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Journal of the American Chemical Society
which was isolated by filtration and dried under vacuum
for 3 hours.
Visible (10-4 M in benzene): λ = 530 nm (ε = 1260 mol-1 L
cm-1). Anal. Calcd. For C42H58Mo2O6: C, 59.3; H, 6.9;
Found: C, 58.6; H, 6.2.
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3
4
5
6
7
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1
Mo2(ArMes2)(O2CMe)3, (1b). Yield: 66%. H NMR (400
MHz, C6D6, 25 ºC): δ = 1.40 (s, 3H, p-MeMes’), 1.93 (s, 3H, p-
MeMes), 2.00 (s, 3H, trans-MeOAc), 2.21 (s, 6H, o-MeMes’),
2.37 (s, 6H, o-MeMes), 2.53 (s, 6H, MeOAc), 6.36 (s, 2H, m-
General
preparation
of
mono(terphenyl)
tris(trifluoroacetate) complexes Mo2(Ar’)(O2CF3)3, (3a,
3c). Solid samples of Mo2(O2CCF3)4 (0.50 g, 0.77 mmol)
and 1 equiv of the appropriate LiAr’ were mixed in a
glovebox and cooled to −40 ºC. Diethylether (15 mL, for
3a) or pentane (15 mL, for 3c) was added and the resulting
suspension was stirred for 24 hours, while reaching slowly
the room temperature. The solvent was then removed
under reduced pressure and the solid residue was extract-
ed with hexane (15 mL). The resulting red-wine-coloured
suspension was centrifuged and the solution was trans-
ferred to a Schlenk tube, concentrated to ca. 5 mL, and
stored in a refrigerator at −23 ºC overnight. A pink crystal-
line solid separated out, which was isolated by filtration
and dried under vacuum for 3 hours.
3
Mes’), 6.66 (s, 2H, m-Mes), 6.95 (d, 1H, JHH = 7.6 Hz, m’-
C6H3), 7.12 (d, 1H, 3JHH = 7.6 Hz, m-C6H3), 7.34 (t, 1H, 3JHH
=
7.6 Hz, p-C6H3) ppm. 13C{1H} NMR (100 MHz, C6D6, 25 ºC):
δ = 20.2 (p-MeMes’), 20.9 (p-MeMes), 21.2 (o-MeMes), 22.4 (o-
MeMes’), 23.0 (trans-MeOAc), 23.8 (MeOAc), 123.6 (m-C6H3),
125.7 (m’-C6H3), 126.4 (p-C6H3), 128.1 (m-Mes), 129.8 (m-
Mes’), 135.6 (p-Mes), 135.9, 136.0 (o-Mes’ and o-Mes), 138.7
(p-Mes’), 140.3 (ipso-Mes), 141.3 (ipso-Mes’), 147.4 (o-
C6H3), 147.9 (o-C6H3), 181.5 (Mo−Car), 183.4 (O2CMe), 183.5
(trans-O2CMe) ppm. UV-Visible (10-4 M in benzene): λ =
530 nm (ε = 1080 mol-1 L cm-1); (10-4 M in diethylether): λ =
280, 445, 530 nm (ε = 17400, 700, 1400 mol-1 L cm-1, respec-
tively). Anal. Calcd. for C30H34Mo2O6: C, 52.8; H, 5.0;
Found: C, 53.1; H, 5.3.
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27
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29
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36
37
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1
Mo2(ArXyl2)(O2CF3)3, (3a). Yield: 63%. H NMR (500
1
Mo2(ArDipp2)(O2CMe)3, (1c). Yield: 50%. H RMN (500
MHz, C6D6, 25 ºC): δ = 1.99 (s, 6H, MeXyl), 2.11 (s, 6H,
MeXyl’), 5.96 (t, 1H, 3JHH = 7.6 Hz, p-Xyl), 6.24 (d, 2H, 3JHH
=
MHz, C6D6, 25 ºC): δ = 1.07, 1.12, 1.31, 1.55 (d, 6H each,
MeDipp), 1.96 (s, 3H, trans-MeOAc), 2.56 (s, 6H, MeOAc), 3.13,
3.21 (sept, 4H each, CHMe2Dipp), 6.48 (t, 1H, p-Dipp’), 6.58
(d, 2H, m-Dipp’), 7.02 (m, 3H, m-Dipp and p-Dipp), 7.10
(d, 1H, m-C6H3), 7.20 (t, 1H, p-C6H3), 7.36 (d, 1H, m’-C6H3)
ppm. All 3JHH constants are about 7.0 Hz. 13C{1H} NMR (125
MHz, C6D6, 25 ºC): δ = 21.7, 22.6 (MeDipp), 22.7 (trans-
MeOAc), 23.6 (MeOAc), 26.7, 26.8 (MeDipp), 30.3, 31.3
(CHMe2Dipp), 121.9 (m-Dipp), 122.5 (m-C6H3 or m’-C6H3),
123.7 (m-C6H3 or m’-C6H3), 123.7 (m-Dipp), 126.0 (p-C6H3),
127.0 (p-Dipp), 129.4 (p-Dipp’), 140.2 (ipso-Dipp), 144.8 (o-
Dipp’), 145.1 (o-C6H3 or o’-C6H3), 145.2 (o-C6H3 or o’-C6H3),
146.5 (ipso-Dipp’), 146.6 (o-Dipp), 182.3 (Mo−Car), 182.7
7.6 Hz, m-Xyl), 6.67 (m, 3H, m-Xyl’ and p-Xyl’), 6.73 (d,
3
3
1H, JHH = 7.6 Hz, m-C6H3), 6.92 (d, 1H, JHH = 7.5 Hz, m’-
C6H3), 7.21 (t, 1H, 3JHH = 7.6 Hz, p-C6H3) ppm. 13C{1H} NMR
(125 MHz, C6D6, 25 ºC): δ = 20.6 (MeXyl’), 21.9 (MeXyl), 124.0
(m-C6H3), 126.6 (m’-C6H3), 127.7 (m-Xyl’), 127.9 (p-Xyl’),
128.4 (p-C6H3), 129.9 (p-Xyl), 130.3 (m-Xyl), 135.5 (o-Xyl),
135.8 (o-Xyl), 140.1 (ipso-Xyl’), 145.6 (ipso-Xyl’), 146.2 (o-
C6H3), 146.7 (o-C6H3), 178.1 (Mo−Car) ppm. Resonances
due to the trifluoroacetate groups were not detected. 19F
NMR (100 MHz, 25 ºC): δ = −72.2 (s, 6F, cis-O2CCF3), −72.9
(s, 3F, trans-O2CCF3) ppm. UV-Visible (10-5 M in diethy-
lether): λ = 525 nm (ε = 2160 mol-1 L cm-1, respectively).
Anal. Calcd. for C28H21F9Mo2O6: C, 41.20; H, 2.59. Found:
C, 41.0; H, 2.8.
(O2CMe), 183.4 (trans-O2CMe) ppm. UV-Visible (10-4
M
in benzene): λ = 535 nm (ε = 1300 mol-1 L cm-1). Anal.
Calcd. For C36H46Mo2O6: C, 56.40; H, 6.05; Found: C, 56.0;
H, 6.3.
1
Mo2(ArDipp2)(O2CF3)3, (3c). Yield: 33%. H NMR (500
MHz, C6D6, 25 ºC): δ = 0.91 (d, 6H, MeDipp’), 1.00 (d, 6H,
MeDipp), 1.14 (d, 6H, MeDipp’), 1.48 (d, 6H, MeDipp), 2.86
(sept, 2H, CHMe2Dipp’), 3.06 (sept, 2H, CHMe2Dipp), 6.30 (t,
1H, p-Dipp’), 6.39 (d, 2H, m-Dipp’), 6.92 (m, 3H, m-Dipp
and p-Dipp), 7.20−7.26 (m, 3H, m-C6H3, m’-C6H3 and p-
1
Mo2(ArTrip2)(O2CMe)3, (1d). Yield: 48%. H NMR (500
MHz, C6D6, 25 ºC): δ = 0.84 (d, 6H, p-MeTrip’), 1.16 (m, 12H,
o-MeTrip’ and p-MeTrip), 1.20 (d, 6H, o-MeTrip), 1.42 (d, 6H,
o-MeTrip’), 1.64 (d, 6H, o-MeTrip), 1.98 (s, 3H, trans-MeOAc),
2.23 (sept, 1H, p-CHMe2Trip’), 2.55 (s, 6H, MeOAc), 2.68
(sept, 1H, p-CHMe2Trip), 3.18 (sept, 2H, o-CHMe2Trip), 3.23
(sept, 2H, o-CHMe2Trip), 6.76 (s, 2H, m-Trip’), 7.04 (s, 2H,
m-Trip), 7.29 (m, 2H, p-C6H3 and m’-C6H3), 7.38 (d, 1H, m-
3
C6H3) ppm. All JHH constants are about 7.0 Hz. 13C{1H}
NMR (125 MHz, C6D6, 25 ºC): δ = 21.6 (MeDipp’), 21.9
(MeDipp), 26.6 (MeDipp’), 27.0 (MeDipp), 30.7 (CHMe2Dipp),
31.6 (CHMe2Dipp’), 122.8 (m-Dipp), 125.5 (m-Dipp’), 125.7
(m-C6H3 or m’-C6H3), 126.8 (m-C6H3 or m’-C6H3), 129.1 (p-
C6H3), 129.2 (p-Dipp), 131.1 (p-Dipp’), 137.7 (ipso-Dipp),
144.4 (o-C6H3 or o’-C6H3), 144.5 (o-C6H3 or o’-C6H3), 145.4
(o-Dipp’), 146.7 (o-Dipp), 148.0 (ipso-Dipp’), 180.1
(Mo−Car) ppm. Resonances due to the trifluoroacetate
groups were not detected. 19F NMR (100 MHz, 25 ºC): δ =
−72.2 (s, 6F, cis-O2CCF3), −74.1 (s, 3F, trans-O2CCF3) ppm.
UV-Visible (10-4 M in diethylether): λ = 535 nm (ε = 1300
mol-1 L cm-1). Anal. Calcd. for C36H37F9Mo2O6: C, 46.57; H,
4.02. Found: C, 46.4; H, 4.4.
3
C6H3) ppm. All JHH constants are about 7.0 Hz. 13C{1H}
NMR (125 MHz, C6D6, 25 ºC): δ = 21.8 (o-MeTrip), 22.4 (o-
MeTrip), 22.7 (trans-MeOAc), 23.5 (p-MeTrip), 23.6 (p-MeTrip),
24.0 (MeOAc), 26.8 (o-MeTrip), 26.9 (o-MeTrip), 30.4 (o-
CHMe2Trip), 31.6 (o-CHMe2Trip), 33.9 (p-CHMe2Trip), 34.3 (p-
CHMe2Trip), 119.7 (m-Trip), 121.6 (m-Trip), 123.4 (p-C6H3),
125.9 (m-C6H3), 128.3 (m-C6H3), 137.9 (ipso-Trip), 144.2
(ipso-Trip), 145.1 (o-Trip), 145.2 (o-C6H3), 145.4 (o-C6H3),
146.6 (o-Trip), 147.3 (p-Trip), 150.5 (p-Trip), 182.5
(O2CMe), 183.1 (Mo−Car), 183.3 (trans-O2CMe) ppm. UV-
7
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