Y. Lei et al. / Inorganica Chimica Acta 368 (2011) 179–186
185
green powder after recrystallization from toluene. Yield: 1.70 g
(78%). 1H NMR (400 MHz, CDCl3): d 2.07 (s, 12H, CH3), 2.31 (s,
12H, CH3), 5.68 (s, 2H, N–H), 6.87, 6.90, 7.10, 7.28 (m, 16H, Ar–
H). 13C NMR (100 MHz, CDCl3): d 17.9, 19.0 (CH3), 123.1, 126.7,
127.6, 128.0, 128.2, 128.6, 134.8, 136.3, 136.8, 145.7 (Ar–C),
153.4 (NCN). FT-IR (KBr, cmꢀ1): 3375 (s), 2917 (m), 1630 (s),
1587 (m), 1462 (m), 1348 (m), 1205 (m), 766 (m). Anal. Calc. for
172.8 (NCN). FT-IR (KBr, cmꢀ1): 2962 (s), 2868 (s), 1618 (s), 1585
(m), 1465 (s), 1359 (s), 1325 (m), 800 (m), 762 (s). Anal. Calc. for
C60H84Al2N4: C, 78.73; H, 9.25; N, 6.12. Found: C, 78.39; H, 9.01;
N, 5.87%.
4.7. Synthesis of Me2AlL2AlMe2 (2)
C
40H42N4: C, 83.01; H, 7.37; N, 9.68. Found: C, 83.18; H, 7.65; N,
2 was prepared by a procedure similar to that of 1. Using AlMe3
(2 mL, 1.0 M, 2 mmol) and H2L2 (0.578 g, 1.0 mmol), 2 was pro-
duced as colorless needle crystals (0.57 g, 0.83 mmol, 83% based
on Al). 1H NMR (400 MHz, C6D6): d ꢀ0.24 (s, 12H, CH3), 1.98 (s,
24H, CH3), 6.64 (s, 4H, Ar–H), 6.73, 6.75, 6.78, 6.79 (m, 12H, Ar–
H). 13C NMR (100 HMz, C6D6): d ꢀ9.0 (Al–CH3), 19.1 (Ar–CH3),
125.2, 128.1, 128.6, 132.7, 133.3, 144.0 (Ar–C), 171.0 (NCN). FT-IR
(KBr, cmꢀ1): 2922 (s), 1624 (s), 1589 (s), 1471 (s), 1390 (s), 1304
(s), 1256 (m), 1199 (m), 1094 (m), 857 (m), 711 (s). Anal. Calc.
for C44H52Al2N4: C, 76.49; H, 7.59; N, 8.11. Found: C, 76.35; H,
7.37; N, 7.78%.
9.16%. HRMS [C40H42N4]+: calcd 578.3409, found 578.3419. mp
278 °C.
4.4. Synthesis of p-cyclohexylene-bis(N,N0-bis(2,6-diisopropylphenyl)
formamidine) 1,4-C6H10[C(N-2,6-iPr2C6H3)(NH-2,6-iPr2C6H3)]2 (H2L3)
H2L3 was prepared by a procedure similar to that of H2L1. Using
1,4-cyclohexanedicarboxylic acid (0.62 g, 3.75 mmol) and 2,6-
diisopropylaniline (3.0 mL, 15.0 mmol), the title compound was
produced as white powder after recrystallization from toluene.
Yield: 2.16 g (71%). 1H NMR (400 MHz, CDCl3):
d 0.97 (d,
J = 6.8 Hz, 12H, CH(CH3)2), 1.12 (d, 12H, CH(CH3)2), 1.25 (d, J = 6.8,
12H, Hz, CH(CH3)2), 1.26 (d, J = 6.8 Hz, 12H, CH(CH3)2), 1.68 (m,
4H, CH2), 1.86 (d, J = 7.2 Hz, 4H, CH2), 2.15 (brs, 2H, CH), 3.04–
3.08 (m, 4H, CH(CH3)2), 3.14–3.20 (m, 4H, CH(CH3)2), 5.20 (s, 2H,
N–H), 6.98 (t, J = 7.6 Hz, 2H, Ar–H), 7.10 (d, J = 8.0 Hz, 8H, Ar–H),
7.25 (t, J = 7.6 Hz, 2H, Ar–H). 13C NMR (100 MHz, CDCl3): d 22.8,
23.0, 24.1, 25.5 (CH(CH3)2), 28.0, 28.1 (CH(CH3)2), 30.3 (Cy–CH2),
38.1 (Cy–CH), 122.9, 123.0, 123.8, 128.3, 132.6, 139.2, 143.7,
147.0 (Ar–C), 159.3 (NCN). FT-IR (KBr, cmꢀ1): 3365 (m), 2961 (s),
2927 (m), 2867 (m), 1632 (s), 1586 (m), 1459 (m), 1432 (m),
1385 (m), 1346 (w), 763 (m). Anal. Calc. for C56H80N4: C, 83.11;
H, 9.96; N, 6.92. Found: C, 83.57; H, 9.69; N, 6.74%. HRMS
[C56H80N4]+: calcd 808.6383, found 808.6425. mp 272 °C.
4.8. Synthesis of Me2AlL3AlMe2 (3)
3 was prepared by a procedure similar to that of 1. Using AlMe3
(2 mL, 1.0 M, 2 mmol) and H2L3 (0. 809 g, 1.0 mmol), 3 was isolated
as pale yellow powder, which was extracted by Et2O. Concentrat-
ing and then cooling the extraction at ꢀ35 °C overnight gave the
titled complex as colorless needle crystals (0.83 g, 0.93 mmol,
93% based on Al). 1H NMR (400 MHz, C6D6): d ꢀ0.49 (s, 12H, Al–
CH3), 0.57 (m, 4H, Cy–CH2), 0.98, 1.01 (d, 48H, CH(CH3)2), 1.09
(m, 4H, Cy–CH2), 1.91 (m, 2H, Cy–CH), 3.19 (m, 8H, CH(CH3)2),
6.93, 6.98 (m, 12H, Ar–H). 13C NMR (100 HMz, C6D6): d ꢀ9.8
(CH3), 22.3, 26.3 (CH(CH3)2), 28.3 (CH(CH3)2), 25.1, 27.8 (Cy–CH2),
40.8 (Cy–CH), 123.4, 126.2, 137.5, 144.6 (Ar–C), 178.4 (NCN). FT-
IR (KBr, cmꢀ1): 2962 (s), 1633 (s), 1586 (m), 1467 (s), 1384 (s),
1321 (s), 1187 (m), 1054 (m), 753 (s). Anal. Calc. for C60H90Al2N4:
C, 78.22; H, 9.85; N, 6.08. Found: C, 77.95; H, 9.61; N, 5.79%.
4.5. Synthesis of p-cyclohexylene-bis(N,N0-bis(2,6-dimethylphenyl)
formamidine) 1,4-C6H10[C(N-2,6-Me2C6H3)(NH-2,6-Me2C6H3)]2
(H2L4)
4.9. Synthesis of Me2AlL4AlMe2 (4)
H2L4 was prepared by a procedure similar to that of H2L1. Using
1,4-cyclohexanedicarboxylic acid (0.62 g, 3.75 mmol) and 2,6-
dimethylaniline (1.85 mL, 15.0 mmol), the title compound was
produced as white powder after recrystallization from THF. Yield:
1.4 g (65%). 1H NMR (400 MHz, CDCl3): d 1.69 (m, J = 9.5, 4H,
CH2), 1.89 (m, J = 7.0 Hz, 4H, CH2), 2.07 (brs, 2H, CH), 2.18(d,
J = 4.8 Hz, 24H, CH3), 5.28 (s, 2H, N–H), 6.85 (t, J = 7.4 Hz, 2H, Ar–
H), 7.03 (m, 10H, Ar–H). 13C NMR (100 MHz, CDCl3): d 17.8, 18.8
(CH3), 30.7 (Cy–CH2), 38.6 (Cy–CH), 122.5, 127.4, 128.2, 128.6,
128.9, 135.9, 136.4, 145.7 (Ar–C), 159.7 (NCN). FT-IR (KBr, cmꢀ1):
3442 (s), 2924 (m), 1641 (s), 1589 (m), 1473 (m), 1389 (w), 1222
(w), 1094 (w), 765 (m). Anal. Calcd. for C40H48N4: C, 82.15; H,
8.27; N, 9.58. Found: C, 81.92; H, 8.36; N, 9.72%. HRMS
[C40H48N4]+: calcd 584.3879, found 584.3853. mp 340 °C.
4 was prepared by a procedure similar to that of 1. Using AlMe3
(2 mL, 1.0 M, 2 mmol) and H2L4 (0.584 g, 1.0 mmol), 4 was pro-
duced as pale yellow powder, which was extracted by THF. Con-
centrating and then cooling the extraction at ꢀ35 °C overnight
gave the titled complex as colorless needle crystals (0.64 g,
0.92 mmol, 92% based on Al). 1H NMR (400 MHz, C6D6): d ꢀ0.35
(s, 12H, CH3), 0.76 (m, 4H, Cy–CH2), 1.53 (m, 4H, Cy–CH2), 1.79
(m, 2H, Cy–CH), 2.11 (s, 24H, Ar–CH3), 6.81–6.89 (m, 12H, Ar–H).
13C NMR (100 HMz, C6D6): d ꢀ8.3 (Al–CH3), 19.1 (Ar–CH3), 27.9
(Cy–CH2), 40.5 (Cy–CH), 125.3, 127.8, 133.9, 141.2 (Ar–C), 177.5
(NCN). FT-IR (KBr, cmꢀ1): 2930 (s), 1639 (s), 1589(m), 1471 (s),
1388 (m), 1211 (m), 769 (s). C42H58Al2N4: C, 74.97; H, 8.69; N,
8.33. Found: C, 74.68; H, 8.51; N, 7.97%.
4.6. Synthesis of Me2AlL1AlMe2 (1)
4.10. Synthesis of L5AlMe2 (5)
AlMe3 (2 mL, 1.0 M, 2 mmol) was added drop by drop to a THF
solution (30 mL) of H2L1 (0.803 g, 1.0 mmol) at room temperature
to give a clear green solution. After the resulting reaction mixture
was stirred for 2 h at room temperature, the solvents were re-
moved under reduced pressure to give pale green powder, which
was extracted by Et2O. Concentrating and then cooling the extrac-
tion at ꢀ35 °C overnight afforded the titled complex as colorless
needle crystals (0.83 g, 0.91 mmol, 91% based on Al). 1H NMR
(400 MHz, C6D6): d ꢀ0.12 (s, 12H, Al–Me2), 0.74, 1.16 (d, 48H,
CH(CH3)2), 3.39 (m, 8H, CH(CH3)2), 6.86, 6.97 (m, 16H, Ar–H). 13C
NMR (100 HMz, C6D6): d ꢀ9.9 (Al–CH3) 22.9, 26.2 (CH(CH3)2),
28.6 (CH(CH3)2), 123.8, 126.2, 128.7, 131.3, 137.5, 144.1 (Ar–C),
AlMe3 (2 mL, 1.0 M, 2 mmol) was added drop by drop to a THF
solution (30 mL) of HL5 (0.881 g, 2.0 mmol) at room temperature to
give a clear green solution. After the resulting reaction mixture was
stirred for 2 h at room temperature, the solvents were removed un-
der reduced pressure to give pale green powder, which was
washed by hexane. Recrystallization from toluene/hexane solution
afforded the titled complex as pale green block crystals (0.9 g, 91%
based on Al). 1H NMR (400 MHz, C6D6): d ꢀ0.06 (s, 6H, Al–Me2),
0.93, 1.26 (d, 24H, CH(CH3)2), 3.62 (m, 4H, CH(CH3)2), 6.59, 6.61,
6.62 (m, 3H, Ar–H), 6.70, 7.02, 7.06, 7.07, 7.11, 7.13 (m, 8H, Ar–
H). 13C NMR (100 HMz, C6D6): d ꢀ9.8 (CH3) 22.9, 25.8 (CH(CH3)2),
28.7 (CH(CH3)2), 124.1, 126.2, 128.2, 130.5, 139.5, 143.8 (Ar–C),