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Reactivities of cyclonickellated complexes with hydroxylamines: formation of κ-hydroxylamine and κ-imine adducts and a κ, κ-aminoxide derivative
This report discusses the reactivities of hydroxylamines with a family of nickellacyclic complexes prepared by C-H nickellation of aryl phosphinites. Treating the dimeric complexes κ C ,κ P -{2-OPR 2 ,4-R′-C 6 H 4 } 2 Ni 2 (μ-Br) 2 (R = i-Pr; R′ = H, Cl, OMe, NMe 2 ) or their monomeric acetonitrile...
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| Published in: | Dalton transactions : an international journal of inorganic chemistry 2023-01, Vol.52 (2), p.366-375 |
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| Main Authors: | , , |
| Format: | Article |
| Language: | |
| Online Access: | Get full text |
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| Summary: | This report discusses the reactivities of hydroxylamines with a family of nickellacyclic complexes prepared by C-H nickellation of aryl phosphinites. Treating the dimeric complexes κ
C
,κ
P
-{2-OPR
2
,4-R′-C
6
H
4
}
2
Ni
2
(μ-Br)
2
(R = i-Pr; R′ = H, Cl, OMe, NMe
2
) or their monomeric acetonitrile adducts κ
C
,κ
P
-{2-OPR
2
,4-R′-C
6
H
4
}Ni(Br)(NCMe) with hydroxylamines showed three types of reactivities depending on the Ni complex, the reaction solvent, and the substrate used: (1) the benzyl-protected substrate PhCH
2
ONH
2
gave simple N-bound adducts with all Ni complexes; (2) the parent Ni dimer (R′ = H) reacted with Et
2
NOH and (PhCH
2
)
2
NOH in CH
2
Cl
2
to give, respectively, the zwitterionic amine oxide κ
C
,κ
P
-{2-OPR
2
-C
6
H
5
}Ni(κ
O
-ONHEt
2
)Br and the bidentate aminoxide (i-R
2
POPh)Ni{κ
O
,κ
N
-ON(CH
2
Ph)
2
}Br; (3) the analogous reaction of substituted Ni complexes (R′ = Cl, OMe, NMe
2
) with hydroxylamines in acetonitrile gave adducts of imines derived from dehydration of Et
2
NOH and (PhCH
2
)
2
NOH. The latter reactivity proceeds optimally in acetonitrile, but it also occurs to a lesser extent in C
6
D
6
if the reaction is allowed to go for more than 24 h. Different mechanistic scenarios have been considered to rationalize the observed hydroxylamine → imine transformation.
Reaction of nickellacyclic complexes with hydroxylamines (RCH
2
)
2
NOH generates κ
O
-hydroxylamine and κ
N
-imine adducts or a κ
O
, κ
N
-aminoxide derivative depending on the reaction solvent and the substituent R. |
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| ISSN: | 1477-9226 1477-9234 |
| DOI: | 10.1039/d2dt02979k |