Reactions of the Trinuclear Cluster (μ2-H)Ru3(CO)9(μ3,η2-SCNHPhNPh): Synthesis and Molecular Structure of Ru3(CO)6(PPh3)(μ2,η2-C6H5)- (μ2-PPh2)(μ3-S), a Complex Containing a Phenyl Ligand with a Rare σ,π-Coordination Mode
Abstract:Reactions of the previously isolated trinuclear cluster
(μ2-H)Ru3(CO)9(μ3,η2-SCNHPhNPh)
(1) with excess diphenylthiourea result in cluster
fragmentation to produce the mononuclear
complex
Ru(CO)2(η2-SCNHPhNPh)2
(2) containing two bidentate diphenylthioureato
ligands.
Room-temperature reactions of 1 with 1 or 2 equiv of
triphenylphosphine result in
substitution of one or two carbonyl groups, respectively, to give the
clusters
(μ2-H)Ru3(CO)8(PPh3)(μ3,η2-SCNHPhNPh)
(3) and
(μ2-H)Ru3(CO)7(PPh3)2(μ3,η2-SCNHPhNPh)
(… Show more
“…The low wavenumber of the IR ν(CO) absorption of the ureato group (1602 cm -1 ) also indicates some delocalization of the double bond between the C−O and C−N bonds , and triosmium thioureato clusters, the sulfur atom spans a metal-metal edge while the unique metal atom is attached to one of the nitrogen atoms. 1 …”
Section: Resultsmentioning
confidence: 99%
“…Therefore, the reactivity of compound 1 with 1 equiv of triphenylphosphine can be compared to that observed for the reference compounds [Ru 3 (μ-H)(μ 3 -PhNCSNHPh)(CO) 9 ], [Ru 3 (μ-H)(μ 3 -ampy)(CO) 9 ] (Hampy = 2-amino-6-methylpyridine), and [Ru 3 (μ-H)(μ 3 -Spy)(CO) 9 ] (HSpy = pyridine-2-thiol), which also undergo carbonyl substitution in an equatorial position cis to both the bridging hydride and the bridging S or NH fragments. However, the reactions with these three cluster compounds are clean, giving single products, whereas, as commented above, that of compound 1 also gives a minor product (which may have the phosphine ligand attached to the O-bonded Ru atom).…”
Section: Resultsmentioning
confidence: 99%
“…For comparison purposes, these results can be contrasted with those reported on the reactions of [Ru 3 (μ-H)(μ 3 -PhNCSNHPh)(CO) 9 ], [Ru 3 (μ-H)(μ 3 -mbim)(CO) 9 ] (Hmbim = 2-mercaptobenzimidazole), and [Ru 3 (μ-H)(μ 3 -ampy)(CO) 9 ] with 2 equiv of triphenylphosphine, which give the symmetric disubstituted derivatives [Ru 3 (μ-H)(μ 3 -L)(PPh 3 ) 2 (CO) 7 ] (L = PhNCSNHPh, mbim, ampy 19 ). The reaction of the thioureato complex takes place at room temperaure whereas those of the other two clusters require mild thermal activation (THF reflux).…”
The ureato-bridged carbonyl cluster [Ru 3 (µ-H)(µ 3 -HNCONMe 2 )(CO) 9 ] (1) (H 2 NCONMe 2 ) N,N-dimethylurea) reacts with 1 equiv of triphenylphosphine or diphenylphosphine to give the isostructural derivatives [Ru 3 (µ-H)(µ 3 -HNCONMe 2 )(L)(CO) 8 ] (L ) PPh 3 , PPh 2 H). The X-ray structure of [Ru 3 (µ-H)(µ 3 -HNCONMe 2 )(PPh 3 )(CO) 8 ] indicates that the substitution has taken place on an equatorial position cis to the bridging NH fragment. Treatment of 1 with bis(diphenylphosphino)methane (dppm) affords a mixture of the symmetric (C s ) and asymmetric (C 1 ) isomers of [Ru 3 (µ-H)(µ 3 -HNCONMe 2 )(µ-dppm)(CO) 7 ]. All these reactions take place at room temperature. The phenyl-bridged bis(diphenylphosphido) derivative [Ru 3 -(µ-η 1 -Ph)(µ 3 -HNCONMe 2 )(µ-PPh 2 ) 2 (CO) 6 ] has been prepared by reaction of 1 with 2 equiv of PPh 3 in the presence of alumina and has been characterized by X-ray diffraction methods. The thermolysis of [Ru 3 (µ-H)(µ 3 -HNCONMe 2 )(PPh 2 H)(CO) 8 ] in refluxing THF leads to the phosphido-bridged derivatives [Ru 3 (µ 3 -HNCONMe 2 )(µ-PPh 2 )(µ-CO) 2 (CO) 6 ] and [Ru 3 (µ-H)(µ 3 -HNCONMe 2 )(µ-PPh 2 ) 2 (CO) 6 ]. It has been observed that carbonyl substitution reactions on compound 1 are easier than those previously reported on clusters containing N-and/or P-donor bridging ligands. This seems to be related to the hard-soft character of the bridging ligand: the harder the ligand the more reactive is the cluster in carbonyl substitution reactions.
“…The low wavenumber of the IR ν(CO) absorption of the ureato group (1602 cm -1 ) also indicates some delocalization of the double bond between the C−O and C−N bonds , and triosmium thioureato clusters, the sulfur atom spans a metal-metal edge while the unique metal atom is attached to one of the nitrogen atoms. 1 …”
Section: Resultsmentioning
confidence: 99%
“…Therefore, the reactivity of compound 1 with 1 equiv of triphenylphosphine can be compared to that observed for the reference compounds [Ru 3 (μ-H)(μ 3 -PhNCSNHPh)(CO) 9 ], [Ru 3 (μ-H)(μ 3 -ampy)(CO) 9 ] (Hampy = 2-amino-6-methylpyridine), and [Ru 3 (μ-H)(μ 3 -Spy)(CO) 9 ] (HSpy = pyridine-2-thiol), which also undergo carbonyl substitution in an equatorial position cis to both the bridging hydride and the bridging S or NH fragments. However, the reactions with these three cluster compounds are clean, giving single products, whereas, as commented above, that of compound 1 also gives a minor product (which may have the phosphine ligand attached to the O-bonded Ru atom).…”
Section: Resultsmentioning
confidence: 99%
“…For comparison purposes, these results can be contrasted with those reported on the reactions of [Ru 3 (μ-H)(μ 3 -PhNCSNHPh)(CO) 9 ], [Ru 3 (μ-H)(μ 3 -mbim)(CO) 9 ] (Hmbim = 2-mercaptobenzimidazole), and [Ru 3 (μ-H)(μ 3 -ampy)(CO) 9 ] with 2 equiv of triphenylphosphine, which give the symmetric disubstituted derivatives [Ru 3 (μ-H)(μ 3 -L)(PPh 3 ) 2 (CO) 7 ] (L = PhNCSNHPh, mbim, ampy 19 ). The reaction of the thioureato complex takes place at room temperaure whereas those of the other two clusters require mild thermal activation (THF reflux).…”
The ureato-bridged carbonyl cluster [Ru 3 (µ-H)(µ 3 -HNCONMe 2 )(CO) 9 ] (1) (H 2 NCONMe 2 ) N,N-dimethylurea) reacts with 1 equiv of triphenylphosphine or diphenylphosphine to give the isostructural derivatives [Ru 3 (µ-H)(µ 3 -HNCONMe 2 )(L)(CO) 8 ] (L ) PPh 3 , PPh 2 H). The X-ray structure of [Ru 3 (µ-H)(µ 3 -HNCONMe 2 )(PPh 3 )(CO) 8 ] indicates that the substitution has taken place on an equatorial position cis to the bridging NH fragment. Treatment of 1 with bis(diphenylphosphino)methane (dppm) affords a mixture of the symmetric (C s ) and asymmetric (C 1 ) isomers of [Ru 3 (µ-H)(µ 3 -HNCONMe 2 )(µ-dppm)(CO) 7 ]. All these reactions take place at room temperature. The phenyl-bridged bis(diphenylphosphido) derivative [Ru 3 -(µ-η 1 -Ph)(µ 3 -HNCONMe 2 )(µ-PPh 2 ) 2 (CO) 6 ] has been prepared by reaction of 1 with 2 equiv of PPh 3 in the presence of alumina and has been characterized by X-ray diffraction methods. The thermolysis of [Ru 3 (µ-H)(µ 3 -HNCONMe 2 )(PPh 2 H)(CO) 8 ] in refluxing THF leads to the phosphido-bridged derivatives [Ru 3 (µ 3 -HNCONMe 2 )(µ-PPh 2 )(µ-CO) 2 (CO) 6 ] and [Ru 3 (µ-H)(µ 3 -HNCONMe 2 )(µ-PPh 2 ) 2 (CO) 6 ]. It has been observed that carbonyl substitution reactions on compound 1 are easier than those previously reported on clusters containing N-and/or P-donor bridging ligands. This seems to be related to the hard-soft character of the bridging ligand: the harder the ligand the more reactive is the cluster in carbonyl substitution reactions.
“…In addition, although the thermal activation of P−C bonds of coordinated triphenylphosphine ligands has been observed on many occasions, ,,,− these reactions generally lead to phosphido-bridged derivatives as well as to benzene, , benzaldehyde, , or biphenyl. , However, very few σ-phenyl-μ-diphenylphosphido derivatives have been isolated, ,,, although they have often been claimed as intermediates in these processes. ,, Compounds containing bridging phenyl ligands arising from P−C bond cleavage reactions are even less common, being restricted to a few compounds of ruthenium ,, and to one of osmium …”
The thermal activation of a triphenylphosphine P−C bond of the
48-electron cationic cluster
complex
[Ru3(μ3-ampy)(PPh3)2(CO)8][BF4]
(2; Hampy = 2-amino-6-methylpyridine) leads
to
the phenyl derivative
[Ru3(μ-Ph)(μ3-ampy)(μ-PPh2)(PPh3)(CO)7][BF4]
(3). Treatment of 3 with
carbon monoxide regenerates 2
via the 50-electron
intermediate
[Ru3(μ-Ph)(μ3-ampy)(μ-PPh2)(PPh3)(CO)8][BF4].
These reactions represent the first reversible triphenylphosphine
P−C
bond activation reaction reported in carbonyl cluster chemistry.
The neutral acyl derivative
[Ru3(μ-PhCO)(μ-Cl)(μ3-ampy)(μ-PPh2)(PPh3)(CO)5],
which arises from the reaction of 3 with
[PPN]Cl, has been characterized by X-ray diffraction methods.
“…The structure is closely related to that of [Ru 3 (μ-SPh)(μ,η 1 :η 6 -Ph)(CO) 8 ] ( 1 ) . In addition to the μ,η 1 :η 6 -mode of Ph bridging, the μ,η 1 :η 2 and μ,η 1 :η 1 modes of Ph are also known, 6a, and there may be intermediates with these types of aryl coordination in the formation of 2 . We are now modifying the reaction conditions to try to improve yields of 2 and 3 so that the reactivities of these compounds may be easily explored.…”
Iodobenzene and 4-iodotoluene react with
[Ru3(CO)12] to give the oxidative
addition products [Ru3(μ-I)(μ,η1:η6-C6H4R)(CO)8]
(R = H, 4-Me), whereas 1-iodonaphthalene and 9-iodophenanthrene give the aryne
clusters
[Ru4(μ4,η2-L)(CO)12]
(L = 1,2-naphthyne, 9,10-phenanthryne).
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