Inorganic Chemistry
Article
7.35−7.32 (m, 14H), 7.19 (t, J = 6.5 Hz, 7H), 7.03 (t, J = 7.0 Hz,
12H), 6.97 (d, J = 8.5 Hz, 2H), 6.51 (t, J = 7.5 Hz, 2H), 6.42 (t, J = 7.5
Hz, 2H), 6.32 (d, J = 7.5 Hz, 2H). 31P−{1H} NMR (202 MHz, CDCl3,
294 K): δ 116.3 (t, J = 13.0 Hz, 1P), −8.8 (d, J = 13.0 Hz, 2P). Anal.
Calcd for C54H43ClIrO3P3: C, 59.12; H, 4.04. Found: C, 61.16; H,
4.09.
Synthesis of [Ir(dppit)(PPh3)2Cl] (2b). [IrCl3(tht)3] (200 mg,
0.36 mmol), diphenyl phenylphosphonite (dppitH2, 120 mg, 0.40
mmol), and PPh3 (200 mg, 0.76 mmol) were added to 10 mL of
degassed decalin and the mixture was heated to 180 °C for 12 h. After
cooling to RT, sodium acetate (100 mg, 1.22 mmol) was added and
the mixture was heated to 135 °C for another 4 h. After cooling to RT
and removal of solvent, the residue was purified by silica gel column
chromatography, eluting with 1:3 mixture of ethyl acetate and hexane.
The white crystals of 2b were obtained by slow diffusion of hexane
into CH2Cl2 solution at RT (130 mg, 0.12 mmol, 35%).
escent metal complexes can be realized via tailored synthetic
protocols.7
Another class of phosphorus donors is triphenylphosphite
P(OPh)3 and diphenyl phenylphosphonite PPh(OPh)2, for
which the phenoxy groups are capable of undergoing facile
cyclometalation and affording the respective M(P∧C2) tripodal
fragment. Bearing such expectation in mind, we then carry out
the reactions of Ir(III) metal reagent [IrCl3(tht)3] with a
mixture of phosphine and phosphite (or phosphonite). The
well controlled reaction stoichiometry is expected to induce
double cyclometalation on the phosphite (or phosphonite)
ligand and afford the anticipated tripodal P∧C2 chelating
arrangement. Thus, the resulting facial tripod is different from
that of the well-known pincer chelate of the types P^C^P and
Spectral Data of 2b. MS (FAB, 35Cl, 193Ir): m/z 1045 (M + 1)+.
1H NMR (500 MHz, CD2Cl2, 294 K): δ 7.64 (d, J = 5.5 Hz, 2H),
7.30−7.18 (m, 19H), 7.06−6.90 (m, 14H), 6.89 (td, J = 7.5, 3.5 Hz,
2H), 6.55 (t, J = 7.5 Hz, 2H), 6.45 (d, J = 7.5 Hz, 2H), 6.40 (t, J = 7.5
Hz, 2H). 31P−{1H} NMR (202 MHz, CD2Cl2, 294 K): δ 144.4 (t, J =
4.8 Hz, 1P), −9.8 (d, J = 4.8 Hz, 2P). Anal. Calcd for C54H43ClIrO2P3:
C, 62.09; H, 4.15. Found: C, 61.85; H, 4.43.
Synthesis of [Ir(dppit)(PMe2Ph)2Cl] (2c). [IrCl3(tht)3] (150 mg,
0.27 mmol), dppitH2 (87 mg, 0.29 mmol), PMe2Ph (81 mg, 0.59
mmol), and sodium acetate (110 mg, 1.35 mmol) were combined in
degassed decalin (10 mL) and the mixture was heated to 180 °C for 30
h. After cooling to RT and removal of solvent, the residue was purified
by silica gel column chromatography, eluting with a 1:3 mixture of
ethyl acetate and hexane. The white crystals of 2c were obtained by
slow diffusion of hexane into a CH2Cl2 solution at RT (121 mg, 0.15
mmol, 57%).
P^N^P, for which only the meridional bonding mode is
reported.8
2. EXPERIMENTAL SECTION
General Procedures. All reactions were performed under argon
atmosphere and solvents were distilled from appropriate drying agents
prior to use. Commercially available reagents were used without
further purification unless otherwise stated. All reactions were
monitored using precoated TLC plates (0.20-mm with fluorescent
indicator UV254). Mass spectra were obtained on a JEOL SX-102A
instrument operating in electron impact (EI) or fast atom bombard-
1
Spectral Data of 2c. MS (FAB, 35Cl, 193Ir): m/z 796 (M)+. H
NMR (500 MHz, CD2Cl2, 294 K): δ 8.03 (dd, J = 7.0, 3.0 Hz, 2H),
7.52 (td, J = 7.0, 1.0 Hz, 1H), 7.32 (t, J = 7.5 Hz, 2H), 7.25 (td, J = 8.0,
3.5 Hz, 2H), 7.16 (t, J = 7.0 Hz, 4H), 6.99 (dd, J = 12.0, 7.5 Hz, 2H),
6.93−6.91 (m, 4H), 6.88−6.84 (m, 2H), 6.79 (t, J = 8.0 Hz, 4H), 1.42
(d, J = 8.5 Hz, 6H), 1.10 (d, J = 9.0 Hz, 6H). 31P−{1H} NMR (202
MHz, CD2Cl2, 294 K): δ 141.3 (t, J = 4.8 Hz, 1P), −42.6 (d, J = 4.8
Hz, 2P). Anal. Calcd for C34H35ClIrO2P3: C, 51.29; H, 4.43. Found: C,
51.08; H, 4.54.
1
ment (FAB) mode. H and 13C NMR spectra were recorded on a
Varian Mercury-400 or an INOVA-500 instrument. Elemental analysis
was carried out with a Heraeus CHN-O Rapid Elementary Analyzer.
Diphenyl phenylphosphonite (dppitH2)9 and [IrCl3(tht)3]10 were
synthesized using methods reported in the literature.
Synthesis of [Ir(tpitH)(PPh3)2Cl2] (1a). [IrCl3(tht)3] (110 mg,
0.20 mmol), triphenylphosphite (tpitH2, 70 mg, 0.22 mmol), and
triphenyl phosphine (PPh3, 115 mg, 0.44 mmol) were added into 10
mL of decalin and the mixture was heated to 180 °C for 12 h. After
cooling to RT, the solution was concentrated and mixed with excess of
hexane to induce precipitation. The white crystals of 1a were obtained
by slow diffusion of hexane into a CH2Cl2 solution at RT (153 mg,
0.14 mmol, 70%).
Synthesis of [Ir(tpit)(tpitH)(PPh3)] (3a). Complex 2a (69 mg,
0.07 mmol), triphenylphosphite (22 mg, 0.07 mmol), and sodium
acetate (12 mg, 0.15 mmol) were added to 10 mL of decalin and the
mixture was heated to 120 °C for 6 h. After cooling to RT and removal
of solvent, the residue was purified by silica gel column
chromatography, eluting with a 4:1 mixture of dichloromethane and
hexane. The white crystals of 3a were obtained by slow diffusion of
hexane into CH2Cl2 solution at RT (54 mg, 0.05 mmol, 77%).
1
Spectral Data of 3a. MS (FAB, 193Ir): m/z 1072 (M)+. H NMR
Spectral Data of 1a. MS (FAB, 35Cl, 193Ir): m/z 1061 (M − Cl)+.
1H NMR (400 MHz, CDCl3, 294 K): δ 7.60−7.64 (m, 12H), 7.10 (t, J
= 7.4 Hz, 6H), 7.00 (t, J = 7.6 Hz, 12H), 6.94−6.84 (m, 6H), 6.71 (d, J
= 8.0 Hz, 1H), 6.64 (t, J = 7.4 Hz, 1H), 6.53 (d, J = 8.0 Hz, 4H), 6.49
(d, J = 8.0 Hz, 1H), 6.02 (t, J = 7.4 Hz, 1H). 31P−{1H} NMR (202
MHz, CDCl3, 294 K): δ 76.6 (t, J = 22.5 Hz, 1P), −12.8 (d, J = 22.5
Hz, 2P). Anal. Calcd for C54H44Cl2IrO3P3: C, 59.12; H, 4.04. Found:
C, 58.43; H, 3.89.
(500 MHz, CD2Cl2, 294 K): δ 7.48 (t, J = 8.0 Hz, 1H), 7.35 (t, J = 8.0
Hz, 2H), 7.26−7.20 (m, 5H), 7.19−7.15 (m, 4H), 7.11 (dd, J = 8.0,
3.0 Hz, 1H), 7.06−7.04 (m, 15H), 6.97 (d, J = 8.5 Hz, 2H), 6.77−6.73
(m, 4H), 6.70 (t, J = 7.5 Hz, 1H), 6.60−6.55 (m, 5H), 6.51 (t, J = 7.5
Hz, 1H), 6.21 (dd, J = 8.0, 3.0 Hz, 1H). 31P−{1H} NMR (202 MHz,
CD2Cl2, 294 K): δ 141.8 (dd, J = 20.0, 12.1 Hz, 1P), 114.5 (dd, J =
20.0, 12.1 Hz, 1P), −4.1 (t, J = 20.0 Hz, 1P). Anal. Calcd for
C54H42IrO6P3: C, 60.50; H, 3.95. Found: C, 60.33; H, 4.02.
Synthesis of [Ir(tpit)(PPh3)2Cl] (2a). [IrCl3(tht)3] (110 mg, 0.20
mmol), triphenylphosphite (70 mg, 0.22 mmol), and PPh3 (115 mg,
0.44 mmol) were added into 10 mL of decalin and the mixture was
heated to 180 °C for 12 h. After cooling to RT, sodium acetate (80
mg, 1.00 mmol) was added and the mixture was heated to 135 °C for
another 4 h. After cooling to RT and removal of solvent, the residue
was purified by silica gel column chromatography, eluting with 1:3
mixture of ethyl acetate and hexane. The white crystals of 2a were
obtained by slow diffusion of hexane into CH2Cl2 solution at RT (138
mg, 0.13 mmol, 65%).
Synthesis of [Ir(tpit)(dppb)Cl] (4a). Complex 2a (100 mg, 0.10
mmol) and 1,2-bis(diphenylphosphino)benzene (dppb, 47 mg, 0.11
mmol) were added to 10 mL of decalin and the mixture was heated to
110 °C for 2 h. After cooling to RT and removal of solvent, the residue
was purified by silica gel column chromatography, eluting with a 4:1
mixture of dichloromethane and hexane. The white crystals of 4a were
obtained by slow diffusion of hexane into CH2Cl2 solution at RT (77
mg, 0.08 mmol, 83%).
Spectral Data of 4a. MS (FAB, 35Cl, 193Ir): m/z 983 (M + 1)+. 1H
NMR (400 MHz, CDCl3, 294 K): δ 7.65−7.54 (m, 10H), 7.37−7.29
(m, 2H), 7.28−7.20 (m, 4H), 7.18−7.09 (m, 8H), 7.08−6.95 (m, 5H),
6.84−6.75 (m, 4H), 6.65 (t, J = 8.0 Hz, 2H), 6.33 (d, J = 8.0 Hz, 2H).
Spectral Data of 2a. MS (FAB, 35Cl, 193Ir): m/z 1061 (M + 1)+.
1H NMR (500 MHz, CDCl3, 294 K): δ 7.63 (dd, J = 7.0, 2.5 Hz, 2H),
1786
dx.doi.org/10.1021/ic202090j | Inorg. Chem. 2012, 51, 1785−1795