345:
260:
178:
160:
bind to strongly electrophilic metal centers of the type use in some catalytic reactions. Tetrafluoroborate and hexafluorophosphate anions are coordinating toward highly electrophilic metal ions, such as cations containing Zr(IV) centers, which can abstract
208:
and colloquially called "BARF". This anion is far less coordinating than tetrafluoroborate, hexafluorophosphate, and perchlorate, and consequently has enabled the study of still more electrophilic cations. Related tetrahedral anions include
512:
Honeychuck, R. V.; Hersh, W. H. (1989). "Coordination of "Noncoordinating" Anions: Synthesis, Characterization, and X-ray
Crystal Structures of Fluorine-Bridged , , and Adducts of . An Unconventional Order of Anion Donor Strength".
659:; B. Grant; A. F. Volpe, Jr. (1992). "-: a convenient reagent for generation and stabilization of cationic, highly electrophilic organometallic complexes".
458:. Using this anion, the first example of a three-coordinate silicon compound, the salt contains a non-coordinating anion derived from a carborane.
186:
567:
Santiso-Quiñones, Gustavo; Reisinger, Andreas; Slattery, John; Krossing, Ingo (2007). "Homoleptic Cu–phosphorus and Cu–ethene complexes".
692:
210:
721:
Jutzi, P.; MĂĽller, C.; Stammler, A.; Stammler, H. G. (2000). "Synthesis, Crystal
Structure, and Application of the Oxonium Acid ".
477:
121:
688:"Tetrakis(3,5-bis(trifluoromethyl)phenyl)borate. Highly lipophilic stable anionic agent for solvent-extraction of cations"
348:
The crystal structure of the compound ,. H atoms are omitted from the image. Color code: red = O, yellow = F, gray = C.
61:
cations (R = methyl or a growing polyethylene chain). Complexes derived from non-coordinating anions have been used to
181:
Structure of the weakly coordinating anion , illustrating its high symmetry. Color code: green = F, red = O, blue = Al.
849:
844:
544:
475:
I. Krossing & I. Raabe (2004). "Noncoordinating Anions - Fact or
Fiction? A Survey of Likely Candidates".
515:
369:
352:
The neutral molecules that represent the parents to the non-coordinating anions are strong Lewis acids, e.g.
88:
wherein hydrocarbons and hydrogen serve as ligands. Non-coordinating anions are important components of many
322:, tend to bind to electrophilic centers, in which cases, the use of a non-coordinating anion is pointless.
275:
243:
50:
781:
Kim, K.-C.; Reed, C. A.; Elliott, D. W.; Mueller, L. J.; Tham, F.; Lin, L.; Lambert, J. B. (2002).
748:
G.Erker (2005). "Tris(pentafluorophenyl)borane: a
Special Boron Lewis Acid for Special Reactions".
361:
337:
were first reported by
Kobayashi and co-workers. For that reason, it is sometimes referred to as
542:
Mayfield, H. G.; Bull, W. E. (1971). "Co-ordinating
Tendencies of the Hexafluorophosphate Ion".
84:. The popularization of non-coordinating anions has contributed to increased understanding of
120:
were considered weakly coordinating anions. Only by exclusion of conventional solvents were
77:
47:
796:
8:
750:
113:
800:
820:
633:
602:
812:
787:
763:
656:
638:
580:
494:
353:
109:
58:
824:
804:
755:
730:
701:
668:
628:
620:
572:
549:
524:
486:
267:
54:
43:
93:
780:
611:
295:
271:
85:
73:
69:
782:
344:
838:
307:
185:
A revolution in this area occurred in the 1990s with the introduction of the
65:
39:
35:
808:
816:
767:
642:
584:
498:
490:
311:
607:): Safe Preparation, Standardized Purification, and Analysis of Hydration"
341:. Kobayashi's method of preparation has been superseded by a safer route.
706:
687:
566:
553:
117:
685:
672:
528:
97:
734:
624:
53:, where the active catalyst is a coordinatively unsaturated, cationic
759:
686:
H. Nishida; N. Takada; M. Yoshimura; T. Sonods; H. Kobayashi (1984).
576:
434:
89:
655:
259:
166:
162:
62:
34:. Non-coordinating anions are useful in studying the reactivity of
290:. Another advantage of these anions is that their salts are more
299:
291:
433:
Another large class of non-coordinating anions are derived from
385:
303:
81:
57:
complex. For example, they are employed as counterions for the
23:
38:
cations. They are commonly found as counterions for cationic
511:
319:
19:
720:
177:
600:
603:"Sodium Tetrakis(3,5-trifluoromethyl)phenylborate (NaBArF
428:
315:
169:
are considered to be low-coordinating with some cations.
124:
found to exist, for example. It is now appreciated that
783:"Crystallographic Evidence for a Free Silylium Ion"
474:
46:. These special anions are essential components of
836:
541:
103:
705:
693:Bulletin of the Chemical Society of Japan
632:
596:
594:
368:. A notable Lewis acid of this genre is
266:In the bulky borates and aluminates, the
165:from these anions. Other anions, such as
16:Anion which interacts weakly with cations
343:
176:
747:
478:Angewandte Chemie International Edition
274:atoms. Related anions are derived from
270:is symmetrically distributed over many
92:, which result from the combination of
837:
591:
429:Other types of non-coordinating anions
294:in non-polar organic solvents such as
122:transition metal perchlorate complexes
601:N. A. Yakelis; R. G. Bergman (2005).
30:, although a more accurate term is
13:
258:
14:
861:
211:tetrakis(pentafluorophenyl)borate
774:
51:alkene polymerisation catalysts
44:unsaturated coordination sphere
741:
714:
679:
649:
560:
535:
505:
468:
172:
1:
461:
370:tris(pentafluorophenyl)borane
276:tris(pentafluorophenyl)boron
7:
302:, and, in some cases, even
10:
866:
201:, commonly abbreviated as
22:that interact weakly with
32:weakly coordinating anion
384:, which abstracts alkyl
362:phosphorus pentafluoride
850:Non-coordinating anions
809:10.1126/science.1073540
569:Chemical Communications
28:non-coordinating anions
845:Coordination chemistry
491:10.1002/anie.200300620
349:
263:
182:
347:
262:
180:
78:living polymerization
707:10.1246/bcsj.57.2600
554:10.1039/J19710002279
801:2002Sci...297..825K
751:Dalton Transactions
673:10.1021/om00059a071
529:10.1021/ic00313a034
516:Inorganic Chemistry
325:Salts of the anion
114:hexafluorophosphate
59:14 valence electron
350:
264:
183:
108:Before the 1990s,
795:(5582): 825–827.
754:(11): 1883–1890.
735:10.1021/om990612w
667:(11): 3920–3922.
625:10.1021/om0501428
619:(14): 3579–3581.
571:(47): 5046–5048.
548:(14): 2279–2281.
523:(14): 2869–2886.
485:(16): 2066–2090.
354:boron trifluoride
339:Kobayashi's anion
110:tetrafluoroborate
86:agostic complexes
857:
829:
828:
778:
772:
771:
760:10.1039/b503688g
745:
739:
738:
718:
712:
711:
709:
683:
677:
676:
653:
647:
646:
636:
598:
589:
588:
577:10.1039/b710899k
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558:
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539:
533:
532:
509:
503:
502:
472:
457:
456:
455:
447:
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336:
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241:
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231:
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222:
221:
207:
200:
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159:
158:
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147:
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135:
134:
133:
55:transition metal
865:
864:
860:
859:
858:
856:
855:
854:
835:
834:
833:
832:
779:
775:
746:
742:
723:Organometallics
719:
715:
684:
680:
661:Organometallics
654:
650:
612:Organometallics
606:
599:
592:
565:
561:
545:J. Chem. Soc. A
540:
536:
510:
506:
473:
469:
464:
454:
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431:
423:
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407:
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383:
379:
375:
367:
359:
333:
330:
329:
328:
326:
296:dichloromethane
289:
285:
281:
272:electronegative
268:negative charge
251:
248:
247:
246:
244:
238:
235:
234:
233:
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220:
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206:
202:
197:
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175:
156:
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152:
151:
149:
144:
141:
140:
139:
137:
132:
129:
128:
127:
125:
106:
74:oligomerization
70:hydrosilylation
40:metal complexes
17:
12:
11:
5:
863:
853:
852:
847:
831:
830:
773:
740:
713:
678:
648:
604:
590:
559:
534:
504:
466:
465:
463:
460:
452:
443:
430:
427:
426:
425:
421:
417:
413:
409:
405:
401:
397:
393:
381:
377:
373:
365:
357:
331:
308:Polar solvents
287:
283:
279:
249:
236:
227:
218:
204:
195:
187:tetrakisborate
174:
171:
154:
142:
130:
105:
104:Pre-"BARF" era
102:
94:Brønsted acids
15:
9:
6:
4:
3:
2:
862:
851:
848:
846:
843:
842:
840:
826:
822:
818:
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806:
802:
798:
794:
790:
789:
784:
777:
769:
765:
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753:
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744:
736:
732:
728:
724:
717:
708:
703:
699:
695:
694:
689:
682:
674:
670:
666:
662:
658:
652:
644:
640:
635:
630:
626:
622:
618:
614:
613:
608:
597:
595:
586:
582:
578:
574:
570:
563:
555:
551:
547:
546:
538:
530:
526:
522:
518:
517:
508:
500:
496:
492:
488:
484:
480:
479:
471:
467:
459:
436:
391:
390:
389:
387:
371:
363:
355:
346:
342:
340:
323:
321:
317:
313:
309:
305:
301:
297:
293:
277:
273:
269:
261:
257:
256:
212:
188:
179:
170:
168:
164:
123:
119:
115:
111:
101:
99:
95:
91:
87:
83:
79:
75:
71:
67:
66:hydrogenation
64:
60:
56:
52:
49:
45:
41:
37:
36:electrophilic
33:
29:
25:
21:
792:
786:
776:
749:
743:
726:
722:
716:
697:
691:
681:
664:
660:
657:M. Brookhart
651:
616:
610:
568:
562:
543:
537:
520:
514:
507:
482:
476:
470:
432:
351:
338:
324:
312:acetonitrile
265:
184:
107:
31:
27:
18:
729:(7): 1442.
700:(9): 2600.
173:Era of BARF
118:perchlorate
98:Lewis acids
48:homogeneous
26:are termed
839:Categories
462:References
310:, such as
90:superacids
76:, and the
435:carborane
167:triflates
817:12161650
768:15909033
643:19079785
585:18049748
499:15083452
163:fluoride
63:catalyze
42:with an
825:9072540
797:Bibcode
788:Science
634:2600718
386:ligands
304:alkanes
300:toluene
292:soluble
116:, and
82:alkenes
24:cations
823:
815:
766:
641:
631:
583:
497:
437:anion
318:, and
242:, and
203:B(ArF)
148:, and
20:Anions
821:S2CID
412:+ B(C
404:Zr(CH
372:, B(C
320:water
189:ion,
813:PMID
764:PMID
639:PMID
581:PMID
495:PMID
364:, PF
360:and
356:, BF
96:and
805:doi
793:297
756:doi
731:doi
702:doi
669:doi
629:PMC
621:doi
573:doi
550:doi
525:doi
487:doi
316:THF
306:.
278:B(C
214:B(C
150:ClO
80:of
841::
819:.
811:.
803:.
791:.
785:.
762:.
727:19
725:.
698:57
696:.
690:.
665:11
663:.
637:.
627:.
617:24
615:.
609:.
605:24
593:^
579:.
521:28
519:.
493:.
483:43
481:.
453:12
444:11
439:CB
424:→
392:(C
388::
314:,
298:,
245:Al
138:PF
136:,
126:BF
112:,
100:.
72:,
68:,
827:.
807::
799::
770:.
758::
737:.
733::
710:.
704::
675:.
671::
645:.
623::
587:.
575::
556:.
552::
531:.
527::
501:.
489::
448:H
422:3
420:)
418:5
416:F
414:6
410:2
408:)
406:3
402:2
400:)
398:5
396:H
394:5
382:3
380:)
378:5
376:F
374:6
366:5
358:3
332:4
327:B
288:3
286:)
284:5
282:F
280:6
255:.
250:4
237:4
232:)
228:5
223:F
219:6
205:4
196:4
191:B
155:4
143:6
131:4
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