Efficient zinc initiators supported by NNO-tridentate ketiminate ligands for
cyclic esters polymerization
Hui-Ju Chuang, Hsiao-Li Chen, Bor-Hunn Huang, Tsung-En Tsai, Pei-Ling Huang, Tzu-Ting Liao and
Chu-Chieh Lin*
Department of Chemistry, National Chung Hsing University, Taichung 402, Taiwan
*Correspondence should be addressed to Chu-Chieh Lin
Fax: (+886) 4-22862547
E-mail: cchlin@mail.nchu.edu.tw
Figure S1. The molecular structure of [L1ZnEt] (1a) with probability ellipsoids drawn at the 40%
probability level. Hydrogen atoms were omitted for clarity. Selected bond lengths (Å) and bond angles
(deg): Zn-C(23) 1.9823(15); Zn-O(1) 2.0291(10); Zn-N(3) 2.0368(12); Zn-N(4) 2.1661(13); C(23)-ZnO(1) 113.52(5); C(23)-Zn-N(3) 136.41(6); O(1)-Zn-N(3) 91.26(4); C(23)-Zn-N(4) 118.17(6); O(1)-ZnN(4) 110.29(5); N(3)-Zn-N(4) 81.75(5).
Figure S2. The molecular structure of [(L1)2Zn] (1c) with probability ellipsoids drawn at the 40%
probability level. Hydrogen atoms were omitted for clarity. Selected bond lengths (Å) and bond angles
(deg): Zn(1)-O(1) 2.0665(15); Zn(1)-N(3) 2.0917(17); Zn(1)-O(2) 2.0903(16); Zn(1)-N(8) 2.0968(18);
Zn(1)-N(7) 2.302(2); Zn(1)-N(4) 2.329(2); O(1)-Zn(1)-N(3) 92.31(7); O(1)-Zn(1)-O(2) 87.05(6); N(3)Zn(1)-O(2) 85.65(7); O(1)-Zn(1)-N(8) 86.01(7); N(3)-Zn(1)-N(8) 176.00(7); O(2)-Zn(1)-N(8) 90.63(7);
O(1)-Zn(1)-N(7) 87.85(8); N(3)-Zn(1)-N(7) 102.12(8); O(2)-Zn(1)-N(7) 170.87(7); N(8)-Zn(1)-N(7)
81.46(7); O(1)-Zn(1)-N(4) 169.88(8); N(3)-Zn(1)-N(4) 82.24(7); O(2)-Zn(1)-N(4) 84.05(8); N(8)-Zn(1)N(4) 98.86(8); N(7)-Zn(1)-N(4) 101.59(9).
Figure S3.13C NMR spectrum of the polymer PDL-150.
Experimental Section
Synthesis of pre-ligands (A-E)
Synthesis of 4-(4-Methylbenzoyl)-3-methyl-1-phenyl-2-pyrazolin-5-one (A). A mixture of 3-methyl-1phenyl-2-pyrazolin-5-one (10.45 g, 60.0 mmol), 4-methylbenzoyl chloride (9.28 g, 60.0
mmol) and
Calcium hydroxide (6.85g, 120.0 mmol) were combined in 1,4-dioxane (70 ml) and heated to reflux for
overnight. The calcium complex was decomposed by pouring the mixture into dilute hydrochloric acid
(200ml, 2N) appeared brown powder to separate. The resulting powder was recrystallized by slowly
cooling a hot ethanol solution. Yield: 15.44 g (88 %). 1H NMR (CDCl3, ppm): δ 7.88 (2H, d, J = 8.0 Hz,
ArH), 7.56 (2H, d, J = 8.0 Hz, ArH), 7.48-7.45 (2H, m, ArH), 7.32-7.27 (3H, m, ArH), 2.43 (3H, s, CH3),
2.18 (3H, s, CH3C=N). 13C NMR (CDCl3, ppm): δ191.8, 161.9 (CO), 148.1, 142.9, 137.5, 134.9, 129.4,
129.3, 128.4, 126.9, 120.9 (Ar and Py), 103.8 (C=C-NH), 21.9(ArCH3), 16.2 (CCH3). Anal. Calcd. (found)
for C18H16N2O2：N, 9.58 (8.95); C, 73.95 (72.21); H, 5.52 (4.99) %.
Synthesis of 4-(4-Tert-butylbenzoyl)-3-methyl-1-phenyl-2-pyrazolin-5-one (B). A mixture of 3methyl-1-phenyl-2-pyrazolin-5-one (10.45 g, 60 mmol) and 4-tert-butylbenzoyl chloride (11.08 g, 60
mmol) was refluxed following the same procedure, as indicated above for the synthesis of A. Yield: 17.05
g (85 %). 1H NMR (CDCl3, ppm): δ7.89 (2H, d, J = 2.0 Hz, ArH), 7.62 (2H, d, J = 6.0 Hz, ArH), 7.51
(4H, d, J = 8.0 Hz, ArH), 7.46 (4H, d, J = 5.2 Hz, ArH), 7.31 (1H, m, ArH), 2.16 (3H, s, CH3C=N), 1.35
(9H, s, C(CH3)3). 13C NMR (CDCl3, ppm): δ191.1, 161.9 (CO), 155.7, 147.8, 137.2, 134.3, 129.0 ,128.0,
126.3, 125.2, 120.5 (Ar and Py), 103.5 (C=C-NH), 35.0 (C(CH3)3), 31.1 (C(CH3)3), 16.0 (CCH3). Anal.
Calcd. (found) for C21H22N2O2: N, 7.98 (8.38); C, 74.85 (75.42); H, 5.86 (6.63) %.
Synthesis of 4-(4-Trifluoromethylbenzoyl)-3-methyl-1-phenyl-2-pyrazolin-5-one (C). A mixture of 3methyl-1-phenyl-2-pyrazolin-5-one (10.5 g, 60.0 mmol), 4-trifluoromethylbenzoyl chloride (12.5 g, 60.0
mmol) was refluxed following the same procedure, as indicated above for the synthesis of A. Yield: 15.45
g (77%). 1H NMR (CDCl3, ppm): δ 7.85 (2H, d, J = 8.0 Hz, ArH), 7.80-7.73 (4H, m, ArH), 7.48 (2H, t, J
= 8.0 Hz, ArH), 7.33 (1H, t, J = 8.0 Hz, ArH), 2.07 (3H, s, CH3C=N). 13C NMR (CDCl3, ppm): δ191.3,
160.4 (CO), 147.7, 141.1, 136.9, 133.5, 133.2, 129.2 (Ar and Py), 125.5 (CF3), 124.9, 122.2, 120.9 (Ar
and Py), 103.5 (C=C-NH), 15.7 (CCH3). Anal. Calcd. (found) for C18H13F3N2O3: N, 8.09 (7.69); C, 62.43
(63.02); H, 3.78 (3.80) %.
Synthesis of 4-(4-Fluorobenzoyl)-3-methyl-1-phenyl-2-pyrazolin-5-one (D). A mixture of 3-methyl-1phenyl-2-pyrazolin-5-one (10.45 g, 60 mmol) and 4-fluorobenzoyl chloride (9.51 g, 60.0 mmol) was
refluxed following the same procedure, as indicated above for the synthesis of A. Yield: 13.87 g (78 %).
H NMR (CDCl3, ppm): δ7.87 (2H, d, J = 1.6 Hz, ArH), 7.68 (2H, t, J = 1.6 Hz, ArH), 7.47 (2H, m, ArH),
1
7.45 (2H, t, J = 8.0 Hz, ArH), 7.33-7.29 (1H, m, ArH), 7.20 (2H, t, J = 8.0 Hz, ArH), 2.12 (3H, s,
CH3C=N). 13CNMR (CDCl3, ppm): δ190.7, 166.1 (CO), 163.6, 161.1, 147.5, 137.1, 133.8, 130.4, 130.3,
129.0, 126.7, 120.7, 115.6, 115.4 (Ar and Py), 103.3 (C=C-NH), 15.8(CCH3). Anal. Calcd. (found) for
C17H13N2O2: N, 9.50 (9.45); C, 69.28 (68.91); H, 4.37 (4.42) %.
Synthesis of 4-(4-Tert-butylbenzoyl)-3-phenyl-1-phenyl-2-pyrazolin-5-one (E). A mixture of 1,3diphenyl-pyrazol-5-one (14.18 g, 60 mmol) and 4-tert-butylbenzoyl chloride (11.08 g, 60.0 mmol) was
refluxed following the same procedure, as indicated above for the synthesis of A. Yield: 18.46 g (78 %).
H NMR (CDCl3, ppm): δ 7.99-7.97 (2H, m, ArH), 7.51-7.06 (12H, m, ArH), 1.24 (9H, s, C(CH3)3). 13C
1
NMR (CDCl3, ppm): δ 191.9, 161.6 (CO), 155.5, 151.4, 137.4, 133.5, 132.5, 129.1, 128.7, 127.7, 126.7,
124.5, 120.9 (Ar and Py), 102.0 (C=C-NH), 34.8 (C(CH3)3), 30.9 (C(CH3)3). Anal. Calcd. (found) for
C26H24N2O2: N, 7.07 (7.06); C, 78.76 (78.76); H, 6.10 (6.10 ) %.
Synthesis of ligands (L1H-L5H)
(Z)-4-((2-(Dimethylamino)ethylamino)(4-methylphenyl)methylene)-3-methyl-1-phenyl-pyrazol-5one (L1H). A mixture of A (2.92 g, 10 mmol) and N,N-dimethylethylenediamine (0.88 g, 10 mmol) was
refluxed in ethanol (40 mL) for 8 h and the mixture was filtered. The filter residue was washed with ice
cold EtOH and then volatile materials were removed under vacuum to give yellow solid. Yield: 3.08 g
(85 %). 1H NMR (CDCl3, ppm): δ 11.21 (1H, br, NH), 7.99 (2H, d, J = 8.0 Hz, ArH), 7.38-7.30 (4H, m,
ArH), 7.20-7.18 (2H, m, ArH), 7.12-7.08 (1H, m, ArH), 3.22 (2H, q, J = 6.0 Hz, NHCH2CH2), 2.47-2.42
(5H, m, NHCH2CH2, CH3), 2.19 (6H, s, N(CH3)2), 1.46 (3H, s, CH3C=N).
C NMR (CDCl3, ppm): δ
13
165.8, 165.6, 160.7, 147.8, 140.4, 139.1, 129.6, 128.5, 127.2, 123.9, 119.1 (Ar and Py), 99.7 (C=C-NH),
58.6 (NHCH2CH2), 45.3 (N(CH3)2), 42.2 (NHCH2CH2), 21.4 (ArCH3), 15.4 (CCH3). Anal. Calcd. (found)
for C22H26N4O: N, 15.46 (15.27); C, 72.90 (72.62); H, 7.23 (7.42) %.
(Z)-4-((2-(Dimethylamino)ethylamino)(4-tert-butylphenyl)methylene)-3-methyl-1-phenyl-pyrazol-5one (L2H). A mixture of B (3.34 g, 10 mmol) and N,N-dimethylethylenediamine (0.88 g, 10 mmol) was
refluxed following the same procedure as L1H, to produce yellow solid. Yield: 3.44 g (85 %). 1H NMR
(CDCl3, ppm): δ 11.23 (1H, br, NH), 8.01 (2H, d, J = 7.6 Hz, ArH), 7.55 (2H, d, J = 8.0 Hz, ArH), 7.38
(2H, t, J = 6.4 Hz, ArH), 7.26 (2H, m, ArH), 7.12 (2H, m, ArH), 3.24 (2H, q, J = 6.4 Hz, NHCH2CH2),
2.47 (2H, t, J = 6.4 Hz, NHCH2CH2), 2.20 (6H, s, N(CH3)2), 1.53 (3H, s, CH3C=N), 1.37(9H, s, C(CH3)3).
C NMR (CDCl3, ppm): δ 166.9, 165.7, 153.7, 147.8, 139.20, 128.5, 127.0, 125.7, 123.9, 119.1, (Ar and
13
Py), 99.7 (C=C-NH), 58.7 (NHCH2CH2), 45.4 (N(CH3)2), 42.3 (NHCH2CH2), 34.8 (C(CH3)3), 31.1
(C(CH3)3), 15.2 (CCH3). Anal. Calcd. (found) for C25H32N4O: N, 14.00 (13.85); C, 74.20 (74.22); H, 7,67
(7.97) %. Mp: 214-216 oC.
(Z)-4-((2-(Dimethylamino)ethylamino)(4-Trifluoromethylphenyl)methylene)-3-methyl-1-phenylpyrazol-5-one (L3H). A mixture of C (3.56 g, 10.0 mmol) and N,N-dimethylethylenediamine (0.88 g,
10.0 mmol) was refluxed following the same procedure as L1H, to produce yellow solid. Yield: 3.33 g
(80 %). 1H NMR (CDCl3, ppm): δ 11.30 (1H, br, NH), 7.98 (2H, d, J = 12.0 Hz, ArH), 7.83 (2H, d, J =
8.0 Hz, ArH), 7.53 (2H, d, J = 8.0 Hz, ArH), 7.41-7.36 (2H, m, ArH), 7.12-7.16(1H, m, ArH), 3.22 (2H, q,
J = 6.0 Hz, NHCH2CH2), 2.55 (2H, t, J = 6.0 Hz, NHCH2CH2), 2.26 (6H, s, N(CH3)2), 1.44 (3H, s,
CH3C=N). 13C NMR (CDCl3, ppm): δ 165.9, 163.7, 147.3, 139.2, 135.3, 132.9, 132.7, 128.9, 128.4, 126.4,
126.3, 125.1, 124.6, 122.3, 119.5 (Ar and Py), 100.1 (C=C-NH), 58.8 (NHCH2CH2), 45.6 (N(CH3)2), 42.6
(NHCH2CH2), 15.8 (CCH3). Anal. Calcd. (found) for C22H23F3N4O: N, 13.45 (13.12); C, 63.45 (63.43); H,
5.57 (6.01) %.
(Z)-4-((2-(Dimethylamino)ethylamino)(4-fluorophenyl)methylene)-3-methyl-1-phenyl-pyrazol-5-one
(L4H). A mixture of D (2.96 g, 10 mmol) and N,N-dimethylethylenediamine (0.88 g, 10 mmol) was
refluxed following the same procedure as L1H, to produce yellow solid. Yield: 3.19 g (87 %). 1H
NMR(CDCl3, ppm): δ 11.24 (1H, br, NH), 8.00 (2H, d, J = 1.2 Hz, ArH), 7.41-7.33 (4H, m, ArH), 7.287.22 (2H, m, ArH), 7.15-7.11 (1H, m, ArH), 3.20 (2H, q, J = 6.0 Hz, NHCH2CH2), 2.47 (2H, t, J = 6.4 Hz,
NHCH2CH2), 2.20 (6H, s, N(CH3)2), 1.48 (3H, s, CH3C=N).
C NMR (CDCl3, ppm): δ 165.6, 164.8,
13
164.3, 162.3, 147.3, 139.1, 129.5, 128.5, 127.5, 124.0, 119.1, 116.3,116.1 (Ar and Py), 99.8 (C=CNH),
58.7 (NHCH2CH2), 45.4 (N(CH3)2), 42.33 (NHCH2CH2), 15.44 (CCH3). Anal. Calcd. (found) for
C21H23FN4O: N, 15.88 (15.29); C, 68.23 (68.83); H, 6.29 (6.33) %. Mp: 140-142 oC.
(Z)-4-((2-(Dimethylamino)ethylamino)(4-tert-butylphenyl)methylene)-3-phenyl-1-phenyl-pyrazol5-one (L5H). A mixture of E (3.95 g, 10 mmol) and N,N-dimethylethylenediamine (0.88 g, 10 mmol) was
refluxed following the same procedure as L1H, to produce yellow solid. Yield: 3.73 g (80 %). 1H NMR
(CDCl3, ppm)：δ 11.56 (1H, br, NH), 8.12-8.09 (2H, m, ArH), 7.43-7.39 (2H, m, ArH), 7.27-6.88 (10H,
m, ArH), 3.36 (2H, q, J = 6.0 Hz, NHCH2CH2), 2.51 (2H, t, J = 6.4 Hz, NHCH2CH2), 2.22 (6H, s,
N(CH3)2), 1.22 (9H, s, C(CH3)3). 13C NMR (CDCl3, ppm)：δ 166.7, 165.7, 153.2, 151.1, 139.1, 133.6,
128.5, 128.4, 128.1, 127.1, 126.9, 124.9, 124.3, 119.6 (Ar and Pr), 98.7 (C=C-NH), 58.6 (NHCH2CH2),
45.4 (N(CH3)2), 42.7 (NHCH2CH2), 34.5 (C(CH3)3), 30.9 (C(CH3)3). Anal. Calcd. (found) for C30H34N4O:
N, 12.01 (11.82); C, 77.22 (77.82); H, 7.34 (7.57) %. IR (KBr, cm-1): 1630 (C=N), 1582 (C=O), 1492
(C=C). Mass spectrum (EI, m/e): 466.3 (M+，22.30 %). Mp: 186-188 oC.