Dehydrohalogenation
of fac-Mn(κ2-N,P-PicP)(CO)3Br (1
H
) and fac-Mn(κ2-N,P-LutP)(CO)3Br (1
Me
) with equimolar K[N(SiMe3)]2 afforded the
reactive, aromatized 18-electron complexes fac-Mn(κ3-N,C,P-PicP)(CO)3 (2
H
) and fac-Mn(κ3-N,C,P-LutP)(CO)3 (2
Me
), respectively, with atypical
binding modes. 2
H
and 2
Me
activate H2 across the Mn(I)–C
bond to furnish hydride complexes fac-Mn(κ2-N,P-PicP)(CO)3H (4
H
) and fac-Mn(κ2-N,P-LutP)(CO)3H (4
Me
), respectively. Both 2
H
and 2
Me
were observed to produce dearomatized 18-electron complexes Mn(κ2-N,P-PicP*)(CO)4 (3
H
) and Mn(κ2-N,P-LutP*)(CO)4 (3
Me
), respectively, when reacted with CO. The reactive Mn(I)–C
moiety of 2
H
and 2
Me
reacts with a variety of electrophiles:
benzyl cyanide to form fac-Mn(κ3-N,N′,P-(LutP-BnCN))(CO)3 (6), E-chalcone to form fac-Mn(κ3-N,C,P-LutP-chalcone)(CO)3 (7), and AlCl3 to form fac-Mn(κ3-N,Cl,P-PicP-AlCl3)(CO)3 (8
H
) and fac-Mn(κ3
-N,Cl,P-LutP-AlCl3)(CO)3 (8
Me
) featuring a rare intramolecular Mn-(μ-Cl)-Al moiety. Mn(I)-catalyzed
Michael addition was explored. Dehydrohalogenation of 1
H
with alkoxides afforded the substituted
complex fac-Mn(κ2-N,P-PicP)(OR)(CO)3 (10
H
) that was also reactive toward H2 forming 4
H
. Under identical conditions with alkoxide
bases, 1
Me
affords 2
Me
demonstrating dichotomous behavior. We
also explored the iPr-substituted analogues of 1
H
and 1
Me
(11
H
and 11
Me
, respectively) and found them to be essentially
identical in behavior. Complexes 1
R
and 11
R
were found to
be excellent catalysts for styrene hydrogenation. The relevance of
the κ3-N,C,P binding mode discovered
herein to catalysis is briefly discussed.
