pressure to afford a red oil which was extracted in pentane
(3 × 20 cm3). On standing overnight a grey precipitate formed,
presumably of MgCl2, so the volatiles were again removed
under reduced pressure and the oil extracted a second time into
pentane. Removal of this pentane afforded the compound as a
red oil. Yield 0.683 g (84%). Accurate analytical data were not
second crop of smaller crystals separated from the washings
overnight. Yield 215 mg (75%) (Found: C, 29.2; H, 4.85; Cl,
17.45; N, 6.95. C10H20Cl2N2NbO3P requires C, 29.2; H, 4.9;
1
Cl, 17.2; N, 6.8%). NMR (CD2Cl2): H (300 MHz), all peaks
were broad, δ 6.22 (s, 5 H, C5H5), 3.78 [d, 9 H, JPH = 10 Hz,
P(OCH3)3] and 3.05 [s, 6 H, NN(CH3)2]; 13C-{1H} (125.7 MHz),
δ 108.61 (br, C5H5), 45.76 [NN(CH3)2], P(OCH3)3 resonance
obscured under the CD2Cl2 resonances; 31P-{1H} (202.34
MHz), δ 222 [br, P(OMe)3]. Mass spectrum: m/z 413 (Mϩ, 4),
287 [M Ϫ P(OMe)3, 4], 229 [M Ϫ P(OMe)3 Ϫ NNMe2, 34], 124
[P(OMe)3, 25], 109 [PO(OMe)2, 39], 93 [P(OMe)2, 66], 62
(POMe, 9) and 15 (Me, 100%).
1
obtained. NMR (CD2Cl2): H (300 MHz), δ 7.32 (m, C6H5),
7.25 (m, C6H5), 7.12 (m, C6H5), 5.70 (s, 5 H, C5H5), 2.73 [s, 6 H,
NN(CH3)2], 2.42 [d, 2 H, JH H = 11.4, CH2], 1.45 [s, 6 H,
C(CH3)2], 1.42 [s, 6 H, C(CH3)2] and Ϫ0.15 (d, 2 H, JH H = 11.4
Hz, CH2); 13C-{1H} (75.5 MHz), δ 154.0 (C6H5, quaternary),
127.8 (C6H5), 125.7 (C6H5), 124.9 (C6H5), 105.6 (C5H5), 81.7 (br,
CH2), 48.2 [NN(CH3)2], 41.8 [C(CH3)2] and 33.4 [C(CH3)2].
Mass spectrum: m/z 485 (Mϩ, 0.5), 351 (M Ϫ CH2CMe2Ph, 1)
and 120 (CMe2Ph, 100%).
cis-Dichloro(ç-cyclopentadienyl)(2,2-dimethylhydrazido)-
(trimethylphosphine)niobium 12 and trans-chloro(ç-cyclopenta-
dienyl)(2,2-dimethylhydrazido)bis(trimethylphosphine)niobium
chloride 13. The compound [Nb(η-C5H5)Cl2(NNMe2)] (0.10 g,
0.34 mmol) was dissolved in toluene (20 cm3) and the solution
was filtered into one side of a thick walled glass H-cell which
had a sinter-glass frit dividing the two sides of the cell. The
apparatus was then evacuated and PMe3 (3 cm3) was condensed
into the other side of the H-cell. Nitrogen gas was admitted,
the apparatus was sealed and allowed to warm to room tem-
perature. Yellow crystals of compounds 12 and 13 formed and
were filtered off, washed in toluene and dried in vacuo. Yield
96 mg (72%, based on the assumption the composition is
1ؒ1.2PMe3) (Found: C, 34.95; H, 6.75; Cl, 16.9; N, 6.3.
1ؒ1.8PMe3, that is a 2:3 mixture of compounds 12 and 13,
requires C, 35.15; H, 6.45; Cl, 16.75; N, 6.6%). The NMR
assignments were confirmed by a C᎐H correlation experiment.
Compound 12: NMR (CD2Cl2), 1H (300 MHz), δ 6.05 (d,
3JPH = 3, 5 H, C5H5), 3.02 [d, 6 H, 5JH H = 1, NN(CH3)2], 1.53 [d,
2JPH = 9, 9 H, P(CH3)3]; 13C-{1H} (125.7 MHz), δ 107.5 (C5H5),
(2,2-Dimethylhydrazido)(ç-methylcyclopentadienyl)bis(2-
methyl-2-phenylpropyl)niobium 9. The compound Mg(CH2-
CMe2Ph)Cl (2.5 cm3 of a 1.33 mol dmϪ3 solution in thf, 3.3
mmol) was added with stirring at room temperature to a solu-
tion of [Nb(η-C5H4Me)Cl2(NNMe2)] (0.400 g, 1.33 mmol) in
thf (40 cm3). The solution rapidly became pale orange and was
stirred for 11 d. The volatiles were removed under reduced pres-
sure to afford a red oil which was dissolved in pentane to ensure
complete precipitation of MgCl2. After filtration the volatiles
were again removed under reduced pressure and the oil
extracted into pentane (3 × 20 cm3). Removal of this pentane
afforded the required compound as a red oil. Yield 0.58 g (88%)
(Found: C, 64.7; H, 7.55; N, 4.55. C28H39N2Nb requires C,
1
67.85; H, 7.75; N, 5.65%). NMR (CD2Cl2): H (300 MHz), δ
7.31 (m, C6H5), 7.22 (m, C6H5), 7.08 (m, C6H5), 5.50 (vt, 2 H,
C5H4CH3), 5.41 (vt, 2 H, C5H4CH3), 2.72 [s, 6 H, NN(CH3)2],
2.31 (d, 2 H, JH H = 9, CH2), 2.02 (s, 3 H, C5H4CH3), 1.45 [s, 6 H,
C(CH3)2], 1.40 [s, 6 H, C(CH3)2] and Ϫ0.15 (d, 2 H, JH H = 9 Hz,
CH2); 13C-{1H} (75.5 MHz), δ 154.1 (C6H5, quaternary), 127.8
(C6H5), 125.7 (C6H5), 124.9 (C6H5), 107.9 (C5H4CH3), 101.9
(C5H4CH3), 82.3 (br, CH2), 48.24 [NN(CH3)2], 41.7 [C(CH3)2],
33.3 [C(CH3)2] and 14.4 (C5H4CH3). Mass spectrum: m/z 497
(Mϩ, 2), 365 (M Ϫ CH2CMe2Ph, 4) and 120 (CMe2Ph, 48%).
IR: νmax/cmϪ1 2829, 1586, 1405 and 1224.
1
46.1 [NN(CH3)2] and 14.8 [d, JPC = 26 Hz, P(CH3)3]; 31P-{1H}
(202.34 MHz), δ 10.1. Compound 13: 1H, δ 6.09 (t, 3JPH = 2.1, 5
H, C5H5), 3.16 [t, 3JPH = 1.2, 6 H, NN(CH3)2], 1.56 [t, 2JPH = 4.5,
18 H, P(CH3)3]; 13C-{1H}, δ 105.0 (C5H5), 46.6 [NN(CH3)2]
and 15.09 [vt, JPC ≈ 3JPC = 12.5 Hz, P(CH3)3]; 31P-{1H}, δ 3.3.
1
Mass spectrum: m/z 364 (Mϩ, 2), 288 (M Ϫ PMe3, 13), 229
(M Ϫ PMe3 Ϫ NNMe2, 34), 76 (PMe3, 99) and 61 (PMe2,
100%).
(ç-Cyclopentadienyl)(2,2-dimethylhydrazido)bis(trimethyl-
silylmethyl)niobium 10. The compound Li(CH2SiMe3) (1.4 cm3
of a 1 mol dmϪ3 solution in pentane, 1.4 mmol) was added with
stirring at room temperature to a solution of [Nb(η-C5H5)-
Cl2(NNMe2)] (0.197 g, 0.68 mmol) in thf (20 cm3). The solution
was stirred for 1 h and the volatiles were then removed under
reduced pressure to afford a red oil which was extracted in
pentane (3 × 10 cm3). Removal of this pentane afforded a red
cis-Dichloro(ç-methylcyclopentadienyl)(2,2-dimethyl-
hydrazido)(trimethylphosphine)niobium 14 and trans-chloro-
(ç-methylcyclopentadienyl)(2,2-dimethylhydrazido)bis(trimethyl-
phosphine)niobium chloride 15a. Compounds 14 and 15a were
prepared in an analogous fashion to 12 and 13 using [Nb-
(η-C5H4Me)Cl2(NNMe2)] (0.54 g, 1.8 mmol). Yield 270 mg
(39%, based on the composition 2ؒ1.1PMe3) (Found: C, 35.35;
H, 6.2; Cl, 18.8; N, 7.55. 2ؒ1.1PMe3, that is a 9:1 mixture of
compounds 14 and 15a, requires C, 35.3; H, 6.0; Cl, 18.45;
N, 7.3%). The NMR assignments were confirmed by a C᎐H
correlation experiment. Compound 14: NMR (CD2Cl2), 1H
(500 MHz), δ 6.20 (m, 1 H, C5H4CH3), 5.95 (m, 1 H, C5H4CH3),
1
oil which was pure by H and 13C-{1H} NMR spectroscopy.
Yield 0.240 g (89%). Analytical data were not obtained. NMR
1
(CD2Cl2): H (300 MHz), δ 6.07 (s, 5 H, C5H5), 2.77 [s, 6 H,
NN(CH3)2], 1.22 (d, 2 H, JH H = 9.8, CH2), 0.02 [s, 18 H,
Si(CH3)3] and Ϫ0.13 (d, 2 H, JH H = 9.8 Hz, CH2); 13C-{1H}
(75.5 MHz), δ 105.9 (C5H5), 50.3 (br, CH2), 48.6 [NN(CH3)2]
and 2.3 [Si(CH3)3]. Mass spectrum: m/z 391 (Mϩ, 13), 376
(M Ϫ Me, 1), 304 (M Ϫ CH2SiMe3, 1), 158 (C5H5Nb, 23) and
73 (SiMe3, 100%).
5.78 (m, 1 H, C5H4CH3), 5.60 (m, 1 H, C5H4CH3), 3.05 [d, 5JPH
=
=
2
0.1, 6 H, N(CH3)2], 2.25 (s, 3 H, C5H4CH3) and 1.51 [d, JPH
9.2 Hz, 9 H, P(CH3)3]; 13C-{1H} (125.7 MHz), δ 111.8 (C5H4-
CH3), 110.5 (C5H4CH3), 101.7 (C5H4CH3), 98.6 (C5H4CH3),
46.6 [N(CH3)2], 15.0 [P(CH3)3] and 14.2 (C5H4CH3); 31P-{1H}
(202.34 MHz), δ 4.8. Compound 15: NMR, 1H, δ 5.86 (m, 2 H,
cis-Dichloro(ç-cyclopentadienyl)(2,2-dimethylhydrazido)-
(trimethyl phosphite)niobium 11. The compound [Nb(η-C5H5)-
Cl2(NNMe2)] (0.200 g, 0.69 mmol) was dissolved in toluene (20
cm3) and placed in one arm of a thick walled glass H-cell which
had a sinter-glass frit dividing the two halves of the cell. A
mixture of P(OMe)3 (ca. 2 cm3) and toluene (10 cm3) was intro-
duced into the other side and cooled to Ϫ78 ЊC. The whole
apparatus was then left under nitrogen to warm up overnight,
during which time large deep ruby red crystals formed. The
supernatant liquid was decanted and the solid washed in a
toluene–P(OMe)3 mixture. The solid was then dried in vacuo. A
C5H4CH3), 5.65 (m, 2 H, C5H4CH3), 3.20 [s, 6 H, N(CH3)2], 2.02
2
(s,
3
H, C5H4CH3), 1.59 [vt, JPH ≈ 4JPH = 4.5, 18 H,
2 × P(CH3)3]; 13C-{1H}, δ 110.2 (C5H4CH3), 96.0 (C5H4CH3),
1
46.1 [N(CH3)2], 14.7 [vt, JPC ≈ 3JPC = 13.5 Hz, P(CH3)3] and
15.2 (C5H4CH3); 31P-{1H}, δ Ϫ0.1. Mass spectrum: m/z 301
(Mϩ Ϫ PMe3, 58), 243 (M Ϫ PMe3 Ϫ NNMe2, 100), 76 (PMe3,
41) and 61 (PMe2, 59).
trans-Chloro(2,2-dimethylhydrazido)(ç-methylcyclopenta-
dienyl)bis(trimethylphosphine)niobium
hexafluorophosphate
15b. A mixture of [Nb(η-C5H4Me)Cl(NNMe2)(PMe3)2]Cl and
1286
J. Chem. Soc., Dalton Trans., 1997, Pages 1281–1288
Green, Malcolm L. H.
