Niobocene Imido Complexes
Organometallics, Vol. 20, No. 14, 2001 3137
1
mull): νNbdN 1265 cm-1; νCtC 2100 cm-1. H NMR (200 MHz,
C6D6): δ 0.26 (s, 18H, C5H4SiMe3), 5.69 (2H), 5.86 (2H), 6.17
(2H), 6.23 (2H) (m, C5H4), 6.63 (2H), 6.69 (2H), 7.12 (1H) (m,
NPh), 7.03 (1H), 7.19 (2H), 7.68 (2H) (m, CtCPh). 13C{1H}
NMR (300 MHz, C6D6): δ 0.3 (C5H4SiMe3), 109.7, 110.7, 115.5,
Ta ble 4. Cr ysta l Da ta a n d Str u ctu r e Refin em en t
for 9
formula
fw
C30H36NNbSi2
559.69
T (K)
293(2)
115.8 (Cipso), 118.0 (C5H4), 120.9, 126.5, 128.5, 160.0 (Cipso
)
cryst syst
space group
a (Å)
b (Å)
c (Å)
triclinic
P1h
10.415(1)
10.858(1)
13.604(1)
101.90(1)
97.95(1)
94.85(1)
1480.7(2)
2
1.255
0.505
584
(NPh), 126.9, 128.6, 131.1, 132.7 (Cipso) (CtCPh), 107.4 (Ct
CNb), 129.2 (CtCNb), Anal. Calcd for C30H36NNbSi2: C, 64.38;
H, 6.48; N, 2.50. Found: C, 64.68; H, 6.52; N, 2.40.
[Nb(dNP h )(η5-C5H4SiMe3)2(CtCBu t)] (10). The synthesis
of 10 was carried out in a manner identical to that of 2. Mg-
(CtCBut)2 (0.09 g, 0.48 mmol) and [Nb(dNPh)(η5-C5H4SiMe3)2-
Cl] (0.46 g, 0.93 mmol) were used. Yield: 0.44 g, 88%. IR (Nujol
R (deg)
â (deg)
γ (deg)
V (Å3)
Z
1
mull): νNbdN 1280 cm-1; νCtC 2080 cm-1. H NMR (200 MHz,
Dc (g cm-3
)
C6D6): δ 0.27 (s, 18H, C5H4SiMe3), 1.45 (s, 9H, C(CH3)3), 5.67
(2H), 5.81 (2H), 6.17 (2H), 6.28 (2H) (m, C5H4), 6.61 (2H), 6.69
(2H), 7.13 (1H) (m, NPh). 13C{1H} NMR (300 MHz, C6D6): δ
0.4 (C5H4SiMe3), 29.7 (C(CH3)3), 32.2 (C(CH3)3), 110.0, 110.3,
115.5 (Cipso), 118.1, 121.5 (C5H4), 120.7, 127.0, 128.5, 160.0
(Cipso) (NPh), 114.9 (CtCNb), 134.7 (CtCNb), Anal. Calcd for
µ (mm-1
F(000)
)
cryst dimens (mm)
θ range (deg)
hkl ranges
0.2 × 0.3 × 0.3
2.19 to 28.00
-13 e h e 13, -14 e k e 14,
0 e l e 17
7433
7137
C
28H40NNbSi2: C, 62.31; H, 7.47; N, 2.60. Found: C, 62.09;
no. of rflns measd
no. of indep rflns
H, 7.38; N, 2.56.
[Nb(dNC6H4Me-4)(η5-C5H4SiMe3)2(CtCSiMe3)] (11). The
synthesis of 11 was carried out in a manner identical to that
of 2. Mg(CtCSiMe3)2 (0.11 g, 0.50 mmol) and [Nb(dNC6H4-
Me-4)(η5-C5H4SiMe3)2Cl] (0.50 g, 0.98 mmol) were used.
Yield: 0.43 g, 77%. IR (Nujol mull): νNbdN 1280 cm-1; νCtC 2090
no. of obsd rflns
3635
1.022
goodness-of-fit on F2
final R indices [I>2σ(I)]a
largest diff peak and hole (e Å-3
R1 ) 0.0642, wR2 ) 0.1510
0.612/-0.672
)
R1 ) ∑||Fo| - |Fc||/∑|Fo|; wR2 ) [∑[w(Fo2 - Fc2)2]/∑[w(Fo2)2]]0.5
.
a
1
cm-1. H NMR (200 MHz, C6D6): δ 0.25 (s, 18H, C5H4SiMe3),
0.39 (s, 9H, CtCSiMe3), 2.08 (s, 3H, NC6H4CH3), 5.65 (2H),
5.77 (2H), 6.12 (2H), 6.21 (2H) (m, C5H4), 6.52 (2H), 6.89 (2H)
(d, NC6H4CH3) (J 8.3 Hz). 13C{1H} NMR (300 MHz, C6D6): δ
0.4 (C5H4SiMe3), 1.1 (CtCSiMe3), 20.9 (NC6H4CH3), 109.8,
110.9, 115.2, 117.5 (Cipso), 118.1 (C5H4), 108.4 (CtCNb), 128.3
(CtCNb), 121.1, 129.0, 130.2 (Cipso) 157.9 (Cipso) (NC6H4CH3).
Anal. Calcd for C28H42NNbSi3: C, 59.02; H, 7.43; N, 2.46.
Found: C, 58.79; H, 7.30; N, 2.50.
(2H), 6.27 (2H) (m, C5H4), 6.56 (2H), 6.71 (2H) (d, NC6H4OCH3)
(J 9.0 Hz). 13C{1H} NMR (300 MHz, C6D6): δ 0.5 (SiMe3), 54.9
(NC6H4OCH3), 32.2 (C(CH3)3), 34.1 (C(CH3)3), 110.0, 111.2,
113.8, 114.0 (Cipso), 115.7 (C5H4), 108.5 (CtCNb), 127.8 (Ct
CNb), 119.8, 121.3, 128.3 (Cipso) 154.9 (Cipso) (NC6H4OCH3).
Anal. Calcd for C29H42NNbOSi2: C, 61.14; H, 7.43; N, 2.46.
Found: C, 60.88; H, 7.38; N, 2.45.
[Nb(dNC6H4Me-4)(η5-C5H4SiMe3)2(CtCBu t )] (12). The
synthesis of 12 was carried out in a manner identical to that
of 2. Mg(CtCBut)2 (0.09 g, 0.48 mmol) and [Nb(dNC6H4Me-
4)(η5-C5H4SiMe3)2Cl] (0.46 g, 0.91 mmol) were used. Yield: 0.36
[Nb(dNBu t){Me2Si(η5-C5H4)2}(CtCSiMe3)] (15). The syn-
thesis of 15 was carried out in a manner identical to that of 2.
Mg(CtCSiMe3)2 (0.11 g, 0.50 mmol) and [Nb(dNBut){Me2Si-
(η5-C5H4)2}Cl] (0.38 g, 0.98 mmol) were used. Yield: 0.32 g,
1
g, 72%. IR (Nujol mull): νNbdN 1290 cm-1; νCtC 2100 cm-1. H
73%. IR (Nujol mull): νNbdN 1235 cm-1; νCtC 2050 cm-1 1H
.
NMR (200 MHz, C6D6): δ 0.25 (s, 18H, SiMe3), 1.43 (s, 9H,
C(CH3)3), 2.10 (s, 3H, NC6H4CH3), 5.68 (2H), 5.80 (2H), 6.16
(2H), 6.28 (2H) (m, C5H4), 6.55 (2H), 6.91 (2H) (d, NC6H4CH3)
(J 8.1 Hz). 13C{1H} NMR (300 MHz, C6D6): δ 0.2 (SiMe3), 20.8
(NC6H4CH3), 32.1 (C(CH3)3), 35.4 (C(CH3)3), 110.6, 114.0 (Cipso),
115.4, 118.2, 118.4 (C5H4), 108.3 (CtCNb), 127.0 (CtCNb),
121.4, 128.8, 129.8 (Cipso) 157.9 (Cipso) (NC6H4CH3). Anal. Calcd
for C29H42NNbSi2: C, 62.90; H, 7.64; N, 2.53. Found: C, 62.74;
H, 7.55; N, 2.46.
NMR (200 MHz, C6D6): δ -0.05 (3H), 0.22 (3H) (s, SiMe2),
0.39 (s, 9H, SiMe3), 0.96 (s, 9H, C(CH3)3), 5.91 (2H), 5.95 (2H),
6.36 (2H), 6.63 (2H) (m, C5H4). 13C{1H} NMR (300 MHz,
C6D6): δ -6.7, -5.4 (SiMe2), 1.4 (SiMe3), 30.6 (C(CH3)3), 68.0
(C(CH3)3), 101.5, 113.4, 114.4, 114.5, 125.6 (Cipso) (C5H4), 107.1
(CtCNb), 128.4 (CtCNb). Anal. Calcd for C21H32NNbSi2: C,
56.36; H, 7.21; N, 3.13. Found: C, 56.17; H, 7.12; N, 3.15.
[Nb(dNBu t){Me2Si(η5-C5H4)2}(CtCBu t)] (16). The syn-
thesis of 16 was carried out in a manner identical to that of 2.
Mg(CtCBut)2 (0.10 g, 0.54 mmol) and [Nb(dNBut){Me2Si(η5-
C5H4)2}Cl] (0.40 g, 1.04 mmol) were used. Yield: 0.30 g, 67%.
[Nb (dNC6H 4OMe-4)(η5-C5H 4SiMe3)2(CtCSiMe3)] (13).
The synthesis of 13 was carried out in a manner identical to
that of 2. Mg(CtCSiMe3)2 (0.10 g, 0.46 mmol) and [Nb(d
NC6H4OMe-4)(η5-C5H4SiMe3)2Cl] (0.46 g, 0.88 mmol) were
IR (Nujol mull): νNbdN 1255 cm-1; νCtC 2080 cm-1 1H NMR
.
(200 MHz, C6D6): δ 0.01 (3H), 0.28 (3H) (s, SiMe2), 0.98 (s,
9H, NC(CH3)3), 1.45 (s, 9H, CC(CH3)3), 5.91 (2H), 6.00 (2H),
6.40 (2H), 6.62 (2H) (m, C5H4). 13C{1H} NMR (300 MHz,
C6D6): δ -6.5, -5.3 (SiMe2), 29.1 (CC(CH3)3), 30.7, 32.5
(C(CH3)3), 72.6 (NC(CH3)3), 101.0, 114.0, 114.3, 114.5, 116.2
(Cipso) (C5H4), 125.5 (CtCNb), 128.9 (CtCNb). Anal. Calcd for
C22H32NNbSi: C, 61.24; H, 7.47; N, 3.25. Found: C, 61.00; H,
7.36; N, 3.22.
used. Yield: 0.35 g, 69%. IR (Nujol mull): νNbdN 1275 cm-1
;
νCtC 2110 cm-1 1H NMR (200 MHz, C6D6): δ 0.26 (s, 18H,
.
SiMe3), 0.39 (s, 9H, SiMe3), 3.23 (s, 3H, NC6H4OCH3), 5.71
(2H), 5.77 (2H), 6.11 (2H), 6.21 (2H) (m, C5H4), 6.54 (2H), 6.69
(2H) (d, NC6H4OCH3) (J 9.0 Hz). 13C{1H} NMR (300 MHz,
C6D6): δ 0.4 (C5H4SiMe3), 1.1 (CtCSiMe3), 54.8 (OCH3), 109.7,
111.3, 113.7, 113.8 (Cipso), 115.4 (C5H4), 108.4 (CtCNb), 129.2
(CtCNb), 119.5, 120.8, 154.3 (Cipso) 155.0 (Cipso) (NC6H4OCH3).
Anal. Calcd for C28H42NNbOSi3: C, 57.41; H, 7.23; N, 2.39.
Found: C, 57.16; H, 7.13; N, 2.41.
[Nb(NHBu t)(η5-C5H5)2(CtCSiMe3)][CF 3COO] (17). CF3-
COOH (0.08 g, 0.69 mmol) was added to a solution of 2 (0.27
g, 0.69 mmol) in Et2O (50 mL) at 0 °C. A red precipitate was
formed, which was isolated by filtration and washed with Et2O.
Drying under vacuum gave a red crystalline solid (0.30 g, yield
[Nb(dNC6H4OMe-4)(η5-C5H4SiMe3)2(CtCBu t)] (14). The
synthesis of 14 was carried out in a manner identical to that
of 2. Mg(CtCBut)2 (0.09 g, 0.48 mmol) and [Nb(dNC6H4OMe-
4)(η5-C5H4SiMe3)2Cl] (0.50 g, 0.95 mmol) were used. Yield: 0.37
86%). IR (Nujol mull): νCtC 2090 cm-1; νN-H 3100 cm-1 1H
.
NMR (200 MHz, d6-acetone): δ 0.18 (s, 9H, SiMe3), 1.46 (s,
9H, C(CH3)3), 6.32 (s, 10H, C5H5), 8.55 (br, 1H, NH). Anal.
1
g, 69%. IR (Nujol mull): νNbdN 1285 cm-1; νCtC 2080 cm-1. H
NMR (200 MHz, C6D6): δ 0.26 (s, 18H, SiMe3), 1.44 (s, 9H,
C(CH3)3), 3.25 (s, 3H, NC6H4OCH3), 5.74 (2H), 5.81 (2H), 6.16
Calcd for
Found: C, 49.62; H, 5.64; N, 2.69.
C21H29F3NNbO2Si: C, 49.90; H, 5.78; N, 2.77.