Four-Coordinate Fe(II) and Mn(II) Alkyl Complexes
Organometallics, Vol. 23, No. 2, 2004 245
P r ep a r a t ion of [Ar NdC(Me)-(Me)CdNAr ]F e(CH2Si-
Me3)2 (6). A 100 mL round-bottomed flask was charged with
4.10 g (7.7 mmol) of 1 and 1.50 g (15.5 mmol) of LiCH2SiMe3.
A 180° needle valve was attached, and approximately 60 mL
of diethyl ether was added by vacuum transfer at -78 °C. The
reaction mixture was maintained at this temperature for 1 h,
and the diethyl ether was removed in vacuo. The purple
residue was transferred into the drybox and extracted with
pentane to afford 4.46 g (91%) of a purple solid identified as
6. Anal. Calcd for C36H62N2FeSi2: C, 68.10; H, 9.84; N, 4.41.
Found: C, 67.86; H, 9.57; N, 4.41. Magnetic susceptibility
as 10. Anal. Calcd for C29H40N2Fe: C, 73.72; H, 8.53; N, 5.93.
Found: C, 73.62; H, 8.07; N, 5.85. Magnetic susceptibility
(benzene-d6): µeff ) 4.59 µB. 1H NMR (benzene-d6): δ -147.96
(1019.38, 1H), -85.51 (559.09, 1H), -75.96 (583.40, 1H),
-73.66 (27.52, 1H), -57.68 (25.60, 1H), -49.61 (389.25, 1H),
-41.28 (212.29, 1H), -33.23 (95.66, 1H), -22.25 (73.69, 1H),
-21.27 (238.03, 1H), -14.81 (40.22, 1H), -12.20 (46.75, 1H),
-4.62 (36.11, 1H), 5.37 (19.53, 1H), 6.02 (25.46, 1H), 14.99
(14.23, 1H), 23.95 (19.25, 2H), 25.36 (92.17, 1H), 26.22 (77.78,
1H), 30.60 (22.06, 2H), 31.41 (29.11, 1H), 41.12 (56.27, 2H),
116.226 (129.843, 1H), 131.79 (841.68, 1H), 137.43 (701.40,
1H), 149.27 (625.18, 1H), 218.68 (130.49, 1H).
1
(benzene-d6): µeff ) 4.71 µB. H NMR (benzene-d6): δ -27.10
P r ep a r a tion of (S)-(tBu Box)F e(CH2SiMe3)2 (11). A pro-
cedure similar to that for 8 was used employing 0.200 g (0.476
mmol) of 3 and 0.090 g (0.957 mmol) of LiCH2SiMe3, yielding
0.221 g (88%) of yellow crystals identified as 11. Anal. Calcd
for C25H52N2O2Si2Fe: C, 57.23; H, 9.99; N, 5.34. Found: C,
56.95; H, 9.28; N, 5.45. Magnetic susceptibility (benzene-d6):
(111.41, 2H, p-C6H3), -0.69 (526.91, 12H, CHMe2), 1.17 (15.77,
4H), 2.72 (185.23, 12H, CHMe2), 14.17 (527.7, 18 H, CH2SiMe3),
two peaks not located.
P r ep a r a tion of [[Ar NdC(Me)-(Me)CdNAr ]F e(µ-Cl)]2
(7). A 50 mL round-bottomed flask was charged with 0.500 g
(0.940 mmol) of 1 and approximately 35 mL of diethyl ether.
The resulting slurry was chilled to -35 °C in the glovebox
freezer for approximately 15 min. Likewise, a scintillation vial
was charged with 0.060 g (0.94 mmol) of LiCH2CH(CH3)2 and
approximately 2 mL of diethyl ether and chilled to -35 °C.
With stirring, the LiCH2Si(CH3)2 solution was added to the
ethereal suspension of 1. The reaction was allowed to warm
to 25 °C and stirred for 45 min. The solution was filtered
through Celite and the solvent removed in vacuo to yield 0.180
g (19%) of a green solid identified as 7. Anal. Calcd for
1
µeff ) 4.83 µB. H NMR (benzene-d6): δ -20.64 (475.30, 18H),
-12.17 (193.93), -6.92 (41.15), -4.81 (75.82), -1.17 (40.06),
1.24 (17.88), 1.73 (22.48), 12.22 (70.57), 13.71 (115.37, 4H),
15.35 (150.24, 18H), 23.51 (194.26, 2H).
P r ep a r a tion of (S)-(tBu Box)F e(CH2P h )2 (12). This mol-
ecule was prepared in a manner identical to that for 8 with
0.208 g (0.495 mmol) of 3 and 0.128 g (0.990 mmol) of
KCH2C6H5, yielding 0.095 g (57%) of a yellow solid identified
as 12 following recrystallization from diethyl ether. Anal. Calcd
for C31H44N2O2Fe: C, 69.92; H, 8.33; N, 5.26. Found: C, 70.02;
C
56H80N4Cl2Fe2: C, 67.81; H, 8.13; N, 5.65. Found: C, 67.58;
H, 8.13; N, 5.18. Magnetic susceptibility (benzene-d6): µeff
)
H, 8.54; N, 5.63. Magnetic susceptibility (benzene-d6): µeff
)
3.86 µB. 1H NMR (benzene-d6): δ -21.19 (41.46, 12H, CHMe2),
-18.06 (34.14, 2H p-C6H3), -9.50 (25.59, 4H), -0.01 (227.57,
4H), 5.42 (22.71, 12H, CHMe2), one not located (CH3).
4.60 µB. 1H NMR (benzene-d6): δ -65.40 (29.12), -44.09
(222.68), -24.28 (293.29), -17.14 (230.16), -6.00 (64.02), 5.68
(105.38), 10.76 (56.56), 17.41 (55.88), 21.39 (73.35), 29.88
(27.2).
P r ep a r a tion of (-)-(Sp a r tein e)F e(CH2SiMe3)2 (8). A 20
mL scintillation vial was charged with 0.200 g (0.554 mmol)
of 2 and approximately 5 mL of diethyl ether. A 10 mL diethyl
ether solution containing 0.104 g (1.11 mmol) of LiCH2SiMe3
was added, and the reaction mixture was stirred for 6 h,
forming a brown solution and white precipitate. The mixture
was filtered through a pad of Celite and the diethyl ether
removed in vacuo, yielding a brown oil. Recrystallization from
pentane afforded 0.170 g (66%) of white crystals identified as
8. Anal. Calcd for C23H48N2FeSi2: C, 59.45; H, 10.41; N, 6.03.
Found: C, 59.36; H, 10.03; N, 6.00. Magnetic susceptibility
P r ep a r a tion of (-)-(Sp a r tein e)Mn (CH2SiMe3)2 (13). A
procedure similar to that for 8 was used with 0.120 g (0.267
mmol) of 4 and 0.050 g (0.531 mmol) of LiCH2SiMe3, yielding
0.097 g (79%) of 13 as white crystals. Anal. Calcd for C23H48N2-
MnSi2: C, 59.57; H, 10.43; H, N, 6.04. Found: C, 59.23; H,
10.20; N, 6.14. Magnetic susceptibility (benzene-d6): µeff ) 5.77
µB.
Ch a r a cter iza tion of Ar NdC(Me)-(Me)CdNAr F e(CO)3
(14). Anal. Calcd for C31H40N2FeO3: C, 68.38; H, 7.40; N, 5.14.
Found: C, 68.28; H, 7.06; N, 5.01. 1H NMR (benzene-d6): δ
1.04 (d, 6.87 Hz, CHMe2), 1.41 (d, 6.60 Hz, CHMe2), 1.51 (s,
6H, Me), 2.99 (sept, 6.87 Hz, 4H), 7.09-7.22 (m, 6H, Ar). 13C
NMR (benzene-d6): δ 17.59 (CHMe2), 24.72 (CHMe2), 24.72
(CHMe2), 28.34 (CH3), 124.34 (Ar), 127.53 (Ar), 140.77 (Ar),
151.37 (Ar), 152.27(CdN), 212.94 (CO). IR (pentane): ν 2030,
1
(benzene-d6): µeff ) 4.83 µB. H NMR (benzene-d6): δ -33.03
(310.62, 1H), -19.23 (129.88, 1H), -18.32 (103.50, 1H), -10.30
(79.62, 1H), -5.83 (71.18, 1H), -1.82 (1.81, 1H), 8.80 (82.76,
1H), 10.14 (156.05, 9H, CH2SiMe3), 12.67 (59.52, 1H), 13.62
(80.16, 1H), 15.71 (151.02, 9H, CH2SiMe3), 24.95 (53.17, 1H),
25.66 (64.50, 1H), 27.42 (63.30, 1H), 78.10 (606.23, 1H), 121.60
(245.85, 1H), 130.33 (296.31, 1H), 214.38 (137.82, 1H), 276.06
(235.70, 1H), 279.57 (330.70, 1H).
1959 cm-1
.
P r epar ation of Ar NdC(Me)-(Me)CdNAr Fe(CH2SiMe3)-
(C6F 5) (15). A 20 mL scintillation vial was charged with 0.100
g (0.157 mmol) of 5 and approximately 5 mL of pentane. A 10
mL pentane solution containing 0.080 g (0.157 mmol) of
B(C6F5)3 was added to the vial, resulting in a dark green
solution. After 30 min, the pentane was removed in vacuo,
yielding a green solid. Successive recrystallizations from
pentane were required to remove Me3SiCH2B(C6F5)3 and
yielding 0.060 g (55%) of pure 15. Anal. Calcd for C38H51BF5N2-
SiFe: C, 63.86; H, 7.19; N, 3.92. Found: C, 63.78; H, 6.84; N,
P r ep a r a tion of (-)-(Sp a r tein e)F e(CH2CMe3)2 (9). This
molecule was prepared in a manner identical to that for 8 with
0.105 g (0.290 mmol) of 2 and 0.045 g (0.582 mmol) of LiCH2-
CMe3 to yield 0.084 g (67%) of white crystals identified as 8.
Anal. Calcd for C25H48N2Fe: C, 69.42; H, 11.19; N, 6.48.
Found: C, 69.08; H, 10.51; N, 6.45. Magnetic susceptibility
1
(benzene-d6): µeff ) 4.68 µB. H NMR (benzene-d6): δ -50.03
(3406.62, 1H), -46.55 (3762.96, 1H), -38.14 (252.55, 1H),
-22.02 (130.08, 1H), -19.77 (112.80, 1H), -11.35 (60.2, 1H),
-10.60 (57.7, 1H), -1.47 (102.50, 1H), 0.091 (41.26, 1H), 3.27
(18.11, 1H), 4.15 (78.50, 1H), 10.26 (67.65, 1H), 17.51 (86.58,
1H), 19.41 (96.41, 1H), 22.25 (242.54, 9H, CMe3), 27.77 (72.95,
1H), 28.44 (72.82, 1H), 30.15 (70.81, 1H), 33.33 (290.80, 9H,
CMe3), 66.50 (334.70, 1H), 117.64 (3024.48, 1H), 129.80
(1124.15, 1H), 205.30 (271.45, 1H), 260.82 (381.55, 1H), 275.94
(377.38, 1H).
2
3.28. H NMR (benzene): δ 28.20 ppm (12.02, 6D). 19F NMR
(benzene-d6): δ -162.32 (m, 2F, m-C6F5), -154.04 (s, 1F,
C6F5), -139.06 (m, 2F, C6F5).
P r ep a r a t ion of [(-)-(Sp a r t ein e)F e(CH2SiMe3)][B(C6-
F 5)3CH2SiMe3] (16). A 20 mL scintillation vial was charged
with 0.020 g (0.0431 mmol) of 8 and 0.022 g (0.0431 mmol) of
B(C6F5)3. Approximately 5 mL of pentane was added. The
solution turned bright yellow and a viscous oil settled out. The
pentane was decanted and the oil dried in vacuo, yielding 0.024
g (57%) of 16. Anal. Calcd for C41H48N2Si2F15BFe: C, 50.42;
H, 4.94; N, 2.87. Found: C, 50.01; H, 4.43; N, 3.03. 19F NMR
(bromobenzene-d5): δ -161.49 (62.05, 3F), -158.69 (96.74, 6F),
P r ep a r a tion of (-)-(Sp a r tein e)F e(CH2P h )2 (10). This
molecule was prepared in a manner identical to that for 8 with
0.203 g (0.562 mmol) of 2 and 0.146 g (1.12 mmol) of
KCH2C6H5, yielding 0.242 g (93%) of a yellow solid identified