Supplement 1. The frequencies of (R and S) transition states of DIPAM, ChxIPAM, BzIPAM, and iPIPAM from B3LYP/3-21G optimized geometries

B3LYP/3-21G

The frequencies of (R-) transition state of DIPAM

-483.8630 21.8922 36.0726

40.6564 45.5333 56.4978

61.7412 82.5414 97.4639

137.6754 146.3370 164.2820

168.3033 177.6212 181.3218

188.7159 190.1887 193.5684

201.8598 211.0582 233.3674

241.4850 247.1601 252.4549

257.6179 268.8012 279.3588

283.7396 298.3793 322.2443

340.3650 357.4467 372.8547

379.8927 395.5735 403.7154

411.5753 411.7123 418.8831

424.6954 429.3755 455.5871

466.2030 480.1128 488.7938

509.8580 541.4780 563.7598

564.5717 577.2509 621.0512

627.1741 639.0321 647.9098

672.2484 736.8856 766.6894

795.0004 804.5764 816.1032

821.9694 823.6931 834.0641

839.2910 846.2893 859.9785

862.3042 869.5641 904.4747

905.6212 910.6086 928.2698

934.8194 938.4924 952.7718

954.8446 960.7226 969.5078

981.1329 982.9296 984.0278

992.6594 1005.8857 1008.8903

1027.6269 1029.1477 1033.5877

1039.5802 1046.2788 1050.0461

1056.9182 1059.6579 1062.4124

1070.6817 1075.9029 1079.0509

1108.2175 1117.0873 1118.5918

1134.8257 1138.7529 1143.6038

1156.8335 1157.6456 1182.4623

1187.3737 1189.8953 1203.9765

1211.0101 1218.3597 1236.4902

1237.3475 1240.5219 1242.8144

1246.7889 1251.3667 1253.0659

1275.1587 1278.5485 1281.5903

1304.0193 1307.4423 1310.5893

1311.4683 1319.3857 1324.4118

1338.0747 1355.4365 1359.7584

1362.6186 1376.3492 1382.8011

1383.7903 1384.8666 1390.3965

1392.6330 1396.6748 1397.9433

1402.1258 1402.8221 1418.0198

1443.3776 1445.4383 1449.1067

1450.1250 1452.1455 1466.0541

1468.5610 1473.7992 1525.8478

1535.3239 1540.7755 1546.3687

1549.8079 1552.7424 1553.5153

1554.6287 1556.8422 1558.7349

1559.4299 1564.2769 1565.5302

1565.8034 1567.0254 1572.2594

1574.5654 1579.0916 1582.7977

1584.5764 1596.7887 3000.4278

3022.1784 3026.8579 3037.7977

3038.5405 3040.7734 3043.3285

3043.9877 3044.7869 3046.1029

3047.0802 3049.3193 3054.8101

3064.0081 3066.7777 3068.8451

3070.3270 3072.8709 3075.0807

3080.3828 3082.1495 3083.9263

3085.2212 3085.7301 3086.6993

3089.7226 3092.3818 3093.6213

3094.8166 3104.9749 3105.5862

3108.8589 3112.2258 3120.7551

3124.0587 3126.5381 3128.9386

3129.0865 3145.7012 3152.5515

3174.4714 3175.6516 3213.1933

The frequencies of (R-) transition state of ChxIPAM

-424.4115 21.1668 34.9880

48.0941 55.7209 63.6312

73.6658 91.8095 112.1569

144.7007 175.9430 178.9847

182.4908 190.2156 194.7304

202.2175 219.9102 235.8695

242.8362 254.5435 261.1310

273.9798 293.0996 304.3939

332.8943 348.4855 357.9184

371.8273 396.0889 407.3455

422.6275 425.2121 434.0954

447.1451 457.3252 473.7141

491.9710 510.7129 516.4864

564.1142 570.5398 615.2778

631.2174 638.6144 675.6800

739.7258 785.2183 800.0723

805.1038 805.9049 818.4794

830.9646 837.1891 844.0389

847.8760 863.7000 869.4394

900.8647 905.1286 911.4165

924.2914 935.4395 937.3668

945.3093 953.3697 964.7813

979.8892 983.4276 997.3086

1000.4417 1015.2754 1028.8958

1036.1441 1040.8456 1043.9457

1054.3110 1060.0656 1063.0315

1072.2694 1080.8998 1081.6116

1092.3124 1110.1862 1118.0549

1130.3150 1138.1530 1153.7495

1172.7140 1179.5755 1188.5342

1195.5428 1213.8189 1219.8086

1223.4335 1237.0125 1240.1398

1249.1905 1267.9822 1275.6593

1284.5552 1293.5103 1303.6660

1311.8819 1314.3258 1320.2398

1323.3453 1337.9517 1355.8572

1361.3547 1364.4365 1374.0148

1381.2796 1384.1688 1387.7390

1391.5249 1394.4936 1395.9142

1396.4886 1400.3213 1404.9066

1406.6279 1407.9270 1413.2413

1444.7061 1447.7035 1452.3593

1467.9176 1475.6594 1527.0387

1532.8393 1536.7485 1538.3320

1543.1857 1545.7914 1550.6664

1551.4073 1553.8698 1557.0417

1558.3230 1561.1962 1565.1226

1567.6841 1573.2618 1579.6409

1582.4453 1598.0240 3002.7567

3027.5521 3028.0139 3029.2618

3030.0933 3032.8585 3036.8922

3037.4102 3038.6939 3041.2781

3042.9670 3043.5843 3046.7760

3053.3704 3058.0928 3059.4976

3068.8123 3072.2483 3072.7726

3075.0150 3079.5421 3082.3602

3082.6377 3084.7115 3085.8552

3089.8146 3094.1405 3094.5819

3096.4403 3099.4347 3101.9380

3106.6226 3124.6128 3128.3078

3143.5644 3178.1495 3209.1954

The frequencies of (R-) transition state of BzIPAM

-458.8409 17.0007 34.5076

41.9327 47.1849 50.4230

62.0677 84.7749 90.3562

139.9761 156.7287 176.3132

187.5562 188.5604 195.1255

204.5225 216.7196 225.3749

234.6816 264.1002 277.6806

288.5845 294.7705 304.3728

333.9918 358.3227 366.5955

391.5845 408.0078 419.6422

420.7139 430.5709 442.9305

465.3315 482.4787 487.5750

505.6764 531.4450 565.7801

573.3761 621.2472 638.7485

648.0807 659.2386 675.0552

734.1898 737.6438 762.5112

790.8023 805.5374 812.3835

819.3394 829.4313 836.6327

846.3166 864.5294 867.8097

873.1130 904.7157 916.3388

929.4657 937.7254 940.5641

953.6726 960.2590 980.3602

983.4364 996.1998 1003.4514

1011.4541 1024.8576 1028.8506

1031.6210 1037.1301 1039.6837

1048.1513 1055.7613 1061.5172

1064.4310 1070.6330 1079.2638

1081.4833 1111.6080 1117.9623

1120.1919 1140.0379 1149.7508

1155.3632 1187.3437 1191.0129

1195.7849 1215.7797 1222.0245

1228.5059 1236.1766 1238.1477

1243.0300 1248.1205 1250.9998

1277.1205 1284.4482 1289.8936

1305.0717 1314.3278 1319.6599

1329.9411 1338.4818 1359.3514

1362.6971 1367.8414 1378.9508

1386.9244 1387.6670 1394.4203

1404.3761 1404.6136 1413.2375

1414.5333 1444.1080 1449.8906

1454.6974 1470.9373 1472.3440

1506.1173 1528.6389 1529.5366

1533.6675 1544.1247 1549.9555

1550.5509 1554.1078 1557.4623

1559.3119 1564.5733 1567.3421

1573.3618 1582.4078 1584.7869

1591.4236 1616.0484 1631.2869

2962.4140 3003.4344 3021.3359

3026.6815 3029.6293 3032.6108

3038.1641 3041.1809 3043.4174

3047.8845 3050.2926 3056.2467

3074.7712 3076.7779 3083.3161

3083.5459 3085.8808 3086.6699

3093.6264 3095.3532 3097.8826

3100.7900 3112.5804 3121.9476

3142.0171 3142.5192 3171.7615

3172.7350 3184.8781 3195.2097

3208.8034 3211.7932 3232.2703

The frequencies of (R-) transition state of iPIPAM

-425.1601 27.0515 32.0363

52.7869 67.6140 80.7806

89.8522 111.2909 140.8950

171.1739 180.4930 187.7499

195.6504 198.5256 218.4040

223.7388 241.7599 251.5140

259.9480 270.5396 272.7761

276.9922 297.8847 317.3906

354.5110 356.7564 371.5127

388.4813 408.9869 411.2824

423.7237 440.8657 454.5533

475.9026 492.3603 518.9851

566.2653 567.8397 572.1089

630.1183 640.0987 674.0083

728.1856 785.1412 800.9827

814.9979 818.7073 832.1374

842.4049 847.2775 864.7345

867.7730 906.0663 919.7407

923.5953 934.3203 937.9178

953.5213 963.2235 965.2930

978.8510 983.2080 997.6202

1000.3226 1016.8289 1030.4803

1037.9961 1044.8656 1060.4137

1062.9257 1072.3324 1081.5052

1109.7546 1118.3287 1131.3980

1138.7224 1154.2001 1157.7782

1182.8974 1185.3906 1197.2554

1202.4623 1216.7975 1222.6314

1237.4798 1240.3795 1249.2176

1269.0725 1276.1032 1284.7396

1305.2386 1314.0165 1320.5954

1337.9382 1358.5627 1362.5071

1376.0167 1378.9084 1384.3613

1386.9267 1394.2428 1395.2468

1396.0120 1405.9475 1406.8610

1434.0022 1444.5671 1448.7005

1450.1891 1453.9874 1469.8606

1475.1771 1525.9076 1534.4045

1543.8130 1549.3373 1551.2439

1553.8027 1556.7314 1558.2075

1560.2332 1565.6944 1566.8261

1567.1286 1572.5855 1573.8938

1582.7998 1584.0450 1599.3731

3020.7238 3029.2474 3030.0351

3036.2620 3037.6827 3037.8716

3041.2008 3043.3610 3043.8413

3047.4946 3051.2270 3059.0921

3059.3579 3071.8612 3076.0921

3082.4663 3082.7570 3085.0197

3091.0583 3094.6871 3095.0245

3098.6120 3099.6278 3102.6928

3106.1924 3108.6794 3114.2694

3122.0462 3124.2750 3130.8103

3143.3987 3177.3671 3208.9022

The frequencies of (S-) transition state of DIPAM.

-522.9617 22.7231 35.9302

40.5852 48.0913 53.7801

64.2440 69.8831 94.3647

125.4617 143.0129 152.1833

166.1826 173.9548 180.8087

185.5548 188.8667 192.4021

194.1382 205.2598 230.7863

239.8212 247.1530 258.6616

261.6259 264.8174 268.4114

284.0844 289.5360 324.2973

340.4539 369.0038 379.0358

383.4719 396.4241 401.8332

411.1635 415.4778 419.8485

422.0958 431.2232 459.7578

466.2669 474.2340 483.6826

495.5859 516.0561 540.3545

564.9398 574.6353 621.0164

626.7622 638.7225 649.8522

703.8010 741.1835 757.4490

792.5204 802.8959 815.7797

817.4264 820.4961 833.7030

838.3669 854.1716 860.6845

866.3699 869.6160 903.7004

908.3688 910.3091 930.2851

933.7844 939.3691 953.2052

958.8135 963.5249 965.0429

976.2355 981.7402 984.3404

988.9181 1005.0125 1010.4816

1027.4502 1028.2494 1032.8030

1037.8728 1045.2039 1047.7800

1058.3678 1059.5751 1065.6603

1069.4734 1076.0843 1084.3891

1104.8258 1115.6392 1118.3876

1126.4678 1138.1397 1143.4860

1153.5766 1156.8222 1180.8842

1186.7967 1201.9297 1205.6184

1211.7861 1221.5888 1227.3870

1235.6751 1236.0950 1239.5625

1242.6300 1249.2613 1251.4767

1274.3839 1278.3315 1288.5196

1303.2443 1307.4236 1309.8707

1311.2672 1319.6515 1323.3622

1326.5042 1360.0562 1363.1046

1371.0501 1372.7485 1374.7841

1381.4687 1384.6922 1387.6106

1392.1981 1395.7078 1399.4718

1400.1876 1405.1740 1420.1584

1423.3673 1444.4493 1449.1243

1450.7701 1452.5485 1462.6121

1467.5574 1473.4934 1529.2784

1536.5167 1542.2690 1543.3521

1546.9533 1549.4592 1551.8942

1554.1970 1555.0880 1557.5200

1558.3437 1564.2466 1564.9846

1567.5609 1568.4962 1571.6600

1574.4982 1575.4928 1581.5148

1584.4276 1610.3804 3002.5577

3003.9976 3022.2984 3037.8099

3038.7742 3043.2576 3043.4327

3044.3911 3047.9461 3048.9610

3049.5809 3051.4777 3061.9249

3064.1867 3067.0319 3071.0651

3072.3724 3074.7290 3076.8400

3082.8925 3084.4228 3084.9667

3085.6786 3087.9721 3089.8056

3094.1073 3094.9886 3095.2057

3102.3364 3104.8320 3107.7842

3110.4121 3112.2555 3121.9453

3126.5732 3127.9139 3129.3627

3131.1096 3146.7683 3154.2675

3173.2292 3180.7037 3212.9731

The frequencies of (S-) transition state of ChxIPAM

-481.7936 16.1789 36.3075

49.5010 53.6597 57.3241

63.9078 75.4440 125.1195

136.3848 149.9149 169.6944

183.6525 188.1493 193.9313

208.8306 211.3656 233.2681

238.6794 244.4220 266.6151

272.2951 291.3411 305.2664

341.0522 354.4740 371.3315

379.9642 397.7392 408.6254

419.2185 425.7920 435.6468

448.7185 460.6566 469.1733

485.3843 492.4183 512.1188

520.4936 568.6511 621.2243

632.4263 640.7198 701.5529

739.8971 783.0956 796.9959

804.8698 807.7653 816.9103

822.1379 834.4181 843.1231

852.6478 863.9899 869.0841

901.5042 905.7418 911.0388

918.6806 935.7655 939.5594

946.1553 954.6487 966.3073

977.6641 980.3316 982.9168

1004.3760 1019.7814 1024.2349

1032.1333 1042.9081 1045.3617

1055.8387 1060.7521 1063.6969

1072.8637 1082.8608 1089.2527

1099.9246 1108.4228 1117.7558

1131.6505 1139.1758 1150.1003

1155.2214 1179.5422 1191.2999

1200.8043 1214.0321 1221.7771

1222.3946 1237.3938 1239.2620

1240.6012 1249.4349 1276.1385

1288.7651 1295.0361 1303.7416

1313.2072 1315.1618 1321.6041

1323.1577 1327.5228 1358.1674

1366.4348 1368.7335 1371.7184

1375.6771 1382.7802 1387.5443

1388.0038 1392.5833 1395.9709

1397.1690 1400.4789 1404.5007

1405.1461 1410.8698 1418.7606

1423.6305 1448.7682 1451.8645

1464.6619 1471.0529 1531.1585

1535.4080 1539.4094 1540.8979

1544.2814 1546.6684 1547.2733

1548.8729 1552.1265 1553.7083

1557.5002 1558.4793 1563.8377

1566.4760 1569.6354 1573.1017

1584.7308 1613.5139 2951.5771

3022.7653 3024.1027 3030.7914

3031.9863 3033.1566 3034.7379

3037.6284 3040.5048 3043.3079

3043.5410 3048.5410 3052.9169

3054.4433 3056.9375 3061.0452

3069.6779 3072.9813 3073.3788

3078.9533 3080.8651 3081.0269

3082.4963 3085.2411 3088.2697

3092.8910 3094.2568 3096.3803

3098.3044 3102.8235 3108.3601

3119.6616 3123.8154 3133.4713

3142.7411 3173.8699 3213.3836

The frequencies of (S-) transition state of BzIPAM

-525.6084 16.2375 28.1118

36.7469 44.5098 47.4687

60.0330 65.9478 83.3145

127.7549 144.9398 151.5081

189.3084 192.9931 197.4240

204.6331 224.1674 231.4703

236.8414 262.0011 280.2917

293.0198 295.9148 307.5198

334.3920 359.2566 388.2890

389.2852 407.1649 414.8415

419.2892 427.9040 445.0451

464.7627 476.6993 483.8623

494.9796 509.1975 528.2435

574.0693 620.7454 638.9294

649.3068 659.6636 704.3149

733.0658 739.0728 766.4249

789.5202 799.7960 812.2948

821.7119 823.6713 835.8863

853.2908 864.4039 865.4788

871.3336 902.5172 911.9065

923.9389 936.4026 941.6197

955.9233 958.8032 977.3573

979.1532 982.7216 1001.0584

1006.8310 1022.6231 1027.1773

1028.8326 1035.4739 1036.3627

1043.3195 1048.6964 1058.3859

1061.6194 1063.7070 1077.7779

1089.8432 1104.9042 1119.1860

1120.4901 1125.6962 1138.8766

1154.1019 1187.4680 1198.5805

1202.6525 1215.1848 1224.3741

1228.7809 1229.5646 1236.9992

1237.8357 1242.5025 1248.9699

1275.2190 1282.4015 1289.3245

1305.4520 1316.6848 1320.3610

1330.6906 1331.5481 1363.7117

1365.3353 1371.6157 1374.3439

1376.6407 1385.5041 1390.9463

1401.7370 1404.8798 1412.8671

1415.2914 1421.1738 1450.1227

1455.1988 1465.1283 1469.5140

1507.7365 1529.9979 1534.3490

1541.1842 1541.8085 1548.2981

1550.9545 1551.8945 1555.4829

1556.5877 1564.2807 1567.7828

1572.8278 1575.2721 1584.1317

1616.2588 1622.7329 1631.4301

2967.0772 2988.4059 3001.7106

3025.2044 3029.9629 3038.1030

3040.5907 3044.4369 3044.9118

3049.8705 3053.2165 3063.1879

3074.2747 3076.0519 3081.9041

3083.0191 3086.5723 3093.5397

3095.1422 3098.7077 3103.5379

3112.0606 3119.9689 3122.3286

3141.4291 3142.4698 3166.1182

3174.0636 3184.7194 3195.1059

3210.2103 3210.5612 3220.1625

The frequencies of (S-) transition state of iPIPAM

-469.3617 27.3803 38.2619

48.6093 58.1000 64.3389

73.4719 112.5408 129.9801

150.0237 179.5029 187.0824

190.9074 199.9279 222.2193

230.7309 242.6865 247.9092

256.7633 270.4005 275.3654

281.1945 297.6075 328.5148

359.8229 372.2813 385.9977

389.0128 409.9542 413.2357

420.2768 437.5479 453.8749

471.7767 482.8302 492.8589

524.1297 568.3166 574.6367

630.0978 642.3501 705.2207

732.4628 782.6083 797.9768

811.3267 819.1117 824.7873

837.0701 852.6156 865.3791

867.1620 906.7096 914.5606

927.7483 933.2418 939.2113

954.9991 964.3108 967.7911

974.9754 979.7170 984.3053

1001.9308 1022.9154 1027.5052

1035.7689 1043.6548 1060.4369

1061.7381 1073.8290 1090.9916

1109.1808 1118.6339 1128.4939

1137.9799 1150.8849 1155.6508

1182.1392 1189.7854 1201.4993

1203.9763 1217.5238 1223.2845

1237.6536 1241.9296 1245.6462

1250.7216 1277.5994 1289.6365

1306.0400 1314.7916 1323.3349

1329.0094 1361.9492 1370.8137

1372.2237 1376.8754 1379.2701

1384.0322 1390.1306 1396.3435

1403.9401 1405.6240 1414.3523

1421.3640 1436.6288 1448.8285

1451.8343 1452.4222 1467.7963

1469.0401 1532.4193 1541.2387

1542.3601 1548.6176 1550.3344

1551.1193 1554.4110 1556.8972

1560.6279 1563.3000 1566.3670

1567.2687 1568.7143 1573.2594

1575.7284 1584.2521 1621.3874