SCHEDULED MAINTENANCE
Reactions of iridium and ruthenium complexes with organic
azides
Abstract
Interaction of N
3
R with Ir(mes)
3
(mes = mesityl,
C
6
H
2
Me
3
-2,4,6) gave products dependent
on the nature of the azide. When R = mes, the tetrazenido
amide complex 1 is obtained in which dehydrogenative coupling of the
mesityl groups via the o-methyls has occurred;
thermolysis of 1 in toluene resulted in cleavage of the tetrazene ring
and formation of amide complex 2. When R = Ph, the aryl
tetrazenido amide complex 3 is formed. Photolysis of a mixture of
N
3
(mes) and [RuCl
2
(PPh
3
)
3
]
followed by phosphine exchange gave the tetrazene complex
[Ru
II
Cl
2
{N
4
(mes)
2
}(PMe
3
)
2
] 4. Thermal reaction of
[RuCl
2
H
2
(PPr
i
3
)
2
]
with N
3
(mes) gave the triazenophosphorane complex
[RuCl
3
(PPr
i
3
){N
3
(mes)
PPr
i
3
}] 5. The ruthenium allyl amide
[Ru(PMe
3
)
3
{NHC
6
H
3
Pr
i
(η
3
-CH
2
CCH
2
)}] 6
bearing a new hybrid ligand was obtained by interaction of
trans-[RuCl
2
(PMe
3
)
4
] with
Li[NH(C
6
H
3
Pr
i
2
-2,6)] in
di-n-butyl ether. Plausible reaction mechanisms accounting for
the formation of the new compounds are proposed. Finally, the crystal
structures of the complexes 1–6 have been determined. Complexes 1
and 2 have pseudo-square planar geometries involving the olefin formed
by the coupled methyl groups of two mesityls and three (1) or two (2)
amide nitrogens and a chlorine atom (2). Compound 3 has a trigonal
bipyramidal metal centre with the axial Ir–N amide bonds longer
than the equatorial ones; 4 has an octahedral structure with a bidentate
tetragonal ligand and trans phosphines whilst 5 is distorted
octahedral with a N,N-chelating phosphazide ligand. Complex 6 is also
octahedral with the allyl groups occupying cis sites and the
three Ru–P bonds in a facial arrangement.
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