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2.3.2. Preparation of 5-[(E)-2-(2-methylphenyl)-1-
diazenyl]quinolin-8-ol (L2H)
ppm. The signal for the phenol was exchanged due to the
presence of water in the solvent. 13C NMR (DMSO-d6);
dC: 158.1 [C8], 151.5 [C10], 149.1 [C2], 138.7 [C5], 137.9
[C8a], 132.5 [C30 and C50], 131.9 [C4], 127.6 [C4a], 124.4
[C20 and C60], 124.1 [C40], 123.4 [C3], 115.2 [C6], 111.8
[C7] ppm.
Recrystallized from a mixture of methanol and benzene
to give brown crystalline product in 69.4% yield; m.p. 184–
185 ꢁC. Anal. Calc. for C16H13N3O: C, 72.99; H, 4.98; N,
1
15.96%. Found: C, 73.10; H, 4.97; N, 16.21%. H NMR
(CDCl3); dH: 9.33 [dd, 1H, H4], 8.87 [dd, 1H, H2], 8.03
[d, 1H, H6], 7.74 [d, 1H, H60], 7.61 [m, 1H, H3], 7.36 [d,
2H, H40 and H50], 7.30 [m, 1H, H-30], 7.27 [d, 1H, H7],
2.77 [s, 3H, CH3] ppm. The signal for the phenol was
exchanged due to presence of water in the solvent. 13C
NMR (CDCl3); dC: 155.2 [C8], 151.2 [C10], 148.4 [C2],
140.4 [C5], 137.9 [C20], 137.7 [C8a], 133.0 [C4], 131.5
[C30], 130.6 [C40], 127.2 [C4a], 126.4 [C-50], 122.8 [C3],
115.8 [C60], 115.6 [C6], 109.9 [C7], 17.7 [CH3] ppm.
2.3.6. Preparation of 5-[(E)-2-(4-ethoxyphenyl)-1-
diazenyl]quinolin-8-ol (L6H)
Recrystallized from chloroform to give dark brown
microcrystalline product in 64.6% yield; m.p. 180–181 ꢁC.
Anal. Calc. for C17H15N3O2: C, 69.61; H, 5.15; N,
1
14.33%. Found: C, 69.50; H, 5.11; N, 14.52%. H NMR
(CDCl3); dH: 9.29 [dd, 1H, H4], 8.84 [dd, 1H, H2], 8.01
[d, 1H, H6], 7.93 [m, 2H, H20 and H60], 7.58 [m, 1H,
H3], 7.23 [d, 1H, H7], 6.99 [m, 2H, H30 and H50], 4.12 [q,
2H, OCH2CH3], 1.48 [t, 3H, OCH2CH3] ppm. The signal
for the phenol was exchanged due to the presence of water
in the solvent. 13C NMR (CDCl3); dC: 161.2 [C8], 154.7
[C10], 148.4 [C2], 147.4 [C40], 140.0 [C5], 137.7 [C8a],
132.9 [C4], 124.6 [C30 and C50], 127.0 [C4a], 114.6 [C20
and C60], 122.6 [C3], 114.5 [C6], 110.0 [C7], 63.6
[OCH2CH3], 14.8 [OCH2CH3] ppm.
2.3.3. Preparation of 5-[(E)-2-(3-methylphenyl)-1-
diazenyl]quinolin-8-ol (L3H)
Recrystallized from a mixture of methanol and benzene
to give brown crystalline product in 64.8% yield; m.p. 159–
160 ꢁC. Anal. Calc. for C16H13N3O: C, 72.99; H, 4.98; N,
1
15.96%. Found: C, 73.20; H, 5.03; N, 16.20%. H NMR
(CDCl3); dH: 9.30 [dd, 1H, H4], 8.86 [dd, 1H, H2], 8.03
[d, 1H, H6], 7.79 [d, 2H, H20 and 60], 7.60 [m, 1H, H3],
7.41 [d, 1H, H50], 7.28 [d, 1H, H40], 7.26 [d, 1H, H7],
2.48 [s, 3H, CH3] ppm. The signal for the phenol was
exchanged due to the presence of water in the solvent.
13C NMR (CDCl3); dC: 155.3 [C8], 153.2 [C10], 148.4
[C2], 139.9 [C5], 138.9 [C-30], 137.7 [C8a], 132.9 [C4],
131.4 [C40], 128.9 [C50], 127.2 [C4a], 123.2 [C20], 122.7
[C3], 120.2 [C60], 115.4 [C6], 110.0 [C7], 21.4 [CH3] ppm.
2.4. Synthesis of the diorganotin complexes
A typical method is described below.
2.4.1. Synthesis of Ph2Sn(L4)2 (4)
L4H (1.0 g, 3.80 mmol) in hot anhydrous benzene (45 ml)
was added drop-wise with continuous stirring to a hot anhy-
drous benzene solution (30 ml) containing Ph3SnCl (1.46 g,
3.80 mmol). The reaction mixture was refluxed for 2 h, then
triethylamine (0.38 ml, 3.80 mmol) was added and reflux
was continued for additional 1.5 h. The reaction mixture
was cooled to room temperature and filtered to remove
Et3NÆHCl. The filtrate was collected; volatiles were
removed and dried in vacuo. The residue was extracted into
hexane and filtered while hot. The crude product was
obtained after evaporation of the hexane. This was then
recrystallized from a mixture of benzene–hexane (1:1),
which upon slow evaporation afforded red crystalline prod-
uct. Yield: 1.02 g (66.2%), m.p. 239–240 ꢁC. Anal. Calc. for
C44H34N6O2Sn: C, 66.27; H, 4.30; N, 10.54%. Found: C,
66.35; H, 4.35; N, 10.60%. IR (cmꢀ1): 1248 m(C(aryl)O).
1H NMR (CDCl3, 500.13 MHz) dH: Ligand skeleton: 9.27
[dd, 2H, H4], 8.61 [dd, 2H, H2], 8.22 [d, 2H, H6], 7.80 [m,
4H, H20 and H60], 7.24 [m, 2H, H3], 7.25 [m, 4H, H30 and
H50], 7.46 [d, 2H, H7], 2.41 [s, 6H, CH3]; Sn–Ph skeleton:
7.59 [m, 4H, H2*], 7.23 [m, 6H, H3* and H4*] ppm. 13C
NMR (CDCl3, 125.76 MHz); dC: 161.1 [C8], 151.4 [C10],
143.4 [C2], 140.6 [C40], 136.5 [C5], 135.4 [C8a], 136.1 [C4],
129.7 [C30 and C50], Not observed, possibly overlapped by
a CH signal [C4a], 122.2 [C20, C60 and C3], 118.5 [C6],
114.5 [C7], 21.4 [CH3]; Sn–Ph skeleton (nJ(119Sn, 13C),
Hz): 148.7 [C-1* (927)], 134.9 [C-2* (55)], 128.5 [C-
4*(17)], 128.3 [C-3* (81)] ppm. 119Sn NMR (CDCl3,
2.3.4. Preparation of 5-[(E)-2-(4-methylphenyl)-1-
diazenyl]quinolin-8-ol (L4H)
Recrystallized from chloroform to give brick red micro-
crystalline product in 63% yield; m.p. 188–189 ꢁC. Anal.
Calc. for C16H13N3O: C, 72.99; H, 4.98; N, 15.96%. Found:
1
C, 72.88; H, 5.01; N, 15.86%. H NMR (CDCl3); dH: 9.29
[dd, 1H, H4], 8.86 [dd, 1H, H2], 8.03 [d, 1H, H6], 8.01 [m,
2H, H20 and H60], 7.59 [m, 1H, H3], 7.32 [m, 2H, H30 and
H50], 7.26 [d, 1H, H7], 2.44 [s, 3H, CH3] ppm. The signal
for the phenol was exchanged due to the presence of water
in the solvent. 13C NMR (CDCl3); dC: 155.1 [C8], 151.3
[C10], 148.3 [C2], 141.1 [C40], 139.9 [C5], 137.7 [C8a],
132.9 [C4], 129.7 [C30 and C50], 127.2 [C4a], 122.8 [C20
and C60], 122.6 [C3], 115.2 [C6], 109.9 [C7], 21.5 [CH3]
ppm.
2.3.5. Preparation of 5-[(E)-2-(4-bromophenyl)-1-
diazenyl]quinolin-8-ol (L5H)
Recrystallized from a mixture of ethanol and benzene to
give yellowish brown precipitate in 65.5% yield; m.p. 210–
211 ꢁC. Anal. Calc. for C15H10BrN3O: C, 54.99; H, 3.07;
N, 12.80%. Found: C, 55.23; H, 3.12; N, 12.86%. 1H
NMR (DMSO-d6); dH: 9.34 [dd, 1H, H4], 9.04 [dd, 1H,
H2], 8.05 [d, 1H, H6], 7.99 [m, 2H, H20 and H60], 7.67
[m, 2H, H30 and H50], 7.82 [m, 1H, H3], 7.25 [d, 1H, H7]