M. J. Calhorda, C. A. Gamelas, C. C. Roma˜o, L. F. Veiros
FULL PAPER
and washed with CH2Cl2. Ϫ C15H12Br2MoO (464.01): calcd. C 4 H, H5Ϫ8), 6.09 (m, 2 H, H1/3), 5.48 (t, 1 H, H2), 5.17 (t, 5 H, Cp,
38.82, H 2.61; found C 38.75, H 2.12. Ϫ Selected IR (KBr): ν˜ ϭ
[3JPH ϭ 2.1 Hz]), 1.66Ϫ1.62 (t, 18 H, CH3).
1
3077, 2045 (sv, CO), 1539, 1413, 946, 856, 760 cmϪ1. Ϫ H NMR
Preparation of Complexes [(η3-Ind)CpMoL2] (5؊9): A suspension
of [IndCpMo(L)Br]Br (L ϭ 5, CO; 6 to 9, NCMe) in toluene (or
NCMe) was treated with a solution of Cp2Co (2 equiv.) in the same
solvent at 0°C. Addition of the ligand (1 or 2 mol) caused an im-
mediate change and after 2 h stirring at room temperature the solu-
tion was separated from [Cp2Co]Br by filtration. The solvent was
removed under vacuum and the residue extracted with Et2O (3 ϫ
30 mL). The product, which separated upon concentration and
cooling of the extract, was identified by comparison of its IR and
1H-NMR spectra with those of an authentic sample.[1,2,11]
([D6]acetone, 300 MHz, room temp.): δ ϭ 7.95 (m, 1 H, H5Ϫ8), 7.74
(m, 2 H, H5Ϫ8), 7.57 (m, 1 H, H5Ϫ8), 7.12 (m, 1 H, H1Ϫ3), 6.65 (t,
1 H, H1Ϫ3), 6.45 (m, 1 H, H1Ϫ3), 6.34 (s, 5 H, Cp).
Preparation of [IndCpMo(NCMe)Br]Br (2):
A solution of
[IndCpMo(CO)Br]Br (0.07 g, 0.15 mmol) in NCMe was refluxed
and irradiated with a 60 Watt tungsten bulb for 5 h. The solution
was evaporated to dryness and the residue efficiently extracted with
CH2Cl2. The purple powder was obtained in 90% yield upon evap-
oration of the solvent. The product was purified by recrystallization
from CH2Cl2/Et2O. Ϫ C16H15Br2MoN (477.05): calcd. C 40.28, H
3.17, N 2.94; found C 40.48, H 3.49, N 3.32. Ϫ Selected IR (KBr):
Preparation of [(η3-Ind)CpMo(CO)2] (5): [IndCpMo(CO)Br]Br:
0.30 g, 0.65 mmol; Cp2Co: 0.24 g, 1.29 mmol. Light protection.
Purple microcrystalline complex (η3-Ind)CpMo(CO)2. Yield: 40%.
1
ν˜ ϭ 3100, 2317, 2278, 1427, 802, 758 cmϪ1. Ϫ H NMR (CD3CN,
300 MHz, room temp.): δ ϭ 7.35 [s (br), 4 H, H5Ϫ8], 5.98 (t, 1 H,
Preparation of [(η3-Ind)CpMo(dppe)] (6): [IndCpMo(NCMe)Br]Br:
0.20 g, 0.42 mmol; Cp2Co: 0.16 g, 0.84 mmol; dppe: 0.17 g,
0.42 mmol. Orange complex. Yield: 80%.
H2), 5.83 (d, 2 H, H1/3), 5.33 (s, 5 H, Cp), 2.12 (s, 3 H, CH3).
Preparation of [IndCpMo(CNCMe3)X]Y (3). ؊ Method (a): A solu-
tion of [IndCpMo(NCMe)Br]Br (0.11 g, 0.23 mmol) in CH2Cl2 was
treated with excess CNtBu (0.25 mL) and refluxed overnight. The
solution was evaporated to dryness to afford the grey complex
[IndCpMo(CNCMe3)Br]Br (3a) in 80% yield. This was recrys-
tallized from CH2Cl2/Et2O. Ϫ C28H39Br2MoN (645.38): calcd. C
52.11, H 6.09, N 2.17; found C 52.44, H 6.17, N 2.60. Ϫ Selected
Preparation of [(η3-Ind)CpMo(PMe3)2] (7). ؊ (a) [IndCpMo-
(NCMe)Br]Br: 0.21 g, 0.44 mmol; Cp2Co: 0.16 g, 0.87 mmol;
PMe3: 0.087 mL, 0.87 mmol. Orange complex. Yield, 90%. Ϫ (b)
[IndCpMo(NCMe)Br]Br: 0.21 g, 0.44 mmol; Cp2Co: 0.16 g,
0.87 mmol; PMe3: 0.044 mL, 0.44 mmol. Orange complex. Yield:
IR (KBr): ν
˜ ϭ 3102, 2982, 2191, 1449, 1373, 1194, 1084, 845, 764 45%.
cmϪ1. Ϫ 1H NMR (CD3CN, 300 MHz, room temp.): δ ϭ
7.69Ϫ7.67 (m, 1 H, H5Ϫ8), 7.56Ϫ7.54 (m, 2 H, H5Ϫ8), 7.47Ϫ7.43
(m, 1 H, H5Ϫ8), 6.02 (t, 1 H, H1Ϫ3), 5.92 (t, 1 H, H1Ϫ3), 5.75 [s
(br), 1 H, H1Ϫ3], 5.58 (s, 5 H, Cp), 1.60 (s, 9 H, CH3). Ϫ Method
(b): Treatment of a solution of [IndCpMo(NCMe)Cl]BF4 (0.18 g,
0.40 mmol) in CH2Cl2 with excess CNtBu (0.14 mL) at room tem-
perature led to an immediate color change from green to dark vi-
olet. After stirring for 4 h the reaction mixture was concentrated
to ca. 5 mL and Et2O was added and caused the precipitation of
the grey-violet complex [IndCpMo(CNCMe3)Cl]BF4 (3b), which
Preparation of [(η3-Ind)CpMo(P(OMe)3)2] (8). ؊ (a) [IndCpMo-
(NCMe)Br]Br: 0.359 g, 0.752 mmol; Cp2Co: 0.285 g, 1.504 mmol;
P(OMe)3: 2.5 mL, excess. Orange complex. Yield, 80%. Ϫ (b)
[IndCpMo(NCMe)Br]Br: 0.179 g, 0.374 mmol; Cp2Co: 0.142 g,
0.748 mmol; P(OMe)3: 44 µL, 0.374 mmol. Orange complex.
Yield: 40%.
Preparation of [(η3-Ind)CpMo(CNCMe3)2] (9). ؊ (a) [IndCpMo-
(NCMe)Br]Br: 0.27 g, 0.35 mmol; Cp2Co: 0.13 g, 0.70 mmol;
CNtBu: 0.10 mL, excess. Reaction solvent: NCMe. Orange com-
plex. Yield, 50%.
Ϫ
(b) [IndCpMo(NCMe)Br]Br: 0.27 g,
was recrystallized from CH2Cl2/Et2O in 85% yield.
Ϫ
0.35 mmol; Cp2Co: 0.13 g, 0.70 mmol; CNtBu: 0.039 mL,
0.35 mmol. Reaction solvent: NCMe. Orange complex. Yield, 30%.
C19H21BClF4MoN (481.58): calcd. C 47.39, H 4.40, N 2.91; found
C 47.48, H 4.25, N 3.41. Ϫ Selected IR (KBr): ν˜ ϭ 3095, 2982,
2193, 1449, 1373, 1194, 1084, 845, 764 cmϪ1. Ϫ 1H NMR ([D6]ace-
tone, 300 MHz, room temp.): δ ϭ 7.89 (d, 1 H, H5Ϫ8), 7.70Ϫ7.54
(m, 2 H, H5Ϫ8), 7.40 (d, 1 H, H5Ϫ8), 6.22 [s (br), 1 H, H1Ϫ3], 5.97
(s, 1 H, H1Ϫ3), 5.83 [s (br), 1 H, H1Ϫ3], 5.79 (s, 5 H, Cp), 1.68 (s,
9 H, CH3).
Preparation of [(η5-Ind)CpMo(η2-PhCCPh)] (10): A suspension of
[IndCpMo(NCMe)Br]Br (0.20 g, 0.42 mmol) in toluene was treated
with a solution of Cp2Co (0.16 g, 0.84 mmol) in the same solvent at
0°C. Addition of DPA (0.075 mL, 0.42 mmol) caused an immediate
change and after 2 h stirring at room temperature the solution was
separated from [Cp2Co]Br by filtration. The solvent was removed
under vacuum and the residue extracted with Et2O (3 ϫ 30 mL).
The garnet-like complex separated upon concentration and cooling
of the extract to give 80% yield. Ϫ C28H22Mo (454.43): calcd. C
74.01, H 4.88; found C 74.40, H 4.90. Ϫ Selected IR (KBr): ν˜ ϭ
3505, 3067, 1580, 1486, 1414, 1261, 824, 756 cmϪ1. Ϫ 1H NMR
(C6D6, 300 MHz, room temp.): δ ϭ 7.69 (d, Ph), 7.52Ϫ7.49 (m,
Ph), 7.32 (t, Ph), 6.99Ϫ6.97 (m, Ph), 6.93Ϫ6.90 (m, 2 H, H5Ϫ8),
6.75Ϫ6.72 (m, 2 H, H5Ϫ8), 5.53 (t, 1 H, H2), 4.21 (s, 5 H, Cp), 3.85
(d, 2 H, H1/3).
Preparation of [IndCpMo(P(OMe)3)Br]Br (4):
A solution of
[IndCpMo(NCMe)Br]Br (0.21 g, 0.43 mmol) in CH2Cl2 was
treated with excess P(OMe)3 (2.5 mL) and refluxed for 4 h. The
solution was evaporated to dryness to afford the complex in 80%
yield. The complex was recrystallized from CH2Cl2/Et2O. Ϫ
C17H21Br2MoO3P (560.08): calcd. C 36.46, H 3.78; found C 36.65,
H 3.49. Ϫ Selected IR (KBr): ν˜ ϭ 3082, 2942, 1425, 1541, 1134,
1042, 716 cmϪ1. Ϫ 1H NMR (CD2Cl2, 300 MHz, room temp.): δ ϭ
7.45 (d, 1 H, H5Ϫ8), 7.36Ϫ7.27 (m, 2 H, H5Ϫ8), 7.21 (d, 1 H, H5Ϫ8),
6.08 (m, 1 H, H1Ϫ3), 5.72 (d, 1 H, H1Ϫ3), 5.01 (t, 5 H, Cp), 4.50 [s
(br), 1 H, H1Ϫ3], 3.67 {d, 9 H, P(OMe)3, [JPH ϭ 9.0 Hz]}.
Attempted Ppreparation of [(η5-Ind)CpMoL] (11, 12) by Reduction
Attempted Preparation of [IndCpMo(PMe3)Br]Br: A solution of
of
[IndCpMo(L)Br]Br:
Treatment
of
a
solution
of
[IndCpMo(NCMe)Br]Br (0.20 g, 0.42 mmol) in CH2Cl2 was [IndCpMo(L)Br]Br [L ϭ P(OMe)3, CNCMe3] in NCMe with a
treated with excess PMe3 (0.15 mL) and stirred for 3 h at room
temperature. The pink precipitate of [IndCpMo(PMe3)2]Br2 was fil-
solution of Cp2Co (2 equiv.) in the same solvent, at 0°C, caused
an immediate change. After 2 h stirring at room temperature the
tered off and washed with CH2Cl2. Yield: 50%. Ϫ C20H30Br2MoP2 solvent was removed under vacuum and the residue extracted with
(588.16): calcd. C 39.91, H 5.02; found C 39.74, H 5.52. Ϫ Selected
toluene (3 ϫ 30 mL). Upon evaporation of the solvent and washing
IR (KBr): ν˜ ϭ 3366, 3092, 2912, 1423, 1300, 965, 845, 779 cmϪ1
.
of the residue with cold pentane, a mixture of two complexes, [(η3-
1
Ϫ H NMR (CD3CN, 300 MHz, room temp.): δ ϭ 7.72Ϫ7.68 (m, Ind)CpMoL2] and [(η5-Ind)CpMoL], was obtained. The previously
338
Eur. J. Inorg. Chem. 2000, 331Ϫ340