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B.J. Wik et al. / Journal of Molecular Catalysis A: Chemical 189 (2002) 23–32
1H, CH2), 7.16 (m, 4H, ArH(3,5)), 7.25 (m, 2H,
ArH(4)), 14.77 (s, 1H, NH). 13C{1H} NMR (75 MHz,
CD2Cl2) δ 187.2, 178.8, 146.1, 136.4, 135.9, 132.6,
132.3, 130.2, 129.5, 129.1, 128.7, 128.4, 127.5,
91.0 (C5Me5), 29.3, 22.0, 20.5, 19.1, 18.8, 17.7, 8.4
(C5Me5). λmax (CD2Cl2) 304 (5.5), 446 (5.3). Anal.
Calcd. for C30H39Cl2IrN2·CH2Cl2: C, 48.00; H,
5.33; N, 3.61; Cl, 18.28. Found: C, 47.98; H, 5.38;
N, 3.95; Cl, 18.26. HRMS (EI) Found: m/z 654.2335
(C30H38ClIrN2, M+-HCl). Calcd. for C30H38ClIrN2:
654.2353.
solvent in vacuo yielded the product 8 (60 mg, 58%).
1H NMR (300 MHz, CD2Cl2) δ 1.30 (s, 15H, Cp∗),
1.83 (s, 3H, Me), 1.94 (s, 3H, Me), 2.06 (s, 3H, Me),
2.14 (d, J = 13.2 Hz, 1H, CH2), 2.21 (s, 3H, Me),
2.37 (s, 3H, Me), 3.01 (d, J = 13.2 Hz, 1H, CH2),
7.05 (m, 6H, ArH). The proposed structure was con-
firmed by COSY, gs-HSQC and gs-HMBC NMR. λmax
(CD2Cl2) 334 (4.4). Anal. Calcd. for C30H38ClIrN2:
C, 55.07; H, 5.85; N, 4.28; Cl, 5.42. Found: C, 54.80;
H, 5.88; N, 4.34; Cl, 3.10. EI MS m/z: 654 (M+,
22.3%).
6 and 7 were made by entirely analogous procedures
to that of 5.
4.3. Protonation of 8 with HCl to yield 5
4.2.6. Cp∗IrClCH2C(=NH(2, 6-iPr2C6H3))CMe=N
(2,6-iPr2C6H3)+Cl− (6)
The addition of one equiv of HCl (1.0 M in ether)
to a solution of 8 (5 mg in 0.5 ml CD2Cl2 in an NMR
tube) caused the clear brown solution to turn dark red.
Yield, 60%. 1H NMR (300 MHz, CD2Cl2) δ 1.09 (4
overlapping d, 1∗2H, CHMe2), 1.27 (d, 12H, CHMe2),
1
The H NMR spectrum of the only observed prod-
uct was identical to the spectrum of 5, except that the
N-bonded proton seen at δ 14.77 in 5 now appeared
at δ 14.2. The chemical shift of this proton has been
observed to change its position somewhat from sam-
ple to sample, an effect that is attributed to the pres-
ence of residual water or other impurities capable of
interacting with this proton via hydrogen bonding.
=
1.37 (s, 15H, Cp ), 2.30 (s, 3H, N CMe), 2.28 (septet,
1H, CHMe2), 2.60 (d, J = 9.7 Hz, 1H, CH2), 2.78
(septet, 1H, CHMe2), 3.45 (septet, 1H, CHMe2), 3.72
(septet, 1H, CHMe2), 3.82 (d, J = 9.7 Hz, 1H, CH2),
7.34 (m, 6H, ArH). λmax (CD2Cl2): 335 (3.8). EI MS
m/z: 765.9 (M+-HCl–H, 0.4%), 731.1 (M+-HCl–Cl,
0.4%), 730.1 (M+-2HCl), 2.4%).
4.4. Alternative synthesis of 5 and 8
4.2.7. Cp∗IrClCH2C(=NH(2, 4, 6-Me3C6H3))
CMe=N(2,4,6-Me3C6H3)+Cl− (7)
Yield, 83%. 1H NMR (200 MHz, CDCl3) δ 1.33 (s,
15H, Cp∗), 1.87 (s, 3H, Me), 2.23 (s, 6H, 2 Me),2.28
(s, 3H, Me), 2.32 (s, 3H, Me), 2.35 (s, 3H, Me), 2.53
(d, J = 10.3 Hz, 1H, CH2), 2.60 (s, 3H, Me), 3.85
(d, J = 10.3 Hz, 1H, CH2), 6.93 (2 br dd, 4H, ArH).
λmax (CD2Cl2) 294 (5.6), 340 (6.0), 445 (5.6). Anal.
Calcd. for C32H43Cl2IrN2: C, 53.47; H, 6.03; N, 3.90;
Cl, 9.86. Found: C, 53.01; H, 5.94; N, 3.85; Cl, 9.90.
EI MS m/z: 683.1 (M+-Cl, 5.6%).
DMSO (0.085 ml, 1.197 mmol) was added to a so-
lution of [Cp∗IrCl2]2 (68 mg, 0.085 mmol) in THF
(15 ml) [55]. This resulted in an immediate color
change from orange to bright yellow. The solu-
tion was filtered and the volatiles were removed in
vacuo. The intermediate Cp∗Ir(dmso)Cl2 (52 mg,
0.11 mmol, 64%) was extracted from the crude mix-
ture by extraction with ether. 1H NMR (200 MHz,
CDCl3) δ 1.72 (s, 15H, Cp∗), 3.21 (s, 6H, Me2SO).
Synthesis of the cyclometalated compound 5 was
achieved by treating a solution of Cp∗Ir(dmso)Cl2
(52 mg, 0.11 mmol) in methanol (5 ml) with the di-
4.2.8. Cp∗IrClCH2C(=N(2, 6-Me2C6H3))CMe=N
(2,6-Me2C6H3) (8)
=
=
Triethylamine (20 l, 0.15 mmol) was added to a
solution of 5 (109 mg, 0.16 mmol) in THF (5 ml) in a
round-bottom flask. After 10 min of stirring, the solu-
tion was filtered and evaporated to dryness. The brown
powder was dissolved in dichloromethane and residual
triethylamine was extracted with water (5 ml) acidi-
fied with a drop of 10% aqueous HCl. Removal of the
imine (2,6-Me2C6H3)N CMeCMe N(2,6-Me2C6H3)
(35 mg, 0.12 mmol). The reaction mixture was stirred
for 21 h during which a dark red color developed.
The volume was reduced to 2 ml by vacuum trans-
fer. Analysis of an aliquot by 1H NMR showed
that 5 had indeed formed. However, since 5 under-
goes facile decomposition at the concentrations of