Journal of Inorganic and General Chemistry
SHORT COMMUNICATION
Zeitschrift für anorganische und allgemeine Chemie
90.3 (s, PtBu2). 19F{1H} NMR (376.5 MHz, [D8]THF): δ = –79.0 (s,
CF3). LIFDI+ (toluene, m/z+): 687.1 (C27H51ClN2P2Re+) ppm.
benzonitrile over five reaction steps starting from a cyclopen-
tadienyl titanium(IV)chloride.[7f,14]
In summary, we demonstrated the synthesis of benzonitrile
upon direct use of molecular N2 as nitrogen source via splitting
into terminal nitrides, benzylation, deprotonation, and oxid-
ation of phenylketimido intermediate 1Ph. The putative nitrile
complex that is formed from oxidation of 1Ph with NCS prior
to product release is inherently not capable of nitrile (M–
NϵC–CHR2) / enimido (M=N–CH=CR2) tautomerization.
Therefore, this rearrangement that was observed in acetonitrile
formation is not a prerequisite for nitrile formation. Our rhe-
nium platform might therefore be suitable for a broad range of
organonitrile target molecules.
Synthesis of [Re(NCHPh)Cl(PNP)] (1Ph): Complex 5Ph (26.5 mg,
31.7 μmol, 1 equiv.) and KN(SiMe3)2 (6.3 mg, 31.7 μmol, 1 equiv.)
were suspended in benzene (4 mL) and stirred for 2 h at room tempera-
ture. The solvent was evaporated and the residue was extracted with
pentanes (3ϫ2 mL). After lyophilization with benzene, the brown ket-
imido complex 1Ph was obtained as a mixture of two diastereomers,
which was not further separated. Yield: 17.3 mg, 25.2 μmol, 80%. An
assignment of all signals to distinct isomers was not possible.
C27H50ClN2P2Re: calcd. (found) C 47.25 (47.67); H 7.46 (7.34); N
4.08 (3.97)%. 1H NMR (400 MHz, C6D6): δ = 1.16 [A9XXЈAЈ9,
5
N = |3JHP + JHP| = 6.3 Hz, 18 H, PC(CH3)3], 1.18 [A9XXЈAЈ9, N =
|3JHP
|3JHP
+
+
5JHP| = 6.5 Hz, 18 H, PC(CH3)3], 1.24 [A9XXЈAЈ9, N =
5JHP| = 6.0 Hz, 18 H, PC(CH3)3], 1.29 [A9XXЈAЈ9, N =
5
|3JHP + JHP| = 6.2 Hz, 18 H, PC(CH3)3], 1.65 (m, 4 H, PCH2), 1.80
Experimental Section
(m, 2 H, PCH2), 1.95 (m, 2 H, PCH2), 3.42 (m, 4 H, NCH2CH2), 3.54
3
4
2
3
(ABCDXXЈDЈCЈBЈAЈ, N = | JHP + JHP | = 1.7, JHH = 13.1, JHH
=
Materials and Methods: All experiments were carried out using stan-
dard Schlenk and glove-box techniques (argon or nitrogen atmo-
sphere). Non-deuterated solvents were dried and deoxygenated using
an MBraun solvent system. Deuterated solvents were obtained from
Euriso-Top GmbH, dried with Na/K (C6D6 and [D8]THF), distilled by
trap-to-trap transfer in vacuo, and degassed by three freeze-pump-thaw
cycles, respectively. N-chlorosuccinimide (Acros Organics) was sub-
limed and benzyl bromide (Sigma-Aldrich) was stirred over CaH2 and
trap-to-trap distilled prior to use. KN(SiMe3)2 (Sigma Aldrich) was
used as purchased. Complex 4 was synthesized as previously pub-
lished.[7d] Elemental analyses were obtained with an Elementar Vario
EL 3 analyzer. NMR spectra were recorded with a Bruker Avance III
300 or a Bruker Avance III 400 MHz and calibrated to the solvent
residual proton resonance (C6D6: δH = 7.16 ppm, δC = 128.39;
[D8]THF: δH = 3.58 ppm). 31P and 19F chemical shifts are reported
relative to external phosphoric acid and CFCl3 (δ = 0.0 ppm). Signal
multiplicities are abbreviated as: s (singlet), d (doublet), t (triplet), q
(quartet), m (multiplet), br (broad). LIFDI mass spectrometry was car-
ried out with a JEOL AccuTOF JMS-T100GCV spectrometer.
3
4
9.3, JHH = 6.3 Hz, 2 H, NCH2CH2), 3.75 (t, JHP = 2.0 Hz, 1 H, N =
CHPh), 3.78 (m, 2 H, NCH2CH2, partially superimposed), 5.47 (t,
4JHP = 2.2 Hz, 1 H, N = CHPh), 6.47 (br., 2 H, CHortho), 6.65 (tt,
3JHH = 7.3, JHH = 1.2 Hz, 1 H, CHpara), 6.73 (tt, JHH = 7.2, JHH
4
3
4
=
1.4 Hz, 1 H, CHpara), 7.18 (m, 2 H, N = CHPh, superimposed by
benzene), 7.35 (m, 2 H, N = CHPh), 7.44 (m, 2 H, N = CHPh) ppm.
13C{1H} NMR (100.6 MHz, C6D6): δ = 27.4 (AXXЈAЈ, N = |1JCP
+
3JCP| = 8.3 Hz, PCH2CH2), 29.6 (AXXЈAЈ, N = |1JCP + 3JCP| = 7.9 Hz,
PCH2CH2), 30.3 [m, PC(CH3)3], 30.5 [m, PC(CH3)3], 36.5 [AXXЈAЈ,
N = |1JCP
+ +
3JCP| = 7.0 Hz, PC(CH3)3], 37.2 [AXXЈAЈ, N = |1JCP
3JCP| = 7.0 Hz, PC(CH3)3], 38.7 [AXXЈAЈ, N = |1JCP + 3JCP| = 8.9 Hz,
PC(CH3)3], 39.2 [AXXЈAЈ, N = |1JCP 3JCP| = 8.5 Hz, PC(CH3)3],
74.0 (AXXЈAЈ, N = |2JCP + 3JCP| = 4.4 Hz, NCH2CH2), 75.0 (AXXЈAЈ,
+
N = |2JCP
+
3JCP| = 4.1 Hz, NCH2CH2), 124.2 (s, CPhpara), 124.8 (s,
CPhpara), 127.5–129.0 (Ph, superimposed by benzene), 132.3 (s,
CPhipso), 132.8 (s, CPhipso), 146.8 (t, JCP = 2.4 Hz, N = CHPh), 150.6
3
(t, 3JCP = 2.3 Hz, N = CHPh) ppm. 31P{1H} NMR (162.0 MHz, C6D6):
δ = 54.8 (s, PtBu2), 56.5 (s, PtBu2) ppm.
Release of Benzonitrile: 1Ph (4.9 mg, 7.14 μmol, 1 equiv.) and hexa-
methylbenzene (1.2 mg, 7.14 μmol, 1 equiv.) as internal standard were
dissolved in C6D6 in a J-Young NMR tube. The solution was frozen
and N-chlorosuccinimide (1.9 mg, 14.28 μmol, 2 equiv.) was added.
The mixture was shaken until warmed to room temperature with con-
comitant darkening of the solution. Formation of 3 (1H: 10.53 ppm)
Synthesis of [(PNP)Re(NCH2Ph)Cl)]OTf (5Ph): AgOTf (8.6 mg,
33.6 μmol, 1 equiv.) was dissolved in Et2O and cooled to –40 °C be-
fore benzyl bromide (ex.) was added. Immediate formation of a yellow
precipitate (AgBr) indicated conversion to benzyl triflate. 2,6-Di-tert-
butyl-4-methylpyridine (13.8 mg, 67.2 μmol, 2 equiv.) was added and
the mixture was stirred for additional 10 min. The reaction solution
was filtered off and added to a solution of nitride 4 (20.0 mg,
33.6 μmol, 1 equiv.) in Et2O (1 mL). Storage at –40 °C for 48–72 h
1
and benzonitrile (38% vs. C6Me6) were confirmed by H NMR spec-
troscopy.
afforded a green precipitate, which was filtered off, washed with Et2O, Crystallographic Results: Suitable single crystals for X-ray structure
extracted with benzene and lyophilized. Yield: 24.4 mg (29.2 μmol, determination of 1Ph were selected from the mother liquor in an argon
87%). C28H51ClF3N2O3P2ReS·(C6H6)0.167: calcd. (found) C 41.01 atmosphere, transferred into protective perfluoro polyether oil, and af-
1
(41.04); H 6.17 (6.23); N 3.30 (3.32)%. H NMR (300 MHz, C6D6): ter selection to the cold gas stream on the diffractometer. Diffraction
3
5
δ = 1.00 [A9XXЈAЈ9, N = | JHP + JHP| = 7.0 Hz, 18 H, PC(CH3)3], data were obtained at 100 K with a Bruker D8 three-circle dif-
3
5
1.08 [A9XXЈAЈ9, N = | JHP + JHP| = 7.2 Hz, 18 H, PC(CH3)3], 2.02
fractometer, equipped with a PHOTON 100 CMOS detector and an
(m, 2 H, PCH2), 2.28 (m, 2 H, PCH2), 3.80 (m, 2 H, NCH2CH2), 4.61
(s, 2 H, NCH2Ph), 4.70 (m, 2 H, NCH2CH2), 7.00 (t, JHH = 7.4 Hz, diation, λ = 0.71073 Å). The data were integrated with SAINT and a
INCOATEC microfocus source with Quazar mirror optics (Mo-Kα ra-
3
1 H, CHpara), 7.13 (m, 2 H, CHmeta, partially superimposed), 7.49 (d,
3JHH = 7.2 Hz, 2 H, CHortho). 13C{1H} NMR (100.6 MHz, C6D6): δ =
semi-empirical absorption correction was applied using SADABS. The
structure was solved and refined using the Bruker SHELX 2014 soft-
24.3 (AXXЈAЈ, N = | 1JCP + 3JCP | = 11.3 Hz, PCH2), 29.5 [A3XXЈAЈ3, ware package.[15] All non-hydrogen atoms were refined with aniso-
2
N = | JCP
2
+
4JCP | = 1.9 Hz, PC(CH3)3], 29.7 [A3XXЈAЈ3, N =
tropic displacement parameters. Hydrogen atoms were refined iso-
tropically on calculated positions using a riding model with their Uiso
4
3
| JCP + JCP | = 1.4 Hz, PC(CH3)3], 37.8 [AXXЈAЈ, N = |1JCP + JCP
|
= 10.7 Hz, PC(CH3)3], 38.1 [AXXЈAЈ, N = |1JCP
PC(CH3)3], 75.0 (s, NCH2Ph), 76.2 (AXXЈAЈ, N = |2JCP
2.7 Hz, NCH2CH2), 127.0 (s, CPhortho), 128.0 (s, CPhpara), 129.1 (s,
+
3JCP | = 8.7 Hz, values constrained to 1.5 Ueq of their pivot atoms for terminal sp3
+
3JCP | =
carbon atoms and 1.2 Ueq for all other carbon atoms. Detailed crystal
data, structure refinements parameters, bond lengths and angles are
CPhmeta), 134.8 (s, CPhipso). 31P{1H} NMR (162.0 MHz, C6D6): δ = summarized in Tables S1–S3 (Supporting Information).
Z. Anorg. Allg. Chem. 0000, 0–0
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