High-Level Systematic ab Initio Comparison of Carbon- and Silicon-Centered SN2 Reactions Attila Á. Dékány, Gyula Z. Kovács, and Gábor Czakó* MTA-SZTE Lendület Computational Reaction Dynamics Research Group, Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science, Institute of Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary * E-mail: gczako@chem.u-szeged.hu 6 F/Cl C-XDITS F 0.0000000000 -0.2893281437 -2.2687906184 H 0.0000000000 0.1808696008 -1.3994614921 C 0.0000000000 1.1229667336 0.1420552288 Cl 0.0000000000 -0.3062312274 1.2250715303 H -0.9564402431 1.3310957170 -0.3098967245 H 0.9564402431 1.3310957170 -0.3098967245 6 F/Br C-XDITS F 0.0000000000 -0.3800543110 -2.8070617181 H 0.0000000000 0.1584835716 -1.9796929376 C 0.0000000000 1.2629440721 -0.5458284269 Br 0.0000000000 -0.1374330672 0.7998128096 H -0.9606432185 1.4251411724 -1.0056134472 H 0.9606432185 1.4251411724 -1.0056134472 6 F/I C-XDITS F 0.0000000000 -0.4404981826 -3.1564998394 H 0.0000000000 0.1188964062 -2.3510416255 C 0.0000000000 1.3288399976 -0.9661899839 I 0.0000000000 -0.0839690230 0.6056425076 H -0.9563616691 1.4605764205 -1.4466296964 H 0.9563616691 1.4605764205 -1.4466296964 6 Cl/Br C-XDITS Cl 0.0000000000 -0.1163040691 -2.6019831774 H 0.0000000000 0.1644929122 -1.3233691954 C 0.0000000000 1.7714178963 0.5866363386 Br 0.0000000000 -0.2613442307 1.0853133096 H -0.8735005001 1.7677035488 -0.0917601310 H 0.8735005001 1.7677035488 -0.0917601310 6 Cl/I C-XDITS Cl 0.0000000000 -0.2302661799 -3.0661756492 H 0.0000000000 0.4960745826 -1.8536567260 C 0.0000000000 1.5812995291 -0.3990590527 I 0.0000000000 -0.1146381048 0.9242680199 H -0.9322779405 1.5967316320 -0.9564083392 H 0.9322779405 1.5967316320 -0.9564083392 6 Br/I C-XDITS Br 0.0000000000 -0.0666857503 -2.4997688973 H 0.0000000000 0.1383528716 -1.0596876291 C 0.0000000000 2.0006304873 0.8460826703 I 0.0000000000 -0.1794501669 1.4996582176 H -0.8709457585 1.9508250667 0.1649952366 H 0.8709457585 1.9508250667 0.1649952366 6 F/Cl C-YDITS Cl 0.0000000000 0.0231111065 -1.5196830007 H 0.0000000000 0.2061678835 -0.2153557651 C 0.0000000000 0.7892109446 1.8756920548 F 0.0000000000 -0.6756938791 1.5224552705 H -0.8822050488 1.1561844209 1.3102124448 H 0.8822050488 1.1561844209 1.3102124448 6 F/Br C-YDITS Br 0.0000000000 -0.0126571271 -0.9605704360 H 0.0000000000 -0.1649584578 0.4962019725 C 0.0000000000 -0.7797995720 2.5761306352 F 0.0000000000 0.6782804330 2.1706559326 H 0.8812980283 -1.1619982538 2.0201485521 H -0.8812980283 -1.1619982538 2.0201485521 6 F/I C-YDITS I 0.0000000000 -0.0090890336 -0.7193197414 H 0.0000000000 -0.1372187920 0.9417009352 C 0.0000000000 -0.7698279215 3.0320411899 F 0.0000000000 0.6786640936 2.5742726242 H 0.8800080736 -1.1684103397 2.4859942000 H -0.8800080736 -1.1684103397 2.4859942000 6 Cl/Br C-YDITS Br 0.0000000000 0.0151782141 -1.3542754116 H 0.0000000000 -0.1387128590 0.0977737183 C 0.0000000000 -1.3926742405 2.1388732178 Cl 0.0000000000 0.5294259501 2.2405357304 H 0.8757948464 -1.5453864732 1.4831006700 H -0.8757948464 -1.5453864732 1.4831006700 6 Cl/I C-YDITS I 0.0000000000 -0.0072780533 -1.0470591005 H 0.0000000000 0.1257078852 0.6105501065 C 0.0000000000 1.3883983711 2.6576352751 Cl 0.0000000000 -0.5362960069 2.7162860170 H -0.8751966487 1.5547392504 2.0044400684 H 0.8751966487 1.5547392504 2.0044400684 6 Br/I C-YDITS I 0.0000000000 -0.0248192120 -1.6497718760 H 0.0000000000 0.2243935936 -0.0072633093 C 0.0000000000 1.7818390646 1.9234208896 Br 0.0000000000 -0.2771312518 2.2997466228 H -0.8728889936 1.8184332875 1.2456685705 H 0.8728889936 1.8184332875 1.2456685705 6 F/Cl C-FSTS-I C 0.0000046634 -1.0995828880 -0.7915801518 Cl -0.0000041880 0.1367095908 1.1707492556 F -0.0000066756 0.6576611409 -1.5404425910 H -0.0005588248 -1.8043528092 0.0316267351 H -0.9097586432 -1.1486594615 -1.3721336258 H 0.9105350300 -1.1486073160 -1.3709193965 6 F/Br C-FSTS-I C -0.0000001815 -1.1179863065 -1.4102057695 Br 0.0000001286 0.0497531215 0.7531413410 F 0.0000004174 0.7151875215 -2.0311190328 H 0.0000419850 -1.8782177296 -0.6384271230 H -0.9115166601 -1.1119890261 -1.9889170947 H 0.9114587788 -1.1119825073 -1.9890082275 6 F/I C-FSTS-I C -0.0000000104 -1.1241648784 -1.8293436078 I 0.0000000039 0.0236642499 0.5659757601 F 0.0000000216 0.7691919572 -2.3104298431 H 0.0000030312 -1.9284428548 -1.1037891890 H -0.9127183280 -1.0766723551 -2.4039613995 H 0.9127145270 -1.0766709430 -2.4039672672 6 Cl/Br C-FSTS-II C -1.6040607049 -0.0020713910 -0.8052168459 Cl 0.3994767291 0.0017994682 -2.2694545571 Br 0.1324703518 0.0007677129 1.1593334110 H -1.7959240125 0.5160725720 -1.7284172127 H -1.6477803962 -1.0784070067 -0.8405349012 H -1.9943041431 0.4628638300 0.0837397778 6 Cl/I C-FSTS-II C -1.6639061181 -0.0019047064 -1.3470343919 Cl 0.4524582550 0.0017728556 -2.6906415902 I 0.0754929778 0.0004452317 0.9120816842 H -1.7890843639 0.5199783955 -2.2790857447 H -1.6999830317 -1.0789055037 -1.3846542071 H -2.1028256428 0.4632091825 -0.4808962251 6 Br/I C-FSTS-II C -1.8707918708 -0.0018810112 -0.5886995507 Br 0.1987837228 0.0007510289 -2.2786338929 I 0.1011519182 0.0004419684 1.5047283517 H -2.0897853531 0.4962570764 -1.5165171947 H -1.9071791758 -1.0798158187 -0.5927328550 H -2.2040574212 0.4907897607 0.3082296749 6 F/Cl C-HMIN F 0.0000000000 -0.2573274794 -2.5610131423 H 0.0000000000 0.2533501191 -0.9971236367 C 0.0000000000 0.8447522382 -0.0434418222 Cl -0.0000000000 -0.2386946709 1.4129107277 H 0.8907256940 1.4631686770 0.0446734233 H -0.8907256940 1.4631686770 0.0446734233 6 F/Br C-HMIN F 0.0000000000 -0.3272805644 -3.1439603000 H 0.0000000000 0.3094763639 -1.6655574958 C 0.0000000000 0.9715267140 -0.7528413062 Br 0.0000000000 -0.1121872674 0.8989281904 H 0.8929176948 1.5879310794 -0.6828652390 H -0.8929176948 1.5879310794 -0.6828652390 6 F/I C-HMIN F 0.0000000000 -0.3929341822 -3.4500305073 H 0.0000000000 0.3562600872 -2.0756677117 C 0.0000000000 1.0645914852 -1.1865366758 I -0.0000000000 -0.0714809701 0.6631782051 H 0.8933994778 1.6819185321 -1.1271429498 H -0.8933994778 1.6819185321 -1.1271429498 6 Cl/I C-HMIN Cl 0.0000000000 -0.1510555773 -3.9170572947 H 0.0000000000 0.1534036364 -1.5340839029 C 0.0000000000 0.9028349109 -0.7422233624 I -0.0000000000 -0.0684658584 1.1890344511 H 0.8970955452 1.5107490306 -0.7750218369 H -0.8970955452 1.5107490306 -0.7750218369 6 F/Cl C-HTS F 0.0000000000 -0.1065531169 -2.7706056931 H 0.0000000000 -0.5855532389 -0.7987020302 C 0.0000000000 0.3117252017 -0.1918875606 Cl -0.0000000000 -0.0824480327 1.5946244208 H 0.8931905739 0.8896562765 -0.3905643510 H -0.8931905739 0.8896562765 -0.3905643510 6 F/Br C-HTS F 0.0000000000 -0.1312373234 -3.4707407156 H 0.0000000000 -0.5472830316 -1.5254941095 C 0.0000000000 0.3637500501 -0.9393830685 Br 0.0000000000 -0.0402585368 1.0140480593 H 0.8968215590 0.9389171437 -1.1247835886 H -0.8968215590 0.9389171437 -1.1247835886 6 F/I C-HTS F 0.0000000000 -0.1370706432 -3.8985504366 H 0.0000000000 -0.5757357497 -1.9589324691 C 0.0000000000 0.3571268664 -1.4088890548 I -0.0000000000 -0.0234136620 0.7580152174 H 0.8985206871 0.9257990379 -1.6039343760 H -0.8985206871 0.9257990379 -1.6039343760 6 F/Cl C-XFSMIN Cl -0.0000000004 0.0000000015 -0.2793109431 F -0.0000000014 -0.0000000028 2.2156468750 C 0.0000000002 0.0000000046 -2.0666545017 H 0.0000000000 1.0251100325 -2.4369023043 H 0.8877714052 -0.5125550539 -2.4369023278 H -0.8877713656 -0.5125550324 -2.4369025047 6 F/Br C-XFSMIN Br 0.0000000003 0.0000000006 -0.1206907282 F 0.0000000005 -0.0000000020 2.2292543387 C 0.0000000001 0.0000000027 -2.1025816361 H -0.0000000000 1.0273747037 -2.4652565992 H 0.8897326148 -0.5136873614 -2.4652567163 H -0.8897326476 -0.5136873806 -2.4652566096 6 F/I C-XFSMIN C -0.0000000000 0.0000000000 -2.2778675892 I -0.0000000000 0.0000000000 -0.0577603268 H 1.0275487770 0.0000000000 -2.6422375301 H -0.5137743885 -0.8898833445 -2.6422375301 H -0.5137743885 0.8898833445 -2.6422375301 F 0.0000000000 0.0000000000 2.2464633304 6 Cl/Br C-XFSMIN Br 0.0000000011 -0.0000000021 -0.6117065857 Cl -0.0000000007 0.0000000010 2.4965286704 C 0.0000000023 -0.0000000040 -2.5652279040 H 1.0286938419 0.0000000000 -2.9170637529 H -0.5143469073 -0.8908749934 -2.9170637962 H -0.5143470242 0.8908751699 -2.9170635639 6 Cl/I C-XFSMIN I -0.0000017763 0.0000017924 -0.4144952466 Cl 0.0000038615 -0.0000031214 2.6146693427 C -0.0000058364 0.0000053312 -2.5959802728 H 0.2483800791 -0.9988076505 -2.9485806752 H -0.9889039854 0.2842191869 -2.9484392815 H 0.7406812783 0.7144090537 -2.9486137937 6 Br/I C-XFSMIN C -0.0000000000 0.0000000000 -3.1891322462 I -0.0000000000 0.0000000000 -1.0113632630 H 1.0295753700 0.0000000000 -3.5385057217 H -0.5147876850 -0.8916384255 -3.5385057217 H -0.5147876850 0.8916384255 -3.5385057217 Br 0.0000000000 0.0000000000 2.2195626154 6 Cl/Br C-YFSMIN Cl 0.0000000007 0.0000000000 -1.9678084490 Br -0.0000000002 0.0000000001 1.5912290978 C 0.0000000012 -0.0000000000 -3.7444717091 H 1.0269159475 0.0000000000 -4.1027598034 H -0.5134579887 -0.8893353263 -4.1027598044 H -0.5134579846 0.8893353192 -4.1027598467 6 Cl/I C-YFSMIN Cl 0.0000000003 0.0000000021 -2.6355460764 I -0.0000000000 -0.0000000003 1.2674442319 C 0.0000000004 0.0000000032 -4.4118520996 H -0.0000000000 1.0273379045 -4.7677263942 H 0.8897007837 -0.5136689828 -4.7677264779 H -0.8897007927 -0.5136689895 -4.7677264897 6 Br/I C-YFSMIN Br 0.0000000003 -0.0000000006 -1.9338120632 I -0.0000000002 -0.0000000001 1.6858210471 C 0.0000000006 -0.0000000009 -3.8825084549 H 1.0297602013 0.0000000000 -4.2289772597 H -0.5148800855 -0.8917984718 -4.2289774184 H -0.5148801253 0.8917985352 -4.2289772504 6 F/Cl C-WPreMIN Cl 0.0000000000 0.0000000000 -1.9298012533 C 0.0000000000 0.0000000000 1.2528440801 F -0.0000000000 0.0000000000 2.6659037430 H 1.0259602986 0.0000000000 0.8999940203 H -0.5129801493 0.8885076819 0.8999940203 H -0.5129801493 -0.8885076819 0.8999940203 6 F/Br C-WPreMIN Br 0.0000000000 0.0000000000 -1.2323660744 C 0.0000000000 0.0000000000 2.1375127937 F -0.0000000000 0.0000000000 3.5477328119 H 1.0265127472 0.0000000000 1.7845159261 H -0.5132563736 0.8889861164 1.7845159261 H -0.5132563736 -0.8889861164 1.7845159261 6 F/I C-WPreMIN I 0.0000000000 0.0000000000 -0.9285121087 C 0.0000000000 0.0000000000 2.7084145354 F -0.0000000000 0.0000000000 4.1150965673 H 1.0271209163 0.0000000000 2.3553553480 H -0.5135604582 0.8895128063 2.3553553480 H -0.5135604582 -0.8895128063 2.3553553480 6 Cl/Br C-WPreMIN Br 0.0000000000 -0.0000000000 -1.7709909420 C 0.0000000000 -0.0000000000 1.5495354216 Cl -0.0000000000 0.0000000000 3.3635167388 H 1.0266648355 0.0000000000 1.2074235052 H -0.5133324178 0.8891178287 1.2074235052 H -0.5133324178 -0.8891178287 1.2074235052 6 Cl/I C-WPreMIN I 0.0000000000 0.0000000000 -1.3764152291 C 0.0000000000 0.0000000000 2.2097471299 Cl -0.0000000000 0.0000000000 4.0190566107 H 1.0270494043 0.0000000000 1.8670550554 H -0.5135247021 0.8894508750 1.8670550554 H -0.5135247021 -0.8894508750 1.8670550554 6 Br/I C-WPreMIN I 0.0000000000 0.0000000000 -2.2196979018 C 0.0000000000 0.0000000000 1.3176073489 Br -0.0000000000 0.0000000000 3.2898405715 H 1.0310759781 0.0000000000 0.9902862012 H -0.5155379891 0.8929379903 0.9902862012 H -0.5155379891 -0.8929379903 0.9902862012 6 F/Cl C-WPostMIN F 0.0000000000 0.0000000000 -2.7380229381 C 0.0000000000 0.0000000000 -0.2470553360 Cl -0.0000000000 0.0000000000 1.6000293449 H 1.0276541907 0.0000000000 -0.5755618797 H -0.5138270954 0.8899746355 -0.5755618797 H -0.5138270954 -0.8899746355 -0.5755618797 6 F/Br C-WPostMIN F 0.0000000000 0.0000000000 -3.4252235914 C 0.0000000000 0.0000000000 -1.0130673110 Br -0.0000000000 0.0000000000 1.0162583808 H 1.0354814840 0.0000000000 -1.3100581504 H -0.5177407420 0.8967532703 -1.3100581504 H -0.5177407420 -0.8967532703 -1.3100581504 6 F/I C-WPostMIN F 0.0000000000 0.0000000000 -3.8416842035 C 0.0000000000 0.0000000000 -1.4985912381 I -0.0000000000 0.0000000000 0.7591354716 H 1.0416398255 0.0000000000 -1.7702596762 H -0.5208199127 0.9020865504 -1.7702596762 H -0.5208199127 -0.9020865504 -1.7702596762 6 Cl/Br C-WPostMIN Cl 0.0000000000 0.0000000000 -3.4574652972 C 0.0000000000 0.0000000000 -0.3670723247 Br -0.0000000000 0.0000000000 1.6154104882 H 1.0307386122 0.0000000000 -0.6916207889 H -0.5153693061 0.8926458228 -0.6916207889 H -0.5153693061 -0.8926458228 -0.6916207889 6 Cl/I C-WPostMIN Cl 0.0000000000 -0.0000000000 -4.0108388164 C 0.0000000000 -0.0000000000 -0.9446950935 I -0.0000000000 0.0000000000 1.2400234079 H 1.0324018407 0.0000000000 -1.2641841301 H -0.5162009204 0.8940862210 -1.2641841301 H -0.5162009204 -0.8940862210 -1.2641841301 6 Br/I C-WPostMIN Br 0.0000000000 0.0000000000 -3.3197507914 C 0.0000000000 0.0000000000 -0.0736160181 I -0.0000000000 0.0000000000 2.1066020287 H 1.0324044584 0.0000000000 -0.3947337702 H -0.5162022292 0.8940884879 -0.3947337702 H -0.5162022292 -0.8940884879 -0.3947337702 6 F/Cl C-WTS F 0.0000000000 0.0000000000 -2.5455295775 C 0.0000000000 0.0000000000 -0.5185603927 Cl -0.0000000000 0.0000000000 1.5942025343 H 1.0641570875 0.0000000000 -0.6382115377 H -0.5320785438 0.9215870714 -0.6382115377 H -0.5320785438 -0.9215870714 -0.6382115377 6 F/Br C-WTS F 0.0000000000 0.0000000000 -3.2953609537 C 0.0000000000 0.0000000000 -1.1894124621 Br -0.0000000000 0.0000000000 1.0133746272 H 1.0599583093 0.0000000000 -1.3493057471 H -0.5299791546 0.9179508228 -1.3493057471 H -0.5299791546 -0.9179508228 -1.3493057471 6 F/I C-WTS F 0.0000000000 0.0000000000 -3.7825650936 C 0.0000000000 0.0000000000 -1.5822523592 I -0.0000000000 0.0000000000 0.7586499620 H 1.0537114448 0.0000000000 -1.7890111773 H -0.5268557224 0.9125408794 -1.7890111773 H -0.5268557224 -0.9125408794 -1.7890111773 6 Cl/Br C-WTS Cl 0.0000000000 0.0000000000 -3.1874519215 C 0.0000000000 0.0000000000 -0.8393876251 Br -0.0000000000 0.0000000000 1.5730286055 H 1.0705910718 0.0000000000 -0.8613806235 H -0.5352955359 0.9271590652 -0.8613806235 H -0.5352955359 -0.9271590652 -0.8613806235 6 Cl/I C-WTS Cl 0.0000000000 0.0000000000 -3.7595009190 C 0.0000000000 0.0000000000 -1.3641089226 I -0.0000000000 0.0000000000 1.2129755974 H 1.0705246037 0.0000000000 -1.4098904801 H -0.5352623019 0.9271015022 -1.4098904801 H -0.5352623019 -0.9271015022 -1.4098904801 6 Br/I C-WTS Br 0.0000000000 0.0000000000 -3.0956682421 C 0.0000000000 0.0000000000 -0.5952351758 I -0.0000000000 0.0000000000 2.0202449864 H 1.0715397851 0.0000000000 -0.6198626820 H -0.5357698925 0.9279806750 -0.6198626820 H -0.5357698925 -0.9279806750 -0.6198626820