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(4) (0.258 g, 0.5 mmol) in n-hexane (10 mL) at À788C. The mixture
was slowly warmed to ambient temperature and stirred for 18 h.
Subsequently, the dark-violet solution was concentrated to an ap-
proximate volume of 2 mL and filtered. The solution was stored at
À788C over a period of 12 h resulting in the deposition of a dark-
violet solid. Removal of supernatant by syringe and drying in
vacuo at ambient temperature for 1 h yielded 6 (0.103 g, 43%) as
a violet solid.
1016 (m), 1007 (m), 978 (m), 900 (w), 824 (m), 798 (s), 787 (s), 732
(s), 557 (m), 426 (m), 400 cmÀ1 (m). MS-CI+ (isobutane): [M+] 396
(100), [impy+H+] 177 (41). M(C21H26N2Zr)=396.11 gmolÀ1. Elemen-
tal analysis(%) calcd: C 63.43, H 6.59, N 7.04; found: C 63.58,
H 6.49, N 7.01.
Preparation of 9: 2-(N-n-Butyl-methylimino)pyridine (impy)
(0.100 g, 0.57 mmol) was added dropwise to a stirred solution of
Cp*2Ti(h2-Me3SiC2SiMe3) (3) (0.236 g, 0.50 mmol) in n-hexane
(10 mL) at 08C. The mixture was slowly warmed to ambient tem-
perature and heated to 558C for 3 d. Then the dark-brown solution
was concentrated to an approximate volume of 2 mL and filtered.
The filtrate was freed of all volatiles in vacuo resulting in 9
(0.121 g, 49%) as a brown solid.
M.p.: 1398C (dec. under Ar). 1H NMR (258C, [D6]benzene,
300.13 MHz): d=1.5–2.1 (broad), 4–6 ppm (broad). EPR (278C, tolu-
ene): g=1.9824, ATi =8.7 G, AN1 =1.8 G, AN2 =2.4 G, DB=1.5 G;
(À1738C, toluene glass) g1 =2.0019, g2 =1.9821, g3 =1.9675, DB1 =
6.9 G, DB2 =6.5 G, DB3 =7.6 G. IR ATR (32 scans): n˜ =3071 (w), 2949
(m), 2895 (m), 2851 (s), 1879 (w), 1604 (w), 1573 (m), 1555 (m),
1477 (m), 1434 (m), 1374 (s), 1345 (m), 1320 (s), 1278 (s), 1246 (s),
1161 (w), 1142 (w), 1128 (m), 1105 (m), 1042 (m), 1018 (s), 988 (m),
948 (m), 901 (w), 794 (m), 724 (s), 708 cmÀ1 (s). MS-CI+ (isobutane):
[M+] 493 (68), [Cp*2Ti+] 318 (11), [impy+H+] 177 (5) [Cp*+] 137 (3).
M(C31H45N2Ti) =493,58 gmolÀ1. Elemental analysis(%) calcd: C 75.44,
H 9.19, N 5.68; found: C 75.13, H 9.43, N 5.80.
M.p.: 2198C (dec. under Ar). 1H NMR (258C, [D6]benzene,
400.13 MHz): d=6.52 (m, 1H, CH), 6.14 (m, 1H, CH), 6.00 (m, 1H,
CH), 5.10 (m, 1H, CH), 2.10 (s, 3H, CH3), 1.81 ppm (s, 30H, Cp*).
13C NMR (258C, [D6]benzene, 100.62 MHz): d=144.1 (CH), 133.1
(Cquart.), 132.2 (Cquart.), 124.3 (CH), 119.5 (CH), 119.0 (Cp*quart.), 99.8
(CH), 19.7 (CH3), 11.2 ppm (Cp*-CH3). IR ATR (32 scans): n˜ =2965
(m), 2900 (m), 2853 (m), 1596 (s), 1532 (w), 1494 (w), 1436 (s), 1377
(s), 1334 (m), 1277 (s), 920 (m), 707 (s), 650 cmÀ1 (m). MS-CI+ (iso-
butane): [M+] 481 (1), [Cp*+] 137 (100), [acpy+H+] 122 (47).
M(C27H37NOZr)=481.19 gmolÀ1
.
Elemental analysis(%) calcd:
C 67.17, H 7.72, N 2.91; found: C 66.95, H 7.75, N 2.99.
Preparation of 7: 2-(N-n-Butyl-methylimino)pyridine (impy)
(0.176 g, 1.0 mmol) was added dropwise to a stirred solution of
[Cp2Ti(h2-Me3SiC2SiMe3)] (1) (0.278 g, 0.8 mmol) in n-hexane (10 mL)
at ambient temperature. The reaction mixture gradually changed
its colour from pale brownish to dark-red within 24 h. The resulting
solution was concentrated to an approximate volume of 4 mL, fil-
tered, and slowly cooled to À788C. Removal of supernatant by syr-
inge, washing with cooled n-hexane (À788C, 33 mL) and drying
in vacuo at ambient temperature for 3 h yielded 7 (0.205 g, 72%)
as dark-red solid.
M.p.: 1068C (dec. under Ar).1H NMR (À758C, [D8]tetrahydrofurane,
400.13 MHz): d=7.57 (m, 1H, CH), 6.95 (m, 1H, CH), 6.43 (m, 1H,
CH), 5.38 (s, 10H, Cp), 5.25 (t, 1H, CH), 3.41 (m, 2H, CH2), 2.34 (s,
3H, CH3), 1.32 (m, 4H, 2 CH2), 0.94 ppm (t, 3H, CH3). 13C NMR
(À758C, [D8]tetrahydrofurane, 100.62 MHz): d=150.5 (CH), 140.4
(Cquart.), 131.8 (Cquart.), 128.2 (CH), 120.2 (CH), 105.5 (Cp), 103.9 (CH),
55.4 (CH2), 37.8 (CH2), 21.8 (CH2), 14.9 (CH3), 13.2 ppm (CH3). IR
(Nujol, 32 scans): n˜ =3096 (w), 3080 (w), 3038 (w), 1913 (w), 1716
(w), 1584 (s), 1547 (w), 1497 (m), 1337 (m), 1307 (w), 1287 (s), 1250
(s), 1221 (w), 1163 (w), 1153 (m), 1132 (m), 1109 (m), 1065 (m), 1020
(m), 1008 (m), 984 (m), 904 (m), 842 (m), 833 (m), 814 (s), 801 (s),
791 (s), 734 (s), 660 (w), 610 (w), 564 (m), 514 (w), 481 (w),
465 cmÀ1 (w). MS-CI+ (isobutane): [M+] 354 (100), [impy+H+] 177
(67). M(C21H26N2Ti) =354.16 gmolÀ1. This complex is extremely air-
sensitive and could not be analysed satisfactorily by CHN analysis.
Preparation of 10: 2-(N-n-Butyl-methylimino)pyridine (impy)
(0.088 g, 0.5 mmol) was added dropwise to a stirred suspension of
[Cp*2ZrCl2] (0.216 g, 0.5 mmol) and lithium sand (0.007 g,
1.0 mmol) in toluene (10 mL) at ambient temperature. The pale
yellow reaction mixture was stirred over 2 d. Within 2 h, the colour
switches to red-brownish and finally to dark-violet at the end of
the reaction time. This solution was freed of all volatiles in vacuo,
the residue dissolved in n-hexane (10 mL) and filtered. The dark-
violet solution was concentrated to an approximate volume of
1 mL and stored at 68C for 2 d resulting in the deposition of 10
(0.201 g, 74%) as a violet solid.
M.p.: 1198C (dec. under Ar). 1H NMR (258C, [D6]benzene,
400.13 MHz): d=7.14 (m, 1H, CH), 6.51 (m, 1H, CH), 6.30 (m, 1H,
CH), 5.47 (m, 1H, CH), 3.51 (m, 2H, CH2), 2.04 (s, 3H, CH3), 1.80 (s,
30H, Cp*), 1.57 (m, 2H, CH2), 1.33 (m, 2H, CH2), 0.97 ppm (m, 3H,
CH3). 13C NMR (258C, [D6]benzene, 75.48 MHz): d=147.08 (CH),
131.97 (Cquart.), 123.86 (CH), 120.19 (CH), 116.32 (Cquart.), 115.66
(Cquart.Cp*), 101.26 (CH), 53.33 (CH2), 37.76 (CH2), 21.64 (CH2), 16.13
(CH3), 14.62 (CH3), 11.82 ppm (Cp*-CH3). IR ATR (32 scans): n˜ =2954
(m), 2899 (m), 2855 (m), 2721 (w), 1638 (w), 1589 (m), 1565 (m),
1497 (m), 180 (m), 1450 (s), 1431 (s), 1375 (s), 1299 (m), 1289 (s),
1227 (m), 1165 (m), 1143 (m), 1128 (m), 1106 (m), 1070 (m), 1051
(m), 978 (m), 781 (m), 726 (s), 700 cmÀ1 (m). MS-CI+ (isobutane):
[M+] 536 (100), [Cp*2Zr+] 360 (2), [impy+H+] 177 (1).
Preparation of 8: To
a
stirred solution of [Cp2Zr(py)(h2-
Me3SiC2SiMe3)] (2) (0.235 g, 0.5 mmol) in n-hexane (10 mL), 2-(N-n-
butyl-methylimino)pyridine (impy) (0.088 g, 0.5 mmol) was added
dropwise at ambient temperature. The reaction mixture was stirred
at 608C for 24 h. The resulting solution was concentrated to an ap-
proximate volume of 4 mL, filtered and slowly cooled to À788C.
Removal of supernatant by syringe, washing with cooled n-hexane
(À788C, 33 mL) and drying in vacuo at ambient temperature for
3 h yielded 8 (0.132 g, 67%) as brownish solid.
M.p.: 1258C (dec. under Ar). 1H NMR (258C, [D6]benzene,
300.13 MHz): d=7.48 (m, 1H, CH), 6.53 (m, 1H, CH), 6.42 (m, 1H,
CH), 5.74 (s, 5H, Cp), 5.44 (m, 1H, CH), 5.25 (s, 5H, Cp), 3.44 (m, 2H,
CH2), 1.79 (s, 3H, CH3), 1.33 (m, 2H, CH2), 1.18 (m, 2H, CH2),
0.86 ppm (t, 3H, CH3). 13C NMR (258C, [D6]benzene, 75.48 MHz): d=
147.8 (CH), 127.2 (CH), 117.4 (CH), 109.3 (Cquart.), 107.6 (Cp), 103.5
(Cp), 101.5 (CH), 54.8 (CH2), 38.0 (CH2), 21.0 (CH2), 14.4 (CH3),
12.3 ppm (CH3). IR (Nujol, 32 scans): n˜ =3113 (w), 3096 (w), 3077
(w), 3039 (w), 1911 (w), 1716 (w), 1598 (s), 1320 (s), 1288 (s), 1234
(m), 1218 (m), 1169 (m), 1151 (m), 1135 (m), 1075 (w), 1062 (w),
M(C31H46N2Zr)=537.95 gmolÀ1
.
Elemental analysis(%) calcd:
C 69.22, H 8.62, N 5.21; found: C 69.11, N 8.61, H 5.10.
Acknowledgements
We are grateful for the GC measurement and hydrogen detec-
tion by L. Dura. Furthermore, we thank our technical and ana-
lytical staff for assistance. Financial support by the DFG (RO
1269/9-1) is gratefully acknowledged.
Keywords: dearomatisation · metallacycles · metallocenes ·
pyridines · reduction
Chem. Eur. J. 2016, 22, 3361 – 3369
3368
ꢀ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim