Organometallics
Article
NMR (CD2Cl2): δ 0.78 (s, 18H, C(CH3)3), 0.86 (t, 12H, JHH = 7.5
Hz, CH2CH3), 2.28, 2.40 (ABX3qd, 8H, JAB = 12.8 Hz, JAX = JBX, calcd
= 3.8 Hz, NCH2CH3), 3.71 (AB spin system, dd, 2H, JAB = 15.0 Hz,
JPH = 1.8 Hz, Cp-CH2−N), 3.78 (br s, 2H, Cp−CH), 3.80 (AB spin
system, d, 2H, JAB = 15.0 Hz, Cp-CH2−N), 4.12 (br s, 2H, Cp−CH),
7.15−7.69 (m, 20H, Ph−CH) ppm. 13C{1H} NMR (CD2Cl2): δ 11.9
(s, 4C, CH2CH3), 30.5 (s, 2C, C(CH3)3), 31.7 (s, 6C, C(CH3)3), 46.7
(s, 4C, CH2CH3), 51.6 (m, 2C, Cp-CH2−N), 67.8 (m, 2C, 3,5-Cp),
72.9 (br s, 2C, 3,5-Cp), 73.7 (d, 2C, JPC = 10 Hz, 1-Cp), 90.8 (d, 2C,
JPC = 27 Hz, 2-Cp), 106.7 (s, 2C, 4-Cp), 127.5 (s, 2C, p-Ph), 127.8 (d,
4C, JPC = 6 Hz, m-Ph), 128.6 (d, 4C, JPC = 8 Hz, m-Ph), 129.7 (s, 2C,
p-Ph), 132.8 (d, 4C, JPC = 18 Hz, o-Ph), 136.8 (d, 4C, JPC = 23 Hz, o-
Ph), 138.8 (s, 2C, ipso-Ph), 142.1 (s, 2C, ipso-Ph) ppm. 15N NMR
(CD2Cl2): δ −327.3 ppm. 31P{1H} NMR (CD2Cl2): δ −25.0 ppm.
HR-MS (C52H66FeN2P2) ESI: [M + H]+ m/z calcd 837.41246, found
837.41549, [err] 3.760 ppm. Anal. Calcd for C52H66FeN2P2 (836.41):
C, 74.63; H, 7.95; N, 3.35. Found: C, 74.71; H, 8.08; N, 3.47.
1,1′-Bis((N,N-diethylamino)methyl)-2,2′-bis(di-isopropyl-
phosphino)-4,4′-bis(tert-butyl)ferrocene (rac-13). 1,1′-Bis(tert-
butyl)-3,3′-bis((N,N-diethylamino)methyl)ferrocene (6) (0.63 g, 1.34
mmol) was dissolved in Et2O (7 mL). Then TMEDA (0.48 mL, 3.22
mmol) and a 1.6 M solution of n-BuLi in hexane (1.93 mL, 3.08
mmol) were successively added at −78 °C. The reaction mixture was
allowed to warm and stirred at room temperature for 24 h. Then the
mixture was cooled to −40 °C, and the chlorodiisopropylphosphine
(0.51 mL, 3.22 mmol) in solution in Et2O (2 mL) was added
dropwise. The red-orange reaction mixture was warmed and stirred
overnight at room temperature. The reaction mixture was hydrolyzed
by the addition of a saturated solution of NaHCO3 (20 mL), the
phases were separated, and the aqueous layer was extracted with
CH2Cl2 (18 mL). The combined organic layers were dried with
MgSO4, and the solvent was removed in vacuo. The crude product
(brown oil) was purified by column chromatography on silica
(EtOAc/heptane, 1:9). Complex 13 was isolated in a pure form as
an orange crystalline solid (0.63 g, 0.90 mmol, 67%). 1H NMR
(CD2Cl2): δ 0.94 (t, 12H, JHH = 7.2 Hz, CH2CH3), 1.00−1.22 (m,
12H, CH(CH3)2), 1.25 (s, 18H, C(CH3)3), 2.30−2.42 (m, 8H,
CH2CH3), 2.49−2.60 (m, 2H, CH(CH3)2), 3.22 (AB spin system, d,
12H, JHH = 4.5 Hz, CH2CH3), 1.16 (s, 18H, C(CH3)3), 2.03, 1.88 (s,
6H each, CH3-furyl), 2.37−2.50 (m, 8H, CH2CH3), 4.01 (AB spin
system, dd, 2H, JAB = 15.5 Hz, JPH = 2.5 Hz, Cp-CH2−N), 4.25 (AB
spin system, dd, 2H, JAB = 15.5 Hz, JPH = 2.5 Hz, Cp-CH2−N), 4.43,
4.64 (br s, 2H each, Cp−CH), 5.72, 5.81 (m, 2H each, furyl−CH),
6.47 (d, 2H, JPH = 3.5 Hz, furyl−CH), 6.97 (t, 2H, JPH = 6.0 Hz, furyl−
CH) ppm. 13C{1H} NMR (C6D6): δ 12.7 (s, 4C, CH2CH3), 13.6 (s,
2C, CH3−furyl), 13.9 (s, 2C, CH3−furyl), 30.7 (s, 2C, C(CH3)3), 32.0
(s, 6C, C(CH3)3), 47.2 (s, 4C, CH2CH3), 51.7 (t, 2C, JPC = 7.6 Hz,
Cp-CH2−N), 69.7, 71.9 (d, 2C each, JPC = 5.5 Hz, 3,5-Cp), 72.4 (d,
2C, JPC = 5 Hz, 1-Cp), 91.0 (d, 2C, JPC = 29 Hz, 2-Cp), 106.7 (s, 2C,
4-Cp), 107.1 (d, 2C, JPC = 2.5 Hz, furyl), 107.5 (d, 2C, JPC = 9 Hz,
furyl), 119.8 (d, 2C, JPC = 14 Hz, furyl), 123.60 (d, 2C, JPC = 32 Hz,
furyl), 151.0 (d, 2C, JPC = 15 Hz, furyl), 152.5, 155.7, 157.2 (s, 2C
each, furyl) ppm. 15N NMR (C6D6): δ −327.2 ppm. 31P{1H} NMR
(C6D6): δ −71.2 ppm. HR-MS (C48H66FeN2O4P2) ESI: [M + H]+
m/z calcd 853.39262, found 853.39200, [err] 3.760 ppm. Anal. Calcd
for C48H66FeN2O4P2 (852.38): C, 67.60; H, 7.80; N, 3.28. Found: C,
67.38; H, 7.64; N, 3.15.
1 , 1 ′ - B i s ( ( p y r r o l i d i n - 1 - y l ) m e t h y l ) - 2 , 2 ′ - b i s -
(diphenylphosphino)-4,4′-bis(tert-butyl)ferrocene (rac-15).
1,1′-Bis(tert-butyl)-3,3′-bis((pyrrolidin-1-yl)methyl)ferrocene (7)
(0.50 g, 1.07 mmol) was dissolved in pentane (7 mL). Then a 1.9
M solution of t-BuLi in pentane (1.3 mL, 2.46 mmol) was added at
−78 °C and stirred for 2 h. The reaction mixture was allowed to warm
and stirred at room temperature overnight. Then the mixture was
cooled to −78 °C, and the chlorodiphenylphosphine (0.46 mL, 2.46
mmol) in solution in Et2O (2 mL) was added dropwise. The red-
orange reaction mixture was warmed and stirred overnight at room
temperature. The reaction mixture was hydrolyzed by the addition of a
saturated solution of NaHCO3 (20 mL), the phases were separated,
and the aqueous layer was extracted with CH2Cl2 (18 mL). The
combined organic layers were dried with MgSO4, and the solvent was
removed in vacuo. The crude product (brown oil) was purified by
column chromatography on silica (EtOAc/heptane, 1:9). Complex 15
was isolated in a pure form as an orange crystalline solid (0.55 g, 0.66
mmol, 62%). Single crystals suitable for X-ray diffraction studies were
obtained from a concentrated solution in pentane kept at room
temperature. 1H NMR: δ 0.79 (s, 18H, C(CH3)3), 1.46 (m, 8H, py-β-
N−CH2), 2.31 (m, 8H, py-α-N−CH2), 3.69 (d, 2H, JAB = 12.4 Hz, Cp-
CH2−N,), 3.78 (d, 2H, J = 12.4 Hz, Cp-CH2−N), 3.76, 4.09 (s, 2H
each, Cp−CH), 7.68−7.14 (m, 20H, Ph) ppm. 13C{1H} NMR: δ 23.8
(s, 4C, py-β-N−CH2), 30.5 (s, 2C, C(CH3)3), 31.7 (s, 6C, C(CH3)3),
52.9 (m, 4C, py-α-N-CH2), 53.5 (s, 2C, Cp-CH2−N), 68.1, 72.4 (br s,
2C each, 3,5-Cp), 73.6 (d, 2C, JPC = 10 Hz, 2-Cp), 91.4 (s, 2C, 1-Cp),
106.7 (s, 2C, 4-Cp), 127.5 (s, 2C, p-Ph), 127.8 (d, 4C, JPC = 6 Hz, m-
Ph), 128.7 (m, 4C, m-Ph), 129.6 (s, 2C, p-Ph), 132.8 (d, 4C, JPC = 18
Hz, o-Ph), 136.6 (d, 4C, JPC = 23 Hz, o-Ph), 138.7 (d, 2C, JPC = 11 Hz,
ipso-Ph), 142.0 (s, 2C, JPC = 11 Hz, ipso-Ph) ppm. 31P{1H} NMR: δ
−24.1 ppm. HR-MS (C52H62FeN2P2) ESI: [M + H]+ m/z calcd
833.38116, found 833.38495, [err] 4.690 ppm. Anal. Calcd for
C52H62FeN2P2 (832.37): C, 74.99; H, 7.50; N, 3.36. Found: C, 74.82;
H, 7.55; N, 3.38.
2H, JAB = 12.9 Hz, Cp-CH2−N), 3.46 (AB spin system, dd, 2H, JAB
=
12.9 Hz, JPH = 1.8 Hz, Cp-CH2−N), 3.91, 4.11 (br s, 2H each, Cp−
CH) ppm. 13C{1H} NMR (CD2Cl2): δ 11.4 (s, 4C, CH2CH3), 20.4 (d,
2C, JPC = 13 Hz, CH(CH3)2), 20.9 (d, 2C, JPC = 8 Hz, CH(CH3)2),
22.5 (d, 2C, JPC = 18 Hz, CH(CH3)2), 23.2 (d, 2C, JPC = 22 Hz,
CH(CH3)2), 24.3 (d, 2C, JPC = 14 Hz, CH(CH3)2), 24.7 (d, 2C, JPC
=
14 Hz, CH(CH3)2), 31.0 (s, 2C, C(CH3)3), 32.3 (s, 6C, C(CH3)3),
46.2 (s, 4C, CH2CH3), 52.6 (m, 2C, Cp-CH2−N), 69.7 (d, 2C, JPC = 9
Hz, 3,5-Cp), 72.1 (br s, 2C, 3,5-Cp), 78.8, 87.5 (d, 2C each, JPC = 13
Hz, 1,2-Cp), 104.0 (s, 2C, 4-Cp) ppm. 15N NMR (CD2Cl2): δ −327.7
ppm. 31P{1H} NMR (CD2Cl2): δ −2.6 ppm. HR-MS (C40H74FeN2P2)
ESI: [M + H]+ m/z calcd 701.47451, found 701.46382, [err] 1.599
ppm. Anal. Calcd for C40H74FeN2P2 (700.41): C, 68.55; H, 10.64; N,
4.00. Found: C, 68.14; H, 10.39; N, 4.12.
1,1′-Bis((N,N-diethylamino)methyl)-2,2′-bis(bis(5-methyl-2-
furyl)phosphino)-4,4′-bis(tert-butyl)ferrocene (rac-14). 1,1′-Bis-
(tert-butyl)-3,3′-bis((N,N-diethylamino)methyl)ferrocene (6) (0.50 g,
1.07 mmol) and TMEDA (0.27 mL, 1.82 mmol) were dissolved in
pentane (10 mL). Then a 1.6 M solution of n-BuLi in hexane (1.54
mL, 2.46 mmol) was added at −78 °C. The reaction mixture was
allowed to warm and stirred at room temperature overnight. Then the
mixture was cooled to −78 °C, and the bromobis(5-methylfuran-2-
yl)phosphine (0.87 g, 3.21 mmol) was added dropwise over 5 min.
After the addition the reaction mixture was warmed and stirred
overnight at room temperature. The reaction mixture was hydrolyzed
by the addition of a saturated solution of NaHCO3 (10 mL), the
phases were separated, and the aqueous layer was extracted with
CH2Cl2 (20 mL). The combined organic layers were dried with
MgSO4, and the solvent was removed in vacuo. The crude product
(amber oil) was purified by column chromatography on silica (EtOAc/
heptane, 1:9). Complex 14 was isolated in a pure form as an orange
crystalline solid (0.44 g, 0.52 mmol, 48%). 1H NMR (C6D6): δ 1.05 (t,
Palladacycle 16. Bis(benzonitrile)palladium(II) chloride (0.24 g,
0.64 mmol) was added to a solution of 1,1′-bis(tert-butyl)-3,3′-
bis((N,N-diethylamino)methyl)ferrocene (6) (0.3 g, 0.64 mmol) in
dichloromethane (10 mL). The reaction mixture was stirred at room
temperature for 8 h and then filtered over Celite. After removal of the
solvent in vacuo, a red oil was obtained. Treatment with ether (3 mL)
afforded complex 16 as a brown powder (0.155 g, 0.24 mmol, 40%).
Single crystals suitable for X-ray diffraction studies were obtained from
low diffusion of pentane in a concentrated solution of complex 16 in
1
dichloromethane. H NMR: δ 1.14 (s, 9H, C(CH3)3), 1.22 (s, 9H,
C(CH3)3), 1.44 (s, 3H, CH2CH3), 1.51 (s, 3H, CH2CH3), 1.62 (s, 3H,
CH2CH3), 1.73 (s, 3H, CH2CH3), 2.53, 3.44 (ABX3qd, 2H, JAB = 52.0
Hz, JAX = JBX calcd = 7.0 Hz, CH2CH3), 2.79 (s, 1H, CH2CH3), 2.86
(s, 2H, CH2CH3), 2.95 (s, 1H, CH2CH3), 2.96 (s, 1H, CpCH2N), 3.27
(s, 2H, CH2CH3), 3.72 (m, 2H, Cp−CH), 3.91 (m, 1H, Cp−CH),
3.96 (s, 1H, Cp−CH), 4.09 (s, 1H, CpCH2N), 4.10 (s, 1H, CpCH2N),
4.34 (m, 1H, CpCH2N), 5.09 (d, 1H, Cp−CH, J = 23.0 Hz), 11.55 (br
5026
Organometallics 2015, 34, 5015−5028