Thiobenzamidato and thiobenzoato complexes of ruthenium, osmium and iridium
Abstract
Thiobenzamide reacted with the complexes
[MCl
2
(PPh
3
)
3
],
[MH(X)(CO)(PPh
3
)
3
] (M = Ru or Os,
X = H or Cl) and
mer-[IrH
3
(PPh
3
)
3
] in boiling
toluene to afford the products
[M{S(NH)CPh}
2
(PPh
3
)
2
],
[MX{S(NH)CPh}(CO)(PPh
3
)
2
] and
[IrH
2
{S(NH)CPh}(PPh
3
)
2
]
respectively. The crystal structure of
[Os{S(NH)CPh}
2
(PPh
3
)
2
]
confirms the expected bis(N,S-chelate) formulation and has established
the presence of cis-phosphorus, cis-nitrogen and
trans-sulfur donor atom pairs within a highly distorted
octahedral co-ordination sphere. Thiobenzoic acid reacted with
[MCl
2
(PPh
3
)
3
] and
[MH(X)(CO)(PPh
3
)
3
] under similar conditions to
yield [M{S(O)CPh}
2
(PPh
3
)
2
]
and [M{S(O)CPh}
2
(CO)(PPh
3
)
2
]
respectively. The reactions of thiobenzoic acid with
mer-[IrH
3
(PPh
3
)
3
] under
conditions of increasing severity give
[IrH
2
{S(O)CPh}(PPh
3
)
3
],
[IrH{S(O)CPh}
2
(PPh
3
)
2
] and
[Ir{S(O)CPh}
3
(PPh
3
)
2
] the
last two of which on carbonylation afford
[IrH{S(O)CPh}
2
(CO)(PPh
3
)
2
]
and [Ir{S(O)CPh}
3
(CO)(PPh
3
)
2
]
respectively. The crystal structure of
[IrH{S(O)CPh}
2
(PPh
3
)
2
] has
established the presence of trans phosphorus and trans
sulfur donor atom pairs, with the η
1
- and
η
2
-thiobenzoate ligands sharing a meridional set of three
co-ordination sites. However, the NMR spectra of this complex show two
high-field
1
H triplets and two
31
P-{
1
H} singlets. Possible explanations
for this anomalous NMR behaviour, which is also found for the
corresponding thioacetate, are advanced.
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