Inorganic Chemistry
Article
an inert atmosphere prior to use. Air-sensitive NMR samples were
prepared in an argon- or nitrogen-filled glovebox or on a high vacuum
line by vacuum transfer of solvent into an NMR tube fitted with a
concentric Teflon valve. 1H and 31P{1H} NMR spectra were recorded
on Bruker Avance III 300, Avance III 400 or Avance III 600 NMR
spectrometers operating at 300.3, 400.13, and 600.13 MHz for 1H, and
121.49, 161.98, and 242.95 MHz for 31P{1H} respectively. All NMR
Synthesis of RuCl(P2P3Cy) (4). Potassium graphite (18 mg, 0.13
mmol) was added to a solution of [RuCl(P2P3Cy)][Cl] (102 mg, 0.116
mmol) in THF (approximately 15 mL). The reaction mixture was
stirred under nitrogen for 20 h. The resulting black suspension was
filtered to give a very dark solution. The solvent was removed under
reduced pressure, and the solid residue extracted with pentane
(approximately 30 mL). The solution was then filtered to give a deep
blue filtrate. The volume of the solution was reduced to 5 mL and
allowed to stand overnight, resulting in the precipitation of a blue solid
which was collected by filtration to afford RuCl(P2P3Cy) (4) (72 mg,
0.085 mmol, 74%). Anal. Found. C 59.91, H 9.51, C42H78ClP4Ru
(MW 843.50) requires C 59.81, H 9.32.
1
spectra were recorded at 298 K, unless otherwise stated. H NMR
spectra were referenced to residual solvent resonances. 31P{1H} NMR
spectra were referenced to external neat trimethylphosphite at 140.85
ppm, and 15N{1H} NMR spectra were reference to external neat
nitromethane at 0 ppm.
Microanalyses were carried out at the Campbell Microanalytical
Laboratory, University of Otago, New Zealand. Details of the X-ray
analyses are given in Table 8.
Synthesis of Fe(H)2(P2P3Cy) (5). Potassium triethylborohydride
(35 mg, 0.25 mmol) was added to a stirring suspension of
[FeCl(P2P3Cy)][BPh4] (120 mg, 0.107 mmol) in toluene (10 mL)
which was stirred under nitrogen for 3 h. Volatiles were removed
under reduced pressure. The orange residue was extracted with
pentane (30 mL) and the resultant solution was filtered and volatiles
removed to afford Fe(H)2(P2P3Cy) (5) (57 mg, 0.075 mmol, 70%
yield) as an orange solid. Anal. Found. C 66.21, H 10.39, C42H80FeP4
(MW 764.84) requires C 65.96, H 10.54. 31P{1H} NMR (162 MHz,
Synthesis of Fe(N2)(P2P3Cy) (1). Potassium graphite (76 mg, 0.56
mmol) was added to a solution of [FeCl(P2P3Cy)][BPh4] (270 mg,
0.242 mmol) in THF (approximately 15 mL). The reaction mixture
was stirred under nitrogen for 20 h. The resulting black suspension
was filtered to give an orange solution. The solvent was removed
under reduced pressure, and the solid residue was extracted into
benzene (approximately 10 mL). The orange solution was filtered and
then reduced to around 1 mL under reduced pressure to precipitate
Fe(N2)(P2P3Cy) (1) as a red/orange solid (63 mg, 0.080 mmol, 33%).
Anal. Found. C 64.17, H 9.65, N 2.47, C42H78FeN2P4 (MW 790.837)
requires C 63.79, H 9.94, N 3.54. Elemental analysis performed on the
crystalline product suggests some loss of weakly bound dinitrogen
ligand upon application of vacuum during analytical procedure,
consistent for complexes of this type.7 31P{1H} NMR (121 MHz,
benzene-d6): δ 175.3 (1P, q, 2JP−P = 36 Hz, PC); 84.2 (3P, d, 2JP−P = 36
benzene-d6): δ 174.4 (1P, q, 2JP−P = 18 Hz, PC); 102.3 (3P, d, 2JP−P
=
1
18 Hz, PE/PT). H NMR (300 MHz, benzene-d6): δ 2.39 (4H, m,
CH2arm); 2.1−1.6 (32H, m, CH2a2rm/CyH); 1.6−1.1 (42H, m, CyH);
2
−12.84 (2H, qd, JH−P = 46 Hz, JH−P = 3 Hz, FeH). 31P{1H} NMR
(243 MHz, toluene-d8, 190 K): δ 175.0 (1P, s br, PC); 113.7 (1P, s br,
PT); 96.8 (2P, s br, PE). 1H NMR (600 MHz, toluene-d8, 190 K, high
field only): δ −7.98 (1H, s br, FeH); −17.67 (1H, s br, FeH).
Synthesis of [FeH(N2)(P2P3Cy)][BF4] (6[BF4]). A solution of
lutidinium tetrafluoroborate (23 mg, 0.12 mmol) in THF (5 mL) was
added to a solution of Fe(H)2(P2P3Cy) (5) (85.0 mg, 0.111 mmol) in
THF (20 mL), and the reaction mixture was stirred overnight under
nitrogen, resulting in a color change from pale orange to a darker
pink/orange. The solution was filtered through Celite and reduced in
volume to 4 mL under reduced pressure. The addition of pentane (30
mL) resulted in the precipitation of a tan solid which was collected by
filtration to afford [FeH(N2)(P2P3Cy)][BF4] (6[BF4]) (58 mg, 0.066
mmol, 59%). Anal. found C 57.35, H 9.19, N 2.57, C42H79BF4FeN2P4
(MW 878.649) requires C 57.41, H9.06, N 3.19. Elemental analysis
performed on the crystalline product suggests some loss of weakly
bound dinitrogen ligand upon application of vacuum during analytical
procedure. 31P{1H} NMR (162 MHz, THF-d8): δ 160.7 (1P, dt,
Hz, PE). H NMR (400 MHz, benzene-d6): δ 2.29 (4H, m, CH2arm);
1
2.13 (8H, m, CH2arm); 2.0−1.7 (26H, m, CyH); 1.48 (24H, m, CyH);
1.4−1.1 (16H, m, CyH). IR (fluorolube): 1996 s, ν(NN) cm−1.
Synthesis of Ru(N2)(P2P3Cy) (2). Potassium graphite (80 mg, 0.59
mmol) was added to a suspension of [RuCl(P2P3Cy)]Cl (125 mg,
0.142 mmol) in THF (approximately 15 mL). The reaction mixture
was stirred under nitrogen for 18 h, after which it was filtered to afford
a dark yellow solution. The solvent was removed under reduced
pressure, and the resulting dark yellow solid was dissolved in pentane
and filtered and the solvent removed under reduced pressure once
more to afford Ru(N2)(P2P3Cy) (2) (41 mg, 0.049 mmol, 35%) as an
orange solid. Anal. Found. C 60.13, H 9.57, N 2.92, C42H78N2P4Ru
(MW 843.50) requires C 60.34, H 9.40, N 3.35. 31P{1H} NMR (121
2
MHz, benzene-d6): δ 160.7 (1P, q, JP−P = 22 Hz, PC); 73.9 (3P, d,
1
2JP−P = 22 Hz, PE). H NMR (300 MHz, benzene-d6): δ 2.1−1.6
2
2
2JPC‑PT = 28 Hz, JPC‑PE = 24 Hz, PC); 79.8 (2P, dd, JPE‑PC = 24 Hz,
2JPE‑PT = 11 Hz, PE); 70.3 (1P, dt, 2JPT‑PC = 28 Hz, 2JPT‑PE = 11 Hz, PT).
1H NMR (400 MHz, THF-d8): δ 2.7−2.2 (12H, m, CH2arm); 2.2−1.1
(66H, m, CyH); −14.62 (1H, tdd, 2JH−P = 69 Hz, 2JH−P = 53 Hz, 2JH−P
= 25 Hz, FeH). IR (fluorolube): 2107 s, ν(NN) cm−1.
(42H, m, CH2arm/CyH); 1.6−1.1 (36H, m, CyH). IR (fluorolube):
2083 s, ν(NN) cm−1.
Synthesis of Ru(15N2)(P2P3Cy) (15N2-2). Ru(N2)(P2P3Cy) (2)
(approximately 40 mg, 50 μmol) was dissolved in benzene-d6 (0.5 mL)
in an NMR tube fitted with a concentric Teflon valve under
dinitrogen. The solution was degassed with three freeze−pump−thaw
cycles before the introduction of 15N2 into the NMR tube headspace.
NMR spectra indicated the successful exchange of the dinitrogen
ligand following thawing of the solution and warming to room
temperature. 31P{1H} NMR (162 MHz, benzene-d6): δ 160.8 (1P,
Synthesis of [RuH(N2)(P2P3Cy)][BF4] (7[BF4]). Solid lutidinium
tetrafluoroborate (11 mg, 0.056 mmol) was added to a stirred solution
of Ru(N2)(P2P3Cy) (2) (45 mg, 0.054 mmol) in THF (20 mL). The
solution was pale green in color after 3 min but then turned to a pale
orange after one hour. The volume of the solution was reduced to ∼5
mL under reduced pressure before pentane (30 mL) was added
resulting in the precipitation of a pale orange solid. This solid was
collected by filtration to afford [RuH(N2)(P2P3Cy)][BF4] (7[BF4])
(40 mg, 0.043 mmol, 80%). Anal. Found. C 54.39, H 8.46, N 2.02,
C42H79BF4N2P4Ru (MW 923.87) requires C 54.60, H 8.62, N 3.03.
Elemental analysis performed on the crystalline product suggests some
loss of weakly bound dinitrogen ligand upon application of vacuum
during analytical procedure. 31P{1H} NMR (243 MHz, THF-d8): δ
2
2
3
dqd, JP−N = 31 Hz, JP−P = 22 Hz, JP−N = 3 Hz, PC); 74.0 (3P, ddd,
2JP−P = 22 Hz, 2JP−N = 5 Hz, 3JP−N = 2 Hz, PE). 15N{1H} NMR (40.56
MHz, benzene-d6): δ −9.0 (1N, s br, Nβ); −52.5 (1N, dqd, 2JN−P = 31
2
1
Hz, JN−P = 5 Hz, JN−N = 5 Hz, Nα).
Synthesis of [Fe(N2)(P2P3Cy)][BPh4] (3[BPh4]). Potassium graph-
ite (17 mg, 0.13 mmol) was added to a solution of [FeCl(P2P3Cy)]-
[BPh4] (132 mg, 0.118 mmol) in THF (approximately 15 mL). The
reaction mixture was stirred under nitrogen for 20 h. The resulting
black suspension was filtered to give a dark red solution. The solvent
was removed under reduced pressure, and the solid residue washed
with pentane (approximately 20 mL). The red solid was collected by
filtration to afford [Fe(N2)(P2P3Cy)][BPh4] (3[BPh4]) (58 mg, 0.052
mmol, 44%). Anal. Found. C 71.15, H 9.05, N 2.07, C66H98BFeN2P4
(MW 1110.05) requires C 71.41, H 8.90, N 2.52. IR (fluorolube):
2059 s, ν(NN) cm−1.
140.7 (1P, dt, 2JP−P = 11 Hz, 2JP−P = 11 Hz, PC); 63.8 (2P, dd, 2JP−P
=
11 Hz, 2JP−P = 11 Hz, PE); 51.4 (1P, dt, 2JP−P = 11 Hz, 2JP−P = 11 Hz,
1
PT). H NMR (600 MHz, THF-d8): δ 2.55 (4H, m); 2.22 (2H, m);
2.12 (4H, m); 2.01 (4H, m); 1.92−1.65 (30H, m); 1.65−1.47 (14H,
m); 1.47−1.20 (20H, m); −11.26 (1H, dtd, 2JH−P = 72 Hz, 2JH−P = 26
2
Hz, JH−P = 23 Hz, RuH). IR (fluorolube): 2172 s, ν(NN) cm−1.
3052
dx.doi.org/10.1021/ic3024953 | Inorg. Chem. 2013, 52, 3043−3053
Gilbert-Wilson, Ryan
