Scavenging with base: reaction of A with LiNiPr2 (LDA). 17.7
mg of (PNP)OsI (0.023 mmol) in a J-Young NMR tube was
dissolved in 0.5 mL of C6D6. The solution was degassed through 3
freeze–pump–thaw cycles using liquid N2. 760 mm of N2 (4 equiv.)
was added to the evacuated head space of the frozen solution and
the reactants were stirred for 1 h at 22 ◦C. During the reaction
the color of the solution turned yellow indicating 90% conversion
(by the 31P NMR) to A. 9 mg of LDA (3 equivalents, 0.073 mmol)
was added to the solution. One freeze–pump–thaw cycle was done
using liquid N2. 760 mm of N2 was added to the evacuated head
space of the frozen suspension, and the reaction mixture was
shaken for 12 h. NMR showed complete consumption of the Os
starting materials with formation of D (spectra shown below) and
C in 9 : 1 ratio. Spectra of (PNP)OsH(N2) have been reported.28
evacuated head space of the frozen solution. The tube was shaken
for 30 min at 22 ◦C and the solution color turned to green followed
by yellow. NMR (1H and 31P) showed complete conversion to
(PN(H)P)RuH3Cl. H NMR (C6D6, 25 ◦C): -12.97 (t, 3 H, J =
1
14.7, RuH3), 0.23, 0.41 (both s, 6 H each, SiMe), 0.69, 0.74 (both
t, 1 H each, J = 5.5, CH2), 1.15, 1.43 (both t, 18 H each, J = 6.1,
◦
1
But), 3.17 (br s, 1 H, NH). 31P{ H} NMR (C6D6, 25 C): 76.4 (s).
b. This reaction tube was degassed through one freeze–pump–
thaw cycle and 4.2 mg (0.034 mol) of LiNiPr2 was added to the
solution. The color of the suspension turned orange. NMR (31P)
after 15 min showed complete conversion into a new compound,
(PNP)RuH3. H NMR (C6D6, 25 ◦C): -15.09 (t, 3 H, J = 13.1,
1
RuH3), 0.45 (s, 12 H, SiMe), 0.81 (t, 4 H, J = 4.5, CH2), 1.13 (t,
◦
1
36 H, J = 6.3, But). 31P{ H} NMR (C6D6, 25 C): 84.5 (s).
c. All volatiles from the above solution of (PNP)RuH3 were
removed under vacuum, 20 mL of pentane was added and the
suspension was filtered. Pentane was again removed under vacuum
and the residue was dissolved in C6D6. The resulting orange
solution was degassed through 3 freeze–pump–thaw cycles and
200 mm of N2O (2 equiv.) was added to the evacuated ◦head space
of the frozen solution. NMR (31P) after 10 min at 25 C showed
~30% conversion into the new compound, (PNP)Ru(H)(N2), and
Alternative synthesis of (PNP )OsH. 20 mg of (PNP)OsI
(0.026 mmol) in a Schlenk flask was dissolved in 5 mL of THF. The
solution was cooled to -20 ◦C, and MeMgBr (solution in THF, 1
equivalent) was added via syringe. The reaction mixture was slowly
warmed to 22 ◦C and 31P NMR of the THF solution after 1 h re-
veals formation of a diamagnetic product, (PNP)Os(CH3)(THF)2.
All volatiles were removed under vacuum, 20 mL of pentane
was added and the suspension was filtered. Pentane was again
removed under vacuum. NMR of the residue after only 10 min
showed the same diamagnetic methyl complex with a singlet by
31P NMR, together with a small amount of a new AB pattern,
D. Consumption of the primary product (PNP)Os(CH3)(THF)2
and formation of D was observed at 22 ◦C. Heating the solution
1
the color of the solution had turned red. 31P{ H} NMR (C6D6,
25 ◦C): 71.4 (s). The color of the solution turned black in another
10 min and 31P NMR showed decay of the unreacted (PNP)RuH3
signal together with an unchanged amount of (PNP)Ru(H)(N2).
The NMR spectra of the product of this reaction is identical to that
of the (PNP)RuH(N2) produced above. In this reaction mixture,
the water produced by hydrogenolysis of N2O decomposes the
residual (PNP)RuH3 within about 20 min.
◦
at 90 C for 10 min showed complete conversion to this second
product, D. 1H NMR (PNP)Os(CH3)(THF)2 (C6D6, 25 ◦C): 0.34
(s, 12 H, SiMe), 1.00–1.06 (m, 4 H, CH2), 1.29 (t, 36 H, J = 4.8, But).
1
Os–Me was not located due to overlap with other signals. 31P{ H}
35,36
(PNP)PtCl. To 0.12 g (0.32 mmol) of Pt(COD)Cl2
in
NMR (C6D6, 25 ◦C): 42.2 (s). 1H NMR of D (C6D6, 25 ◦C): -3.0
(dd, 1 H, J = 12.2 and 15.3, Os–H), 0.14, 0.18, 0.53, 0.54 (all s,
3 H each, SiMe), 1.86 (d, 3 H, J = 13.1, CH3), 1.10 (d, 9 H, J =
12.7 Hz, But), 1.19 (d, 3 H, J = 12.3 Hz, CH3), 1.30 (t, 9 H, J =
13.5 Hz, But), 1.38 (t, 9 H, J = 12.7 Hz, But), 1◦5.30 (dd, 1 H, J =
10 mL THF was added (PNP)MgCl(dioxane), 0.19 g (0.32 mmol).
After stirring vigorously for 24 h at 25 ◦C, the volatiles were
removed under vacuum, the solid residue was extracted with
toluene, and these toluene extracts were concentrated, then mixed
with an equal volume of pentane, and the resulting solution cooled
1
10.7 and 36.5, = CH). 31P{ H} NMR (C6D6, 25 C): 27.1 and 54.0
1
for 2 days to yield 0.14 g of solid (63% yield). H NMR (C6D6):
(both d, J = 324 Hz).
0.31 (12H, SiMe), 0.67 (t, 4 H, J = 6, CH2), 1.40 (t, 36 H, J = 8,
1
tBu). 31P{ H} NMR (C6D6): 41.6 (singlet with 195Pt satellites, JPtP
=
Reaction of (PNP)RuCl with Mg in the presence of N2. 40
2592). ESI + MS (in MeCN): M+, 680; (MH - Cl)+, 644, both
mg of activated Mg (32 equivalents, 1.64 mmol) and 30 mg of
with correct isotopic pattern.
26
(PNP)RuCl (0.051 mol) was placed into the Schlenk flask in
5 mL of THF. The solution and Mg was degassed through 3
freeze–pump–thaw cycles using liquid N2. 760 mm of N2 was then
added to the evacuated head space of the frozen solution. The
reagents were stirred for 1 d at 22 ◦C and the color of the solution
turned red. All volatiles was removed under vacuum, 1.0 mL of
C6D6 was added to dissolve all red solid and filtered through the
glass filter into a J-Young NMR tube.◦NMR reveals formation of
Computational details. All calculations were carried out using
Density Functional Theory as implemented in the Jaguar 6.0
suite37 of ab initio quantum chemistry programs. Geometry
optimizations were performed with the B3LYP38–41 functional and
the 6-31G** basis set with no symmetry restrictions. Transition
metal was represented using the Los Alamos LACVP basis.42,43
The energies of the optimized structures were reevaluated by
additional single-point calculations on each optimized geometry
using Dunning’s correlation-consistent triple-z basis set44 cc-
pVTZ(-f) that includes a double set of polarization functions.
For all transition metals, we used a modified version of LACVP,
designated as LACV3P, in which the exponents were decontracted
to match the effective core potential with the triple-z quality basis.
The models used in this study consist of ~90 atoms, which
represent the non-truncated substrates that were also used in the
experimental work.
1
(PNP)RuH(N2). H NMR (C6D6, 25 C): -27.3 (t,1 H, J = 18.2,
Ru–H), 0.31 and 0.33 (both s, 6 H each, SiMe), 0.76–0.80 (m, 4 H,
CH2), 1.25 (t, 36 H, J = 6 Hz, all But, accidentally degenerate).
◦
1
31P{ H} NMR (C6D6, 25 C): 71.4 (s). IR (C6D6 solution): n(N2)
2042 cm-1.
Alternate synthesis of (PNP)RuH(N2). a. 10 mg of (PNP)RuCl
(0.017 mol) in a J-Young NMR tube was dissolved in 0.5 mL of
C6D6. The solution was degassed through 3 freeze–pump–thaw
cycles using liquid N2. 760 mm of H2 (5 equiv.) was added to the
This journal is
The Royal Society of Chemistry 2011
Dalton Trans., 2011, 40, 1105–1110 | 1109
©