Organometallics
Article
CDCl3) δ 0.84 (t, 3JHH = 7.5, 3H, CH3), 1.06 (d, 3JHH = 6.9, 3H CH3),
1.39 (quint, 3JHH = 7.0, 2H, CH2), 2.29 (s, 6H, ArMe2), 2.58 (sext, 3JHH
= 6.8, 1H, CH), 3.64 (s, 2H, CH2), 6.81 (s, 2H, o-aryl H), 6.89 (s, 1H,
p-aryl H); 13C NMR (100 MHz, CDCl3) δ 11.7, 16.2, 21.4, 26.1, 47.0,
48.6, 127.4, 128.6, 134.2, 138.2, 212.3.
X-ray diffraction analysis were grown by layering CH2Cl2/hexanes at
room temperature in the air.
1
Characterization data for 9b: H NMR (400 MHz, CDCl3) δ 0.87
3
(t, JHH = 7.3, 3H, CH3), 1.26−1.29 (overlapped, CH2), 1.53 (quint,
3
3JHH = 7.5, 2H, CH2), 2.29 (s, 6H, ArMe2), 2.43 (t, JHH = 7.3, 2H,
CH2), 3.59 (s, 2H, CH2), 6.81 (s, 2H, o-aryl H), 6.89 (s, 1H, p-aryl H);
13C NMR (100 MHz, CDCl3) 13.9, 21.4, 22.4, 26.0, 41.8, 50.2, 127.3,
128.7, 134.4, 138.3, 209.1.
Characterization data for 11a (63%): IR (cm−1) 1616 (s, νNO), 1955
(s, νCO); MS (LREI-MS, m/z, probe temperature 150 °C) 495 [M+,
184W]; MS (HREI-MS, m/z, 182W) calcd for C20H25NO182
W
Preparation of Cp*W(NO) (CO)(η2-CH2CHCHMe2) (10). A
Parr 5500 reactor was charged with 1 (0.200 g, 0.477 mmol) and n-
pentane (ca. 100 mL). The reactor was sealed and purged with CO gas
and finally pressurized to 750 psig of CO. The contents were heated to
80 °C while being stirred for 18 h. The reactor was then cooled to
room temperature, and the gas was carefully vented. The final orange
reaction mixture was collected, and the solvent was removed in vacuo
to give a dark orange oily residue. The crude product was purified via
flash column chromatography on silica with a gradient 0−100% EtOAc
in hexanes as eluent. Two isomers of 10 were isolated as an orange
solid (28 mg, 13% yield).
1
493.13675, found 493.13717; H NMR (400 MHz, C6D63) δ 1.57 (d,
3JHH = 6.5, 3H, CHCH3), 1.59 (s, 15H, C5Me5), 2.44 (d, JHH = 10.5,
3
1H, PhCHCHCH3), 3.52 (dq, JHH = 10.5, 6.5, 1H, PhCHCHCH3),
3
3
6.94 (t, JHH = 7.3, 1H, p-aryl H), 7.03 (d, JHH = 7.3, 2H, o-aryl H)
7.26 (t, 3JHH = 7.8, 2H, m-aryl H); 13C APT NMR (100 MHz, C6D6) δ
10.2 (C5Me5), 21.4 (PhCHCHCH3), 50.8 (PhCHCHCH3), 55.5
(PhCHCHCH3), 105.1 (C5Me5), 124.6 (p-aryl C), 125.4 (o-aryl C),
128.1 (m-aryl C), 147.0 (i-aryl C), 226.1 (W−CO). Anal. Calcd for
C20H25NOW: C, 48.50; H, 5.09; N, 2.83. Found: C, 48.47; H, 5.08; N,
2.83.
Characterization data for 11b (37%): 1H NMR (400 MHz, C6D6) δ
Characterization data for 10a (52%): IR (cm−1) 1951 (s, νCO) 1614
(s, νNO); MS (LREI, m/z, probe temperature 150 °C) 447 [M+, 184W],
3
1.54 (s, 15H, C5Me5), 2.15 (d, JHH3 = 5.8, 3H, CHCH3), 2.29−2.35
(m, 1H, PhCHCHCH3), 4.06 (d, JHH = 11.1, 1H, PhCHCHCH3),
1
3
3
419 [M+ − CO, 184W], 417 [M+ − NO, 184W]; H NMR (600 MHz,
6.88 (t, JHH = 7.1, 1H, p-aryl H), 6.99 (d, JHH = 7.6, 2H, o-aryl H)
7.10 (t, 3JHH = 7.7, 2H, m-aryl H); 13C APT NMR (100 MHz, C6D6) δ
10.0 (C5Me5), 24.1 (PhCHCHCH3), 43.8 (PhCHCHCH3), 59.8
(PhCHCHCH3), 104.8 (C5Me5), 125.2 (p-aryl C), 125.8 (o-aryl C),
128.0 (m-aryl C), 143.9 (i-aryl C), 225.2 (W−CO).
3
C6D6) δ 0.898 (obscured, 1H, CHCH2), 1.24 (d, JHH = 6.3, 3H,
CHMe2), 1.29 (d, 3JHH = 6.3, 3H, CHMe2), 1.60 (s, 15H, C5Me53), 1.65
(obscured, 1H, CHMe2), 1.68 (m, 1H, CHCH2), 2.43 (dd, JHH
=
2
9.8, JHH = 4.4, 1H, CHCH2); 13C APT NMR (150 MHz, C6D6) δ
1
X-ray Crystallography. Data collection was carried out at −173.0
2 °C on a Bruker X8 APEX II diffractometer with graphite-
monochromated Mo Kα radiation.
10.3 (C5Me5), 24.4 (CHMe2), 30.1 (CHMe2), 37.3 (s, JWC = 11.1,
1
CHCH2), 38.6 (CHMe2), 59.2 (s, JWC = 38.8, CHCH2), 104.52
(C5Me5), 225.5 (W−-CO).
Data for 11 were collected to a maximum 2θ value of 55.078° in
0.5° oscillations with 3.0 s exposures. The structure was solved by
direct methods16 and expanded using Fourier techniques. The C12−
C20 fragment was disordered in two orientations with a
0.782(6):0.218(6) occupancy ratio. All non-hydrogen atoms were
refined anisotropically, and hydrogen atoms were placed in calculated
positions. The final cycle of full-matrix least-squares analysis was based
on 4227 observed reflections and 223 variable parameters.
Neutral-atom scattering factors were taken from Cromer and
Waber.17 Anomalous dispersion effects were included in Fc;18 the
values for Δf′ and Δf″ were those of Creagh and McAuley.19 The
values for mass attenuation coefficients were those of Creagh and
Hubbell.20 All refinements were performed using SHELXL-201421 via
the OLEX2 interface.22 X-ray crystallographic data for the structure are
presented in Table S1 in the Supporting Information, as are full details
of the crystallographic analysis.
Characterization data for 10b (48%): 1H NMR (600 MHz, C6D6) δ
0.88 (m, 1H, CHCH2), 0.900 (d, 3JHH = 6.8, 3H, CHMe2), 1.39 (d,
3JHH = 6.6, 3H, CHMe2), 1.60 (s, 15H, C5Me5), 1.969 (m, 1H, CH
CH2), 1.973 (m, 1H, CHCH2), 2.90 (m, 1H, CHMe2); 13C APT
NMR (150 MHz, C6D6) δ 10.4 (C5Me5), 20.5 (CHMe2), 25.8 (s, 1JWC
1
= 36.1, CHCH2), 28.9 (CHMe2), 33.6 (CHMe2), 65.2 (s, JWC
=
9.9, CHCH2), 104.54 (C5Me5), 227.7 (W-CO).
Preparation of Cp*W(NO) (CO)(η2-MeCHCHPh) (11). In a
glovebox, a Parr pressure reactor was charged with 3 (0.200 g, 0.43
mmol) and mesitylene (ca. 20 mL). The pressure reactor was sealed
and purged five times with carbon monoxide before being finally
pressurized to 750 psig. The reactor was connected to the mechanical
stirrer, and its contents were heated to 80 °C while being stirred for 18
h. The reactor was cooled to room temperature, and the gas was
carefully vented. The final reaction mixture was transferred to a round-
bottom flask, and the volatiles were removed in vacuo. The crude
product was then purified by flash column chromatography on silica
with a gradient 0−100% EtOAc in hexanes as eluent to give two
isomers of Cp*W(NO)(CO)(η2-MeCHCHPh) (11) as an orange
solid (0.0222 g, 19% yield). Crystals of 11 suitable for a single-crystal
Computational Methods. Density functional theory23 was
applied to determine the structural and energetic features of the
various organometallic complexes described in this article. All
theoretical calculations were performed using Gaussian 09.24 The 6-
31+G(d) basis set25,26 was used for all atoms (C, H, O, N) except W,
which was treated using the Stuttgart pseudopotential and associated
basis set.27 The hybrid exchange correlation functional PBE0 was also
used.28 It mixes 25% of Hartree−Fock exchange into the gradient-
corrected PBE exchange and correlation functional29 and yields
reliable thermochemistry data for reactions involving transition-metal
complexes.30 All structures were calculated without geometrical
constraints, and all stationary points were characterized as minima
or transition states by frequency calculations (i.e., only one negative
4091
Organometallics 2015, 34, 4085−4092