325:
186:
364:
208:
198:
107:
223:
axis of the amine is presented as horizontal, and the pair of dots represent the lone pair of the nitrogen atom collinear with that axis. A mirror plane can be imagined to relate the two amine molecules on either side of the arrows. If the three R groups attached to the nitrogen are all unique, then
251:
of the nitrogen atom and substituents, the nitrogen "moving" through the plane formed by the substituents (although the substituents also move - in the other direction); the molecule passing through a
511:
Halpern, Arthur M.; Ramachandran, B. R.; Glendening, Eric D. (June 2007). "The
Inversion Potential of Ammonia: An Intrinsic Reaction Coordinate Calculation for Student Investigation".
134:; 5.8 kcal/mol), a narrow barrier width (distance between geometries), and the low mass of hydrogen atoms, which combine to give a further 80-fold rate enhancement due to
554:
Kölmel, C.; Ochsenfeld, C.; Ahlrichs, R. (1991). "An ab initio investigation of structure and inversion barrier of triisopropylamine and related amines and phosphines".
424:
395:
755:
693:
639:
252:
52:
784:
150:). Consequently, amines of the type RR′R"N usually are not optically stable (enantiomers racemize rapidly at room temperature), but
324:
774:
862:
MRostami; et al. (2017). "Design and synthesis of Ʌ-shaped photoswitchable compounds employing Tröger's base scaffold".
800:
Cleeton, C.E.; Williams, N.H. (1934). "Electromagnetic waves of 1.1 cm wave-length and the absorption spectrum of ammonia".
714:
655:
968:
978:
973:
889:
MKazem; et al. (2017). "Facile preparation of Λ-shaped building blocks: Hünlich base derivatization".
286:
due to a narrow tunneling barrier, and not due to thermal excitation. Superposition of two states leads to
352:
analogs (including the Hünlich's base) are examples of compounds whose nitrogen atoms are chirally stable
303:
287:
126:, inverting 30 billion times per second. Three factors contribute to the rapidity of the inversion: a low
745:
685:
259:
59:
809:
386:
348:
Conformational strain and structural rigidity can effectively prevent the inversion of amine groups.
248:
111:
48:
349:
944:
906:
571:
528:
283:
151:
135:
119:
32:
838:
780:
751:
689:
659:
620:
536:
337:
271:
185:
127:
74:. The general phenomenon of pyramidal inversion applies to many types of molecules, including
936:
898:
871:
846:
817:
722:
677:
651:
610:
602:
563:
520:
493:
466:
438:
404:
357:
255:
123:
55:
770:
709:
454:
813:
927:
MRostami, MKazem (2019). "Optically active and photoswitchable Tröger's base analogs".
615:
590:
170:
962:
948:
910:
575:
434:
363:
353:
318:
267:
263:
225:
63:
741:
429:
390:
313:
was slowed by a factor of 50 by placing the nitrogen atom in the vicinity of a
118:
The identity of the inverting atom has a dominating influence on the barrier.
67:
663:
540:
532:
433:, 2nd ed. (the "Gold Book") (1997). Online corrected version: (2006–) "
442:
310:
162:
158:
139:
95:
83:
75:
20:
902:
875:
821:
624:
497:
408:
837:
Mark W. Davies, Michael
Shipman, James H. R. Tucker, and Tiffany R. Walsh
640:"Quantum chemical study of the umbrella inversion of the ammonia molecule"
236:
71:
606:
940:
726:
567:
524:
484:
Arvi Rauk; Leland C. Allen; Kurt Mislow (1970). "Pyramidal
Inversion".
470:
91:
40:
36:
850:
207:
197:
333:
314:
166:
147:
131:
87:
79:
146:) inverts very slowly at room temperature (energy barrier: 132
51:
of the atom and substituents, the molecule or ion passing through a
773:; Robert Leighton; Matthew Sands (1965). "The Hamiltonian matrix".
106:
291:
240:
105:
750:(6th ed.), New York: Wiley-Interscience, pp. 142–145,
747:
Advanced
Organic Chemistry: Reactions, Mechanisms, and Structure
114:
for inversion of an amine and a phosphine. The y-axis is energy.
224:
the amine is chiral; whether it can be isolated depends on the
656:
10.1002/1097-461X(2000)80:1<1::AID-QUA1>3.0.CO;2-D
323:
638:
Ghosh, Dulal C.; Jana, Jibanananda; Biswas, Raka (2000).
367:
rigid Tröger's base scaffold prevents nitrogen inversion
169:, etc. are also optically stable near room temperature.
835:
Control of
Pyramidal Inversion Rates by Redox Switching
266:, nitrogen inversion provides a low energy pathway for
779:. Vol. III. Massachusetts, USA: Addison-Wesley.
712:(1970). "Nitrogen Inversion: Experiment and Theory".
457:(1970). "Nitrogen Inversion: Experiment and Theory".
591:"Chiral Phosphines in Nucleophilic Organocatalysis"
845:; 128(44) pp. 14260–14261; (Communication)
302:The inversion of ammonia was first detected by
589:Xiao, Y.; Sun, Z.; Guo, H.; Kwon, O. (2014).
8:
420:
418:
180:
951:– via The Royal Society of Chemistry.
644:International Journal of Quantum Chemistry
614:
332:The system interconverts by oxidation by
258:. For a compound that would otherwise be
58:. For a compound that would otherwise be
362:
184:
486:Angewandte Chemie International Edition
396:Angewandte Chemie International Edition
377:
317:alcohol group compared to the oxidized
183:
595:Beilstein Journal of Organic Chemistry
228:required for the molecule's inversion.
922:
920:
7:
430:Compendium of Chemical Terminology
14:
309:In one study the inversion in an
66:, pyramidal inversion allows its
206:
196:
173:can also influence the barrier.
776:The Feynman Lectures on Physics
393:(1970). "Pyramidal Inversion".
356:and therefore have significant
157:are. Appropriately substituted
328:Nitrogen inversion Davies 2006
47:) "turns inside out". It is a
1:
513:Journal of Chemical Education
189:Nitrogen inversion in ammonia
16:Fluxional scientific equation
290:, which is used in ammonia
995:
682:Chemistry of the Elements
680:; Earnshaw, Alan (1997).
214:
929:New Journal of Chemistry
715:Fortschr. Chem. Forsch.
443:10.1351/goldbook.P04956
235:Pyramidal inversion in
903:10.1055/s-0036-1588180
876:10.1055/s-0036-1588913
822:10.1103/PhysRev.45.234
498:10.1002/anie.197004001
459:Fortschr. Chem. Forsch
409:10.1002/anie.197004001
368:
329:
304:microwave spectroscopy
288:energy level splitting
216:Inversion of an amine.
190:
115:
686:Butterworth-Heinemann
678:Greenwood, Norman N.
366:
327:
188:
109:
120:Inversion of ammonia
35:in compounds with a
814:1934PhRv...45..234C
771:Feynman, Richard P.
740:Smith, Michael B.;
607:10.3762/bjoc.10.218
435:Pyramidal inversion
282:Ammonia exhibits a
112:reaction coordinate
25:pyramidal inversion
969:Physical chemistry
941:10.1039/C9NJ01372E
727:10.1007/BFb0050820
568:10.1007/BF01113258
525:10.1021/ed084p1067
471:10.1007/BFb0050820
369:
330:
284:quantum tunnelling
262:due to a nitrogen
245:nitrogen inversion
191:
177:Nitrogen inversion
155:-chiral phosphines
136:quantum tunnelling
116:
39:molecule, such as
29:umbrella inversion
979:Organic chemistry
935:(20): 7751–7755.
897:(13): 1641–1645.
851:10.1021/ja065325f
839:J. Am. Chem. Soc.
757:978-0-471-72091-1
695:978-0-08-037941-8
556:Theor. Chim. Acta
338:sodium dithionite
336:and reduction by
272:chiral resolution
270:, usually making
249:rapid oscillation
233:
232:
229:
49:rapid oscillation
33:fluxional process
986:
953:
952:
924:
915:
914:
886:
880:
879:
870:(6): 1214–1222.
859:
853:
832:
826:
825:
797:
791:
790:
767:
761:
760:
737:
731:
730:
706:
700:
699:
684:(2nd ed.).
674:
668:
667:
635:
629:
628:
618:
586:
580:
579:
562:(3–4): 271–284.
551:
545:
544:
508:
502:
501:
481:
475:
474:
451:
445:
422:
413:
412:
382:
358:optical activity
256:transition state
218:
210:
200:
181:
124:room temperature
56:transition state
994:
993:
989:
988:
987:
985:
984:
983:
974:Stereochemistry
959:
958:
957:
956:
926:
925:
918:
888:
887:
883:
861:
860:
856:
833:
829:
802:Physical Review
799:
798:
794:
787:
769:
768:
764:
758:
739:
738:
734:
708:
707:
703:
696:
688:. p. 423.
676:
675:
671:
637:
636:
632:
588:
587:
583:
553:
552:
548:
510:
509:
505:
483:
482:
478:
453:
452:
448:
423:
416:
387:Leland C. Allen
384:
383:
379:
374:
346:
300:
280:
278:Quantum effects
222:
179:
145:
138:. In contrast,
104:
46:
17:
12:
11:
5:
992:
990:
982:
981:
976:
971:
961:
960:
955:
954:
916:
881:
854:
827:
808:(4): 234–237.
792:
785:
762:
756:
732:
701:
694:
669:
630:
581:
546:
503:
492:(6): 400–414.
476:
446:
414:
403:(6): 400–414.
376:
375:
373:
370:
345:
342:
299:
296:
279:
276:
231:
230:
220:
212:
211:
204:
203: ⇌
201:
193:
192:
178:
175:
171:Steric effects
143:
128:energy barrier
103:
102:Energy barrier
100:
44:
15:
13:
10:
9:
6:
4:
3:
2:
991:
980:
977:
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967:
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950:
946:
942:
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923:
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917:
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840:
836:
831:
828:
823:
819:
815:
811:
807:
803:
796:
793:
788:
786:0-201-02118-8
782:
778:
777:
772:
766:
763:
759:
753:
749:
748:
743:
736:
733:
728:
724:
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705:
702:
697:
691:
687:
683:
679:
673:
670:
665:
661:
657:
653:
649:
645:
641:
634:
631:
626:
622:
617:
612:
608:
604:
601:: 2089–2121.
600:
596:
592:
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573:
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406:
402:
398:
397:
392:
388:
381:
378:
371:
365:
361:
359:
355:
354:stereocenters
351:
350:Tröger's base
343:
341:
339:
335:
326:
322:
320:
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312:
307:
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42:
38:
34:
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26:
22:
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746:
742:March, Jerry
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594:
584:
559:
555:
549:
516:
512:
506:
489:
485:
479:
462:
458:
449:
428:
400:
394:
380:
347:
331:
319:hydroquinone
308:
301:
281:
274:impossible.
268:racemization
264:stereocenter
244:
243:is known as
234:
215:
152:
122:is rapid at
117:
110:Qualitative
64:stereocenter
28:
24:
18:
721:: 311–377.
650:(1): 1–26.
519:(6): 1067.
465:: 311–377.
391:Kurt Mislow
385:Arvi Rauk;
226:free energy
130:(24.2
68:enantiomers
963:Categories
710:J. M. Lehn
455:J. M. Lehn
372:References
344:Exceptions
247:. It is a
163:sulfoxides
96:sulfoxides
84:phosphines
76:carbanions
949:164362391
864:Synthesis
664:1097-461X
541:0021-9584
533:1938-1328
311:aziridine
306:in 1934.
159:sulfonium
140:phosphine
62:due to a
37:pyramidal
21:chemistry
911:99294625
744:(2007),
625:25246969
576:98837101
315:phenolic
298:Examples
237:nitrogen
92:stibines
72:racemize
891:Synlett
810:Bibcode
616:4168899
167:arsines
161:salts,
88:arsines
41:ammonia
31:) is a
947:
909:
783:
754:
692:
662:
623:
613:
574:
539:
531:
334:oxygen
292:masers
260:chiral
253:planar
241:amines
148:kJ/mol
132:kJ/mol
94:, and
80:amines
60:chiral
53:planar
27:(also
945:S2CID
907:S2CID
572:S2CID
529:eISSN
425:IUPAC
219:The C
843:2006
781:ISBN
752:ISBN
690:ISBN
660:ISSN
621:PMID
537:ISSN
239:and
937:doi
899:doi
872:doi
847:doi
818:doi
723:doi
652:doi
611:PMC
603:doi
564:doi
521:doi
494:doi
467:doi
439:doi
437:".
405:doi
360:.
142:(PH
70:to
43:(NH
19:In
965::
943:.
933:43
931:.
919:^
905:.
895:28
893:.
868:49
866:.
841:;
816:.
806:45
804:.
719:15
658:.
648:80
646:.
642:.
619:.
609:.
599:10
597:.
593:.
570:.
560:82
558:.
535:.
527:.
517:84
515:.
488:.
463:15
461:.
427:,
417:^
399:.
389:;
340:.
321:.
294:.
165:,
98:.
90:,
86:,
82:,
78:,
23:,
939::
913:.
901::
878:.
874::
849::
824:.
820::
812::
789:.
729:.
725::
698:.
666:.
654::
627:.
605::
578:.
566::
543:.
523::
500:.
496::
490:9
473:.
469::
441::
411:.
407::
401:9
221:3
153:P
144:3
45:3
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