Dalton Transactions
Page 14 of 18
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DOI: 10.1039/C8DT04905J
(Py−CH2−), 28.4 (CH(CH3)2), 25.0 (CH(CH3)2), 22.9 (CH(CH3)2). MS (DEI): m/z (%) 808 (< 1, [M] ), 765 (< 5, [M-
C3H7]+), 424 (5, [CaL]+), 385 (45, [L]+), 342 (30, [L-C3H7]+), 292 (15, [C20H24N2]+), 279 (20, [C19H23N2]+), 249 (40,
[C17H17N2]+), 235 (50, [C16H15N2]+), 177 (40, [C12H19N]+), 162 (100, [C12H18]+), 106 (50, [C7H8N]+), 103 (40, [C8H7]+),
79 (30, [C H N]+), 44 (25, [C H ]+). IR (pure, /cm-1): 2860 (m), 2810 (m), 1625 (m), 1597 (m), 1568 (w), 1545 (w),
υ
5
5
3 8
1535 (w), 1511 (w), 1479 (m), 1460 (s), 1429 (m), 1413 (m), 1380 (m), 1344 (m), 1320 (m), 1308 (m), 1252 (m),
1224 (m), 1214 (w), 1178 (m), 1141 (m), 1099 (m), 1080 (m), 1055 (m), 1038 (m), 1023 (m), 1007 (m), 994 (w),
975 (m), 933 (m), 914 (vw), 886 (vw), 837 (vw), 815 (w), 801 (w), 779 (m), 758 (m), 750 (m), 699 (m), 663 (w),
647 (w), 634 (m), 616 (vw), 601 (w), 588 (m), 552 (w), 536 (w), 510 (m), 460 (m). Due to the sensitivity of this
compound during handling and weighing no reliable CHN analytical data have been obtained.
[Ca{Dipp−N=C(tBu)N−CH2CH(CH3)−Py}2] (2d). [Ca{Dipp−N=C(tBu)N−CH2CH(CH3)−Py}2] was prepared in analogy
to 2b using 186 mg (0.49 mmol) of (R)-1d, respectively 183 mg (0.48 mmol) of (S)-1d and 287 mg (0.57 mmol)
of [(thf)2Ca{N(SiMe3)2}2] in toluene (20 mL). Recrystallization of the obtained solid from toluene (4 ml) at 5 °C
led to formation of 50 mg (26%) of (R,R)-2d, respectively 31 mg (16%) of (S,S)-2d as pale yellow crystals. M. p.
1
3
4
203−208 °C (dec.). H NMR (C6D6, 297.0 K, 400.22 MHz): δ 8.56 (dd, JH,H = 5.2 Hz, JH,H = 2.0 Hz, 2H, Py N–CH),
3
4
3
4
7.23 (dd, JH,H = 7.6 Hz, JH,H = 2.0 Hz, 2H, Dipp m-CH), 7.11 (dd, JH,H = 7.6 Hz, JH,H = 2.0 Hz, 2H, Dipp m-CH),
7.07–7.02 (m, 4H, Py m-CH, Dipp p-CH), 6.61 (d, JH,H = 8.0 Hz, 2H, Py o-CH), 6.67–6.64 (m, 2H, Py p-CH), 3.69–
3
3.61 (m, 4H, CH(CH3)2, N−CH2−), 3.55 (sept, 3JH,H = 6.8 Hz, 2H, CH(CH3)2), 3.34–3.28 (m, 2H, N−CH2−), 2.67–2.62
(m, 2H, Py−CHCH3), 1.65 (d, 3JH,H = 6.8 Hz, 6H, CH(CH3)2), 1.51 (d, 3JH,H = 6.8 Hz, 6H, CH(CH3)2), 1.22 (d, 3JH,H = 6.8
3
3
Hz, 6H, CH(CH3)2), 0.98 (d, JH,H = 6.8 Hz, 6H, CH(CH3)2), 0.92 (d, JH,H = 6.8 Hz, 6H, Py−CHCH3), 0.84 (s, 18H,
C(CH3)3). 13C{1H} NMR (C6D6, 297.0 K, 100.65 MHz): δ 172.9 (NC(tBu)N), 167.5 (Py i-C), 150.2 (Dipp i-C), 146.1
(Py N–CH), 141.1 (Dipp o-C), 138.1 (Py m-C), 123.0 (Dipp m-C), 122.8 (Dipp m-C), 121.3 (Py o-C), 120.9 (Py p-C),
119.6 (Dipp p-C), 57.6 (N−CH2−), 45.2 (Py−CHCH3), 41.7 (C(CH3)3), 29.6 (C(CH3)3), 28.3 (CH(CH3)2), 27.8
(CH(CH3)2), 24.5 (CH(CH3)2), 24.3 (CH(CH3)2), 23.9 (CH(CH3)2), 23.3 (CH(CH3)2), 15.2 (Py−CHCH3). MS (DEI): m/z
(%) 796 (5, [M]+), 753 (40, [M-C3H7]+), 418 (5, [CaL]+), 379 (55, [L]+), 336 (35, [L-C3H7]+), 322 (15, [L-C3H7-CH3]+),
259 (5, [L-C8H11N]+), 244 (45, [C16H24N2]+; [C17H26N]+), 229 (85, [C16H23N]+), 217 (60, [C14H20N2]+), 203 (30,
[C13H19N2]+), 146 (10, [C10H12N]+), 120 (100, [C7H8N2]+; [C8H10N]+), 106 (10, [C7H8N]+), 57 (10, [C4H9]+), 41 (5,
[C H N]+). IR (pure, /cm-1): 2955 (m), 2867 (w), 1651 (m), 1590 (w), 1568 (w), 1514 (w), 1470 (m), 1452 (m),
υ
2
3
1426 (m), 1379 (m), 1357 (m), 1331 (w), 1312 (m), 1258 (w), 1235 (w), 1178 (w), 1158 (w), 1097 (w), 1056 (w),
1039 (w), 1020 (w), 1004 (w), 995 (w), 932 (w), 897 (w), 861 (w), 829 (w), 782 (m), 750 (m), 713 (m), 681 (w),
647 (w), 636 (w), 585 (w), 550 (w), 522 (w). Anal. Calcd. for C50H72CaN6 (797.22 g/mol): C, 75.33; H, 9.10; N,
10.54. Found: C, 75.05; H, 9.13; N, 10.34.
[(tmeda)Sr{Dipp−N=C(H)N−C2H4−Py}2] (3a). [(tmeda)Sr{Dipp−N=C(H)N−C2H4−Py}2] was prepared in analogy to
2b using 249 mg (0.80 mmol) of 1a and 445 mg (0.81 mmol) of [(thf)2Sr{N(SiMe3)2}2] in toluene (16 mL).
Recrystallization of the obtained solid from a mixture of toluene (1 ml) and TMEDA (0.2 ml) at r.t. led to
formation of 126 mg (38%) of 3a as pale yellow crystals. Physical and analytical data show cocrystalline toluene
(1 eq), which is partly lost by drying in vacuo M. p. 75−77 °C (dec.). 1H NMR (C6D6, 296.9 K, 250.13 MHz): δ 8.78
(s, broad, 2H, Py N−CH), 7.99 (s, 2H, NC(H)N), 7.19 (d, 3JH,H = 6.8 Hz, 4H, Dipp m-CH), 7.13–7.09 (m, 4H, Dipp p-
CH, Tol m-CH), 7.06–6.99 (m, 4H, Py m-CH, Tol o-CH, Tol p-CH), 6.76–6.74 (m, 2H, Py o-CH), 6.67–6.65 (m, 2H,
Py p-CH), 3.67 (s, broad, 4H, N−CH2−), 3.43 (s, broad, 4H, CH(CH3)2), 2.96 (t, 3JH,H = 6.8 Hz, 4H, Py−CH2−), 2.17 (s,
broad, 4H, tmeda N−CH2−), 2.14 (s, broad, 12H, tmeda N(CH3)2), 2.11 (s, broad, 3H, Tol CH3), 1.16–1.14 (m, 24H,
CH(CH3)2). 13C{1H} NMR (C6D6, 296.9 K, 62.90 MHz): δ 168.4 (NC(H)N), 162.1 (Py i-C), 151.2 (Dipp i-C), 149.9 (Py
N−CH), 142.8 (Dipp o-C), 137.9 (Tol i-C), 136.7 (Py m-C), 129.3 (Tol o-C), 128.6 (Tol m-C), 125.7 (Tol p-C), 123.7
(Py o-C), 123.2 (Dipp m-C), 122.0 (Dipp p-C), 121.1 (Py p-C), 57.7 (tmeda N−CH2−), 55.1 (N−CH2−), 45.9 (tmeda
N(CH3)2), 43.2 (Py−CH2−), 28.2 (CH(CH3)2), 24.8 (CH(CH3)2), 21.4 (Tol CH3). MS (DEI): m/z (%) 704 (< 1, [M-
tmeda]+), 661 (< 1, [M-tmeda-C3H7]+), 309 (60, [L]+), 266 (20, [L-C3H7]+), 230 (40, [L-C5H4N]+), 203 (95,
[C13H19N2]+), 172 (60, [C11H12N2]+), 146 (55, [C10H12N]+), 106 (100, [C7H8N]+), 93 (80, [C6H7N]+), 78 (15, [C5H4N]+),
43 (25, [C H ]+). IR (pure, /cm-1): 3050 (vw), 2961 (w), 2929 (w), 1660 (m), 1628 (w), 1584 (w), 1567 (w), 1459
υ
3
7
(w), 1430 (w), 1395 (w), 1380 (w), 1362 (w), 1317 (w), 1257 (w), 1235 (w), 1220 (w), 1186 (w), 1157 (w), 1107
(w), 1096 (w), 1076 (w), 1051 (w), 1025 (w), 986 (w), 937 (w), 888 (w), 845 (w), 822 (w), 795 (w), 782 (w), 770