“…These two resonances compared well with those of its sodium salt 1d (δ 7.44 and 8.10 ppm) and again suggested a thiolate coordination mode without N -oxide moiety participation. Surprisingly, the six CO resonances were almost identical with those of Os 3 (CO) 10 (μ-H)(μ-η 1 -S-R) (R = Et, Ph, and Py) reported by Lewis et al The presence of a noncoordinated N -oxide moiety was also indicated by the high polarity of the molecule, which was eluted with a highly polar solvent from a silica gel TLC plate. The IR spectrum of 1 exhibited a peak at 1222 cm -1 , which was attributed to the absorption of the uncoordinated N−O bond 1a…”
Section: Resultssupporting
confidence: 77%
“…However, the propyl group is slightly disordered in the crystal (see Figure ). The S−C(14) bond length of1.73(2) Å is shorter than that in complex 1 [1.79(1) Å] and those of bridging sulfido compounds, , but it is close to that of the thione form found in monometal complexes 1b 3 ORTEP diagram of Os 3 (CO) 9 (μ-H)(CNPr)(η 2 -SC 5 H 4 N(O)) ( 4b ). 4 ORTEP diagram of Os 3 (CO) 10 (μ-η 1 -CNHCH 2 Ph)(μ-η 1 -S-C 5 H 4 N(O)) ( 5a ). …”
The reaction of 1-hydroxypyridine-2-thione with
Os3(CO)11(NCMe) has yielded three
new
complexes
Os3(CO)10(μ-H)(μ-η1-S-C5H4N(O))
(1, 11% yield),
Os3(CO)10(μ-H)(η2-S-C5H4N(O))
(2, 16% yield), and
Os3(CO)9(μ-H)(μ-η2:η1-SC5H4N(O))
(3, 3% yield). Similarly, treatment of
complex Os3(CO)10(NCMe)2
with this ligand has produced the major complexes 1 and
trace
of 3. Prolonging the above two reactions increased the
yield of 3. Treatment of 1-hydroxypyridine-2-thione with triosmium isocyanide complexes
Os3(CO)10(CNR)(NCMe) (a, R =
CH2Ph; b, R = Pr) has led to the formation of
Os3(CO)9(μ-H)(CNR)(η2-SC5H4N(O))
(4), Os3(CO)10(μ-η1-CNHCH2Ph)(μ-η1-S-C5H4N(O))
(5), and
Os3(CO)9(μ-H)(CNR)(μ-η1-S-C5H4N(O))
(6). The
4:5 ratio depended upon the nature of the alkyl
groups of the coordinated isocyanide.
Reaction of either 1 or 2 with
Me3NO resulted in CO loss and formation of complex
3.
Thermolysis of 1 at 80 °C generated
Os3(CO)9(μ-H)(μ3-pyS)
(7),
Os3(CO)9(μ-OH)(μ3-pyS)
(8),
and byproduct CO2. Upon being heated at 80 °C,
3 was converted to 7 and 8 in a ratio
of 1:4
as indicated by an in-situ NMR study. These observations show that
3 is an intermediate
for the formation of 8 from 1. Crystal
structures of 1, 4b, 5a, and
8 were determined by
X-ray diffraction analyses. The overall results indicate that the
N-oxide group in these
complexes exhibits versatile bonding modes on triosmium clusters.
“…These two resonances compared well with those of its sodium salt 1d (δ 7.44 and 8.10 ppm) and again suggested a thiolate coordination mode without N -oxide moiety participation. Surprisingly, the six CO resonances were almost identical with those of Os 3 (CO) 10 (μ-H)(μ-η 1 -S-R) (R = Et, Ph, and Py) reported by Lewis et al The presence of a noncoordinated N -oxide moiety was also indicated by the high polarity of the molecule, which was eluted with a highly polar solvent from a silica gel TLC plate. The IR spectrum of 1 exhibited a peak at 1222 cm -1 , which was attributed to the absorption of the uncoordinated N−O bond 1a…”
Section: Resultssupporting
confidence: 77%
“…However, the propyl group is slightly disordered in the crystal (see Figure ). The S−C(14) bond length of1.73(2) Å is shorter than that in complex 1 [1.79(1) Å] and those of bridging sulfido compounds, , but it is close to that of the thione form found in monometal complexes 1b 3 ORTEP diagram of Os 3 (CO) 9 (μ-H)(CNPr)(η 2 -SC 5 H 4 N(O)) ( 4b ). 4 ORTEP diagram of Os 3 (CO) 10 (μ-η 1 -CNHCH 2 Ph)(μ-η 1 -S-C 5 H 4 N(O)) ( 5a ). …”
The reaction of 1-hydroxypyridine-2-thione with
Os3(CO)11(NCMe) has yielded three
new
complexes
Os3(CO)10(μ-H)(μ-η1-S-C5H4N(O))
(1, 11% yield),
Os3(CO)10(μ-H)(η2-S-C5H4N(O))
(2, 16% yield), and
Os3(CO)9(μ-H)(μ-η2:η1-SC5H4N(O))
(3, 3% yield). Similarly, treatment of
complex Os3(CO)10(NCMe)2
with this ligand has produced the major complexes 1 and
trace
of 3. Prolonging the above two reactions increased the
yield of 3. Treatment of 1-hydroxypyridine-2-thione with triosmium isocyanide complexes
Os3(CO)10(CNR)(NCMe) (a, R =
CH2Ph; b, R = Pr) has led to the formation of
Os3(CO)9(μ-H)(CNR)(η2-SC5H4N(O))
(4), Os3(CO)10(μ-η1-CNHCH2Ph)(μ-η1-S-C5H4N(O))
(5), and
Os3(CO)9(μ-H)(CNR)(μ-η1-S-C5H4N(O))
(6). The
4:5 ratio depended upon the nature of the alkyl
groups of the coordinated isocyanide.
Reaction of either 1 or 2 with
Me3NO resulted in CO loss and formation of complex
3.
Thermolysis of 1 at 80 °C generated
Os3(CO)9(μ-H)(μ3-pyS)
(7),
Os3(CO)9(μ-OH)(μ3-pyS)
(8),
and byproduct CO2. Upon being heated at 80 °C,
3 was converted to 7 and 8 in a ratio
of 1:4
as indicated by an in-situ NMR study. These observations show that
3 is an intermediate
for the formation of 8 from 1. Crystal
structures of 1, 4b, 5a, and
8 were determined by
X-ray diffraction analyses. The overall results indicate that the
N-oxide group in these
complexes exhibits versatile bonding modes on triosmium clusters.
“…Although the chemical shifts of the supported cluster differ by an average of 1.4 ppm from those of 4, this appears to be well within the normal range of variation observed among (m-H)Os3(CO)10(m-OX) derivatives. 20 Thus these 13C NMR results fully support the as- However, in spite of the existence of an extensive array of nonorganometallic mixed polyhydride-phosphine complexes of rhenium,4 which are perhaps of a greater variety than for any other transition metal, the possibility that some of these might be formulated as containing the t?2-H2 ligand has scarcely been addressed. The one very important exception is the study of ReH7(PPh3)2 by Crabtree,2 in which convincing evidence has been provided (via *H NMR spectroscopy) for its formulation as Re(H2)H5(PPh3)2.…”
In recent years, there has been great interest in the use of transition-metal carbonyl clusters to prepare highly dispersed metal particles on oxide supports.1"4 In addition to providing a route to novel catalysts, these supported clusters may also afford relatively well-defined surface structures. Definitive assignments have proven elusive, however, even within the application of such techniques as extended X-ray absorption fine structure (EXAFS) spectroscopy5,6 and magic-angle-spinning nuclear magnetic resonance (MAS NMR) spectroscopy.7 In this communication we show for the first time that it is possible to obtain highly resolved (line widths <2 ppm) 13C NMR spectra of a supported transition-metal carbonyl cluster through the use of high-field operation as well as magic-angle spinning.Impregnation of silica or alumina with a solution of Os3(CO)12, followed by thermal activation at 100-150 °C, apparently produces a single, strongly bound cluster believed to have one of the structures 1-3.8 It has not been possible to distinguish unambiguously between these possibilities using IR data in the carbonyl stretch region8"11 or EXAFS data.5'6'10•11 Although structure 1 has been most widely accepted, on the basis of gas evolution measurements,8 both 25 and 312 have also been suggested to be the correct structure. We show below that the three possibilities can be distinguished readily by 13C NMR analysis, which provides incisive spectroscopic evidence in support of structure 1.
“…The carbonyls attached to an Os atom with a bridging ligand (other than CO) do not normally undergo mutual CO exchange. 28 The only CO ligand available for exchange with carbonyls a is carbonyl d. This occurs through a mutual exchange of the carbonyls on Os(3).…”
Section: Results and Discussion [Os 4 (L-h)(l-oh)(l-co)(co) 12 ] (1)mentioning
A synthetic route to [Os4(mu-H)(mu-OH)(mu-CO)(CO)12] ( 1) has been devised through the activation of [Os4(CO)14] with Me3NO. The pyrolysis and photolysis of the reactant in the presence of a trace amount of water produces 1 in low yield. The solid-state structure of [Os4(mu-H)(mu-OH)(mu-CO)(CO)12 x H2O] (1 x H2O) reveals a butterfly Os4 skeleton with bridging H, OH and CO ligands as well as hydrogen-bonded molecules of water in the crystal lattice. A low-temperature 13C{1H} NMR spectroscopic study revealed a merry-go-round exchange of CO ligands around the Os3 plane containing the asymmetric bridging CO. The exposure of 1 x H2O to D2O yielded [Os4(mu-H)(mu-OD)(mu-CO)(CO)12]2. Although the solid-state, intramolecular structure of 2 closely matched that of 1 x H2O, the intermolecular structure did not: its crystal lattice contained no water of crystallization, a previously unreported crystallographic isotope effect.
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