Tungsten Imido Amidinate and Guanidinate Complexes
Et2O at -30 °C. The mixture was warmed to room temperature
and stirred for 4 h. The resulting colorless solution was then added
to a solution of W(NC6H5)Cl4(OEt2) (1.80 g, 3.66 mmol) in 50
mL of Et2O at -30 °C. The reaction mixture was stirred overnight.
All volatiles were then removed under reduced pressure, and the
resulting solid was extracted with Et2O (100 mL). The Et2O extract
was dried in vacuo to yield pure 4 as a purple powder (1.25 g,
pure 7 as a pink powder (1.25 g, 62%). 1H NMR (300
MHz,C6D6): δ 0.21 (s, 9H, Si(CH3)3), 0.56 (s, 9H, Si(CH3)3), 1.32
(d, 6H, J ) 6 Hz, CH(CH3)3), 1.40 (s, 3H, N2CCH3), 5.23 (septet,
1H, CH(CH3)2). 13C NMR (C6D6): δ 1.4 (Si(CH3)3), 2.1 (Si(CH3)3),
23.6 (NCH(CH3)2), 26.8 (N2CCH3), 66.6 (NCH(CH3)2), 170.5
(N2CCH3). HRMS (EI): calcd for WC11H28N3Si2Cl3 [M]+ m/z
547.0397; found 547.0385.
1
W(NPh)Cl3[iPrNC(Me)NiPr] (8). Methyllithium (1.6 M in Et2O,
1.91 mL, 3.1 mmol) was added dropwise to a solution of
1,3-diisopropylcarbodiimide (0.48 mL, 2.9 mmol) in 100 mL of
Et2O at -30 °C. The mixture was warmed to room temperature
and stirred for 4 h. The resulting colorless solution was then added
to a solution of W(NC6H5)Cl4(OEt2) (1.50 g, 3.06 mmol) in 50
mL of Et2O at -30 °C. The reaction mixture was warmed to room
temperature and stirred overnight. The liquid portion of the mixture
was collected by filtration, and the solid residue was extracted with
Et2O (3 × 10 mL). The liquid portions were combined and dried
under vacuum to yield pure 8 as a purple crystalline solid (1.06 g,
62%). H NMR (300 MHz, C6D6): δ 1.21 (s, 9H, C(CH3)3), 1.58
(s, 3H, N2CCH3), 1.62 (s, 9H, C(CH3)3), 6.51 (t, 1H, J ) 8 Hz,
CH), 6.83 (t, 2H, J ) 8 Hz, CH), 7.31 (d, 2H, J ) 8 Hz, CH). 13
C
NMR (C6D6): δ 22.2 (N2CCH3), 31.4 (C(CH3)3), 32.1 (C(CH3)3),
59.9 (C(CH3)3), 63.4 (C(CH3)3), 130.0 (CH), 131.1 (CH), 173.1
(N2CCH3). There are two aromatic carbons that could not be
located because of overlap with other peaks. Anal. Calcd for
WC16H26N3Cl3: C, 34.90; H, 4.76; N, 7.63. Found: C, 35.39; H,
4.32; N, 7.36.
W(NiPr)Cl3[tBuNC(Me)NtBu] (5). Methyllithium (1.6 M in
Et2O, 1.64 mL, 2.6 mmol) was added dropwise to a solution of
1,3-di-tert-butylcarbodiimide (0.405 g, 2.62 mmol) in 100 mL of
Et2O at -30 °C. The mixture was warmed to room temperature
and stirred for 4 h. The resulting colorless solution was then added
to a solution of W(NCH(CH3)2)Cl4(OEt2) (1.20 g, 2.62 mmol) in
50 mL of Et2O at -30 °C. The reaction mixture was stirred
overnight in the absence of light. All volatiles were then removed
under reduced pressure, and the resulting solid was extracted with
Et2O (100 mL). The Et2O extract was dried in vacuo to give pure
5 as a purple powder (0.880 g, 65%). 1H NMR (300 MHz, C6D6):
δ 1.22 (s, 9H, C(CH3)3), 1.28 (d, 6H, J ) 6 Hz, CH(CH3)2), 1.56
(s, 3H, N2CCH3), 1.58 (s, 9H, C(CH3)3), 5.12 (septet, 1H,
WNCH(CH3)2). 13C NMR (C6D6): δ 22.1, 23.0, 31.4 (C(CH3)3),
32.0 (C(CH3)3), 67.1 (C(CH3)3), 68.4 (C(CH3)3), 88.9 (NCH(CH3)2),
167.1 (N2CCH3). IR (cm-1): 2922 (s), 2849 (s), 1585 (w), 1463
(m), 1376 (m), 1259 (m), 1186 (m), 1097 (w), 827 (w). UV-vis
[ether, λmax (ꢀ)]: 309 (4700), 478 nm (2100 M-1 cm-1). Anal. Calcd
for WC13H28N3Cl3: C, 30.23; H, 5.46; N, 8.13. Found: C, 29.99;
H, 5.68; N, 7.91.
W(NCy)Cl3[tBuNC(Me)NtBu] (6). A solution of methyllithium
(1.6 M in Et2O, 1.26 mL, 2.01 mmol) in Et2O was added dropwise
to a solution of 1,3-di-tert-butylcarbodiimide (0.310 g, 2.01 mmol)
in 100 mL of Et2O at -30 °C. The mixture was warmed to room
temperature and stirred for 4 h. The resulting colorless solution
was then added to a solution of W(NC6H11)Cl4(OEt2) (1.00 g, 2.01
mmol) in 50 mL of Et2O at -30 °C. The reaction mixture was
stirred overnight in the absence of light. All volatiles were then
removed under reduced pressure, and the resulting solid was
extracted with hexane (100 mL). The hexane extract was dried in
vacuo to yield pure 6 as a purple powder (0.65 g, 58%). 1H NMR
(300 MHz, C6D6): δ 0.28 (s, 3H, N2CCH3), 1.02 (br, 4H, CH2),
1.25 (s, 9H, C(CH3)3), 1.60 (s, 9H, C(CH3)3), 1.87 (br, 6H, CH2),
1.97 (s, 3H, N2CCH3), 5.22 (m, 1H, WNCH). 13C NMR (C6D6): δ
22.2, 24.3, 25.7, 31.4, 32.0, 33.4, 59.6 (C(CH3)3), 61.9 (C(CH3)3),
73.5 (WNCH), 172.7 (N2CCH3). Anal. Calcd for WC16H32N3Cl3:
C, 34.52; H, 5.79; N, 7.55. Found: 34.33; H, 5.53; N, 7.32.
W(NiPr)Cl3[Me3SiNC(Me)NSiMe3] (7). Methyllithium (1.6 M
in Et2O, 1.78 mL, 2.85 mmol) was added dropwise to a solution of
1,3-trimethylsilylcarbodiimide (0.531 g, 2.85 mmol) in 100 mL of
Et2O at -30 °C. The mixture was warmed to room temperature
and stirred for 4 h. The resulting colorless solution was then added
to a solution of W(NCH(CH3)2)Cl4(OEt2) (1.30 g, 2.85 mmol) in
50 mL of Et2O at -30 °C. The reaction mixture was stirred
overnight in the absence of light. All volatiles were then removed
under reduced pressure, and the resulting solid was extracted with
hexane (100 mL). The hexane extract was dried in vacuo to give
1
67%). H NMR (300 MHz, CDCl3): δ 1.49 (d, 6H, J ) 6 Hz,
CH(CH3)2), 1.51 (d, 6H, J ) 6 Hz, CH(CH3)2), 2.07 (s, 3H,
N2CCH3), 4.34 (septet, 1H, CH(CH3)2), 4.86 (septet, 1H, CH(CH3)2),
7.13 (t, 1H, J ) 8 Hz, CH), 7.45 (d, 2H, J ) 8 Hz, CH), 7.57 (t,
2H, J ) 8 Hz, CH). 13C NMR (CDCl3): δ 12.9 (N2CCH3), 22.4
(CH(CH3)2), 24.9 (CH(CH3)2), 52.1 (CH(CH3)2), 56.3 (CH(CH3)2),
128.2 (CH), 129.4 (CH), 131.2 (CH), 151.7 (Cipso), 172.1 (N2CCH3).
Anal. Calcd for WC14H26N3Cl3: C, 32.18; H, 4.24; N, 8.04.
Found: C, 32.46; H, 4.41; N, 7.86.
W(NiPr)Cl3[iPrNC(Me)NiPr] (9). Methyllithium (1.6 M in Et2O,
1.78 mL, 2.9 mmol) was added dropwise to a solution of
1,3-diisopropylcarbodiimide (0.45 mL, 2.9 mmol) in 100 mL of
Et2O at -30 °C. The mixture was warmed to room temperature
and stirred for 4 h. The resulting colorless solution was then added
to a solution of W(NCH(CH3)2)Cl4(OEt2) (1.30 g, 2.85 mmol) in
50 mL of Et2O at -30 °C. The reaction mixture was warmed to
room temperature and stirred overnight in the absence of light. The
liquid portion of the mixture was collected by filtration, and the
solid residue was extracted with Et2O (3 × 10 mL). The liquid
portions were combined and dried under vacuum to yield pure 9
1
as a purple crystalline solid (0.97 g, 70%). H NMR (300 MHz,
C6D6): δ 0.89 (s, 3H, N2CCH3) 1.23 (d, 6H, J ) 6 Hz, CH(CH3)2),
1.26 (d, 6H, J ) 7 Hz, WNCH(CH3)2), 1.60 (d, 6H, J ) 6 Hz,
CH(CH3)2), 3.71 (septet, 1H, CH(CH3)2), 4.00 (septet, 1H, CH(CH3)2),
5.24 (septet, 1H, WNCH(CH3)2). 13C NMR (C6D6): δ 11.4
(N2CCH3), 22.5, 23.1, 24.7, 51.9 (CH(CH3)2), 54.2 (CH(CH3)2),
67.0 (WNCH(CH3)2), 171.5 (N3C). IR (cm-1): 2924 (s), 2853 (s),
2724 (w), 1462 (s), 1377 (m), 1303 (w), 1213 (w), 722 (w). UV-
vis [ether, λmax (ꢀ)]: 307 (4100), 486 nm (1900 M-1 cm-1). Anal.
Calcd for WC11H28N3Cl3: C, 27.04; H, 4.95; N, 8.60. Found: C,
27.31; H, 4.77; N, 8.39.
W(NCy)Cl3[iPrNC(Me)NiPr] (10). Methyllithium (1.6 M in
Et2O, 1.59 mL, 2.5 mmol) was added dropwise to a solution of
1,3-diisopropylcarbodiimide (0.35 mL, 2.9 mmol) in 100 mL of
Et2O at -30 °C. The mixture was warmed to room temperature
and stirred for 4 h. The resulting colorless solution was then added
to a solution of W(NC6H11)Cl4(OEt2) (1.30 g, 2.54 mmol) in 50
mL of Et2O at -30 °C. The reaction mixture was warmed to room
temperature and stirred overnight in the absence of light. The liquid
portion of the mixture was collected by filtration, and the solid
residue was extracted with Et2O (3 × 10 mL). The liquid portions
were combined and dried under vacuum to give pure 10 as a purple
1
crystalline solid (0.86 g, 64%). H NMR (300 MHz, CDCl3): δ
1.55 (m, 16H, 4CH3 + 2CH2), 2.02 (s, 3H, N2CCH3), 2.05 (m,
6H, 3CH2), 4.23 (septet, 1H, CH(CH3)2), 4.77 (septet, 1H,
Inorganic Chemistry, Vol. 45, No. 1, 2006 265