230
A. Bacchi et al. / Inorganica Chimica Acta 342 (2003) 229Á235
/
means of the X-ray diffraction analysis carried out on
PdL3, H2L4×H2O and PdL4. Finally, the complexes are
tested as catalysts in the homogeneous hydrogenation of
n(NH); 3061 m, n(CH pyrrole); 2944Á
/
2850 s, n(CH2
/
alkyl.); 1638 sh, n(CÄN).
/
phenylacetylene.
2.2.1.4. N,N?-Cycloexylenebis(pyrrol-2-
ylmethyleneamine) (H2L4×H2O). M.p.: 203 8C (dec.).
1H NMR (CDCl3): d 1.30Á
1.77 (m br, 8H, CH2); 3.00
(m, 2H, CH); 6.18 (t, 2H, H pyrrole b); 6.34 (q, 2H, H
pyrrole g); 6.79 (s, br, 2H, H pyrrole a); 7.66 (s, 2H, H
imine); 10.41 (s, br, 2H, D2O exchangeable, NH). FT-IR
(cmꢂ1, KBr): 3400 w, n(NH); 3066 m, n(CH pyrrole);
/
/
2. Experimental
2.1. General procedures
The reagents of commercial quality were used without
further purification, with the exception of phenylacety-
lene, that was distilled and stored under nitrogen.
Physical measurements and the general procedure for
the hydrogenation of phenylacetylene were made as
described elsewhere [8]; thermogravimetric analysis was
2932Á
/
2857 s, n(CH2); 1633 sh, n(CÄ
/
N).
2.2.2. Complexes
The ligand and the nickel acetate are dissolved in the
minimum amount of EtOH; the resulting solution is
stirred at room temperature (r.t.) until a precipitate
appears. The solid is filtered, washed with absolute
EtOH and recrystallized from CH2Cl2/n-C6H14.
carried out with a TGA PerkinÁ
/
Elmer Delta in the
200 8C (58 minꢂ1). GC analyses were per-
range 30Á
/
formed on a DANI HP 3800 flame-ionization gas-
chromatograph (OV 101 on CHP capillary column).
All new compounds gave satisfactory elemental ana-
lyses.
2.2.2.1. Ni(L1). Reaction time: 1 h. Colour: dark red.
1
M.p.: :
/
290 8C (dec.). Yield: 97%. H NMR (CDCl3):
d 6.22 (d, br, 2H, H pyrrole b); 6.78 (d, 2H, H pyrrole
g); 6.82 (s, br, 2H, H pyrrole a); 7.02 (m, 2H, H phenyl
meta); 7.16 (m, 2H, H phenyl ortho); 7.56 (s, 2H, H
2.2. Synthesis and characterization
imine). FT-IR (cmꢂ1, KBr): 3030Á
/3100 w, n(CHar.);
2.2.1. Ligands
1550 sh, n(CÄ
/
N). The same product is obtained from
the template reaction between Ni(CH3COO)2, pyrrole 2-
The ligands were prepared according to the method
already described [1], which involved a condensation
reaction of pyrrole 2-carboxaldehyde and diamine in a
2:1 molar ratio, with EtOH as solvent.
carboxaldehyde and o-phenylenediamine.
2.2.2.2. Ni(L2). Reaction time: 4 h. Colour: yellowÁ
/
orange. M.p.: 214 8C (dec.). Yield: 87%. 1H NMR
(CDCl3): d 3.58 (s, 4H, H alkyl.); 6.10 (s, br, 2H, H
pyrrole b); 6.55 (s, br, 2H, H pyrrole g); 6.78 (s, br, 2H,
H pyrrole a); 7.13 (s, 2H, H imine). FT-IR (cmꢂ1, KBr):
3070 m, n(CH pyrrole); 2919 s, n(CH alkyl.); 1589 sh,
2.2.1.1. N,N?-Phenylenebis(pyrrol-2-ylmethyleneamine)
(H2L1). Yield: 80%. M.p.: 200 8C (dec.) (lit. [6]
1
204 8C). H NMR (CDCl3): d 6.07 (t, 2H, H pyrrole
b); 6.30 (s, br, 2H, H pyrrole g) 6.46 (d, 2H, H pyrrole
a); 7.13 (q, 2H, H phenyl meta); 7.30 (q, 2H, H phenyl
ortho); 7.75 (s, 2H, H imine); 12.30 (s, br, 2H, D2O
exchangeable, NH). FT-IR (cmꢂ1, KBr): 3400 w, br,
n(CÄ
/
N).
2.2.2.3. Ni(L3). Reaction time: 3 h. Colour: red. M.p.:
1
n(NH); 3077 m, n(CHar.); 1616 sh, n(CÄ
/N).
ꢀ
/
300 8C. Yield: 96%. H NMR (CDCl3): d 1.79Á1.80
/
(m, br, 2H, CH2CH2CH2); 3.12 (t, 4H, CH2CH2CH2);
6.13 (d, br, 2H, H pyrrole b); 6.59 (d, 2H, H pyrrole g);
6.93 (s, br, 2H, H pyrrole a); 7.19 (s, 2H, H imine). FT-
IR (cmꢂ1, KBr): 3100 w, n(CH pyrrole); 2924 s, n(CH
2.2.1.2. N,N?-Ethylenebis(pyrrol-2-ylmethyleneamine)
(H2L2). Yield: 95%. M.p.: 179Á180 8C (dec.) (lit. 178Á
180 8C [1]). H NMR (CDCl3): d 3.81 (s, 4H, CH2);
6.26 (q, 2H, H pyrrole b); 6.50 (q, 2H, H pyrrole g); 6.91
(m, br, 2H, H pyrrole a); 7.29 (s, 2H, H imine); 8.07 (s,
br, 2H, D2O exchangeable, NH). FT-IR (cmꢂ1, KBr):
/
/
1
alkyl.); 1594 sh, n(CÄ
/
N).
3176 s, br n(NH); 2942Á
/2868 s, n(CH alkyl.); 1642 sh,
2.2.2.4. Ni(L4). Reaction time: 1 h. Colour: yellow.
1
M.p.: 272 8C (dec.). Yield: 95%. H NMR (CDCl3): d
n(CÄN).
/
1.20 (d, 4H, CH2); 1.74 (s, br, 2H, CH2); 2.11 (s, br, 2H,
CH2); 3.48 (s, br, 2H, CH); 6.10 (s, br, 2H, H pyrrole b);
6.53 (d, 2H, H pyrrole g); 6.76 (s, br, 2H, H pyrrole a);
7.05 (s, 2H, H imine). FT-IR (cmꢂ1, KBr): 3070 w,
2.2.1.3. N,N?-Propylenebis(pyrrol-2-ylmethyleneamine)
(H2L3). Yield: 64%. M.p.: 119Á
/
120 8C (dec.) (lit. 119Á
/
120 8C [6]). 1H NMR (CDCl3): d 1.95 (m, 2H,
CH2CH2CH2); 3.60 (t, 4H, CH2CH2CH2); 6.22 (t, 2H,
H pyrrole b); 6.46 (t, 2H, H pyrrole g); 6.85 (s, br, 2H, H
pyrrole a); 8.02 (s, 2H, H imine); 9.27 (s br, 2H, D2O
exchangeable, NH). FT-IR (cmꢂ1, KBr): d 3400 w,
n(CH pyrrole); 2850Á
/
2939 s, n(CH alkyl.); 1579 sh,
n(CÄN).
/
The Pd complexes are obtained in the same way as Ni
ones, but palladium acetate is dissolved in MeCN.