Organometallics
Article
two times with n-pentane (50 mL each). n-Pentane was condensed off,
and diallylmethylphosphane (4) (1.78 g, 13.9 mmol, 65%) was
obtained after vacuum distillation (bp 70 mbar, 70 °C). NMR data are
confirmed by NMR spectroscopy and correct values in hydrogen
and nitrogen content in elemental analysis. Carbon values are too low,
as organoboranes tend to form boron carbides as well as glassy boric
12
1
20
in agreement with literature values. H NMR (300 MHz, C D ): δ
acid with carbon enclaves during combustion.
6
6
1
[
ppm] = 5.70 (m, 2H, CHCH ), 4.94 (m, 4H, CHCH ), 2.01 (m,
H NMR (300 MHz, C D ): δ [ppm] = 2.73 (m, 6H, N−CH ),
2
2
6
6
2
2
13
1
3
4
H, P−CH ), 0.78 (d, J = 4.0 Hz, 3H, CH ). C{ H} NMR (75.6
1.93 [m-overlap, 30H, H-2 (24H) and H-3 (6H)], 1.67 (quint, J
=
2
P,H
3
H,H
2
MHz, C D ): δ [ppm] = 133.4 (d, J = 6 Hz, CHCH ), 115.9 (d,
7.7 Hz, 6H, N−CH −CH −CH −B), 1.50 (broad, 6H, H-1), 1.44 (m,
6
6
P,C
2
2
2
2
3
1
1
3
1
1
JP,C = 8 Hz, CHCH ), 33.3 (d, J = 16 Hz, P−CH ), 9.3 (d, J
6H, H-3), 1.13 (t, J = 7.7 Hz, 6H, CH −B). B NMR (96 MHz,
2
P,C
2
P,C
H,H
2
31
1
13 1
=
19 Hz, CH ). P{ H} NMR (121 MHz, C D ): δ [ppm] = −43.8.
Me N−CH −CH −CH −BBN (6). Dimeric 9-BBN (114 mg, 0.47
C
6
D
6
): δ [ppm] = 65 (τ1/2 = 220 Hz, av boron nuclei). C{ H} NMR
3
6
6
(75.6 MHz, C D ): δ [ppm] = 58.1 (N−CH ), 33.8 (C-2), 29.7
2
2
2
2
6
6
2
mmol) was added to a solution of allyldimethylamine (5) (80 mg, 0.93
mmol) in n-pentane, and the solution was stirred at ambient
temperature for 3 d. The solvent was removed in vacuo (allowing
recording NMR spectra of the crude product), and the resulting
colorless solid was dissolved in n-hexane (5 mL). The solution was
decanted off the solid residuals, and the hydroboration product was
crystallized at −80 °C in the form of colorless needles. The
supernatant solution was removed by a syringe, and the crystalline
solid dried in vacuo to yield hydroboration product 6 (120 mg, 62%).
The identity of 6 was confirmed by NMR spectroscopy, mass
spectrometry, and X-ray crystallography. The purity was confirmed by
(broad, C-1), 24.1 (C-3), 23.3 (broad, CH −B), 20.2 (N−CH −CH −
2
2
2
+
•
CH −B). HR-MS (EI, 70 eV): calcd for C H BN
found 503.50134. Anal. Calcd for C H BN : C 78.8, H 12.0, N 2.8.
Found: C 75.3 due to boron carbide formation, H 12.0, N 2.6.
503.49994,
2
33 60
3
33
60
3
2
0
MeP(CH −CH −CH −BBN) (10). To a solution of diallylmethyl-
2
2
2
2
phosphane (4) (69 mg, 0.54 mmol) in n-hexane (5 mL) was added 9-
BBN dimer (133 mg, 0.54 mmol), and the colorless solution was
stirred at ambient temperature for 3 d. The solvent was removed in
vacuo to yield the hydroboration product (10) (0.16 g, 0.43 mmol,
80%). The missing yield is addressed to the sample used for NMR
measurements performed for reaction control. The identity of 10 was
confirmed by NMR spectroscopy and mass spectrometry. The purity
was confirmed by NMR spectroscopy and a correct value in hydrogen
content in the elemental analysis. Carbon values are too low, as
organoboranes and phosphanes tend to form boron carbides as well as
glassy boric acid or phosphoric acid, respectively, with carbon enclaves
1
NMR spectroscopy and elemental analysis. H NMR (500 MHz, Tol-
3
d , 373 K): δ [ppm] = 2.22 (t, J = 6.9 Hz, 2H, N−CH ), 2.05 (m,
8
H,H
2
2
1
2
2
H, H-3), 2.02 (s, 6H, CH ), 1.94 (m, 4H, H-2), 1.82 (m, 4H, H-2),
3
.64 (m, 2H, H-3), 1.44 (quint., 2H, N−CH −CH −CH B), 0.81 (m,
2
2
2
11
1
H, CH −B), 0.69 (br, 2H, H-1). B{ H} NMR (160 MHz, C D ,
2
6
6
98 K): δ [ppm] = 5 (τ1 = 60 Hz). 13C{ H} NMR (126 MHz, Tol-
1
20
1
/2
during combustion. H NMR (500 MHz, C D ): δ [ppm] = 2.6−0.9
6
6
d , 373 K): δ [ppm] = 66.4 (N−CH ), 48.1 (CH ), 33.8 (C-2), 26.7−
(broad signals at 2.31, 2.24, 2.11, 1.95, 1.84, 1.68, 1.41, 1.11, 1.00, total
8
2
3
2
11
1
2
1
5.2 (broad, C-1), 24.7 (C-3), 21.3 (N−CH −CH −CH −B), 19.4−
of 40H, CH CH CH -9-BBN), 0.75 (d, J = 9 Hz, CH3). B{ H}
2
2
2
2 2 2 P,H
8.6 (broad, N−CH −CH −CH −B). HR-MS (EI, 70 eV): calcd for
NMR (160 MHz, C D ): δ [ppm] = 88 (τ = 420 Hz, tricoord), −7
13
2
2
2
6
6
1/2
+
•
C H BN 207.21528, found 207.21446. Anal. Calcd for C H BN:
(τ1/2 = 220 Hz, tetracoord). C-DEPT135 NMR (76 MHz, C D ): δ
13
26
13 26
6 6
C 75.4, H 12.7, N 6.8. Found: C 75.0, H 13.0, N 6.6.
MeN(CH −CH −CH −BBN) (7). To a solution of diallylmethyl-
[ppm] = 34.9, 33.2, 32.3, 31.1 (neg, broad, C-1), 27.0, 26.8, 26.2, 25.9,
2
2
2
2
25.0, 23.9, 23.6, 23.3, 18.8 (all peaks broad, more than 11 due to P−C
2
31
1
amine (2) (100 mg, 0.90 mmol) in n-hexane (5 mL) was added 9-
BBN dimer (221 mg, 0.91 mmol), and the solution was stirred at
ambient temperature for 2 d. The solvent was removed in vacuo to
record NMR spectra of the crude product. The residue was dissolved
in n-hexane (5 mL), and the hydroboration product 7 was crystallized
at −80 °C. The supernatant was decanted off and removed via a
syringe. The crystalline solid was dried in vacuo to yield pure product 7
coupling), 5.5 (neg, d, J = 22 Hz, CH ). P{ H} NMR (202 MHz,
P,C 3
+•
C D ): δ [ppm] = 3.1. HR-MS (EI, 70 eV): calcd for C H B P
6
6
23 43 2
3
1
72.32830, found 372.32738. Anal. Calcd for C H B P: C 74.2, H
23 43 2
20
1.7. Found: C 72.5 due to boron carbide formation, H 11.7.
Quantum-Chemical Calculations. Density functional theory
(
DFT) calculations were performed using the Turbomole 7.0 software
2
1
2
2
package. Structures were optimized at the PBEh-3c level of theory.
(
236 mg, 0.66 mmol, 73%). The identity of 7 was confirmed by NMR
Stationary points were characterized by harmonic frequency analyses.
Herein, minima exhibited no imaginary frequency, and transition
points exactly one imaginary frequency. Thermochemical corrections
to Gibbs free energies were calculated at the temperatures of
coalescence obtained from the VT-NMR experiments. In addition,
single-point energies at the PW6B95-D3BJ(abc)/def2-TZVP level of
24
spectroscopy, mass spectrometry, and X-ray crystallography. The
purity was confirmed by NMR spectroscopy and correct values in
hydrogen and nitrogen content in elemental analysis. Carbon values
are too low, as organoboranes tend to form boron carbides as well as
glassy boric acid with carbon enclaves during combustion. Addition of
2
0
1
2
3
WO reduces this effect. H NMR (500 MHz, Tol-d , 373 K): δ
3
8
theory were calculated, both applying the COSMO approach
3
[
ppm] = 2.65 (t, J = 7.7 Hz, 4H, N−CH ), 2.22 (s, 3H, CH ), 1.99
m, 4H, H-3), 1.89 (m, 16H, H-2), 1.54 (quint, J = 7.7 Hz, 4H,
H,H
2
3
(toluene, ε = 2.37) to include solvation effects and in the gas phase. To
3
(
H,H
accelerate the geometry optimizations and frequency calculations, the
N−CH −CH −CH −B), 1.45 (m, 4H, H-3), 1.26 (broad, 4H, H-1),
25
2
2
2
density-fitting RI-J approach was used. The absolute values for Gibbs
3
11
1
.05 (t, J = 7.6 Hz, 4H, CH −B). B NMR (160 MHz, Tol-d , 273
H,H
2
8
free energy as well as Cartesian coordinates for all compounds are
provided in the Supporting Information.
Crystallography. Crystal structures were determined at 100.0(1)
K): δ [ppm] = 88 (τ1/2 = 850 Hz, tricoord), −7 (τ = 740 Hz,
1/2
tetracoord); (353 K): δ [ppm] = 48 (τ1/2 = 290 Hz). 13C{ H} NMR
1
(
3
126 MHz, Tol-d , 373 K): δ [ppm] = 60.6 (N−CH ), 43.2 (CH ),
8
2
3
K by X-ray diffraction using Cu Kα radiation (λ = 1.541 Å) on an
4.0 (C-2), 29.1 (broad, C-1), 24.2 (C-3), 22.3 (CH −B), 19.6 (N−
26
2
Agilent SuperNova diffractometer. Using Olex2, the structures were
27
+
•
CH −CH −CH −B). HR-MS (EI, 70 eV): calcd for C H B N
3
2
2
2
23 43
2
solved with the ShelXS structure solution program using direct
55.35761, found 355.35720. Anal. Calcd for C H B N: C 77.8, H
27
23
43
2
methods and refined with the ShelXL refinement package using
1
2.2, N 3.9. Found: C 77.1, H 12.2, N 3.9, under addition of WO and
3
least-squares minimization. Data are listed in Table S1. CCDC
Data Center.
C 76.0 and 75.4 without addition of WO due to boron carbide
formation; all four measurements show precise values for H and N.
3
20
N(−CH −CH −CH −BBN) (9). To a solution of triallylamine (8)
2
2
2
3
(
(
57 mg, 0.42 mmol) in n-hexane (5 mL) was added dimeric 9-BBN
152 mg, 0.62 mmol), and the colorless solution was stirred at ambient
temperature for 3 d. The solvent was removed in vacuo (allowing
recording NMR spectra of the crude product), and the residue
dissolved in n-hexane (5 mL). The hydroboration product (9) was
crystallized at −80 °C. The supernatant was decanted off and removed
via a syringe, and the crystalline solid was dried in vacuo (95 mg, 0.23
mmol, 43%). The identity of 9 was confirmed by NMR spectroscopy,
mass spectrometry, and X-ray crystallography. The purity was
ASSOCIATED CONTENT
■
*
S
Supporting Information
G
Organometallics XXXX, XXX, XXX−XXX
K?rte, Leif A.
