Article
Organometallics, Vol. 29, No. 13, 2010 2855
(t, 12 H, J = 7.1 Hz), 1.13-1.42 (m, 16 H), 1.55-1.75 (m, 8 H),
7.05-7.09 (m, 2 H); 7.17-7.21 (m, 2 H). 13C NMR (CDCl3, 75
MHz): δ 14.82, 24.10, 27.49, 42.53, 68.62, 123.10, 127.19,
148.64. HRMS (EI): calcd for C24H41Nþ m/z 342.3155, found
m/z 342.3150. Anal. Calcd for C24H41N: C, 83.90; H, 12.03; N,
4.07. Found: C, 84.00; H, 12.23; N, 4.02.
Preparationof1,1,3,3-Tetrabutylisoindolin-2-oxyl(5d, TBINO).
m-CPBA (779 mg, 3.84 mmol) was added to a solution of 1,1,3,3-
tetrabutylisoindoline (4d; 879 mg, 2.56 mmol) in CH2Cl2 (18 mL).
The rest of the procedure was the same as the preparation of
1,1,3,3-tetramethylisoindolin-2-oxyl (4c). A yellow oil with high
viscosity (906 mg, 2.53 mmol, 99%) was obtained after rotary
evaporation. Rf = 0.81 (9:1 hexane/ethyl acetate). HRMS (FAB):
calcd for C24H40NOþ m/z 358.3104, found m/z 358.3119. Anal.
Calcd for C24H40NO: C, 80.39; H, 11.24; N, 3.91. Found: C,
80.41; H, 11.38; N, 3.89.
or 110 °C under N2 in the absence of light. After the mixture was
cooled to room temperature, the solvent was removed under
vacuum. The residue was purified by chromatography on silica
gel with a solvent mixture of hexane and CH2Cl2 ranging from
10:1 to 7:1 as eluent to give orange solids of Rh(tmp)R with 1H
NMR spectra identical with those of an authentic sample.
ACCA between Rh(tmp) and TMINO (4a). Degassed TMINO
(0.055 mmol, 10.5 mg) was added to a benzene solution of
Rh(tmp) (0.0088 mmol, 4.0 mL) under N2 with stirring. The
mixture was heated under N2 in the absence of light for 4 h. Then
the reaction mixture was cooled to room temperature, and the
solvent was removed under vacuum. The residue was purified by
chromatography on silica gel with a solvent mixture of hexane
and CH2Cl2 ranging from 10:1 to 7:1 as eluent to give Rh-
(tmp)Me (0.0064 mmol, 5.8 mg) in 73% yield and was identified
by 1H NMR spectroscopy.
Preparation of 2-Benzyl-1,1,3,3-tetrakis(3-phenylpropyl)isoindo-
line (3e). Ph(CH2)3Br (11.7 mL, 75.8 mmol) was used. The
procedure was the same as the preparation of 2-benzyl-1,1,3,3-
tetramethylisoindoline (3c). A pale yellow oil of 2-benzyl-1,1,3,3-
tetrakis(3-phenylpropyl)isoindoline with high viscosity was ob-
tained (1.42 g, 2.1 mmol, 16%). Rf = 0.23 (1:9 ethyl acetate/
ACCA between Rh(tmp) and TEINO (4b). Degassed TEINO
(0.055 mmol, 13.5 mg) was used as substrate. The rest of the
procedure was same as the reaction between Rh(tmp) and
TMINO. Yields of 9% of Rh(tmp)Me (0.0008 mmol, 0.7 mg)
and 44% of Rh(tmp)Et5 (0.0039 mmol, 3.5 mg) were isolated
1
and identified by H NMR spectroscopy. Rh(tmp)Et:8 Rf =
0.44 (1:5 CH2Cl2/hexane); 1H NMR (C6D6) δ -4.31 (dq, 2 H,
2JRhH = 3.0 Hz, 3JHH = 7.5 Hz), -3.83 (dt, 3 H, 3JRhH = 1.5
Hz, 3JHH = 7.5 Hz), 1.88 (s, 12 H), 2.12 (s, 12 H), 2.44 (s, 12 H),
6.93 (s, 4 H), 7.19 (s, 4 H), 8.75 (s, 8 H).
1
hexane). H NMR (CDCl3, 300 MHz): δ 0.83-0.91 (m, 2 H),
1.25-1.36 (m, 4 H), 1.43-1.53 (m, 4 H), 1.65-1.71 (m, 4 H), 1.81
(m, 4 H), 2.34-2.42 (m, 4H), 2.56 (t, 2H, J = 7.8 Hz), 3.90 (s, 2 H),
6.91-6.96 (m, 2 H), 7.03-7.06 (m, 6 H), 7.08-7.31 (m, 21 H). 13
C
NMR (CDCl3, 75 MHz): δ 27.32, 37.19, 38.99, 47.39, 71.24,
123.99, 126.28, 126.63, 127.33, 128.73, 128.93, 129.06, 129.95,
142.68, 143.35, 145.23. HRMS (EI): calcd for C51H55Nþ m/z
680.4251, found m/z 680.4214. Anal. Calcd for C51H55N: C,
89.82; H, 8.13; N, 2.05. Found: C, 89.93; H, 8.11; N, 2.04.
Preparation of 1,1,3,3-Tetrakis(3-phenylpropyl)isoindolin-2-
oxyl (5e, TPPINO). m-CPBA (549 mg, 2.70 mmol) was added
to a solution of 2-benzyl-1,1,3,3-tetrakis(3-phenylpropyl)iso-
indoline (3e; 1.23 g, 1.80 mmol) in CH2Cl2 (20 mL), The solution
changed to yellow after 4 days, and a suspension formed. The
rest of the procedure was the same as the preparation of 4c. A
yellow oil with high viscosity (595 mg, 0.981 mmol, 54%) was
obtained after rotary evaporation. Rf = 0.47 (9:1 hexane/ethyl
acetate). HRMS (FAB): calcd for C44H48NOþ m/z 606.3730,
found m/z 606.3726. Anal. Calcd for C44H48NO: C, 87.08; H,
7.97; N, 2.31. Found: C, 86.70; H, 7.98; N, 2.24.
ACCA between Rh(tmp) and TPINO (4c). Degassed TPINO
(0.055 mmol, 16.6 mg) was used as substrate. The rest of the
procedure was same as the reaction between Rh(tmp) and
TMINO. Yields of 14% of Rh(tmp)Me (0.0012 mmol, 1.1 mg)
and 41% of Rh(tmp)nPr (0.0036 mmol, 3.3 mg) were isolated
and identified by 1H NMR spectroscopy. Rh(tmp)nPr:8 1H
2
NMR (C6D6, 300 MHz) δ -4.44 (dt, 2 H, JRhH = 3.0 Hz,
3JHH = 7.5 Hz), -3.88 (sextet, 2 H, J = 7.5 Hz), -1.42 (t, 3 H,
J = 7.4 Hz), 1.90 (s, 12 H), 2.18 (s, 12 H), 2.44 (s, 12 H), 7.11 (s,
4H), 7.20 (s, 4 H), 8.76 (s, 12 H).
ACCA between Rh(tmp) and TBINO (4d). Degassed TBINO
(0.055 mmol, 19.7 mg) was used as substrate. The rest of the
procedure was same as the reaction between Rh(tmp) and
TMINO. Yields of 10% of Rh(tmp)Me (0.0009 mmol, 0.8 mg)
and 22% of Rh(tmp)nBu (0.0019 mmol, 1.8 mg) were isolated
and identified by 1H NMR spectroscopy.
Preparation of 2-Benzyl-1,1,3,3-tetraphenylisoindoline (3f).
PhBr (8.0 mL, 75.8 mmol) was used. The procedure was the
same as the preparation of 2-benzyl-1,1,3,3-tetramethylisoindo-
line (3c). A white solid of 2-benzyl-1,1,3,3-tetraphenylisoindo-
Preparation of (5,10,15,20-Tetramesitylporphyrinato)butylrho-
dium(III) (Rh(tmp)nBu).7 A red suspension of Rh(tmp)I (0.035 g,
0.034 mmol) in EtOH (20 mL) and a solution of NaBH4 (0.005 g,
0.123 mmol) in aqueous NaOH (1.4 mL, 0.5 M) were purged with
N2 separately for about 15 min. The solution of NaBH4 was
added slowly to the suspension of Rh(tmp)I via a cannula over
a period of 30 min. The mixture was heated to 55 °C for 3 h.
line was obtained (1.25 g, 2.43 mmol, 19%). Mp: 209.9-210.2 °C.
1
Rf = 0.15 (1:9 ethyl acetate/hexane). H NMR (CDCl , 300
3
MHz): δ 4.13 (s, 2 H), 6.25 (d, 2 H, J = 6.9 Hz), 6.83-6.85 (m,
3 H), 7.05-7.26 (m, 24 H). 13C NMR (CDCl3, 75 MHz): δ 49.27,
82.44, 125.48, 126.79, 127.38, 128.00, 129.94, 130.79, 141.52,
145.90, 146.38. HRMS (EI): calcd for C39H31Nþ m/z 513.2451,
found m/z 513.2431.
n
Then the brown mixture was cooled to 0 °C under N2. BuBr
(1.12 mmol) was added with a syringe. The mixture was warmed
to room temperature and stirred for 3 h. The orange mixture was
worked up by addition with CH2Cl2/H2O. Then it was extracted
with CH2Cl2 (3 ꢀ 50 mL), washed with H2O, dried over MgSO4,
filtered, and evaporated off to dryness. The mixture was purified
by silica gel chromatography with a solvent mixture of CH2Cl2
and hexane (1:5) as eluent. Then the solid obtained was recrys-
tallized from CH2Cl2/hexane. A red solid was obtained (45 mg,
Preparation of 1,1,3,3-Tetraphenylisoindolin-2-oxyl [TPhINO]
(5f). m-CPBA (177 mg, 1.03 mmol) was added to a solution of
2-benzyl-1,1,3,3-tetraphenylisoindoline (3f; 117 mg, 0.23 mmol)
in CH2Cl2 (15 mL). The solution turned yellow after 4 days with
some suspension formed. The rest of the procedure was the same
as the preparation of 1,1,3,3-tetramethylisoindoline-2-oxyl (4c).
A yellow solid (71.1 mg, 0.162 mmol, 71%) was obtained after
rotary evaporation. The crude product was recrystallized from
ethyl acetate/hexane. A white crystal was obtained. Mp: 248.3-
248.5 °C. Rf = 0.41 (10:1 hexane/ethyl acetate). HRMS (FAB):
calcd for C32H24NOþ m/z 439.1931, found m/z 439.1924. Anal.
Calcd for C32H24NO: C, 87.64; H, 5.52; N, 3.19. Found: C, 87.80;
H, 5.53; N, 3.23.
1
0.049 mmol, 49%). Rf = 0.47 (1:5 CH2Cl2/hexane). H NMR
(C6D6, 300 MHz): δ -4.45 (dt, 2 H, 2JRhH = 3.0 Hz, 3JHH = 7.8
Hz), -3.94 (quintet, 2 H, J = 7.2 Hz), -1.14 (sextet, 2 H, J = 7.5
Hz), -0.67 (t, 3H, J = 7.2 Hz), 1.91 (s, 12 H), 2.18 (s, 12 H), 2.44
(s, 12 H), 7.12 (s, 4 H), 7.20 (s, 4 H), 8.75 (s, 8 H). HRMS (FAB):
calcd for C60H61N4Rhþ m/z 941.4024, found 941.3954. Anal.
Calcd for C60H61N4Rh: C, 76.58; H, 6.53; N, 5.95. Found: C,
76.02; H, 6.64; N, 5.96.
General Procedure for ACCA of Rh(tmp) with Nitroxides.5 To
a Teflon screw-head stoppered flask, a benzene solution of
Rh(tmp) (0.0088 mmol, 4.0 mL) was added with a nitroxide
(0.055 mmol). Then the reaction mixture was then heated to 70
ACCA Study between Rh(tmp) and TPPINO (4e). Degassed
TPPINO (0.055 mmol, 33.4 mg) was used as substrate. The rest
of the procedure was same as the reaction between Rh(tmp)
and TMINO. Yields of 12% of Rh(tmp)CH2Ph (0.0011 mmol,