In:
Chemistry – A European Journal, Wiley, Vol. 28, No. 34 ( 2022-06-15)
Abstract:
The primary phosphines MesPH 2 and t BuPH 2 react with 9‐iodo‐ m ‐carborane yielding B9‐connected secondary carboranylphosphines 1,7‐H 2 C 2 B 10 H 9 ‐9‐PHR (R=2,4,6‐Me 3 C 6 H 2 (Mes; 1 a ), t Bu ( 1 b )). Addition of tris(pentafluorophenyl)borane (BCF) to 1 a , b resulted in the zwitterionic compounds 1,7‐H 2 C 2 B 10 H 9 ‐9‐PHR( p ‐C 6 F 4 )BF(C 6 F 5 ) 2 ( 2 a , b ) through nucleophilic para substitution of a C 6 F 5 ring followed by fluoride transfer to boron. Further reaction with Me 2 SiHCl prompted a H−F exchange yielding the zwitterionic compounds 1,7‐H 2 C 2 B 10 H 9 ‐9‐PHR( p ‐C 6 F 4 )BH(C 6 F 5 ) 2 ( 3 a , b ). The reaction of 2 a , b with one equivalent of R'MgBr (R’=Me, Ph) gave the extremely water‐sensitive frustrated Lewis pairs 1,7‐H 2 C 2 B 10 H 9 ‐9‐PR( p ‐C 6 F 4 )B(C 6 F 5 ) 2 ( 4 a , b ). Hydrolysis of the B−C 6 F 4 bond in 4 a , b gave the first tertiary B ‐carboranyl phosphines with three distinct substituents, 1,7‐H 2 C 2 B 10 H 9 ‐9‐PR( p ‐C 6 F 4 H) ( 5 a , b ). Deprotonation of the zwitterionic compounds 2 a , b and 3 a , b formed anionic phosphines [1,7‐H 2 C 2 B 10 H 9 ‐9‐PR( p ‐C 6 F 4 )BX(C 6 F 5 ) 2 ] − [DMSOH] + (R=Mes, X=F ( 6 a ), R= t Bu, X=F ( 6 b ); R=Mes, X=H ( 7 a ), R= t Bu, X=H ( 7 b )). Reaction of 2 a , b with an excess of Grignard reagents resulted in the addition of R’ at the boron atom yielding the anions [1,7‐H 2 C 2 B 10 H 9 ‐9‐PR( p ‐C 6 F 4 )BR’(C 6 F 5 ) 2 ] − (R=Mes, R’=Me ( 8 a ), R= t Bu, R’=Me ( 8 b ); R=Mes, R’=Ph ( 9 a ), R= t Bu, R’=Ph ( 9 b )) with [MgBr(Et 2 O) n ] + as counterion. The ability of the zwitterionic compounds 3 a , b to hydrogenate imines as well as the Brønsted acidity of 3 a were investigated.
Type of Medium:
Online Resource
ISSN:
0947-6539
,
1521-3765
DOI:
10.1002/chem.202200531
Language:
English
Publisher:
Wiley
Publication Date:
2022
detail.hit.zdb_id:
1478547-X
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