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5 h. Then, ethanol was evaporated and the product was
extracted in chloroform. The organic layers were col-
lected, dried over MgSO4 and, after vacuum evapora-
tion of the solvent, the amine was obtained as a dark
red liquid.
carried out transforming into their chloro-bridge deriv-
atives as reported below. From these, pure acetate
complexes were recovered as follows: sodium acetate
(Pd:OAc = 1:2) was added to 30 mL of an acetone-
dichloromethane solution of 0.07 mmol of [Pd(l-
Cl)L]2 and was stirred for 14 h. The resulting suspen-
sion was evaporated to dryness and the complex was
extracted in CH2Cl2 and filtered through a pad of
Kiesselgur. By addition of n-hexane and further evap-
oration of the CH2Cl2, a yellow solid was obtained
which was filtered off, washed with cold n-hexane and
dried in vacuum (yields: 85–90%). All these com-
pounds, except 2.2a, acquire pasty textures. IR
(KBr): 2.2a: 1610 s (C@N), 1252 vs, 1029 s (C–O–C),
1542 s, 836 m (Ar), 1573 vs (C@O); 2.1b–d, 2.2b–d:
1608 s m(C@N), 1251 vs, 1062 m, 1119 s m(C–O–C),
1543 s, 834 m m(Ar), 1573 vs m(C@O). Analysis (%):
2.1b: calc.: C, 53.16; H, 6.11; N, 2.30; found: C,
54.94; H, 5.95; N, 2.30; 2.1c: calc.: C, 57.47; H, 6.82;
N, 2.31; found: C, 57.12; H, 6.62; N, 2.72; 2.1d: calc.:
C, 57.47; H, 6.82; N, 2.31; found: C, 57.07; H, 6.58; N,
2.88; 2.2a: calc.: C, 65.57; H, 8.70; N, 1.96; found: C,
65.68; H, 8.78; N, 1.99; 2.2b: calc.: C, 59.52; H, 7.56;
N, 1.98; found: C, 59.51; H, 7.37; N, 1.98; 2.2c: calc.:
C, 59.52; H, 7.56; N, 1.98; found: C, 59.50; H, 7.41;
N, 1.88; 2.2d: calc.: C, 53.33; H, 6.49; N, 2.00; found:
C, 53.02; H, 6.20; N, 2.24.
4.4. p-(1,4,7-Trioxanonanyl)benzaldehyde and
p-(1,4,7,10-tetraoxadodecanyl) benzaldehyde
To a solution of 4-hydroxybenzaldehyde (35.42
mmol) in 100 mL of acetone, was added 38.96 mmol
of the corresponding tosylate, and 70.8 mmol of
K2CO3. The mixture was then refluxed for 48 h. and
the yellow suspension was filtered to remove the excess
of K2CO3 and KCl formed. The filtrate was taken to
dryness and the residue was chromatographied on a sil-
ica column using a mixture of n-hexane/ethyl acetate 2:3
as eluent.
4.5. Imines (HL) (1.1b–d, 1.2a–d)
All the imines were synthesized by condensation of
their respective aldehydes and anilines in absolute etha-
nol with acetic acid as catalyst [28]. Yields were in the
range 60–70%. IR (KBr): 1.2a: 1623 s (C@N), 1253 vs,
1025 s (C–O–C), 1680 s, 842 m (Ar) cmꢀ1; 1.1b–d,
1.2b–d: 1623 s m(C@N), 1254 vs, 1025 m, 1141 s m(C–
O–C), 1609 s, 842 m m(Ar) cmꢀ1. Analysis (%): 1.1b:
calc.: C, 67.39; H, 7.92; N, 3.14; found: C, 67.50; H,
7.74; N, 3.06. 1.1c: calc.: C, 73.43; H, 8.90; N, 3.17;
found: C, 73.23; H, 8.68; N, 3.47; 1.1d: calc.: C, 73.43;
H, 8.40; N, 3.17; found: C, 73.33; H, 8.66; N, 3.66;
1.2a: calc.: C, 80.82; H, 10.82; N, 2.55; found: C,
81.15; H, 11.11; N, 2.57; 1.2b: calc.: C, 73.16; H, 9.50;
N, 2.58; found: C, 73.01; H, 9.49; N, 2.34; 1.2c: calc.:
C, 73.16; H, 9.50; N, 2.58; found: C, 73.36; H, 9.69;
N, 2.68; 1.2d: calc.: C, 65.27; H, 8.12; N, 2.64; found:
C, 65.59; H, 8.35; N, 2.33.
4.7. [Pd(l-Cl)L]2 derivatives (3.1b–d, 3.2a–d)
To a stirred solution of [Pd(l-OAc)L]2 (1.75 mmol) in
20 mL of dichloromethane was added dropwise the stoi-
chiometric amount of a solution of HCl in methanol
(Pd:HCl = 1:1). After 1 h stirring the solvent was evap-
orated and the product was chromatographied through
a silica column using different eluents: CH2Cl2 for 3.2a;
a 98.5:1.5 CH2Cl2/methanol mixture for 3.1d and 3.2d,
and a 99.9:0.1 CH2Cl2/methanol mixture for 3.1b, 3.1c,
3.2b and 3.2c. The solutions obtained were taken to dry-
ness and dissolved in dichloromethane. 3.2a precipitates
by adding acetone. The other complexes precipitate by
adding n-hexane. The solids were filtered off, washed
with the appropriate solvent and vacuum dried. All of
them are yellow solids with different grades of pasty tex-
ture. Yields: 60–95%. IR (KBr): 3.2a: 1610 s (C@N),
1250 vs, 1029 s (C–O–C),1582 s, 832 m (Ar), 250 Pd-
Cl (Nujol) cmꢀ1; 3.1b–d, 3.2b–d: 1607 s (C@N), 1251
vs, 1031 m, 1114 s (C–O–C), 1580 vs, 831 m (Ar), 248
Pd-Cl (Nujol); Analysis (%): 3.1b: calc.: C, 51.20; H,
5.84; N, 2.39; found: C, 50.88; H, 5.59; N, 2.30; 3.1c:
calc.: C, 55.68; H, 6.57; N, 2.40; found: C, 55.32; H,
6.44; N, 2.66; 3.1d: calc.: C, 55.68; H, 6.57; N, 2.40;
found: C, 55.41; H, 6.36; N, 2.42; 3.2a: calc.: C, 64.33;
H, 8.46; N, 2.02; found: C, 64.13; H, 8.09; N, 2.05;
3.2b: calc.: C, 58.06; H, 7.38; N, 2.06; found: C, 57.34;
H, 6.95; N, 2.05; 3.2c: calc.: C, 58.06; H, 7.38; N, 2.06;
4.6. [Pd(l-OAc)L]2 derivatives (2.1b–d, 2.2a–d)
A mixture of 1.29 mmol of paladium acetate [29]
and the stoichiometric amount of the corresponding
imine (3.86 mmol) in 15 mL of glacial acetic acid
was stirred at 50 ꢁC for 14 h. The compounds were iso-
lated in different ways depending on their nature. 2.2a
was filtered off from the resulting suspension, washed
with cold acetone and dried in vacuum, obtaining a
yellow solid (yield: 91%). To obtain 2.1d and 2.2d,
the acetic acid was evaporated, the reddish solid was
dissolved in CH2Cl2 and then filtered through a pad
of Kiesselgur. N-hexane was added and CH2Cl2 was
evaporated to obtain a yellow solid which was filtered
off, washed with cold n-hexane, and vacuum dried.
Yields: 85–99%. Complexes 2.1b, 2.1c, 2.2b and 2.2c
were not obtained pure in this way. Purification was