Inorganic Chemistry
Article
Layering this solution with Et2O resulted in blue plates after 2 days.
Yield: 56 mg (76%). Compound 2·BPh4 was either not soluble (C6D6,
toluene-d8, MeOH-d4) or not stable (acetone-d6) in solvents other
than CD3CN. Due to an exchange of the coordinated MeCN with the
deuterated solvent, the coordinated acetonitrile ligands could not be
detected. 1H NMR (400 MHz, CD3CN, 23 °C) δ: −12.31 (t, 1H, 2JHP
= 60 Hz, Fe−H), 1.35 (m, 18H, PC(CH3)3), 1.40 (m, 18H,
PC(CH3)3), 3.22 (m, 2H, CH2PtBu2), 3.41 (m, 2H, CH2PtBu2), 6.83
(t, 4H, JHH = 7.1 Hz, BPh-Hpara), 6.98 (t, 8H, JHH = 7.4 Hz, BPh-
Hmeta), 7.26 (br, 8H, BPh-Hortho), 7.88 (s, 2H, pyrazine-H) ppm.
31P{1H} NMR (161 MHz, CD3CN, 23 °C) δ: 107 (s) ppm. 13C {1H}
NMR (100 MHz, CD3CN, 23 °C) δ: 28.7 (br, 6C, 2 PC(CH3)3), 28.9
(br, 6C, 2 PC(CH3)3), 32.3 (br, 2C, 2 CH2PtBu2), 35.5 (br, 2C, 2
PC(CH3)3), 36.6 (br, 2C, 2 PC(CH3)3), 122.7 (s, 4C, BPh−Cpara),
126.5 (br, 8C, BPh−Cmeta), 136.7 (br, 8C, BPh−Cortho), 137.1 (br, 2C,
pyrazine-CH), 164.8 (q, 4C, 1JPB = 49 Hz, BPh−Cipso), 162.9 (br, 2C,
2 pyrazine-C) ppm. Anal. Calcd for C48H66BFeN3OP2: C, 70.85; H,
8.18; N, 5.16. Found: C, 70.71; H, 8.07; N, 4.94.
CH2PtBu2), 3.53 (m, 2H, CH2PtBu2), 7.97 (s, 2H, pyrazine-H) ppm.
31P{1H} NMR (161 MHz, CD3CN, 23 °C) δ: 115 (s) ppm. 13C {1H}
NMR (100 MHz, CD3CN, 23 °C) δ: 29.3 (br, 6C, 2 PC(CH3)3), 30.9
(br, 6C, 2 PC(CH3)3), 33.9 (t, 2C, 2JCP = 5 Hz, 2 CH2PtBu2), 35.6 (br,
3
2C, 2 PC(CH3)3), 37.7 (br, 2C, 2 PC(CH3)3), 139.5 (t, 2C, JCP = 5
2
Hz, pyrazine-CH), 158.9 (t, 2C, JCP = 7 Hz, 2 pyrazine-C), 221.6 (t,
2
1C, JCP = 22 Hz, Fe−CO) ppm. IR (KBr, disk): 1896 (υ CO). Anal.
Calcd for C23H43ClFeN2OP2: C, 53.45; H, 8.39; N, 5.42. Found: C,
53.02; H, 8.42; N, 5.25.
3
3
[Fe(H)(Py-d5)(CO)(tBu-PNzP)*] (6·Py-d5). Complex 5 (25 mg, 0.05
mmol) together with 1.2 equiv of tBuOK (7 mg, 0.10 mmol) were
dissolved in THF, leading to formation of a dark red solution. After
stirring for 30 min, the solvent was removed under vacuum and the
residue was washed with pentane. The brown solid was dried to give
complex A. Once dried, A was dissolved in neat Py-d5, leading to the
1
formation of complex 6·Py-d5. H NMR (400 MHz, CD3CN, 23 °C)
δ: −19.24 (dd, 1H, 2JHP = 55 Hz, 2JHP = 60 Hz, Fe−H), 0.96 (m, 18H,
3
PC(CH3)3), 1.25, 1.43 (d, 9H each, JHP = 11 Hz, PC(CH3)3), 3.89,
2
2
trans-[Fe(H)(CO)(MeCN)(tBu-PNzP)][BPh4] (trans-3·BPh4). Com-
plex 2-BPh4 (50 mg, 0.06 mmol) was dissolved with MeCN (3 mL) in
a Teflon capped tube and immersed in a bath of liquid nitrogen. The
tube was evacuated on a high-vacuum line and cooled with liquid
nitrogen, and 1 atm of carbon monoxide was added. The reaction was
allowed to warm up to ambient temperature, and after 2 h under
carbon monoxide atmosphere the color changed from blue to yellow-
orange. All volatiles were removed in vacuo to give 3·BPh4 together
4.21 (dd, 1H each, JHP = 12 Hz, JHH = 16 Hz, CH2PtBu2), 5.19 (s,
1H, CHPtBu2), 7.08, 7.92 (s, 1H each, pyrazine-H) ppm. 31P{1H}
2
NMR (161 MHz, CD3CN, 23 °C) δ: 96.5, 104.9 (d, 1P each, JPP
=
110 Hz) ppm. 13C {1H} NMR (100 MHz, CD3CN, 23 °C) δ: 28.5,
29.5, 30.4, 31.4 (br, 3C, C(CH3)3), 37.4, 36.8, 37.1 (br, 1C each,
PC(CH3)3), 38.4 (d, 1C, JCP = 9 Hz, CH2PtBu2), 37.6 (d, 1C, JCP
=
2
2
2
20 Hz, CH2PC(CH3)3), 69.3 (d, 1C, JCP = 40 Hz, CH-PC(CH3)3),
2
116.6 (m, 1C, pyrazine-CH), 117.6 (d, 1C, JCP = 10 Hz, pyrazine-
1
2
with small amounts of 4·BPh4. Yield: 46 mg (94%). H NMR (400
CH), 138.8 (d, 1C, JCP = 16 Hz, pyrazine-CH) 153.2, 164.7 (br, 1C
MHz, CD3CN, 23 °C) δ: 0.88 (t, 1H, 2JHP = 53 Hz, Fe−H), 1.44 (m,
each, pyrazine-C), 222.3 (br, 1C, Fe−CO) ppm. IR (pyridine, liquid):
1868 (ν CO). The coordination of pyridine is reversible; when 6·Py-d5
was placed under vacuum, pyridine was partially removed, which does
not allow one to obtain elemental analysis.
18H, PC(CH3)3), 1.50 (m, 18H, PC(CH3)3), 3.48 (m, 2H,
3
CH2PtBu2), 3.50 (m, 2H, CH2PtBu2), 6.83 (t, 4H, JHH = 7.1 Hz,
BPh-Hpara), 6.98 (t, 8H, 3JHH = 7.4 Hz, BPh-Hmeta), 7.26 (br, 8H, BPh-
Hortho), 8.13 (s, 2H, pyrazine-H) ppm. 31P{1H} NMR (161 MHz,
CD3CN, 23 °C) δ: 109 (s) ppm. 13C {1H} NMR (100 MHz, CD3CN,
23 °C) δ: 28.3 (d, 6C, 2JCP = 2 Hz, 2 PC(CH3)3), 29.7 (d, 6C, 2JCP = 2
trans-[Fe(PNzPtBu-COO)(H)(CO)] (8). Complex 5 (50 mg, 0.09
mmol) together with 1.2 equiv of tBuOK (13 mg, 0.12 mmol) were
dissolved in THF, leading to formation of a dark red solution. After
stirring for 1 h, the solvent was removed under vacuum. The desired
product was washed with pentane. The solid was dried to give
compound A, which upon addition of THF-d8 gave a suspension that
was placed in a J. Young NMR tube. The suspension was degassed by a
3 freeze−pump−thaw cycles and filled with 1 bar of CO2. After 6 h
complete reaction occurred, leading to the formation of a brown-
1
Hz, 2 PC(CH3)3), 33.3 (d, 2C, JCP = 9 Hz, 2 CH2PtBu2), 36.0 (br,
2C, 2 PC(CH3)3), 37 (br, 2C, 2 PC(CH3)3), 122.7 (s, 4C, BPh−
Cpara), 126.6 (q, 8C, 3JCB = 2.8 Hz, BPh−Cmeta), 136.7 (br, 8C, 2JCB = 2
3
Hz, BPh−Cortho), 140.0 (d, 2C, JCP = 4 Hz, pyrazine-CH), 164.8 (q,
1
2
4C, JPB = 49 Hz, BPh−Cipso), 160.0 (d, 2C, JCP = 5 Hz, 2 pyrazine-
C), 217 (br, 1 C, Fe−CO) ppm. IR (KBr, disk): 1948 (υ CO). Due to
its instability and tendency to form 4·BPh4, elemental analysis will be
given for 4·BPh4.
1
yellow clear solution; 99.9% yield by NMR spectroscopy. H NMR
2
2
(400 MHz, CD3CN, 23 °C) δ: −22.45 (dd, 1H, JHP = 47 Hz, JHP
=
cis-[Fe(H)(CO)(MeCN)(tBu-PNzP)][BPh4] (4·BPh4). Complex 3·
BPh4 (50 mg, 0.06 mmol) was dissolved in CH3CN (2 mL) in a
Teflon capped tube and heated at 90 °C for 30 min. Removal of the
solvent in vacuo gave 4-BPh4, together with some impurities. After
washing the yellow solid with pentane, pure 4·BPh4 was obtained.
57, Hz Fe−H), 0.989 (m, 18H, PC(CH3)3), 1.47, 1.59 (d, 9H, 3JHP = 9
Hz, PC(CH3)3), 3.41 (m, 1H, CH2PtBu2), 3.71 (m, 1H, CH2PtBu2),
4.61 (s, 1H, CHPtBu2), 8.42, 8.52 (s, 1H each, pyrazine-CH) ppm.
31P{1H} NMR (161 MHz, CD3CN, 23 °C) δ: 138.4, 147.8 (d, 1P
each, JPP = 128 Hz) ppm. 13C {1H} NMR (100 MHz, CD3CN, 23
2
1
2
Yield: 46 mg (91%). H NMR (400 MHz, CD3CN, 23 °C) δ: −17.0
°C) δ: 29.6, 30.1, 31.0 (d, 3C each, JCP = 4 Hz, PC(CH3)3), 30.7 (s,
3C, PC(CH3)3), 34.5 (d, 1C, JCP = 17 Hz, CH2PC(CH3)3), 35.3 (d,
1C, JCP = 22 Hz, PC(CH3)3), 36.9 (d, 1C, JCP = 7 Hz, PC(CH3)3),
2
2
(t, 1H, JHP = 53 Hz, Fe−H), 1.27 (m, 18H, PC(CH3)3), 1.44 (m,
18H, PC(CH3)3), 3.68 (m, 2H, CH2PtBu2), 3.77 (m, 2H, CH2PtBu2),
2
2
3
3
2
2
6.83 (t, 4H, JHH = 7.1 Hz, BPh-Hpara), 6.98 (t, 8H, JHH = 7.4 Hz,
BPh-Hmeta), 7.26 (br, 8H, BPh-Hortho), 8.58 (s, 2H, pyrazine-H) ppm.
31P{1H} NMR (161 MHz, CD3CN, 23 °C) δ: 113 (s) ppm. 13C {1H}
37.5 (d, 1C, JCP = 8 Hz, PC(CH3)3), 38.7 (d, 1C, JCP = 3 Hz,
PC(CH3)3), 59.7 (s, 1C, CHPtBu2), 138.6 (d, 1C, JCP = 9 Hz,
4
4
pyrazine-CH), 139.8, (d, 1C, JCP = 7 Hz, pyrazine-CH), 158.4, 159.1
3
NMR (100 MHz, CD3CN, 23 °C) δ: 28.7 (br, 6C, 2 PC(CH3)3), 29.2
(br, 1C each, pyrazine-CH), 170.7 (d, 1C, JCP = 9 Hz, O(OC)-
2
(br, 6C, 2 PC(CH3)3), 33.5 (br, 2C, 2 CH2PtBu2), 36.5 (t, 2C, JCP
=
CHPC(CH3)3), 225.1 (t, 1C, 2JCP = 25 Hz, Fe−CO) ppm. Complex 8
in the absence of CO2 is unstable, which does not allow one to obtain
its elemental analysis nor the IR spectrum.
11 Hz, 2 PC(CH3)3), 37.4 (br, 2C, 2 PC(CH3)3), 122.7 (s, 4C, BPh−
Cpara), 126.6 (q, 8C, 3JCB = 2.8 Hz, BPh−Cmeta), 136.7 (br, 8C, 2JCB = 2
Hz, BPh−Cortho), 141.5 (br, 2C, pyrazine-CH), 158.9 (br, 2C, 2
pyrazine-C), 164.8 (q, 4C, 1JPB = 49 Hz, BPh−Cipso), 221.6 (t, 1C, 2JCP
= 22 Hz, Fe−CO) ppm. IR (KBr, disk): 1918 (υ CO). Anal. Calcd for
C49H66BFeN3OP2: C, 69.92; H, 7.90; N, 4.99. Found: C, 70.04; H,
7.72; N, 4.83.
trans-[Fe(H)2(CO)(tBu-PNzPtBu)] (9). Complex 5 (50 mg, 0.09
mmol) together with 1.2 equiv of tBuOK (13 mg, 0.12 mmol) were
dissolved in THF, leading to formation of a dark red solution. After
stirring for 1 h, the solvent was removed under vacuum and the
residue was washed with pentane. The resulting solid was dried to give
compound A, to which C6D6 was added to give a suspension that was
placed in a J. Young NMR tube. The suspension was degassed by 3
freeze−pump−thaw cycles and filled with 1 bar of H2. After 24 h
complete reaction occurred leading to the formation of a clear red
solution. This solution was filtered through Celite. Removal of the
[Fe(H)(Cl)(CO)(tBu-PNzP)] (5). Complex 4 (150 mg, 0.17 mmol)
together with 2.2 equiv of Bu4NCl (86 mg, 0.37 mmol) were dissolved
in THF, giving a dark orange solution. After stirring for 30 min the
solvent was removed under vacuum. The desired product was
extracted from the crude residue with benzene. Removal of the
1
1
solvent in vacuo gave pure 5. Yield: 86 mg (98%). H NMR (400
solvent by vacuum yielded complex 7. Yield: 30 mg (68%). H NMR
MHz, CD3CN, 23 °C) δ: −20.7 (t, 1H, 2JHP = 56 Hz, Fe−H), 1.01 (m,
(400 MHz, tol-d8, 23 °C) δ: −7.07 (t, 1H, 2JHP = 36 Hz, Fe−H), 1.31
18H, PC(CH3)3), 1.45 (m, 18H, PC(CH3)3), 2.63 (m, 2H,
(m, 36H, PC(CH3)3), 2.77 (m, 4H, CH2PtBu2), 7.72 (s, 2H, pyrazine-
K
Inorg. Chem. XXXX, XXX, XXX−XXX