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count solvent effects), we believe it is sufficient to support our in-
terpretation of the NMR spectra.
(10 mL), and the filtrates combined. The solvent was then removed
under vacuum to leave an off-white solid. The product was recrys-
tallised from acetonitrile to give a white solid (0.16 g, 34%). Ele-
mental analysis calcd (%) for C25H19NP2 (395.37) C 75.95, H 4.84, N
1
Crystallographic details
3.54; found: C 76.28, H 4.85, N 3.73; H NMR (300 MHz, CDCl3): d=
1.60 (s, 3H, NCH3), 7.43 (m, 8H, (C12H8P)2), 7.81 (m, 4H,
(C12H8P)2NCH3), 7.90 ppm (m, 4H, (C12H8P)2); 31P NMR (122 MHz,
CDCl3): d=63.7 ppm (s); MS (EI): m/z: 395.1 [C25H19NP2]+, 212.1
[C13H11NP]+.
XRD experiments on 8, 9, 13–16, 18, 20 and 21 were performed at
100 K by using a Bruker Kappa Apex II CCD diffractometer using
MoKa radiation (l=0.71073 ꢁ). Single crystals were coated in inert
oil and mounted on a glass fibre. Intensities were integrated from
several series of exposures in f and w calculated by the Apex II
program[26] after unit cell determination. Absorption corrections
were based on equivalent reflections using SADABS,[27] and struc-
Synthesis of N,N’-bis(dibenzophosphole)ethylamine (4)
2
tures were refined against all Fo data with H atoms riding in calcu-
The same method was used as for 3, except that methylamine was
replaced with ethylamine. Precipitation from acetonitrile yielded 4
as a white powder (0.22 g, 46%). Elemental analysis calcd (%) for
C26H21NP2 (409.40): C 76.28, H 5.17, N 3.42; found: C 75.98, H 5.36,
N 3.38; 1H NMR (300 MHz, CDCl3): d=0.51 (t, 3JHH =7.14 Hz, 3H,
(C12H8P)2NCH2CH3), 2.46 (q, J=7.21 Hz, 2H, (C12H8P)2NCH2CH3),
7.37–7.50 (m, 8H, (C12H8P)2NCH2CH3), 7.80–7.91 ppm (m, 8H,
(C12H8P)2NCH2CH3); 31P NMR (122 MHz, CDCl3): d=59.0 ppm (s); MS
(EI): m/z: 409.2 [M]+, 226.1 [(C12H8P)NCH3]+.
lated positions by using SHELXTL.[28] The crystal structure of 9 dis-
played residual electron density 1.387(11) ꢁ from P1. This was at-
tributed to partial oxidation during transfer to the diffractometer
and was modelled as a partially occupied (15%) O atom. The disor-
dered isopropyl group of 20 was modelled over two positions.
Synthesis of N,N-bis(2,3,4,5-tetraethylphospholyl)methylamine
(1)
A solution of 1-chloro-2,3,4,5-tetraethylphosphole (2.0 mL, 2m in
hexane, 4.0 mmol) was added dropwise to a stirred solution of
methylamine (1.0 mL, 2m in THF, 2.0 mmol) and triethylamine
(1.4 mL, 10.0 mmol) in CH2Cl2 (5 mL). The yellow phosphole solu-
tion de-colourised immediately with the formation of a precipitate.
After stirring for 1 h, the reaction mixture was concentrated under
reduced pressure. The residue was extracted with toluene and re-
crystallised from methanol to give a white solid (0.28 g, 33%). Ele-
mental analysis calcd (%) for C25H43NP2 (419.56): C 71.57, H 10.33, N
Synthesis of N,N-bis(dibenzophosphole)-n-butylamine (5)
The same method was used as for 3, except that methylamine was
replaced with n-butylamine. Recrystallisation from ethanol yielded
5 as a white crystalline solid (0.12 g, 24%). Elemental analysis calcd
(5) for C28H25NP2 (437.45): C 76.88, H 5.76, N 3.20; found: C 76.49, H
5.97,
N
3.14; 1H NMR (300 MHz, CDCl3): d=0.31 (t, 3H,
NCH2CH2CH2CH3), 0.60–0.74 (m, 2H, NCH2CH2CH2CH3) 0.81–1.00 (m,
2H, NCH2CH2CH2CH3), 1.25 (s, 2H), 2.37 (quin, J=7.62 Hz, 2H,
(NCH2CH2CH2CH3) 7.35–7.47 (m, 8H, (C12H8P)2) 7.76–7.85 ppm (m,
8H, (C12H8P)2); 31P NMR (122 MHz, CDCl3): d=58.9 ppm (s); MS (EI):
m/z: 437.2 [M]+, 381.1 [(C12H8P)2N]+, 254.2 [(C12H8P)NBu]+.
1
3.34; found: C 71.56, H 9.78, N 3.93; H NMR (300 MHz, CDCl3): d=
1.04 (t, 3JHH =7.6 Hz, 12H, PCCCH2CH3), 1.24 (t, 3JHH =7.3 Hz, 12H,
PCCH2CH3), 1.90 (t, 3JHP =2.9 Hz, 3H, NCH3), 2.23–2.39 (m, 8H,
PCCCH2CH3), 2.40–2.59 ppm (m, 8H, PCCH2CH3); 31P NMR (121 MHz,
CDCl3): d=71.9 ppm (s); MS (CI): m/z: 420.4 [M+H]+; HRMS (EI): m/
z: calcd for C25H43NP2+H+: 420.2949 [M+H]+; found: 420.2949.
Synthesis of N-2,3,4,5-tetraethylphospholyl-N-diphenylphos-
phanoisopropylamine (6)
Synthesis of N,N-bis(2,3,4,5-tetraethylphospholyl)ethylamine
(2)
1-chloro-2,3,4,5-tetraethylphosphole (0.24 mL, 1.1 mmol) was
added dropwise to a stirred solution of triethylamine (0.2 mL,
1.4 mmol) and isopropylamine (40 mL, 0.50 mmol) in CH2Cl2 (10 mL)
at 08C, resulting in the formation of a white precipitate. Chlorodi-
phenylphosphine (0.14 mL, 0.54 mmol) was dissolved in CH2Cl2
(5 mL) and added dropwise to the solution, resulting in further pre-
cipitate formation. The solution was allowed to warm to RT over
30 min before filtration and removal of the solvent under reduced
pressure, leaving an oily solid. Recrystallisation from acetonitrile af-
forded the product as a white powder (0.17 g, 36%). Elemental
analysis calcd (%) for C27H37NP2 (437.54): C 74.12, H 8.52, N 3.20;
The same method was used as for 1, except that methylamine was
replaced with ethylamine. Recrystallisation from acetonitrile yielded
2 as a white solid (0.25 g, 57%). H NMR (300 MHz, CDCl3): d=0.57
1
(t, 3JHH =7.1 Hz, 3H, NCH2CH3), 1.03 (t, 3JHH =7.6 Hz, 12H,
PCCCH2CH3), 1.25 (t, 3JHH =7.3 Hz, 12H, PCCH2CH3), 2.23–2.39 (m,
8H, PCCCH2CH3), 2.39–2.61 ppm (m, 8H, PCCH2CH3); 31P NMR
(122 MHz, CDCl3): d=66.7 ppm (s); MS (EI): m/z: 433 [M]+; HRMS
(EI): m/z: calcd for C26H45NP2: 433.3027 [M]+; found: 433.3011.
found:
C 74.46, H 8.77, N
3.12; 1H NMR (300 MHz, 208C,
Synthesis of N,N-bis(dibenzophosphole)methylamine (3)
[D8]toluene) d=0.92 (t, 6H 3JHH =7.4 Hz, PCCCH2CH3), 0.96 (t, 6H
3JHH =7.5 Hz, PCCH2CH3), 1.10 (t, 2.4H, 3JHH =7.4 Hz, PCCCH2CH3),
1.17 (d, 2.4H 3JHH =6.3 Hz, CH(CH3)2), 1.25 (t, 2.4H 3JHH =7.5 Hz,
5-Chlorodibenzophosphole (0.498 g, 2.27 mmol) was dissolved in
THF (20 mL). Methylamine (2m solution in THF, 0.57 mL,
1.14 mmol) and triethylamine (0.825 mL, 5.7 mmol) were dissolved
in THF (60 mL) separately and the solution was cooled to À788C.
The chlorophosphole solution was added to the solution of the
amines dropwise and a cream precipitate formed. The solution was
allowed to warm slowly to RT over 16 h before the THF was re-
moved under vacuum. The resulting solid was dissolved in diethyl
ether, and the solution filtered to remove the ammonium salt by-
product. The remaining solid was washed with diethyl ether
3
PCCH2CH3), 1.28 (d, 6H JHH =6.5 Hz, CH(CH3)2), 2.00–2.67 (m, 11H,
unresolved ethyl CH2 protons for both rotamers), 2.90 (m, 1H,
CH(CH3)2), 3.62 (m, 0.4H, CH(CH3)2), 7.04–7.25 (m, 8.4H, unresolved
aryl protons for both rotamers), 7.48 (m, 1.6H, ArH), 7.79 ppm (m,
2
4H, ArH); 31P NMR (121 MHz, 208C, [D8]toluene) d=42.0 (d, JPP
=
2
2
19 Hz, PPh2), 43.4 (d, JPP =21 Hz, PPh2), 50.7 (d, JPP =19 Hz, PC4Et4),
61.8 ppm (d, JPP =21 Hz, PC4Et4); MS (EI): m/z: 437 [M]+. HRMS (EI):
2
m/z: calcd for C27H37NP2+: 437.2401[M]+; found: 437.2412.
ChemCatChem 2013, 5, 2946 – 2954 2952
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