Treatment of a 1-alkyl-2-imidazoline
![[upper bond 1 start]](https://www.rsc.org/images/entities/char_e010.gif)
N(R)(CH
2
)
2
N
![[double bond, length as m-dash]](https://www.rsc.org/images/entities/char_e001.gif)
C
![[upper bond 1 end]](https://www.rsc.org/images/entities/char_e011.gif)
H with a
µ-dichloro-dirhodium(
I) or -diplatinum(
II)
complex [{Rh(µ-Cl)(cod)}
2
] or
[{Pt(µ-Cl)Cl(PEt
3
)}
2
] gave the
mononuclear 1-alkyl-2-imidazoline complex
[RhCl{
![[upper bond 1 start]](https://www.rsc.org/images/entities/char_e010.gif)
N
![[double bond, length as m-dash]](https://www.rsc.org/images/entities/char_e001.gif)
C(H)N(R)CH
2
C
![[upper bond 1 end]](https://www.rsc.org/images/entities/char_e011.gif)
H
2
}(cod)] (R = Et
1a or CH
2
Ph
1b) or
trans-[PtCl
2
{
![[upper bond 1 start]](https://www.rsc.org/images/entities/char_e010.gif)
N
![[double bond, length as m-dash]](https://www.rsc.org/images/entities/char_e001.gif)
C(H)N(R)CH
2
C
![[upper bond 1 end]](https://www.rsc.org/images/entities/char_e011.gif)
H
2
}(PEt
3
)]
(R = Et
2a or CH
2
Ph
2b)
(cod = cycloocta-1,5-diene). A single-crystal X-ray
diffraction study of
2a revealed it to have a square-planar
geometry about platinum, the imidazoline ring being coplanar with this
plane, and a Pt–N distance of 2.088(11) Å; the
Pt–P bond length of 2.231(4) Å indicates that the
imidazoline ligand has a marginally stronger trans influence
than analogues of its isomer such as
![[upper bond 1 start]](https://www.rsc.org/images/entities/char_e010.gif)
CN(R)(CH
2
)
2
N
![[upper bond 1 end]](https://www.rsc.org/images/entities/char_e011.gif)
R. The rhodium complexes
1a and
1b have been shown to catalyse cyclopropanation
of styrene and ethyl diazoacetate in high yields.