Organometallics
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∼(2.6ꢀ3.4)/1 ratio in CDCl3, since the ratio is variable upon each time of
preparation of “Ir(ttp)SbF6”. Rf = 0.00 (CH2Cl2). NMR data for “Ir-
(1:2)). Rf = 0.50 (CH2Cl2/hexane =1: 1). 1H NMR (CDCl3, 300 MHz):
δ 0.23 (d, 2 H, J = 8.7 Hz) (Ir-aryl o-H), 2.68 (s, 12 H) (tolyl CH3), 4.98
(d, 2 H, J = 8.4 Hz) (Ir-aryl m-H), 7.52 (d, 8 H, J = 7.8 Hz) (m-tolyl H),
7.99 (d, 8 H, J = 6.6 Hz) (o-tolyl H), 8.59 (s, 8 H) (pyrrole H). 13C NMR
(CDCl3, 100 MHz): δ 21.7, 85.4, 98.9, 123.7, 127.6, 131.2, 131.5, 133.7,
134.3, 137.4, 138.7, 142.7. HRMS (FABMS): calcd for [C54H40N4IIr]+:
m/z 1064.1921, found m/z 1064.1927.
(ttp)SbF6” (Ir(ttp)SbF6/[Ir(ttp)(CO)]SbF6
=
3.4/1): 1H NMR
(CDCl3, 400 MHz) δ 2.73 (s, 12 H) (tolyl CH3), 7.11 (d, 4 H, 3JHH
=
7.7 Hz) (m-tolyl H), 7.64 (d, 4 H, 3JHH = 7.7 Hz) (m-tolyl H), 8.09 (dd, 4
H, 3JHH = 7.6 Hz, 4JHH = 1.6 Hz) (o-tolyl H), 8.16 (dd, 4 H, 3JHH = 7.6 Hz,
4JHH = 1.9 Hz) (o-tolyl H), 9.10 (s, ∼6.2 H), 9.12 (s, ∼1.8 H) (pyrrole
H); 1H NMR (C6D6, 400 MHz) δ 2.40 (s, 12 H) (tolyl CH3), 7.24 (d, 4
H, 3JHH = 7.6 Hz) (m-tolyl H), 7.32 (d, 4 H, 3JHH = 7.6 Hz) (m-tolyl H),
7.90(d, 4 H, 3JHH = 7.7Hz) (o-tolylH), 8.22 (dd, 4 H, 3JHH = 7.9Hz, 4JHH
(ii). Conversion of 2o to 3a. Ir(ttp)C6H4(p-I) (2o; 50.0 mg, 0.047
mmol), K2CO3 (130 mg, 0.94 mmol, 20 equiv), Ir(ttp)(CO)Cl (48.1
mg, 0.052 mmol, 1.1 equiv), and benzene (3 mL) were heated at 200 °C
in a Teflon-screw-capped tube under N2 for 24 h to give Ir(ttp)(p-
C6H4)Ir(ttp) (3a; 65.9 mg, 0.037 mmol, 78%; CH2Cl2/hexane (1/1)).
Preparation of β-Hydroxyethyl(5,10,15,20-tetrakis(p-tolyl)porphyri-
nato)iridium(III) (Ir(ttp)CH2CH2OH, 9). A suspension of Ir(ttp)(CO)Cl
(84 mg, 0.091 mmol) in THF (20 mL) in a Teflon-screw-capped
250 mL round-bottomed flask and a solution of NaBH4 (68.7 mg, 1.82
mmol) in aqueous NaOH (1.0 M, 1.5 mL) were purged with N2 for 15
min separately. The solution of NaBH4 was added slowly to the
suspension of Ir(ttp)(CO)Cl via a cannula under N2. The mixture
was heated at 50 °C under N2 for 2 h to give a deep brown solution. The
mixture was then cooled to room temperature, and 2-iodoethanol (156.2
mg, 71 μL, 0.91 mmol) was added under N2. The reaction mixture was
further heated at 50 °C for 2 h. The reaction mixture was dried and
purified by column chromatography with alumina using CH2Cl2/hexane
(1/2) as an eluent. The major deep brown fraction was collected and
dried. The product was recrystallized in CH2Cl2/hexane to obtain a
deep brown solid of Ir(ttp)CH2CH2OH (9; 74.5 mg, 0.082 mmol,
90%). Rf = 0.26 (CH2Cl2/hexane (1/1)). 1H NMR (400 MHz, CDCl3):
δ ꢀ5.29 (t, 2 H, J = 7.3 Hz) (IrꢀCH2-CH2), ꢀ2.43 (t, 1 H, J = 6.2 Hz)
(Ir-(CH2)2OH), ꢀ2.16 (q, 2 H, J = 6.9 Hz) (Ir-CH2-CH2-), 2.68 (s, 12
H) (tolyl CH3), 7.52 (d, 8 H, J = 7.9 Hz) (m-tolyl H), 7.98 (dd, 4 H, J =
8.2 Hz, J = 2.2 Hz) (o-tolyl H), 8.02 (dd, 4 H, J = 8.2 Hz, J = 2.3 Hz) (o-
tolyl H), 8.54 (s, 8 H) (pyrrole H). 13C NMR (100 MHz, CDCl3):
δ ꢀ14.7, 21.7, 59.0, 124.1, 127.6, 127.7, 131.6, 133.6, 134.0, 137.4, 138.6,
143.4. HRMS (FABMS): calcd for [C50H41N4OIr]+ ([M]+) m/z
906.2904, found m/z 906.2912.
1
= 1.0 Hz) (o-tolyl H), 9.08 (s, 8 H) (pyrrole H). The H NMR of
[Ir(ttp)(CO)]SbF6 is identical with that of [Ir(ttp)]SbF6, except the
pyrrole signal, which appears at 9.12 ppm in CDCl3. 13C NMR of
Ir(ttp)SbF6 (as a major species without a CO ligand; CDCl3, 100 MHz):
δ 21.7, 123.2, 127.8, 128.4, 132.6, 133.9, 134.7, 137.4, 138.5, 141.6. HRMS
([M]+) of 1d was nottaken, as theHRMSofanalogous Ir(ttp)BF410e only
gave Ir(ttp)+ ion ([M ꢀ BF4]+).
Preparation of 4,40-Bis[(5,10,15,20-tetrakis(p-tolyl)porphyrinato)-
iridium(III)] Biphenyl ([Ir(ttp)(p-C6H4)2Ir(ttp)], 3b). (a). Conversion
of 4,40-Diiodobiphenyl to Ir(ttp)(p-C6H4)2(p-I) (2q). Ir(ttp)(CO)Cl
(50.0 mg, 0.054 mmol), K2CO3 (149 mg, 1.08 mmol, 20 equiv), 4,40-
diiodobiphenyl (107 mg, 0.32 mmol, 6 equiv), and benzene (3 mL) were
heated in a Teflon-screw-capped glass tube at 200 °C under N2 for 24 h
and purified to give a deep brown solid of Ir(ttp)(p-C6H4)2(p-I) (2q;
46.8 mg, 0.041 mmol, 76%; CH2Cl2/hexane (1/2)). Rf = 0.57 (CH2Cl2/
hexane (2/1)). 1H NMR (CDCl3, 300 MHz): δ 0.63 (d, 2 H, J = 8.4 Hz)
(Ir-aryl-o-H), 2.68 (s, 12 H) (tolyl CH3), 4.95 (d, 2 H, J = 8.7 Hz)
(Ir-aryl-m-H), 6.28 (d, 2 H, J = 8.4 Hz) (Ir-aryl-aryl-o-H), 7.14 (d, 2 H,
J = 8.4 Hz) (Ir-aryl-aryl-m-H), 7.51 (d, 4 H, J = 6.9 Hz) (m-tolyl H), 7.53
(d, 4 H, J = 6.9 Hz) (m-tolyl H), 8.01 (d, 8 H, J = 7.5 Hz) (o-tolyl H),
8.60 (s, 8 H) (pyrrole H). 13C NMR of Ir(ttp)(p-C6H4)2(p-I) could not
be obtained, due to its poor solubility in CDCl3 and THF-d8. HRMS
(FABMS): calcd for [C60H44N4IIr]+ ([M]+) m/z 1140.2234, found m/z
1140.2277.
(b). Conversion of 2q to 3b. Ir(ttp)(p-C6H4)2(p-I) (2q; 50 mg,
0.044 mmol), K2CO3 (121 mg, 0.88 mmol, 20 equiv), Ir(ttp)(CO)Cl
(44.7 mg, 0.048 mmol, 1.1 equiv), and benzene (3 mL) were heated in a
Teflon-screw-capped glass tube at 200 °C under N2 for 19 h to give a
deep brown solid of Ir(ttp)(p-C6H4)2Ir(ttp) (3b;10d 58.4 mg, 0.031
mmol, 71%; CH2Cl2/hexane (1/1)).
Preparation of (μ-Oxo)bis((aqua)(5,10,15,20-Tetrakis(p-tolyl)-
porphyrinato)iridium(III)) ((H2O)(ttp)IrOIr(ttp)(OH2), 8b). Ir(ttp)-
CH2CH2OH (9; 2.6 mg, 0.003 mmol) and benzene-d6 (0.5 mL) were
degassed in a Teflon-screw-capped NMR tube for three free-
zeꢀthawꢀpump cycles and then flame-sealed under vacuum. Residual
water (∼2.4 equiv) was observed by 1H NMR spectroscopy. The
reaction mixture was heated at 120 °C for 23 days to yield brown
(H2O)Ir(ttp)OIr(ttp)(OH2) (8b) in 72% NMR yield (Figure S4a,b in
the Supporting Information). Ir(ttp)C6D5 (δ(pyrrole) 8.79 ppm)
(presumably formed by the reaction of Ir(ttp)OH and C6D6)43 and
unreacted 9 (δ(pyrrole) 8.76 ppm) were observed in 7% and 2% NMR
yields, respectively. C2H4 (δ(C2H4) 5.23 ppm)42 was also observed.
The coordinated water in 8b underwent H/D exchange with excess D2O
in benzene-d6 at room temperature in air in 1.5 days, and the ratio of D to
Preparation of 1,4-Bis[(5,10,15,20-tetrakis(p-tolyl)porphyrinato)-
iridium(III)] Benzene ([Ir(ttp)(p-C6H4)Ir(ttp)], 3a). (a). From 1,4-Di-
bromobenzene. Ir(ttp)C6H4(p-Br) was prepared in 76% yield from the
reaction of 1,4-dibromobenzene (1.1 equiv) with Ir(ttp)(CO)Cl and
K2CO3 in benzene in a Teflon-screw-capped tube under N2 at 200 °C
for 11 h.10d Ir(ttp)C6H4(p-Br) (50 mg, 0.049 mmol), K2CO3 (136 mg,
0.98 mmol, 20 equiv), Ir(ttp)(CO)Cl (49.8 mg, 0.054 mmol, 1.1 equiv),
and benzene (3 mL) were then heated at 200 °C in a Teflon-screw-
capped tube under N2 for 14 h to give Ir(ttp)(p-C6H4)Ir(ttp) (3a; 54.2
mg, 0.029 mmol, 59%; CH2Cl2/hexane (1/1)). Rf = 0.32 (CH2Cl2/
hexane (1/1)). 1H NMR (CDCl3, 400 MHz): δ ꢀ2.00 (s, 4 H) (Ir-aryl
H), 2.66 (s, 24 H) (tolyl CH3), 7.39 (d, 8 H, 3JHH = 7.4 Hz) (m-tolyl H),
7.41 (d, 8 H, 3JHH = 7.8 Hz) (m-tolyl H), 7.44 (dd, 8 H, 3JHH = 7.6 Hz,
4JHH = 1.7 Hz) (o-tolyl H), 7.79 (dd, 8 H, 3JHH = 7.6 Hz, 4JHH = 1.8 Hz)
1
H in the coordinated water was observed to be ∼2.9/1 by H NMR
spectroscopy. The sample of 8b in benzene-d6 completely decomposed
1
in air in 3 days. H NMR (C6D6, 400 MHz): δ ꢀ10.89 (s, 4 H) (Ir-
OH2), 2.43 (s, 24 H) (tolyl CH3), 7.24 (d, 8 H, J = 7.7 Hz) (m-tolyl H),
7.38 (d, 8 H, J = 7.4 Hz) (m-tolyl H), 7.62 (dd, 8 H, J = 7.4 Hz, J = 1.6
Hz) (o-tolyl H), 7.89 (dd, 8 H, J = 7.7 Hz, J = 1.8 Hz) (o-tolyl H), 8.36 (s,
16 H) (pyrrole H). 13C NMR (C6D6, 100 MHz): δ 21.6, 123.5, 127.4,
130.6, 132.9, 135.1, 136.9, 139.3, 142.4. One m-tolyl’s carbon signal
was shielded by the residual benzene peak. HRMS (FABMS): calcd
for [C96H72N8OIr2]+ ([M ꢀ 2H2O]+) m/z 1737.5092, found m/z
1737.5052.
(o-tolyl H), 8.18 (s, 16 H) (pyrrole H). 13C NMR with complete 13
C
signals could not be obtained, since 3a was only springly soluble in
CDCl3 and THF-d8. HRMS (FABMS): [C10113CH76N8193Ir191Ir]+ m/z
1797.5456, found m/z 1797.5470.
(b). From 1,4-Diiodobenzene. (i). Conversion of 1,4-Diiodoben-
zene to Ir(ttp)C6H4(p-I) (2o). Ir(ttp)(CO)Cl (50.0 mg, 0.054 mmol),
K2CO3 (149 mg, 1.08 mmol, 20 equiv), 1,4-diiodobenzene (178.4 mg,
0.54 mmol, 10 equiv), and benzene (4 mL) were heated in the Teflon-
screw capped glass tube at 200 °C under N2 for 11 h to give
Ir(ttp)C6H4(p-I) (2o) (53.2 mg, 0.050 mmol, 92%) (CH2Cl2/hexane
Optimization of Base-Promoted PhꢀBr Cleavage by Ir(ttp)(CO)Cl. (a).
Reaction of Ir(ttp)(CO)Cl with PhBr. Ir(ttp)(CO)Cl (15 mg, 0.016 mmol)
and PhBr (1 mL) were heated in a Teflon-screw-capped tube at 200 °C
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dx.doi.org/10.1021/om200251k |Organometallics 2011, 30, 4269–4283