.49
LP (1) N1 / BD*(1) C3-C4 / 45.17 / - / 41.82 / -
LP (1) N1 / BD*(1) S-N2 / - / 40.14 / - / 43.07
LP (1) N2 / BD*(1) S-N1 / 67.35 / 69.70 / 21.60 / 22.27
LP (1) S / BD*(1) N1-H / - / 3.31 / - / 5.69
LP (2) S / BD*(1) N1-H / - / 16.24 / - / 16.49
LP (1) S / BD*(1) N2-H / 9.59 / 6.53 / - / -
LP (2) S / BD*(1) N2-H / 17.96 / 22.56 / - / 2.22
LP (1) S / BD*(1) N1-C4 / 11.26 / 13.14 / 5.23 / 10.47
LP (2) S / BD*(1) N1-C4 / 8.16 / 7.12 / 9.33 / 11.47
LP (1) S / BD*(1) N2-C1 / 9.63 / 13.69 / 2.97 / 7.74
LP (2) S / BD*(1) N2-C1 / 33.28 / 22.35 / 31.23 / 22.44
Table S20. NBO stabilization energies/kJmol-1 for TB4.
Donor NBO (i) Acceptor NBO (j) TB4aa TB4ea TB4ae TB4ee
LP (1) N2 / BD*(1) C1-He / 9.21 / 12.14 / - / -LP (1) N2 / BD*(1) C1-Ha / - / - / 37.21 / 31.23
LP (1) N2 / BD*(1) C1-C2 / 41.53 / 32.65 / 6.11 / 7.49
LP (1) N1 / BD*(1) C4-Ha / 19.67 / 12.98 / - / 13.23
LP (1) N1 / BD*(1) C4-He / - / 25.24 / 20.68 / 22.90
LP (1) N1 / BD*(1) C3-C4 / 35.75 / - / 29.68 / -
LP (1) N1 / BD*(1) S-N2 / 71.92 / 8.12 / 68.61 / 9.04
LP (1) N2 / BD*(1) S-N1 / 22.77 / 28.84 / 7.83 / 4.94
LP (1) S / BD*(1) N1-H / 8.29 / - / 5.19 / -
LP (2) S / BD*(1) N1-H / 17.16 / - / 22.23 / -
LP (1) S / BD*(1) N2-H / - / - / - / -
LP (2) S / BD*(1) N2-H / 11.51 / 14.53 / 2.68 / -
LP (1) S / BD*(1) N1-C4 / 11.55 / 3.64 / 14.48 / 2.85
LP (2) S / BD*(1) N1-C4 / 23.82 / 23.73 / 14.65 / 22.77
LP (1) S / BD*(1) N2-C1 / 12.64 / 15.82 / 12.31 / 10.76
LP (2) S / BD*(1) N2-C1 / - / - / - / -
Table S21. NBO stabilization energies/kJmol-1 for TB5.
Donor NBO (i) Acceptor NBO (j) TB5aa TB5ea TB5ae TB5ee
LP (1) N2 / BD*(1) C1-He / 5.48 / 4.94 / 3.64 / 3.77LP (1) N2 / BD*(1) C1-Ha / 4.90 / 4.31 / 38.68 / 34.58
LP (1) N2 / BD*(1) C1-C2 / 46.51 / 44.25 / 3.98 / 2.97
LP (1) N1 / BD*(1) C4-Ha / 4.60 / 9.46 / 6.61 / 11.93
LP (1) N1 / BD*(1) C4-He / 28.63 / 40.69 / 27.84 / 40.19
LP (1) N1 / BD*(1) C3-C4 / 16.33 / 2.55 / 12.85 / -
LP (1) N1 / BD*(1) S-N2 / 72.79 / 43.37 / 71.04 / 49.86
LP (1) N2 / BD*(1) S-N1 / 5.69 / 4.94 / 28.26 / 22.06
LP (1) S / BD*(1) N1-H / 9.92 / 2.68 / 7.33 / 2.22
LP (2) S / BD*(1) N1-H / 17.96 / 6.20 / 23.44 / 11.13
LP (1) S / BD*(1) N2-H / - / - / - / 2.47
LP (2) S / BD*(1) N2-H / 5.86 / 5.53 / 12.89 / 10.63
LP (1) S / BD*(1) N1-C4 / 9.46 / 3.43 / 12.64 / 7.07
LP (2) S / BD*(1) N1-C4 / 32.48 / 30.85 / 22.60 / 24.78
LP (1) S / BD*(1) N2-C1 / 14.36 / 12.43 / 15.49 / 11.01
LP (2) S / BD*(1) N2-C1 / - / 2.68 / - / 2.97
Table S22. NBO stabilization energies/kJmol-1 for B.
Donor NBO (i) Acceptor NBO (j) Baa Bae Bee
LP (1) N2 / BD*(1) C1-He / 16.24 / - / 5.11LP (1) N2 / BD*(1) C1-Ha / 31.14 / 14.69 / 22.73
LP (1) N2 / BD*(1) C1-C2 / - / 37.63 / 18.63
LP (1) N1 / BD*(1) C4-Ha / 31.14 / 23.44 / 22.73
LP (1) N1 / BD*(1) C4-He / 16.20 / 22.90 / 5.15
LP (1) N1 / BD*(1) C3-C4 / - / - / 18.63
LP (1) N1 / BD*(1) S-N2 / 57.52 / 68.52 / 20.51
LP (1) N2 / BD*(1) S-N1 / 57.52 / 3.43 / 20.60
LP (1) S / BD*(1) N1-H / 5.20 / 8.71 / -
LP (2) S / BD*(1) N1-H / 20.13 / 19.38 / -
LP (1) S / BD*(1) N2-H / 5.20 / - / -
LP (2) S / BD*(1) N2-H / 20.13 / - / -
LP (1) S / BD*(1) N1-C4 / 13.81 / 10.21 / 4.60
LP (2) S / BD*(1) N1-C4 / 15.91 / 29.22 / 23.78
LP (1) S / BD*(1) N2-C1 / 13.81 / 7.62 / 4.65
LP (2) S / BD*(1) N2-C1 / 15.95 / 11.05 / 23.86