Organometallics
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temperature for 30 min before sodium tetraphenylborate (0.172 g,
0.500 mmol) was added to the solution. A yellow precipitate formed,
and the reaction mixture was stirred at room temperature for 1 h. The
yellow precipitate was collected by filtration, washed with methanol (3
× 3 mL), and dried under vacuum. Yield: 0.333 g, 87%; mp 134−136
°C (dec). Anal. Found: C, 70.04; H, 5.86; and N, 9.21. Calcd for
C45H45BN5Rh: C, 70.23; H, 5.89; and N, 9.21. ESI-MS (ESI+, MeOH),
the reaction, leading to the formation of a yellow precipitate;
the reaction mixture was then stirred for a further 15 min. The
yellow product was collected by filtration, washed with
methanol (3 × 4 mL) and n-pentane (3 × 4 mL), and dried
in vacuo. The desired complex, [Rh(PyT)(CO)2]BPh4, was
collected as a yellow solid. Yield: 0.312 g, 87%; mp 128−130
°C (dec).
Method B. Methanol (3 mL) and pentane (20 mL) were added to a
Schlenk containing [Rh(PyT)(COD)]BPh4 (2a, 0.170 g, 0.221 mmol)
under an atmosphere of argon. The reaction mixture was degassed via
three freeze−pump−thaw cycles and left under vacuum. The reaction
mixture was then placed under an atmosphere of carbon monoxide
using a balloon for 1 h. The carbon monoxide balloon was removed,
and the pale yellow solid was collected by filtration, washed with
methanol (2 × 2 mL) and pentane (3 × 5 mL), and dried in vacuo.
The 1H NMR spectrum of the solid showed that approximately 40% of
the starting material had converted to the desired dicarbonyl product.
The carbonylation process had to be repeated twice to obtain
complete conversion. Yield: 0.107 g, 72%.
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m/z (%, assignment): 450.09 (100%, [M]+) amu. H NMR (CD2Cl2,
600 MHz): δ 7.40−7.37 (m, 3H, m- and p-CH of CH2Ph), 7.38 (br m,
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8H, o-CH of BPh4), 7.29 (d, JH4−H3 = 2.5 Hz, 1H, Pz-H3), 7.17 (m
(dd), 3J = 7.5 Hz, 4J = 1.8 Hz, 2H, o-CH of CH2Ph), 7.15 (d, 3J = 2.5
Hz, 1H, H5), 6.99 (t, 3J = 7.5 Hz, 8H, m-CH of BPh4), 6.86 (t, 3J = 7.4
Hz, 4H, p-CH of BPh4), 6.40 (s, 1H, triaz-CH), 6.28 (apparent t (dd),
3JH3−H4, H5−H4 = 2.5 Hz, 1H, Pz-H4), 5.18 (s, 2H, PhCH2), 4.69 (br s,
2H, CH of COD (trans to Pz)), 4.47 (s, 2H, Pz-CH2), 4.44 (br s, 2H,
CH of COD (trans to triaz), 2.56 (m, 4H, CHaHb of COD), 2.07 (m,
4H, CHaHb of COD) ppm. 13C{1H} NMR (CD2Cl2, 150 MHz): δ
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164.6 (q, JB−C = 49.4 Hz, ipso-C of BPh4), 141.7 (Pz- C3), 139.3
(triaz ipso-C), 136.4 (o-CH of BPh4), 134.4 (Pz-C5), 133.3 (ipso-C of
CH2Ph), 129.8 (p-CH of CH2Ph), 129.7 (m-CH of CH2Ph), 128.8 (o-
CH of CH2Ph), 126.3 (m-CH of BPh4), 124.5 (triaz CH), 122.4 (p-
CH of BPh4), 107.5 (s, Pz-C4), 85.8 (d, 1JRh−C = 11.9 Hz, CH of COD
(trans to Pz)), 84.7 (d, 1J Rh−C = 11.3 Hz, CH of COD (trans to triaz),
55.8 (s, PhCH2), 45.3 (Pz-CH2), 30.9 (CH2 of COD, same resonances
for all four CH2) ppm.
Note: the complex is not very stable in solution (in CD2Cl2) at
room temperature. NMR spectra were therefore acquired at −30 °C
for characterization purposes.
Anal. Found: C, 64.68; H, 4.70; and N, 9.66. Calcd for
C39H33BN5O2Rh: C, 65.29; H, 4.64; and N, 9.76. ESI-MS (ESI+,
MeOH), m/z (%, assignment): 397.98 (100, [M]+) amu. FTIR
(CH2Cl2): 2105 (s, νCO) and 2045 (s, νCO) cm−1. 1H NMR
Synthesis of [Rh(PyS)(COD)]BPh4 (2b). The synthesis was
performed in an analogous fashion to the synthesis of 2a; see
Supporting Information.
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(CD2Cl2, 600 MHz): δ 7.68 (d, JH4−H3 = 2.5 Hz, 1H, Pz-H3), 7.42−
7.36 (m, 3H, m- and p-CH of CH2Ph), 7.37 (br m, 8H, o-CH of
Synthesis of [Rh(PyT)(COD)]BArF (2c). [Rh(COD)2][BArF ]
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BPh4), 7.24 (m (dd), J = 7.8 Hz, J = 2.6 Hz, 2H, o-CH of CH2Ph),
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7.20 (d, 3JH4−H5 = 2.5 Hz, 1H, Pz-H5), 6.97 (t, 3J = 7.5 Hz, 8H, m-CH
of BPh4), 6.83 (t, J = 7.4 Hz, 4H, p-CH of BPh4), 6.40 (apparent t
(dd), JH3−H4, H5−H4 = 2.5 Hz, 1H, Pz- H4), 6.33 (s, 1H, triaz-CH),
(0.090 mg, 0.076 mmol) and PyT (1a, 0.018 g, 0.076 mmol) were
placed under vacuum for 5 min before being backfilled with argon in a
Schlenk flask. Tetrahydrofuran (10 mL) was added, resulting in the
formation of a dark yellow solution, which was allowed to stir for an
hour. The solvent was then removed in vacuo, and dichloromethane (5
mL) added to dissolve the residue. n-Pentane (20 mL) was added with
vigorous stirring. The reaction mixture was then filtered, and the solid
residue was washed with pentane (2 × 20 mL) and dried under
vacuum to yield the product as a dark yellow solid. Yield: 0.090 g,
90%; mp 130−132 °C. Anal. Found: C, 48.97; H, 3.23; and N, 4.93.
Calcd for C53H37BF24 N5Rh: C, 48.46; H, 2.84; and N, 5.33. ESI-MS
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5.29 (s, 2H, PhCH2), 4.22 (s, 2H, Pz-CH2) ppm. H NMR (−30 °C,
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CD2Cl2, 600 MHz): δ 7.66 (d, JH4−H3 = 2.5 Hz, 1H, Pz-H3), 7.40−
7.36 (br m, 11H, o-CH of BPh4 (8H) and m- and p-CH (3H) of
CH2Ph), 7.22−7.19 (m, 3H, o-CH of CH2Ph and Pz-H5), 6.95 (t, 3J =
7.5 Hz, 8H, m-CH of BPh4), 6.80 (t, 3J = 7.5 Hz, 4H, p-CH of BPh4),
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6.38 (apparent t (dd), JH3−H4,H5−H4 = 2.5 Hz, 1H, H4), 5.98 (s, 1H,
triaz-CH), 5.23 (s, 2H, PhCH2), 4.03 (s, 2H, Pz-CH2) ppm. 13C{1H}
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NMR (−30 °C, CD2Cl2, 150 MHz): δ 183.1 (d, JRh−C = 69.4 Hz,
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(ESI+, MeOH): 449.97 ([M]+, 100%) amu. H NMR (CDCl3, 500
CO), 182.4 (d, 1JRh−C = 69.8 Hz, CO), 164.0 (d, 1JB−C = 49.0 Hz, ipso-
C of BPh4), 145.8 (Pz-C3), 139.3 (ipso-C of triazole), 135.7 (o-CH of
BPh4), 134.92 (C5), 132.4 (ipso-C of CH2Ph), 129.7 (p-CH of
CH2Ph), 129.4 (m-CH of CH2Ph), 128.66 (o-CH of CH2Ph), 126.2
(m-CH of BPh4) 124.3 (triazole-CH), 122.3 (p-CH of BPh4), 107.9
(C4), 55.7 (PhCH2), 44.3 (PzCH2) ppm.
MHz): δ 7.70 (br s, 8H, o-CH of BArF ), 7.51 (br s, 4H, p-CH of
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BArF ), 7.43 (s, 1H, H5′), 7.39−7.37 (m, 3H, p- and m-CH of Ph),
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7.33 (d, JH4−H5 = 2.0 Hz, 1H, H5), 7.29 (d, JH4−H3 = 2.0 Hz, 1H,
H3), 7.21 (d, JH−H = 6.5 Hz, 2H, o-CH of Ph), 6.28 (t, JH−H = 2.5
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b
a
Hz, 1H, H4), 5.43 (s, 2H, CH2 ), 5.24 (s, 2H, CH2 ), 4.77 (br s, 2H,
CH of COD), 4.48 (br s, 2H, CH of COD), 2.56−2.54 (m, 4H, CH2
of COD), 2.09−2.08 (m, 4H, CH2 of COD) ppm. 13C{1H} NMR
Syntheses of [Rh(PyS)(CO)2]BPh4 (4b), [Ir(PyT)(CO)2]BPh4 (5a),
[Ir(PyS)(CO)2]BPh4 (5b), and [Ir(PyT)(CO)2]BArF (5c). The syntheses
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(CDCl3, 100 MHz): δ 161.7 (q, 1JB−C = 49.0 Hz, ipso-C to B, BArF ),
of 4b and 5a−c were performed in an analogous fashion to the
synthesis of [Rh(PyT)(CO)2]BPh4 (4a), method B. See Supporting
Information.
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142.2 (C5), 139.0 (Cq of triaz), 134.9 (o-CH to B, BArF and Cq of
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Ph), 133.6 (C3), 131.6 (p-CH of Ph), 130.5 (m-CH of Ph), 129.1 (qq,
2JF−C = 30.0 Hz, 3JB−C = 3.0 Hz, CCF3), 128.7 (o-CH of Ph), 124.7 (q,
Synthesis of [Rh(PyT)(CO)2]BArF (4c) and [Rh(PyS)(CO)2]BArF
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1JF−C = 272.3 Hz, CF3), 122.8 (C5′), 117.7 (sept, 3JF−C = 4.0 Hz, p-CH
(4d). The syntheses of 4c and 4d were performed in an analogous
fashion to the synthesis of [Rh(PyT)(CO)2]BPh4 (4a), method A,
with dichloromethane as the solvent; see Supporting Information.
Synthesis of [Ir(PyS)(CO)2]BArF (5d). [Ir(COD)2]BArF (0.150 g,
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to B, BArF ), 108.0 (C4), 86.2 (d, JRh−C = 13.0 Hz, CH of COD),
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b
a
85.1 (d, JRh−C = 13.0 Hz, CH of COD), 56.3 (CH2 ), 45.5 (CH2 ),
30.6 (CH2 of COD), 30.5 (CH2 of COD) ppm.
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0.012 mmol) was dissolved in dichloromethane (10 mL), and a
solution of PyS (1b, 0.027 mg, 0.012 mmol) in dichloromethane (2
mL) was added dropwise, resulting in a color change from purple to
bright yellow. This solution was allowed to stir for 3 h before three
freeze−pump−thaw cycles were performed. The reaction mixture was
then exposed to an atmosphere of carbon monoxide from a balloon
and stirred for 2 h, resulting in a very pale yellow solution. The balloon
was then removed, and the flask backfilled with nitrogen. The volume
was reduced (∼2 mL), and pentane (∼20 mL) added, yielding a bright
orange solid upon stirring. This was washed with pentane (2 × ∼20
mL) to yield a bright orange-yellow solid, which was dried in vacuo to
yield the product. Yield: 0.130 g, 82%. Anal. Found: C, 41.20; H, 2.06;
and N, 5.36. Calcd for C46H23BF24IrN5O2: C, 41.33; H, 1.73; and N,
5.24. FTIR (CH2Cl2) ν: 2098 (s, νCO) and 2034 (s, νCO) cm−1. HR-
Syntheses of [Ir(PyT)(COD)]BPh4 (3a) and [Ir(PyS)(COD)]BPh4
(3b). The syntheses of 3a and 3b were performed in an analogous
fashion to the synthesis of [Rh(PyT)(COD)]BPh4, 2a; see Supporting
Information.
Synthesis of [Ir(PyT)(COD)]BArF (3c). The synthesis of 3c was
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performed in an analogous fashion to the synthesis of [Rh(PyT)-
(COD)]BArF , 2c; see Supporting Information.
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Synthesis of [Rh(PyT)(CO)2]BPh4 (4a). Method A (preferred
method for the synthesis of 4a). A solution of PyT (1a, 0.120 g,
0.500 mmol) in methanol (15 mL) was added slowly to a
solution of [Rh(μ-Cl)(CO)2]2 (0.097 g, 0.25 mmol) in
methanol (15 mL) using a cannula over 15 min. The resulting
yellow solution was stirred for 20 min at room temperature.
Sodium tetraphenylborate (0.172 g, 0.500 mmol) was added to
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dx.doi.org/10.1021/om201171b | Organometallics 2012, 31, 1790−1800