Dalton Transactions
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resonances of the ebthi ligand appear as broad multiplets washed several times with 1 mL of n-hexane. The formed
between 1.90 and 2.98 ppm, 20 H). NMR (100 MHz, [D6] orange sticky solid was dissolved in diethyl ether, which was
benzene, 297 K): δ = 21.1 (Me-Ph) 22.8, 23.06, 23.22, 23.4, 23.6, subsequently removed in a vacuum. After adding a mixture of
23.70, 23.73, 24.7, 27.3, 27.6 (CH2 ebthi), 30.3 (Me-t-Bu), 42.0 ether/n-hexane (1 : 1), filtration and standing for one week at
(CH2-Ph), 62.0 (Cq-t-Bu), 98.2, 104.7 105.8, 106.5 (CHvCH, −78 °C, light orange crystals formed which were isolated and
ebthi), 117.2, 120.6, 122.5, 123.82, 123.86, 126.7 (Cq-ebthi), identified as a 2 : 1 mixture of 3e and 4 by NMR spectroscopy.
127.3, 129.3, (CH-Ph), 134.9, 136.8 (Cq-Ph), 157.4 (CuN), 231.3 1H NMR (300 MHz, [D6]benzene, 297 K): δ = 1.47 (s, 9H, t-Bu,
(CvN) ppm. IR (ATR, cm−1): ν = 2110 (w, CuN). MS: m/z (CI): 3e), 2.22 (m, 6H, Me-Ph, 3e), 3.14–0.9 (m, 30H, CH2-ebthi, 3e +
2
2
569 [M]+, 542 [M+−CuN]+, 188 [Me3d-NC-CH2-xylene]+.29
4), 3.96 (d, J = 15.5 Hz, 1H, CH2-Ph, 3e), 4.20 (d, J = 15.5 Hz,
1H, CH2-Ph, 3e), 4.56 (d, J = 2.9 Hz, 0.5H, ebthi, 4), 4.61 (d, 3J =
Synthesis of complex 3d
2.8 Hz, 1H, ebthi, 3e), 4.75 (d, J = 2.9 Hz, 0.5H, ebthi, 4), 4.99
To a solution of rac-(ebthi)Zr(η2-Me3SiC2SiMe3) (1) (0.263 g, (d, J = 2.8 Hz, 1H, ebthi, 3e), 5.31 (d, J = 2.9 Hz, 0.5H, 4), 5.56
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0.50 mmol) in benzene (10 mL) t-BuNC (0.057 mL, 0.5 mmol) (d, J = 2.9 Hz, 0.5H, 4), 5.75 (d, J = 2.9 Hz, 1H, ebthi, 3e), 5.99
was added. Immediately a colour change from green to orange (d, J = 2.9 Hz, 1H, CH-ebthi, 3e), 6.80 (s, 1H, Ph, 3e), 6.92 (s,
3
was observed. After stirring the reaction mixture for 2 h at 2H, H-Ph, 3e); (6.72 and 2.17 (m, traces of free mesitylene))
room temperature further t-BuNC (0.115 mL, 1.0 mmol) and ppm. 13C NMR (100 MHz, [D6]benzene, 297 K): δ = 21.4
an excess (1 mL, 8.30 mmol) of mesitylene were added. After (Me-Ph, 3e), 22.8, 22.91, 22.95, 23.21, 23.62, 23.72, 23.73, 24.7,
heating the reaction mixture for 12 days at 80 °C, all volatiles 27.4, 27.5 (CH2-ebthi, 3e), 22.7, 23.20, 23.6, 23.7, 24.5, 24.8,
were removed in a vacuum and the remaining dark oil was 25.5, 26.0, 29.4, 30.3 (CH2-ebthi, 4), 30.2 (Me-t-Bu, 3e), 42.4
washed twice with 1 mL of n-hexane. The obtained orange-red (CH2-Ph, 3e), 62.0 (Cq-t-Bu, 3e), 96.6, 98.4, 100.3, 100.6 (CH-
sticky solid was dissolved in diethyl ether, which was sub- ebthi, 4), 98.2, 104.8 105.7, 106.4 (CH-ebthi, 3e), 113.3, 116.0,
sequently removed in a vacuum. After adding a mixture of 126.0, 127.5, 129.6 (Cq-ebthi, 4), 117.2, 120.8, 122.6, 123.8,
ether/n-hexane (1 : 1), filtration from the insoluble oily precipi- 123.9, 126.7 (Cq-ebthi, 3e), 128.4, 128.8 (CH-Ph, 3e), 137.9,
tate and standing for three weeks at −78 °C, orange-red crystals 138.3 (Cq-Ph, 3e), 157.5 (CuN, 3e), 213.6 (CuN, 4), 231.7
formed which were isolated and identified as a 1 : 1 mixture of (CvN, 3e) ppm. MS: m/z (CI): 760 [M]+ (4), 583 [M]+ (3e), 556
3d and 4 by NMR spectroscopy. When pure diethyl ether is [M+−CuN]+, 201 [Me3d-NC-CH2-C6H4Me2]+. The n-hexane frac-
1
used for crystallisation a 1 : 4 (3d : 4) mixture was obtained. H tions were combined and the volume was reduced in a
NMR (400 MHz, [D6]benzene, 297 K): δ = 1.49 (s, 9H, t-Bu, 3d), vacuum. After one week at −78 °C a grey precipitate could be
2.08 (s, 3H, Me-Ph, 3d), 3.14–0.9 (m, 40H, CH2-ebthi, 3d + 4), isolated. Recrystallisation from benzene afforded colourless
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3.89 (d, J = 15.5 Hz, 1H, CH2-Ph, 3d), 4.44 (d,2J = 15.5 Hz, 1H, crystals of pure 3e which were suitable for X-ray crystallogra-
1
CH2-Ph, 3d), 4.56 (m, 2H, ebthi, 3d + 4), 4.75 (d, J = 2.9 Hz, 1H, phy. 3e: H NMR (300 MHz, [D6]benzene, 297 K): δ = 1.47 (s,
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4), 4.90 (d, J = 2.9 Hz, 1H, ebthi, 3d), 5.31 (d, J = 2.9 Hz, 1H, 9H, t-Bu), 2.22 (m, 6H, Me-Ph), 3.14–0.9 (m, 20H, CH2-ebthi),
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4), 5.56 (d, J = 2.9 Hz, 1H, 4), 5.79 (d, J = 2.9 Hz, 1H, ebthi, 3.96 (d, 2J = 15.5 Hz, 1H, CH2-Ph), 4.20 (d, 2J = 15.5 Hz, 1H,
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3d), 5.90 (d, J = 2.9 Hz, 1H, CH-ebthi, 3d), 7.01–7.13 (m, 3H, CH2-Ph), 4.61 (d, J = 2.8 Hz, 1H, ebthi), 4.99 (d, J = 2.8 Hz,
Ph, 3d), 7.35 (dd, J = 7.5, 1.5 Hz, 1H Ph, 3d) ppm. 13C NMR 1H, ebthi), 5.75 (d, J = 2.9 Hz, 1H, ebthi), 5.99 (d, J = 2.9 Hz,
(75 MHz, [D6]benzene, 297 K): δ = 21.4 (Me-Ph, 3d), 22.7, 22.8, 1H, CH-ebthi), 6.80 (s, 1H, Ph), 6.92 (s, 2H, Ph), (6.72 and 2.17
23.2, 23.5, 23.6, 23.72, 23.73, 23.8, 23.9, 24.5, 24.6, 25.5, 24.8, (m, traces free mesitylene) ppm. 13C NMR (75 MHz, [D6]
25.5, 26.0, 29.4, 30.3, 32.0 (CH2-ebthi, 3d + 4), 30.0 (Me-t-Bu, benzene, 297 K): δ = 21.4 (Me-Ph), 22.8, 22.91, 22.95, 23.2, 23.6,
3d), 39.5 (CH2-Ph, 3d), 62.8 (Cq-t-Bu, 3d), 96.6, 98.4, 100.3, 23.72, 23.73, 24.7, 27.4, 27.5 (CH2-ebthi), 30.2 (Me-t-Bu), 42.4
100.6 (CH-ebthi, 4), 98.5, 105.0, 105.6, 106.1 (CH-ebthi, 3d), (CH2-Ph), 62.0 (Cq-t-Bu), 98.2, 104.8 105.7, 106.4 (CH-ebthi),
113.3, 116.0, 126.0, 127.5, 129.6 (Cq-ebthi, 4), 117.0, 121.3, 117.2, 120.8, 122.6, 123.8, 123.9, 126.7 (Cq-ebthi), 128.4, 128.8
122.7, 122.8, 123.7, 126.1 (Cq-ebthi, 3d), 131.1, 130.4, 127.48, (CH-Ph), 137.9, 138.3 (Cq-Ph), 157.5 (CuN), 231.7 (CvN),
126.7 (CH-Ph, 3d), 136.71, 136.72 (Cq-Ph, 3d), 157.5 (CuN, (21.3, 127.4, 137.6 free mesitylene) ppm.
3d), 213.6 (CuN, 4), 230.0 (CvN, 3d) ppm. MS: m/z (CI): 760
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[M]+ (4) 569 [M]+ (3d), 542 [M+−CuN]+, 188 [Me3d-NC-CH2-
C6H4Me]+.28
Conflicts of interest
Synthesis of complex 3e
To a solution of rac-(ebthi)Zr(η2-Me3SiC2SiMe3) (1) (0.263 g, There are no conflicts to declare.
0.50 mmol) in benzene (10 mL) t-BuNC (0.057 mL, 0.5 mmol)
was added. Immediately a colour change from green to orange
was observed. After stirring the reaction mixture for 2 h at
room temperature further t-BuNC (0.115 mL, 1.0 mmol) and
an excess (1 mL, 7.25 mmol) of mesitylene were added. After
Acknowledgements
heating the reaction mixture for 12 days at 80 °C, all volatiles We thank our technical and analytical staff for assistance.
were removed in a vacuum and the remaining dark oil was General support by LIKAT is gratefully acknowledged.
This journal is © The Royal Society of Chemistry 2019
Dalton Trans., 2019, 48, 16525–16533 | 16531