Cyclic and acyclic compartmental Schiff bases, their reduced analogues and related mononuclear and heterodinuclear complexes

Article abstract of DOI:10.1016/j.ica.2004.06.007

[1+1] macrocyclic and [1+2] macroacyclic compartmental ligands (H ₂L), containing one N₂O₂, N₃O ₂, N₂O₃, N₄O₂ or O ₂N₂O₂ Schiff base site and one O ₂O_n (n=3, 4) crown-ether like site, have been prepared by self-condensation of the appropriate formyl- and amine precursors. The template procedure in the presence of sodium ion afforded Na₂(L) or Na(HL)·nH₂O. When reacted with the appropriate transition metal acetate hydrate, H₂L form M(L)·nH₂O, M(HL)(CH₃COO)·nH₂O, M(H₂L)(X) ₂·nH₂O (M=Cu²⁺, Co²⁺, Ni ²⁺; X=CH₃COO^-, Cl^-) or Mn(L)(CH ₃COO)·nH₂O according to the experimental conditions used. The same complexes have been prepared by condensation of the appropriate precursors in the presence of the desired metal ion. The Schiff bases H ₂L have been reduced by NaBH₄ to the related polyamine derivatives H₂R, which form, when reacted with the appropriate metal ions, M(H₂R)(X)₂ (M= Co²⁺, Ni²⁺; X=CH₃COO^-, Cl^-), Cu(R)·nH₂O and Mn(R)(CH₃COO)·nH₂O. The prepared ligands and related complexes have been characterized by IR, NMR and mass spectrometry. The [1+1] cyclic nature of the macrocyclic polyamine systems and the site occupancy of sodium ion have been ascertained, at least for the sodium (I) complex with the macrocyclic ligand containing one N₃O₂ Schiff base and one O₂O₃ crown-ether like coordination chamber, by an X-ray structural determination. In this complex the asymmetric unit consists of one cyclic molecule of the ligand coordinated to a sodium ion by the five oxygen atoms of the ligand. The coordination geometry of the sodium ion can be described as a pentagonal pyramid with the metal ion occupying the vertex. In the mononuclear complexes with H₂L or H₂R the transition metal ion invariantly occupies the Schiff base site; the sodium ion, on the contrary, prefers the crown-ether like site. Accordingly, the heterodinuclear complexes [MNa(L)(CH₃COO)_x] (M=Cu²⁺, Co ²⁺, Ni², x=1; M=Mn³⁺, x=2) have been synthesised by reacting the appropriate formyl and amine precursors in the presence of M(CH₃COO)_n·nH₂O and NaOH in a 1:1:1:2 molar ratio. The reaction of the mononuclear transition metal complexes with Na(CH₃COO)·nH₂O gives rise to the same heterodinuclear complexes. Similarly [MNa(R)(CH₃COO) _x] have been prepared by reaction of the appropriate polyamine ligand H₂R with the desired metal acetate hydrate and NaOH in 1:1:2 molar ratio.

Full text of DOI:10.1016/j.ica.2004.06.007

Inorganica Chimica Acta 357 (2004) 4191–4207
www.elsevier.com/locate/ica
Cyclic and acyclic compartmental Schiff bases, their
reduced analogues and related mononuclear and
heterodinuclear complexes
*
U. Casellato, S. Tamburini, P. Tomasin , P.A. Vigato
Istituto di Chimica Inorganica e delle Superfici, Area della Ricerca C.so Stati Uniti 4, 35127 Padova, Italy
Received 27 February 2004; accepted 2 June 2004
Available online 2 July 2004
Abstract
[1+1] macrocyclic and [1+2] macroacyclic compartmental ligands (H2L), containing one N2O2, N3O2, N2O3, N4O2 or O2N2O2
Schiff base site and one O2On (n ¼ 3, 4) crown-ether like site, have been prepared by self-condensation of the appropriate formyl-
and amine precursors. The template procedure in the presence of sodium ion afforded Na2(L) or Na(HL) ꢀ nH2O. When reacted with
the appropriate transition metal acetate hydrate, H2L form M(L) ꢀ nH2O, M(HL)(CH3COO) ꢀ nH2O, M(H2L)(X)2 ꢀ nH2O
(M ¼ Cu2þ, Co2þ, Ni2þ; X ¼ CH3COOꢁ, Clꢁ) or Mn(L)(CH3COO) ꢀ nH2O according to the experimental conditions used. The same
complexes have been prepared by condensation of the appropriate precursors in the presence of the desired metal ion. The Schiff
bases H2L have been reduced by NaBH4 to the related polyamine derivatives H2R, which form, when reacted with the appropriate
metal ions, M(H2R)(X)2 (M ¼ Co2þ, Ni2þ; X ¼ CH3COOꢁ, Clꢁ), Cu(R) ꢀ nH2O and Mn(R)(CH3COO) ꢀ nH2O. The prepared li-
gands and related complexes have been characterized by IR, NMR and mass spectrometry. The [1+1] cyclic nature of the mac-
rocyclic polyamine systems and the site occupancy of sodium ion have been ascertained, at least for the sodium (I) complex with the
macrocyclic ligand containing one N3O2 Schiff base and one O2O3 crown-ether like coordination chamber, by an X-ray structural
determination. In this complex the asymmetric unit consists of one cyclic molecule of the ligand coordinated to a sodium ion by the
five oxygen atoms of the ligand. The coordination geometry of the sodium ion can be described as a pentagonal pyramid with the
metal ion occupying the vertex. In the mononuclear complexes with H2L or H2R the transition metal ion invariantly occupies the
Schiff base site; the sodium ion, on the contrary, prefers the crown-ether like site. Accordingly, the heterodinuclear complexes
[MNa(L)(CH3COO)x] (M ¼ Cu2þ, Co2þ, Ni2, x ¼ 1; M ¼ Mn3þ, x ¼ 2) have been synthesised by reacting the appropriate formyl and
amine precursors in the presence of M(CH3COO)n ꢀ nH2O and NaOH in a 1:1:1:2 molar ratio. The reaction of the mononuclear
transition metal complexes with Na(CH3COO) ꢀ nH2O gives rise to the same heterodinuclear complexes. Similarly
[MNa(R)(CH3COO)x] have been prepared by reaction of the appropriate polyamine ligand H2R with the desired metal acetate
hydrate and NaOH in 1:1:2 molar ratio.
Ó 2004 Elsevier B.V. All rights reserved.
Keywords: Compartmental ligands; Heterodinuclear complexes; Schiff base; Macrocycles; Polyamines
1. Introduction
close proximity confers them the capability to undergo
two similar or dissimilar recognition processes, for in-
stance the coordination of two identical or different
metal ions in a well defined stereochemistry and at an
appropriate distance each other. This causes a mutual
influence between the two metal ions giving rise to sys-
tems with new physico-chemical properties which have
been used in the design of molecular magnetic or optical
devices, molecular probes for the selective recognition of
charged and/or or neutral molecules or polynuclear
Compartmental systems have received a growing in-
terest in the recent past owing to their ability to give rise
to compounds with unusual, although preordered,
properties [1–5]. The presence of two recognition sites in
* Corresponding author. Tel.: +39-049-829-5969; fax: +39-04-987-
02911.
E-mail address: patrizia.tomasin@icis.cnr.it (P. Tomasin).
0020-1693/$ - see front matter Ó 2004 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2004.06.007

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U. Casellato et al. / Inorganica Chimica Acta 357 (2004) 4191–4207
catalytic systems. It was proved, in fact, that two metal
ions, communicating each other through suitable
bridging groups, can give rise to antiferro- or ferro-
magnetic interactions, to electron-transfer processes or
can produce asymmetric or symmetric activation of
specific molecules and hence peculiar, highly selective
and efficient catalytic processes [6–13].
Moreover dinucleating systems containing a para-
magnetic centre fixed in one chamber (i.e., lantha-
nide(III), manganese(II), etc.) can influence considerably
the properties of the second metal ion coordinated to
the adjacent chamber (i.e., an alkali metal ion) and hence
can serve as molecular devices for its recognition and
qualitative detection in the solid state and in solution
[14].
To this purpose in the recent past a large variety of
acyclic and cyclic compartmental systems of the type
reported in Scheme 1 have been successfully proposed.
In these studies Schiff bases have been extensively
studied owing to their relatively easy synthesis and their
versatility in the formation of stable complexes. The
acyclic [2+1] and the [2+2] macrocyclic compartmental
ligands derive from the condensation reaction of 2,6-
diformyl-4-substituted phenol and the appropriate
amine H2N–R–NH2 in a 2:1 or 1:1 molar ratio. The
asymmetric acyclic and cyclic ligands have been pre-
pared by a step by step procedure. On changing the head
or the lateral units these ligands have been conveniently
diversified. As can be seen in Scheme 1 the acyclic li-
gands are asymmetric in nature, while the cyclic ligands
can be symmetric or asymmetric [1–5].
The best way for their preparation is to carry out the
condensation reaction of appropriate formyl and amine
precursors in the presence of a templating agent (i.e.,
Naþ). Nevertheless the possibility to obtain these com-
pounds by self-condensation of appropriate precursors
has been successfully experienced in the past. They are
identical to the compounds obtained by demetallation of
the related Schiff bases complexes. Their cyclic or acyclic
nature was inferred especially by mass spectrometry and
definitively demonstrated by single crystal X-ray struc-
tural determinations [1,4,15,16].
The symmetric cyclic ligands usually form homo-
dinuclear complexes, although hetero-dinuclear com-
plexation was observed, using particular experimental
conditions. This last complexation is generally favoured
by the protonations of the nitrogens of one compart-
ment, which makes the two sites no longer equivalent
and hence accessible to two different and subsequent
complexation reactions [1].
The ability to form heterodinuclear complexes is re-
lated to the possibility to synthesise stable mononuclear
complexes to be used as ‘‘ligand’’ for further complex-
ation or to have dinuclear systems capable to suffer a
transmetallation process at one of the two chambers.
Thus the possibility to have two well defined and dif-
ferent recognition processes at the two adjacent sites of
the compartmental systems is especially related to the
use of asymmetric compartmental ligands. The presence
of different donor atoms in the two chains, R and R’, in
fact, allows a different recognition process at the two
chambers [1,4,14]. More recently the two chambers have
been significantly diversified by the introduction of
polyetheric chains. These systems form stable hetero-
dinuclear complexes. No scrambling or migration pro-
cesses have been observed, thus pure positional isomers
are recovered. In several cases the marked differences in
the two coordination chambers allows the preparation
of hetero-dinuclear complexes in a one pot reaction.
Thus s,f-lanthanide(III)–sodium(I) or d,f-transition
metal lanthanide(III) complexes have been obtained and
characterized by NMR spectroscopy or X-ray diffrac-
tometry [16–20].
Moreover, one chamber of these compartmental li-
gand can recognise a metal ion while the other chamber
can give rise to a selective recognition process via the
Z
Z
Z
Z
N
N
OH
OH
NR'
NR'
N
N
OH
OH
N
N
N
N
OH
OH
N
N
N
N
OH
OH
O
O
R
R
R
R'
R
R
Z
Z
Z
Z
[2+1]
acyclic
[2+2]
[2+2]
symmetric
asymmetric
Scheme 1. [1+2] Acyclic and [2+2] macrocyclic compartmental ligands.

U. Casellato et al. / Inorganica Chimica Acta 357 (2004) 4191–4207
4193
formation of hydrogen bonding and/or complexation of
anions or organic molecule to the coordinated metal ion
[21–29].
We have already reported [18] the preparation and
the properties of a series of macrocycles H2LA–H4LD,
their corresponding mononuclear complexes with d
metal ions (Co2þ, Ni2þ, Cu2þ, Mn3þ) and the related
s,d-heterodinuclear ones.
In the present paper, we have enlarged the study with
other cyclic and acyclic Schiff bases (H2LE–H4LN)
(Scheme 2) together with those of some reduced ana-
logues. In particular the role of the different coordina-
tion cavity or the different donor set on the coordination
of transition metal ions as Co2þ, Ni2þ, Cu2þ, Mn3þ has
been studied. Also the use of the obtained mononuclear
complexes as ligands for the preparation of the hetero-
dinuclear complexes [MNa(L)(CH3COO)x] ꢀ nH2O or
Furthermore, these Schiff bases can be reduced to the
corresponding amine derivatives, which have a higher
stability (they do not suffer the hydrolytic processes
encountered with the Schiff base analogues), a greater
flexibility, maintaining an appreciable capability to form
complexes with transition metal ions. The availability of
these polyamine systems allows a useful comparison
between Schiff bases and their reduced analogues about
the different recognition processes in consequence of the
change from imine to amine groups inside the two ad-
jacent coordinating sites.
n
2
R
H2LA
H2LB
1
2
O
CH3
OH
OH
N
N
H2LC
H2LD
N
O
CH3
R
1
N
n
(CH2)11CH3
O
H2LE
H2LF
1
2
N
CH3
N
O
O
OCH2CH3
H2LI
COOH
n
OH
N
N
n
1
N
N
OH
H3LG
H3LH
O
2
OH
OH
OCH2CH3
m
1
R'
N
n
H2LL
O
O
1
2
(CH2)mR'
(CH2)mR'
OH
OH
N
N
O
2
1
H2LM
H4LN
N
n
COOH
1
Scheme 2. The prepared cyclic and acyclic ligands H2LAꢀ ꢀ ꢀH4LN.

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U. Casellato et al. / Inorganica Chimica Acta 357 (2004) 4191–4207
[MNa(R)(CH3COO)x] ꢀ nH2O (M ¼ Co2þ, Ni2þ, Cu2þ
x ¼ 1; M ¼ Mn3þ, x ¼ 2, n ¼ 4) have been successfully
experienced.
For both cyclic and acyclic derivatives additional
functionalities have been inserted (i.e., carboxylic or
pyridine groups) in order to verify their influence in the
coordination ability of the ligands towards different
metal ions and to study the physico-chemical properties
of the resulting mononuclear and/or heterodinuclear
complexes.
2.2.1.3. H2LE, H2LF . To a methanolic solution (50 ml)
of the appropriate diformyl derivative, 3,30-(3,6-diox-
aoctane-1,8-diyldioxy)bis(2-hydroxybenzaldehyde) or 3,30-
(3-oxapentane-1,5-diyldioxy)bis(2-hydroxybenzaldehyde)
(2 mmol), the desired polyamine,1,5-diamino-3-aza(do-
decyl)pentane or 1,7-diamino-4-aza(methyl)heptane, (2
mmol) in methanol (25 ml) was added dropwise. The
dark yellow solution was stirred under reflux for 2 h.
The solvent was removed by distillation under reduced
pression and the resulting oil or residue dissolved in
CHCl3 (10 ml) and precipitated with diethyl ether/pe-
troleum ether (1:1 50 ml) this last solubilization/precip-
itation process being repeated three/four times. The final
yellow product was collected by filtration, and washed
with diethyl ether/petroleum ether and dried in vacuo.
The products can be further purified by chromatogra-
phy on alumina using CHCl3 as eluent (yield 54–59%).
Anal. Calc. for H2LE: C, 68.09; H, 8.91; N, 7.01.
Found: C, 68.09; H, 8.92; N, 6.74%. IR (cmꢁ1): 1633
m(C@N).
2. Experimental
2.1. Materials
The hydrate metal acetates, 3-ethoxy-2-hydroxy-
benzaldehyde, the polyamines and the other reagents
were commercial products, used as received by Aldrich.
Dimethylsulfoxide was purified by standard methods
[30] while the other solvents were reagent grade, used as
received. The diformyl precursors 3,3-(3-oxapentane-
1,5-diyldioxy)bis(2-hydroxybenzaldehyde) (H2LI), the
disodium derivative (Na2LI) and 3,30-(3,6-dioxaoctane-
1,8-diyldioxy)bis(2-hydroxybenzaldehyde) (H2LII) were
prepared by literature methods [17–33].
Anal. Calc. for H2LF ꢀ 0.5H2O: C, 63.76; H, 7.53; N,
8.26. Found: C, 63.78; H, 7.64; N, 8.16%. IR (cmꢁ1):
1634 m(C@N); 1025, 1087 m(C–O).
Na2(LD) was prepared according to literature [17].
2.2.1.4. Na(H2LG) ꢀ H2O, Na(H2LH) ꢀ H2O. To an
aqueous solution (5 ml) of 2,3-diaminopropionic acid
monochlorohydrate or 2,4-diaminobutirric acid dichlo-
rohydrate (5 mmol), respectively, 5 and 10 mmol of
NaOH in methanol (5ml) were added. The solution was
stirred for 15 min, then added with a methanol solution of
3,30-(3-oxapentane-1,5-diyldioxy)bis(2-hydroxybenzal-
dehyde) (H2LI), finally refluxed for 2 h. The solvent was
evaporated at reduced pressure and the resulting orange-
yellow or yellow residue was washed twice with ethanol,
collected by filtration and dried in vacuo (69–70%).
Anal. Calc. for Na(H2LG) ꢀ H2O: C, 55.51; H, 5.10; N,
6.16. Found: C, 55.67; H, 5.33; N, 6.18%. IR (cmꢁ1):
1630 m(C@N); 1635 masym(COO).
The preparation and the manipulation of the co-
balt(II) complexes have been carried out in dry boxes or
under a nitrogen atmosphere.
Caution. Although during these experiments no ac-
cidents have occurred, extreme care should be taken
when perchlorates are handled, because they may ex-
plode spontaneously and may be sensitive to shock. The
perchlorates should only be prepared in small quantities.
2.2. Ligands
2.2.1. Macrocyclic Schiff bases
2.2.1.1. H2LA, H2LB. The yellow ligands H2LA and H2LB
were prepared according to literature (62–65% yield) [16].
Anal. Calc. for Na(H2LH) ꢀ H2O: C, 56.30; H, 5.10; N,
5.20. Found: C, 56.41; H, 5.38; N, 5.98%. IR (cmꢁ1):
1630 m(C@N); 1636 masym(COO).
2.2.1.2. H2LC, H2LD. A methanol solution (3 ml) of 1,5-
diamino-3-azamethylpentane (1 mmol) was diluted with
diethylether (400 ml). A CHCl3 solution (5 ml) of 3,30-
(3-oxapentane-1,5-diyldioxy)bis(2-hydroxybenzaldehyde)
2.2.2. Macroacyclic Schiff bases
or
3,30-(3,6-dioxaoctane-1,8-diyldioxy)bis(2-hydroxy-
2.2.2.1. H2LI . To a pale yellow CHCl3 solution (60 ml)
of 3-ethoxysalicylaldehyde (24.07 mmol) ethylenedia-
mine (12.03 mmol) was added. The yellow solution was
refluxed for 2 h, then reduced in volume and allowed to
stand. The resulting yellow precipitate was collected by
filtration, washed twice with diethylether (20 ml) and
dried in vacuo (80% yield).
Anal. Calc. for H2LI ꢀ H2O: C, 64.16; H, 7.00; N, 7.48.
Found: C, 64.81; H, 6.87; N, 7.70%. IR (cmꢁ1): 1634
m(C@N), 1249, 1077 m(C–O).
benzaldehyde) (1 mmol) was added dropwise at room
temperature. The yellow precipitate was stirred for
20 min, then filtered, well washed with a diethylether/
petroleum ether solution and dried in vacuo (55–60%).
Anal. Calc. for H2LC: C, 63.68; H, 7.05; N, 8.91.
Found: C, 62.67; H, 6.88; N, 8.45%. IR (cmꢁ1): 1633
m(C@N).
Anal. Calc. for H2LD: C, 62.29; H, 6.59; N, 9.47. Fo-
und: C, 62.71; H, 6.73; N, 9.28%. IR (cmꢁ1): 1634 m(C@N).

U. Casellato et al. / Inorganica Chimica Acta 357 (2004) 4191–4207
4195
2.2.2.2. H2LL, H2LM. 2-(Aminomethyl)pyridine or 2-(2-
aminoethyl)pyridine (6 mmol) was added to a pale
yellow CHCl3 solution (60 ml) of, respectively, 3,30-(3-ox-
apentane-1,5-diyldioxy)bis(2-hydroxybenzaldehyde) or
3,30-(3,6-dioxaoctane-1,5-diyldioxy)bis(2-hydroxybenz-
aldehyde) (3 mmol). The resulting dark yellow solution
was refluxed for 2 h, then evaporated to dryness. The
yellow oil obtained was treated four times with diethyl
ether (4 ꢂ 100 ml). The yellow solution obtained was
allowed to stand for 20 min until a yellow microcrys-
talline precipitate separated. This was collected by fil-
tration, washed with diethyl ether (50 ml) and dried in
vacuo (78–82%).
room temperature for 30 min, then evaporated to dry-
ness. The residue was treated with H2O (100 ml), filtered
off and dissolved in CHCl3 or CHCl3/MeOH (4:1). The
resulting solution was anhydrified over molecular sieves,
then evaporated to dryness. The cream or white residue
was dissolved in CHCl3 or MeOH and precipitated by
the addition of diethyl ether or petroleum ether. The
obtained cream or white precipitate was collected by
filtration, washed with diethyl ether or petroleum ether
and dried in vacuo (39–40% yield).
Anal. Calc. for H2RA: C, 63.15; H, 7.23; N, 6.69.
Found: C, 63.53; H, 7.72; N, 6.24%. IR: (cmꢁ1): 3291
m(N–H); 1231, 1076 m(C–O).
Anal. Calc. for H2LL: C, 68.43; H, 5.74; N, 10.64.
Found: C, 69.40; H, 5.38; N, 10.29%. IR (cmꢁ1): 1633
m(C@N).
Anal. Calc. for H2RB ꢀ 0.5CHCl3: C, 56.82; H, 6.16;
N, 6.46. Found: C, 56.05; H, 6.33; N, 6.39%. IR (cmꢁ1):
3302 m(N–H); 1229, 1075 m(C–O).
Anal. Calc. for H2LM: C, 68.21; H, 6.40; N, 9.36.
Found: C, 67.35; H, 6.38; N, 9.39%. IR (cmꢁ1): 1636
m(C@N); 1255, 1046 m(C–O).
2.2.3.2. Na(HRD). To a CHCl3/MeOH solution (50 ml)
of Na2(LD)(1 mmol), an excess (4 mmol) of NaBH4 was
added. The solution, turned from yellow to a pale yel-
low, was stirred at room temperature for 1 h. A pale
yellow precipitate formed, which was filtered, well wa-
shed with EtOH and subsequently diethyl ether, and
dried in vacuo (40% yield).
Anal. Calc. for Na(HRD) ꢀ 1CHCl3: C, 50.63; H, 5.49;
N, 7.38. Found: C, 50.06; H, 5.85; N, 7.24%. IR: (cmꢁ1):
3279 m(N–H).
2.2.2.3. Na(HLL) ꢀ H2O. 2-(Aminomethyl)pyridine (10
mmol) in 10 ml of methanol was added dropwise to a
methanol solution (50 ml) of Na2LI (5 mmol). The yel-
low solution obtained was refluxed for 2 h; the solvent
was evaporated to dryness under reduced pressure and
the brown residue was washed twice with diethyl ether,
filtered and dried in vacuo (55%).
Anal. Calc. for Na(HLL) ꢀ H2O: C, 63.60; H, 5.52; N,
9.89. Found: C, 62.99; H, 5.02; N, 8.98%. IR (cmꢁ1):
1633 m(C@N).
2.2.3.3. H2RI , H2RL, H2RM. To a CHCl3/MeOH (60 ml)
solution of appropriate acyclic Schiff base H2LI, H2LL,
H2LM (1 mmol) an excess of NaBH4 (ꢃ5 mmol) was
added under vigorous stirring. The solution, turned
from yellow to white or pale-yellow, was maintained
under stirring for 1–2 h, then reduced in volume and
allowed to stand (for H2RI) or evaporated to dryness
(for H2RL or H2RM). H2RI was collected from the so-
lution by filtration, washed with methanol and dried in
vacuo. The residue was treated with CHCl3 (H2RL) or
CH2Cl2/MeOH (H2RM); the solution was clarified by
filtration and maintained over molecular sieves over-
night, then partially evaporated (H2RL) or totally
evaporated (H2RM). The subsequent addition of diethyl
ether to the chloroform solution of H2RL produces a
white precipitate which was collected by filtration and
dried in vacuo. The residue of H2RM was dissolved in
MeOH (10ml); the subsequent addition of petroleum
ether to the clarified methanolic solution caused the
precipitation of H2RM as a white oil which was collected
and dried in vacuo (40–43% yield).
2.2.2.4. Na(H3LN)ꢀH2O. To a water solution (3 ml)
of glycine (8 mmol), NaOH (8 mmol) in MeOH
(5ml) was added dropwise. To the resulting solution
3,30-(3-oxapentane-1,5-diyldioxy)bis(2-hydroxybenzalde-
hyde) (4 mmol) in MeOH (40 ml) was added. The
resulting solution was refluxed for 2 h, then evapo-
rated to dryness. The maroon residue was dissolved
in MeOH (5 ml) filtered and precipitate with H2O
(10 ml). The maroon precipitate was collected by
filtration, washed with diethyl ether and dried in
vacuo (yield 64%).
Anal. Calc. for Na(H3LN) ꢀ H2O: C, 52.81; H, 5.04; N,
5.60. Found: C, 53.37; H, 4.67; N, 5.13%. IR (cmꢁ1):
1655 m(C@N); 1611 masym(COO).
2.2.3. Macrocyclic and macroacyclic polyamines
A general methodology was used for all the cyclic and
acyclic polyamine derivatives. The desired compound
was obtained by reduction of the appropriate Schiff base
with an excess of NaBH4.
Anal. Calc. for H2RI ꢀ H2O: C, 63.48; H, 7.99; N,
7.40. Found: C, 64.01; H, 8.09; N, 6.96%. IR (cmꢁ1):
3291 m(N–H); 1230–1069 m(C–O).
Anal. Calc. for H2RL ꢀ H2O: C, 65.68; H, 6.61; N,
10.21. Found: C, 64.82; H, 6.11; N, 9.81%. IR(cmꢁ1):
3289 m(N–H).
2.2.3.1. H2RA, H2RB. A CHCl3/MeOH solution (60 ml)
of appropriate Schiff base (7 mmol) was reacted with an
excess (36 mmol) of NaBH4. The solution, turned from
dark yellow to pale yellow (or cream), was stirred at

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U. Casellato et al. / Inorganica Chimica Acta 357 (2004) 4191–4207
H2RM is an oil; consequently the elemental analysis
was not carried out. IR (cmꢁ1): 3257 m(N–H); 1230, 1082
m(C–O).
resulting solution was refluxed for 2 h then evaporated
to dryness. The residue was treated with CHCl3 (5 ml).
The solution, clarified by filtration, separates by addi-
tion of diethylether (10 ml) a precipitate (dark green for
Cu complexes, red for Ni complexes) which was filtered,
washed with CHCl3/Et2O (1:2) and dried in vacuo (50–
55% yield).
2.2.3.4. Na(HRL) ꢀ H2O. An excess of NaBH4 (12
mmol) was added under stirring at room temperature to
a methanol–chloroform solution (50 ml) of Na(HLL) ꢀ
H2O (3 mmol). The cream solution obtained was stirred
for 1 h, then allowed to stand for 2 h. The solvent was
evaporated to dryness and the cream residue was dis-
solved with CHCl3 (60 ml); the solution was clarified by
filtration, then evaporated to dryness. The solution ob-
tained by dissolving the residue in CHCl3 (10 ml) was
filtered and treated with diethyl ether (40 ml). The cream
precipitate obtained was filtered and dried in vacuo
(42% yield).
Anal. Calc. for Cu(HLE)(CH3COO): C, 61.48; H,
7.60; N, 5.97. Found: C, 61.74; H, 8.13; N, 6.82%. IR
(cmꢁ1): 1636 m(C@N); leff ¼ 2:1 BM.
Anal. Calc. for Ni(H2LE)(CH3COO)2 ꢀ H2O: C, 49.94;
H, 5.48; N, 4.48. Found: C, 50.13; H, 5.15; N, 5.18%. IR
(cmꢁ1): 1623 m(C@N); leff ¼ 2:3 BM.
2.3.2. Mononuclear acyclic Schiff bases complexes
2.3.2.1. M(L) (M ¼ Ni2þ,Cu2þ; H2L ¼ H2LI , H2LL),
Co(H2LI )(CH3COO)2 and Mn(LI )(CH3COO)ꢀH2O.
To a methanolic solution (30 ml) of the diformyl de-
rivative 3-ethoxysalicylaldehyde or 3,30-(3-oxapentane-
1,5-diyldioxy)bis(2-hydroxybenzaldehyde) (1 mmol), the
appropriate amine (2 mmol) (respectively, ethylenedia-
mine and 2-aminomethylpyridine) in methanol (10 ml)
and, after a stirring of 15 min, the desired metal(II)
acetate hydrate (1 mmol) were added. The resulting
solution was refluxed for 2 h then evaporated to dryness.
The residue was treated with CHCl3 (5 ml); the resulting
solution, clarified by filtration, separated a precipitate
when treated with diethyl ether (20 ml). This was col-
lected by filtration, washed with CHCl3/Et2O (1:4) and
dried in vacuo.
Anal. Calc. for Na(HRL) ꢀ H2O: C, 61.32; H, 6.18; N,
9.53. Found: C, 61.70; H, 5.65; N, 8.93%. IR (cmꢁ1):
3278 m(N–H).
2.3. Complexes
2.3.1. Mononuclear complexes with cyclic Schiff bases
2.3.1.1. Ni(LE) ꢀ 2H2O. To a methanolic solution (60
ml) of 3,30-(3-oxapentane-1,5-diyldioxy)bis(2-hydroxy-
benzaldehyde) (1 mmol), 1,5-diamino-3-aza(dodecyl)-
pentane (1 mmol) in methanol (10 ml) and after a
stirring of 10 min, Ni(II) acetate hydrate (1 mmol) in
methanol (10 ml) were added. The solution, turned into
orange-red, was refluxed for 2 h, then evaporated to
dryness. The residue was dissolved in ethanol and, after
filtration, a orange-red precipitate was obtained by ad-
dition of diethyl ether; it was collected by filtration,
washed with ethanol/diethyl ether and dried in vacuo
(55% yield).
Alternatively the same complexes have been obtained
by reacting equimolecular amounts of the preformed
Schiff base and the appropriate metal acetate hydrate
and following the same synthetic procedure (60–65%
yield).
Anal. Calc. for Ni(LI) (orange red precipitate): C,
58.15; H, 5.37; N, 6.78. Found: C, 58.59; H, 5.49; N,
6.69%. IR (cmꢁ1): 1617 m(C@N); leff ¼ 0:4 BM.
Anal. Calc. for Cu(LI) (dark green): C, 57.48; H, 5.31;
N, 6.70. Found: C, 57.21; H, 4.89; N, 6.54%. IR (cmꢁ1):
1631 m(C@N); 1238, 1080 m(C–O); leff ¼ 1:9 BM.
Anal. Calc. for Co(H2LI)(CH3COO)2 (brick red): C,
54.04; H, 5.67; N, 5.25. Found: C, 54.04; H, 5.44; N,
5.71%. IR (cmꢁ1): 1639 m(C@N); 1246, 1084 m(C–O);
leff ¼ 3:2 BM.
Anal. Calc. for Ni(LE) ꢀ 2H2O: C, 60.45; H, 8.06; N,
6.22. Found: C, 60.19; H, 8.71; N, 6.26%. IR (cmꢁ1):
1625 m(C@N); leff ¼ 2:2 BM.
2.3.1.2. Ni(H2LE)(CH3COO)2 ꢀ 4H2O and Cu(HLE)
(CH3COO). To a methanolic solution (50 ml) of
3,30-(3-oxapentane-1,5-diyldioxy)bis(2-hydroxybenzalde-
hyde) (1 mmol), 1,5-diamino-3-aza(dodecyl)pentane (1
mmol) and the desired metal(II) acetate (1 mmol) in
methanol (10 ml) were added in succession. The solution
was refluxed for 2 h then evaporated to dryness. The
residue was treated with CHCl3 (5 ml). To the resulting
solution, clarified by filtration, diethylether was added;
the obtained precipitate was collected by filtration and
dried in vacuo.
Anal. Calc. for Mn(LI)(CH3COO) ꢀ H2O (brown): C,
52.39; H, 5.80; N, 5.55. Found: C, 53.23; H, 5.18; N,
5.04%. IR (cmꢁ1): 1624 m(C@N); 1253, 1083 m(C–O);
leff ¼ 6:2 BM.
Anal. Calc. for Ni(LL) ꢀ H2O (orange-red): C, 59.93;
H, 5.03; N, 9.32. Found: C, 60.77; H, 4.85; N, 8.46%. IR
(cmꢁ1): 1630 m(C@N); leff ¼ 3:0 BM.
Alternatively the same complexes have been obtained
by reacting a chloroform solution (60 ml) of the
appropriate macrocycle (1 mmol) with the desired
metal(II) acetate (1 mmol) in methanol (5 ml). The
Anal. Calc. for Cu(LL) ꢀ 2CHCl3ꢀH2O (dark green): C,
45.65; H, 3.83; N, 6.65. Found: C, 44.73; H, 3.74; N,
7.61%. IR (cmꢁ1): 1639 m(C@N); leff ¼ 1:75 BM.

U. Casellato et al. / Inorganica Chimica Acta 357 (2004) 4191–4207
4197
2.3.3. Mononuclear complexes with cyclic polyamine
derivatives
2.3.4.2. M(RI ) ꢀ nH2O (M ¼ Ni2þ,Cu2þ, n ¼ 2,3). To a
CHCl3 solution (50 ml) of H2RI (1 mmol) the appro-
priate metal(II) acetate (1 mmol) in methanol (5 ml) and
subsequently [N(Bu)4](OH) (2 mmol) were added. The
solution was refluxed for 2 h then evaporated to dryness.
The residue was dissolved in EtOH, clarified by filtra-
tion, and precipitated by addition of diethyl ether. The
product obtained was collected by filtration, washed
with an ethanol/diethyl ether solution and dried in va-
cuo (65% yield).
Anal. Calc. for Ni(RI) ꢀ 3H2O (orange-red): C, 51.98;
H, 6.76; N, 6.06. Found: C, 51.33; H, 5.84; N, 5.51%. IR
(cmꢁ1): 3258 m(N–H), 1229, 1059 m(C–O); leff ¼ 3:0 BM.
Anal. Calc. for Cu(RI) ꢀ 2H2O (dark green): C,
52.45; H, 6.60; N, 6.12. Found: C, 52.79; H, 6.33; N,
5.41%. IR (cmꢁ1): 3224 m(N–H); 1232, 1070 m(C–O);
leff ¼ 1:9 BM.
2.3.3.1. Cu(RA) ꢀ 2H2O, M(H2RA)(CH3COO)2 (M ¼
Co2þ, Ni2þ) and Mn(RA)(CH3COO)ꢀ2H2O. To a
CHCl3/MeOH solution (50 ml) of the appropriate poly-
amine (1 mmol) the desired metal(II) acetate (1 mmol) in
methanol (10 ml) was added. The resulting solution was
refluxed for 2 h then evaporated to dryness. The residue
was treated with CHCl3 (10 ml); to the resulting solution,
clarified by filtration, diethyl ether (40 ml) was added
and the obtained precipitate was washed with CHCl3/
Et2O (1:4) and dried in vacuo (52–55% yield).
Anal. Calc. for Ni(H2RA)(CH3COO)2 (pale green): C,
52.46; H, 6.10; N, 4.71. Found: C, 52.57; H, 6.00; N,
4.88%. IR (cmꢁ1): 3230 m(N–H); 1589 masym(COO); 1400
m
sym(COO), 1240, 1087 m(C–O); leff ¼ 3:0 BM.
Anal. Calc. for Cu(RA) ꢀ 2H2O (green): C, 51.21;
H, 6.25; N, 5.43. Found: C, 50.85; H, 5.38; N, 5.06%.
IR (cmꢁ1): 3222 m(N–H); 1223, 1071 m(C–O); leff ¼ 1:8
BM.
2.3.4.3. Cu(RL) ꢀ H2O. Copper(II) acetate hydrate (1
mmol) in methanol (5 ml) was added to a CHCl3 solu-
tion (50 ml) of the polyamine H2RL ꢀ H2O (1 mmol). The
solution was refluxed for 2 h then reduced in volume.
The resulting green precipitate was collected by filtra-
tion, washed with diethylether and dried in vacuo (55%
yield).
Anal. Calc. for Cu(RL) ꢀ H2O: C, 49.11; H, 5.81; N,
5.21. Found: C, 49.00; H, 5.80; N, 4.90%. IR (cmꢁ1):
3250 m(N–H); leff ¼ 1:73 BM.
Anal. Calc. for Co(H2RA)(CH3COO)2 (green): C,
52.44; H, 6.09; N, 4.70. Found: C, 53.21; H, 6.62; N,
4.59%. IR (cmꢁ1): 3225, m(N–H) 1576 masym(COO); 1408,
1383 msym(COO), 1228, 1065 m(C–O); leff ¼ 3:6 BM.
Anal. Calc. for Mn(RA)(CH3COO)ꢀ2H2O (brown): C,
50.89; H, 6.23; N, 4.95. Found: C, 51.33; H, 5.42; N,
4.48%. IR (cmꢁ1): 3233 m(N–H); 1589 masym(COO); 1400
m
sym(COO); 1240, 1021 m(C–O); leff ¼ 5:9 BM.
2.3.5. Heterodinuclear Schiff bases complexes
2.3.4. Mononuclear complexes with acyclic polyamine
derivatives
2.3.5.1. MNa(L)(CH3COO) ꢀ nH2O (M ¼ Co2þ, Ni2þ
,
Cu2þ
;
H2L ¼ H2LF , H2LI , H2LL), MNa(HLL)-
2.3.4.1. M(H2RI ) (CH3COO)2 (M ¼ Co2þ, Ni2þ) and
Mn(RI )(CH3COO)ꢀH2O. To a CHCl3 solution (50 ml)
of H2RI (1 mmol) the appropriate metal acetate (1
mmol) in methanol (5 ml) was added. The solution was
refluxed for 2 h then evaporated to dryness. The residue
was dissolved in EtOH (15 ml), clarified by filtration,
and precipitated by addition of diethyl ether (50 ml).
The product obtained was collected by filtration, washed
twice with an ethanol/diethyl ether solution and dried in
vacuo (62–65% yield).
(CH3COO)2 ꢀ nH2O (M ¼ Cu2þ, Ni2þ), NiNa(L) ꢀ H2O
(H3L ¼ H3LG, H3LH), MNa(HLN)ꢀH2O (M ¼ Cu2þ
,
Ni2þ), MnNa(LI )(CH3COO)2 ꢀ nH2O, MnNa(LM)-
(CH3COO) ꢀ H2O. These different synthetic procedure
were employed:
(A) To a methanol solution or suspension (30 ml) of
the appropriate Schiff base (1 mmol) the desired metal
acetate (1 mmol) in methanol (10 ml) was added. The
resulting suspension, was refluxed for 15 min and, after
the addition of NaOH (2 mmol) in 10 ml of MeOH,
maintained under reflux for additional 2 h. Then it was
allowed to stand overnight and the resulting precipitate
was collected by filtration, washed with methanol and
dried in vacuo.
(B) To a methanolic solution (30 ml) of the sodium
derivative Na2 ꢁ n(HnL) (1 mmol) the desired metal ac-
etate (1 mmol) in 10 ml of methanol was added. The
resulting suspension was refluxed for 15 min and, after
the addition of NaOH (2 mmol) in 10 ml of MeOH,
maintained under reflux for 2 h. Then it was allowed to
stand overnight and the precipitate obtained was col-
lected by filtration, washed with methanol and dried in
vacuo.
Anal. Calc. for Ni(H2RI)(CH3COO)2 (pale green): C,
53.66; H, 6.38; N, 5.21. Found: C, 53.84; H, 6.65; N,
5.48%. IR (cmꢁ1): 3220 m(N–H); 1583 masym(COO); 1410
m
sym(COO); 1056, 1227 m(C–O); leff ¼ 3:5 BM.
Anal. Calc. for Co(H2RI)(CH3COO)2 ꢀ 2H2O (dark
green): C, 52.73; H, 6.73; N, 4.92. Found: C, 52.53; H,
6.24; N, 5.36%. IR (cmꢁ1): 3227 m(N@H); 1570
m
asym(COO), 1393 msym(COO); 1233, 1066 m(C–O);
leff ¼ 3:6 BM.
Anal. Calc. for Mn(RI)(CH3COO)ꢀH2O (brown): C,
53.88; H, 6.37; N, 5.71. Found: C, 53.46; H, 6.31; N,
5.48%. IR (cmꢁ1): 3243 m(N–H); 1566 masym(COO); 1410
m
sym(COO), 1237, 10063 m(C–O); leff ¼ 6:1 BM.

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U. Casellato et al. / Inorganica Chimica Acta 357 (2004) 4191–4207
(C) Alternatively, to a methanolic solution (30 ml) of
Anal. Calc. for CuNa(HLN) ꢀ H2O (brown): C, 47.02;
H, 4.13; N, 4.98. Found: C, 46.30 H, 4.53; N, 4.90%. IR
(cmꢁ1): 1644 m(C@N); 1601 masym(COO); leff ¼ 1:6 BM.
NB: SEM-EDS investigations show all the prepared
heterodinuclear complexes have a M:Na ¼ 1:1 ratio.
the appropriate diformyl precursor (1 mmol), the ap-
propriate polyamine (1 mmol), metal acetate hydrate (1
mmol) and NaOH (2 mmol) were added in succession.
The resulting suspension was refluxed for 2 h then al-
lowed to stand for 3 h. The precipitate was collected by
filtration, washed with methanol and dried in vacuo (50–
55% yield).
2.3.6. Heterodinuclear complexes with polyamine deriva-
tives
Anal. Calc. for NiNa(LF)(CH3COO) (emerald green):
C, 54.57; H, 6.0; N, 6.58. Found: C, 53.85; H, 5.94; N,
6.72%. IR (cmꢁ1): 1632 m(C@N); 1597 masym(COO); 1324
2.3.6.1. MNa(R)(CH3COO) ꢀ nH2O, MnNa(R)(CH3-
COO)2 (M ¼ Co2þ,Ni2þ,Cu2þ
;
H2R ¼ H2RA, H2RI ,
m
sym(COO); 1217, 1089 m(C–O); leff ¼ 3:5 BM.
H2RL, H2RM; n ¼ 1,2). The complexes have been pre-
pared following the same procedures employed for the
synthesis of the analogous Schiff base complexes. To a
methanol solution or suspension (30 ml) of the appro-
priate polyamine H2R (1 mmol) the desired metal(II)
acetate (1 mmol) in methanol (10 ml) was added. The
resulting suspension was refluxed for 15 min and, after
the addition of NaOH (2 mmol) in 10 ml of MeOH, was
maintained under reflux for additional 2 h. Then it was
allowed to stand. The resulting precipitate was collected
by filtration, washed with methanol and dried in vacuo
(45–50% yield).
Anal. Calc. for NiNa(LG) ꢀ H2O (orange): C, 49.35;
H, 4.14; N, 5.48. Found: C, 49.73; H, 4.36; N, 6.16%.
IR (cmꢁ1): 1617 m(C@N); 1614 masym(COO); leff ¼ 2:8
BM.
Anal. Calc. for NiNa(LH) ꢀ H2O (orange-red): C,
49.26; H, 4.65; N, 4.79. Found: C, 48.34; H, 4.15; N,
5.55%. IR (cmꢁ1): 1618 m(C@N); 1613 masym(COO); 1314
m
sym(COO); 1227, 1087 m(C–O), leff ¼ 2:7 BM.
Anal. Calc. for NiNa(LI)(CH3COO) ꢀ H2O (red): C,
51.50; H, 5.30; N, 5.46. Found: C, 51.53; H, 5.27; N,
5.62%. IR (cmꢁ1): 1618 m(C@N); 1601 masym(COO); 1314
m
asym(COO); 1227, 1087 (C–O); leff ¼ 0:3 BM.
Anal. Calc. for NiNa(RA)(CH3COO) ꢀ 2.5H2O (or-
ange): C, 47.87; H, 6.03; N, 4.65. Found: C, 47.16; H,
5.23; N, 4.54%. IR (cmꢁ1): 1571 masym(COO); 1315
Anal. Calc. for CuNa(LI)(CH3COO) (brown): C,
52.85; H, 5.04; N, 5.60. Found: C, 52.75; H, 5.05;
N, 6.12%. IR (cmꢁ1): 1632 m(C@N); 1599
m
sym(COO); 1246, 1091 m(C–O) leff ¼ 2:2 BM.
m
asym(COO); 1312 msym(COO); 1238, 1081 m(C–O);
Anal. Calc. for CuNa(RA)(OH) ꢀ H2O (green): C,
leff ¼ 2:0 BM.
49.12; H, 5.81; N, 5.21. Found: C, 48.49; H, 4.93; N,
4.65%. IR (cmꢁ1): 3226 m(N–H); leff ¼ 1:8 BM.
Anal. Calc. for CoNa(LI)(CH3COO) ꢀ H2O (dark
green): C, 51.47; H, 5.30; N, 5.46. Found: C, 52.10; H,
5.51; N, 6.28%. IR (cmꢁ1):1638 m(C@N); 1604
Anal. Calc. for CoNa(RA)(CH3COO) ꢀ 2H2O (dark
green): C, 48.58; H, 5.95; N, 4.72. Found: C, 48.09; H,
5.22; N, 4.24%. IR (cmꢁ1): 3232 m(N–H); 1570
m
asym(COO); 1312 msym(COO); 1224, 1084 m(C–O);
leff ¼ 2:1 BM.
masym(COO), 1314 msym(COO); 1237, 1079 m(C–O);
Anal. Calc. for MnNa(LI)(CH3COO)2 (brown): C,
52.38; H, 5.13; N, 5.09. Found: C, 53.31; H, 5.48; N,
5.19%. IR (cmꢁ1):1625 m(C@N); 1598 masym(COO); 1332
leff ¼ 2:6 BM.
Anal. Calc. for MnNa(RA)(CH3COO)2 (brown): C,
50.99; H, 5.60; N, 4.57. Found: C, 50.53; H, 5.31; N,
4.32%. IR (cmꢁ1): 1569; masym(COO); 1409 msym(COO);
1237, 1079 m(C–O) leff ¼ 5:0 BM.
m
sym(COO); 1252, 1084 m(C–O); leff ¼ 5:0 BM.
Anal. Calc. for NiNa(LL)(CH3COO) ꢀ 2H2O (brown):
C, 56.25; H, 5.96. Found: N, 6.90; C, 56.03; H, 5.12; N,
6.90%. IR (cmꢁ1): 1635 m(C@N); leff ¼ 3:1 BM.
Anal. Calc. for NiNa(HLL)(CH3COO)2 ꢀ 4H2O (yel-
low-orange): C, 50.96; H, 5.91; N, 6.99. Found: C,
50.49; H, 5.56; N, 6.89%. IR (cmꢁ1): 1635 m(C@N);
leff ¼ 3:1 BM.
Anal. Calc. for NiNa(RI)(CH3COO) (grey): C, 52.94;
H, 5.86; N, 5.61. Found: C, 53.16; H, 5.75; N, 5.34%. IR
(cmꢁ1): 3283 m(N–H); 1566
sym(COO); 1228, 1064 m(C–O); leff ¼ 3:0 BM.
Anal. Calc. for CuNa(RI)(CH3COO) (green): C,
masym(COO); 1313
m
52.43; H, 5.80; N, 5.56. Found: C, 53.18; H, 5.87; N,
5.71%. IR (cmꢁ1): 3226 m(N–H); 1568 masym(COO); 1308
Anal. Calc. for CuNa(HLL)(CH3COO)2 ꢀ 2H2O (ha-
zel-brown): C, 54.43; H, 5.00; N, 7.93. Found: C, 53.89;
H, 4.07; N, 7.92%. IR (cmꢁ1): 1625 (C@N); leff ¼ 1:8
BM.
m
sym(COO); 1234, 1070 m(C–O); leff ¼ 1:9 BM.
Anal. Calc. for CoNa(RI)(CH3COO) ꢀ 2H2O (green):
C, 49.35; H, 6.21; N, 5.23. Found: C, 49.52; H, 5.73; N,
5.12%. IR (cmꢁ1): 1570, masym(COO); 1297 msym(COO);
1236, 1072 m(C–O); leff ¼ 2:1 BM.
Anal. Calc. for NiNa(LM)(CH3COO) ꢀ 2H2O (yel-
low): C, 55.76; H, 5.85; N, 7.22. Found: C, 56.03; H,
5.12; N, 6.90%.
Anal. Calc. for NiNa(HLN) ꢀ H2O (hazel-brown): C,
47.43; H, 4.13; N, 5.03. Found: C, 47.00 H, 4.53N,
4.90%. IR (cmꢁ1): 1639 m(C@N); 1600 masym(COO);
leff ¼ 3:6 BM.
Anal.
Calc.
for
MnNa(RI)(CH3COO)2 ꢀ H2O
(brown): C, 50.36; H, 5.99; N, 4.89. Found: C, 50.61; H,
5.47; N, 5.08%. IR (cmꢁ1): 3283 m(N–H), 1570
m
asym(COO); 1411 msym(COO); 1228, 1064 m(C–O);
leff ¼ 4:7 BM.

U. Casellato et al. / Inorganica Chimica Acta 357 (2004) 4191–4207
4199
Anal. Calc. for CuNa(RL)(CH3COO) ꢀ H2O (dark
2.5. Physico-chemical measurements
brown): C, 57.61; H, 4.83; N, 8.94. Found: C, 57.72; H,
4.84; N, 8.97%. IR (cmꢁ1): 3330 m(N–H); 1580
m
IR spectra were recorded as KBr pellets on a Mattson
5000 FT-IR spectrometer. The same instrument, con-
nected to a Quantum microscope equipped with a MCT
detector, was used to collect the spectral data directly on
the samples and avoid the risk of metathetic processes
with KBr matrix.
Spectra in the UV–Vis region were collected in the
solid state and in CHCl3, MeOH or DMSO with a UV
500 Spectronic Unicam.
asym(COO); 1315 msym(COO); leff ¼ 1:92 BM.
Anal. Calc. for NiNa(RM)(CH3COO) ꢀ 1.5H2O (pale
green): C, 56.27; H, 6.03; N, 7.29. Found: C, 56.01; H,
5.91; N, 7.39%. IR (cmꢁ1): 3267 1570 masym(COO); 1308
m
sym(COO); 1232, 1080 m(C–O); leff ¼ 3:5 BM.
NB: SEM-EDS investigations show all the prepared
heterodinuclear complexes have a M:Na ¼ 1:1 ratio.
2.4. Crystal data
1H, and 13C NMR spectra and 2D COSY and NO-
ESY experiments were recorded at 300.13 MHz on a
Bruker AMX300 spectrometer at room temperature.
Some of the signals were assigned by the spin decoupling
technique. All the samples examined were dissolved in
deuterated chloroform or methanol used also as internal
references.
The morphology, homogeneity and the metal:sodi-
um ¼ 1:1 ratio in the complexes were checked by using a
Philips XL40 model scanning electron microscopy
equipped with an EDAX DX PRIME X-ray energy
dispersive spectrometer [35].
The water content in the prepared samples was
evaluated by thermal analysis curves using a Netzsch
STA 429 thermoanalytical equipment. The tests were
performed in a nitrogen atmosphere (flux rate 250 ml/
min; heating rate 5°C minꢁ1) and in air under the same
conditions. Neutral alumina (Carlo Erba product) was
used as reference material.
All mass spectrometric measurements were performed
on a VG ZAB 217 instrument (VG analytical Ltd.) op-
erating in fast atom bombardment (FAB) conditions (8
keV Xe atom bombarding a nitrobenzylalcohol solution
of the sample) [36,37]. Also ESI-MS spectra have been
recorded by using a LCQ mass spectrometry (Finnigam)
and methanol solutions of the samples (10ꢁ5 M).
Magnetic susceptibilities were determined by the
Faraday method at room temperature, the apparatus
Crystals of Na(HRD) ꢀ H2O were grown from a
methanolic solution of the crude product.
The ORTEP representation of the crystal structure is
shown in Fig. 1 with the label scheme used. All geo-
metric and intensity data were taken using an automated
four-cyrcle Philips PW1100 (FEBO system) X-ray dif-
ꢀ
fractometer, using the Mo Ka radiation (k ¼ 0:7107 A)
and x ꢁ 2h method. Lattice parameters were obtained
from least-squares refinement of the setting angles of 30
reflections with 10 6 2h 6 26°. Intensity data were re-
duced by routine procedures and calculations were
carried out by the application of direct methods pro-
gram of SHELXS-86 [30]. The refinement calculations
were carried out using SHELXS-93 program [34]. The
benzene rings were refined as rigid bodies, the hydrogen
atoms were included in the idealised positions with fixed
ꢀ
ꢀ
C–H distances (0.97 A in CH2 groups and 0.93 A in CH
benzenic groups).
Crystal data: 0.25 ꢂ 0.20 ꢂ 0.15 mm, monoclinic,
ꢀ
ꢀ
space group P21=n, a ¼ 14:669ð5Þ A, b ¼ 8:316ð5Þ A,
3
ꢀ
ꢀ
c ¼ 19:470ð6Þ A, b ¼ 91:73ð4Þ°, V ¼ 2374ð2Þ A ,
Dc ¼ 1.266 g cmꢁ3, Z ¼ 4. l(Mo Ka) ¼ 0.105 mmꢁ1
,
T ¼ 293ð2Þ K, 2221 reflections with I > 4sðIÞ used,
R ¼ 0:086, Rw ¼ 0:19.
(Oxford
Instruments)
being
calibrated
with
HgCo(NCS)4 [38]. Diamagnetic corrections were per-
formed [39].
3. Results and discussion
3.1. Cyclic and acyclic Schiff bases
The [1+1] cyclic Schiff bases H2LAꢀ ꢀ ꢀH2LF, contain-
ing one N3O2, or N2O2 Schiff base site and one adjacent
O2O3 or O2O4 crown-ether like site, have been prepared
as yellow or yellow-orange air stable solids by self-
condensation in methanol, under diluted conditions, of
equimolecular amounts of the diformyl precursors 3,30-
(3-oxapentane-1,5-diyldioxy)bis(2-hydroxybenzaldehyde)
Fig. 1. ORTEP drawing (30% probability ellipsoids) of NaHRD ꢀ H2O
with the atom labelling.

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U. Casellato et al. / Inorganica Chimica Acta 357 (2004) 4191–4207
The condensation of 2,3-diaminopropionic acid
.
- 17 (- OH )
483
H
H
monochlorohydrate or 2,4-diaminobutirric acid dichlo-
rohydrate with 3,30-(3-oxapentane-1,5-diyldioxy)bis(2-
hydroxybenzaldehyde in the presence of NaOH affords
the [1+1] cyclic complexes Na(H2LG) ꢀ H2O and
Na(H2LH) ꢀ H2O. Their IR spectra show two strong
bands at 1630 and 1635 or 1636 cmꢁ1, due, respectively,
to m(C@N) and masym(COO).
O
O
C
N
- 29 ( - CH3N)
471
445
403
374
OH
OH
O
- 55 (- C3H5N)
- 97 ( - CH3CH2N)
500
N
CH3
O
N
C
- 126 (- C2H5)
MH+
m/z= 500
3-Ethoxy-2-hydroxybenzaldehyde reacts with ethy-
lenediamine in a 2:1 molar ratio and in alcoholic solu-
tion to form the corresponding [1+2] acyclic Schiff bases
H2LI, as confirmed by a strong IR band at 1634 cmꢁ1
m(C@N) and the 1H NMR peak at 8.29 ppm (CH@N) in
CDCl3. This yellow solid has an inner N2O2 and an
outer O2O2 coordination chamber.
The condensation of the diformyl derivatives H2LI or
H2LII or the sodium derivative Na2(LI) with monoam-
ines bearing also additional groups (i.e., NH2(CH2)n
C6H4N with n ¼ 1 or 2 and H2NCH2COOH) gives rise
to the corresponding [1+2] side off acyclic compounds,
H2LL, Na(HLL) ꢀ H2O, H2LM and Na(H3LN) ꢀ H2O,
containing one inner O2O3 or O2O4 and one outer
N2N2O2 or N2O2O2 adjacent coordination site.
The formation of [1+2] entities for the acyclic com-
pounds was proved by ESI-MS spectra: the fragmenta-
tion pathway is consistent with the proposed structure
(Scheme 4).
Scheme 3. Fragmentation pathway of H2LF.
(H2LI) or 3,30-(3,6-dioxaoctane-1,8-diyldioxy)bis(2-hy-
droxybenzaldehyde) (H2LII) and the appropriate poly-
amine. As we have already pointed out they can be
prepared also by demetallation with guanidinium sul-
phate of the appropriate macrocyclic barium diperchl-
orate complex [16,20]. The [1+1] cyclic nature of these
systems was inferred by FAB and/or ESI-MS spectra,
where the formation of the parent peak [M + H]þ and/or
[M + Na]þ at the appropriate m=z values were detected.
Thus, for example, the ESI-MS spectra of H2LG show
the formation of [M + H]þ at m=z ¼ 500 and a frag-
mentation pathway consistent with the proposed struc-
ture (Scheme 3).
A similar series of macrocyclic compounds, contain-
ing Naþ into the crown-ether chamber, have been pre-
pared using Na2(LI) instead of H2LI as formyl
precursor. It must be noted that Na2(LI) was obtained
as a yellow intermediate product during the synthesis of
the diformyl precursor H2LI by reaction of diethyle-
neglicol ditosylate with 2,3-dihydroxybenzaldehyde in
the presence of NaH and in anhydrous dimethylsulph-
oxide [25].
In these complexes a strong IR band at 1655–1633
cmꢁ1 due to m(C@N) occurs; furthermore, an additional
strong IR absorption at 1611 cmꢁ1, due to the
m
asymm(COO), has been observed for Na(H3LN) ꢀ H2O.
1
Their H NMR spectra in CDCl3 or CD3OD show
the characteristic iminic peak at 8.54–8.19 ppm. For
H2LL
1H NMR investigation in CDCl3 proves the
a
In these condensations the homodinuclear macrocy-
clic complexes [Na2(L)] ꢀ nH2O can be obtained which
can evolve into the mononuclear one, Na(HL) ꢀ nH2O,
where the sodium(I) resides into the crown-ether
chamber, in solution and/or in consequence of crystal-
lization efforts. The same occurs also when the corre-
sponding polyamine derivatives are formed. The
crystallization from methanol of the crude product
gives rise to the mononuclear sodium macrocycles (see
later).
presence of a singlet at 13.72 ppm, ascribed to
the phenolic OH protons, a singlet at 8.53 ppm due to
the iminic protons, a doublet at 8.54 ppm, a triplet at
7.68 ppm, a doublet at 7.48 ppm and a triplet at 7.01
ppm due to the pyridine protons, while at 6.94–6.80 ppm
a triplet and a doublet due to the aromatic protons oc-
cur. The singlet at 4.96 ppm is attributed to the
methylenic groups bond to the Schiff base moiety
and finally the two triplets at 4.25 and 4.00 ppm are due
to the methylenic protons of the other crown like
moiety.
Again mass spectrometry investigations confirm the
[1+1] cyclic nature of these complexes. The IR spectra of
these compounds show a strong band at 1634–1630
cmꢁ1 due to m(C@N), confirming the formation of the
1
Similarly the H NMR spectrum in CDCl3 of H2LM
shows three multiplets at 8.53, 7.54, 7.10 ppm due to the
pyridine protons, a singlet at 8.21 ppm due to the iminic
protons. Furthermore, the peaks due to the aromatic
protons lie in the range 6.94–6.66 ppm, while the triplet
at 4.20–4.15 ppm is assigned to the aliphatic protons
ArOCH2. The multiplet at 4.03–3.96 ppm is due
to the aliphatic protons CNCH2 while the triplet at
3.90–3.85 ppm is assigned to the aliphatic protons
(OCH2CH2OAr). Finally the singlet at 3.73 ppm and the
triplet at 3.17–3.10 ppm are ascribed to the aliphatic
1
Schiff bases. In addition, H NMR spectra of all these
compounds in CDCl3 show a peak at 8.50–8.15 ppm due
to CH@N iminic protons, while the peak at 9.99–9.94
ppm due to the CH@O formyl protons, clearly detect-
able in the precursors H2LI, H2LII and Na2(LI) is
completely absent. Other significative variations occur
also in the peaks due to the other protons when com-
pared with those of the precursors (see Table 1).

Table 1
1H NMR data of Schiff base ligands and related complexes
HC@N
H–Ar
CH2O
CNCH2
CH2N
Other signals
H2LC (CDCl3)
H2LD (CDCl3)
H2LE (CDCl3)
8.20 s (2H )
6.88 dd (2H)
6.69 m (4H)
6.75 m (6H)
4.19 t (4H CH2OAr);
3.95 m (4H); 3.86 t (4H)
4.20 m (4H CH2OAr);
3.95 m (4H)
3.63 m (4H)
2.78 m
2.32 s (3H NCH3)
13.91 s (2H ArOH)
0.82 t (3H CH3)
(4H CH2NMe)
2.78 m, m
8.19 s (2H)
8.18 s (2H)
3.63 m (4H)
3.63 m (4H)
3.58 m (4H)
2.32 2s (3H NCH3)
1.18 m (20H (CH2)10Me)
2.16 s (3H NCH3)
(4H CH2NMe)
2.46 m (6H)
6.79 m (6H)
4.22 m (4H CH2OAr);
3.92 m (4H)
H2LF ꢀ 0.5H2O
8.26–8.25 d
(2H)
6.94–6.59 m (6H)
4.20–4.13 m (4H CH2OAr);
3.91–3.85 m (4H);
3.73 s (4H)
2.42–2.34 m
1.86–1.76 m
(4H CH2)
(CDCl3)
(4H CH2NMe)
H2LI ꢀ H2O (CDCl3)
8.29 s (2H)
6.90–6.85 dd (2H);
6.82–6.78 dd (2H);
6.76–6.72 t (2H)
4.12–4.02 q (4H CH2OAr)
3.92 s (4H)
1.41–1.15 t (6H CH3)
13.6 s (2H ArOH)
13.72 s (2H ArOH)
H2LL (CDCl3)
H2LM (CDCl3)
8.53 s (2H)
8.21 s (2H)
6.94–6.80 t, d, d (6H)
4.25 t (4H CH2OAr)
4.00 t (4H)
8.54)7.01 d, t, d, t (8H Pyr)
4.96 s
(4H NCH2Pyr)
4.03–3.96 m (4H)
6.94–6.90 dd (2H);
6.81–6.76 dd (2H);
6.73–6.66 t (2H)
4.20–4.15 t
3.17–3.10 t
8.54–8.51 dd (2H Pyr); 7.59–7.50
m (2H Pyr); 7.14–7.06 m (4H Pyr)
(4H CH2OAr)
3.90–3.85 t (4H);
3.73 s (4H)
(4H CH2Pyr)
Na(HLL) ꢀ H2O
8.54 s (2H)
7.00–6.94 t, d, d (6H)
6.92–6.45 d, d, t (6H)
4.26 t (4H CH2OAr)
4.00 t (4H)
8.54–7.21 d, t, d, t (8H Pyr)
4.97 s
(4H NCH2Pyr)
(CDCl3)
Na(H3LN) ꢀ H2O
(CDCl3)
8.19 s (2H)
8.54 s (2H)
4.23–3.93 3t (12H CH2)
Ni(LI) (CDCl3)
7.95–7.91 dd (2H);
7.81–7.77 dd (2H);
7.63–7.55 t (2H)
6.89–6.78 m (4H);
6.56–6.49 t (2H)
5.34–5.24 q (4H ArOCH2)
4.73 s
2.71 t (6H CH3)
(4H CNCH2)
NiNa(LI)(CH3COO)
7.86 s (2H)
4.81–4.71 q (4H ArOCH2)
3.53 s
1.25–1.18 t (6H CH3)
ꢀ H2O (CD3OD)
(4H CNCH2)

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U. Casellato et al. / Inorganica Chimica Acta 357 (2004) 4191–4207
F1= C8H9N2
F2= C7H8N2
H
C
O
-105 (- F1)
-120 (- F2)
-132 (- F3)
CH2
516
501
489
F3= C7H8N
OH
OH
N
CH2
CH2
N
N
O
O
-105 (- F1)
621
396
Na+
O
N
C
CH2
H
[M+Na]+ m /z= 621
Scheme 4. Fragmentation pathway of H2LM
.
protons CH2OCH2CH2OCH2 and CH2Py, respectively.
2D COSY and NOESY experiments at 298K corrobo-
rate these assignments.
Thus, the 1H NMR spectrum of H2RA in CDCl3,
reported as an explanatory example, shows multiplets at
6.67–6.63 ppm due to the aromatic protons, at 4.14–4.10
and 3.86 ppm due to the methylenic protons of the
CH2O crown-ether chain and two singlets at 3.75 ppm
and at 2.84 ppm, respectively, due to the methylenic
protons C6H3–CH2–N and NHCH2 (see Table 2).
Again, as above reported for the related Schiff bases,
FAB or ESI-MS spectra confirm the cyclic or acyclic
nature of the reduced compounds (see for example
Scheme 5).
3.2. Polyamine derivatives
The cyclic and acyclic Schiff bases (or their sodium
derivatives) have been reduced to the corresponding
polyamines by reaction with an excess of NaBH4. The
compounds are soluble in chlorinated solvents and in-
soluble in H2O and hence can be purified by extracting
the residue of the reaction with CHCl3.
Apart from these molecular species, the FAB spectra
were uninformative: no fragment ions were detected
with significant abundance. In particular the [M/2þꢀ, [M/
The reduced polyamine derivatives maintain the [1+1]
cyclic or [1+2] acyclic nature of the related Schiff bases
as indicated by IR, NMR and mass spectrometry. The
IR spectra show absorption bands at 3385–3257 cmꢁ1
þ
2 + H] and [M/2 + CH2]+ꢀ ions are completely absent,
indicating a higher stability of the compounds under
investigation.
due to m(NH) while the strong bands at 1636–1630 cmꢁ1
,
due to m(C@N), characteristic of the related Schiff bases,
are completely absent.
Moreover in their 1H NMR spectra in CDCl3 the
singlet at 8.50–8.15 ppm due to the iminic protons
(CH@N) is completely absent, while new peaks at 3.96–
3.75 ppm, due to ArCH2N protons, have been detected.
3.3. Structure of Na(HRD) ꢀ H2O
The reduction of these Schiff bases to the corre-
sponding polyamine derivatives was definitively con-
firmed by the single-crystal X-ray structure of
Table 2
1H NMR data of polyamines
H–Ar
CH2O
NHCH2
ArCH2N
Other signals
H2RA (CDCl3)
6.67–6.63 m (6H)
4.14–4.10 m (4H 2.84 s (4H)
CH2OAr) 3.86
m (8H)
3.75 s (4H)
H2RB ꢀ 0.5CHCl3
(CDCl3)
6.67–6.60 m (6H)
4.30–3.81 m
(16H CH2)
Na(HRD) ꢀ 1CHCl3
(CD3OD)
6.91 dd (2H) 6.68 t
(2H) 6.77 dd (2H)
4.20 m
(4H CH2OAr)
3.93 m
2.64 m (4H)
2.76 s (4H)
3.84 s (4H )
2.48 m
(4H NMeCH2)
1.95 s (3H CH3N)
(4H CH2O)
4.10–3.99 q
(4H ArOCH2)
4.18–4.13 t
(4H CH2OAr)
3.89–3.83 t
(4H CH2O)
H2RI ꢀ H2O (CDCl3) 6.78–6.57 m (6H)
3.91 s (4H)
3.96 s (4H)
1.44–1.37 t
(6H CH3)
H2RM (CDCl3)
6.83–6.78 dd (2H)
6.70–6.60 m (4H)
3.07–2.95 m (8H
N(CH2)2 Pyr)
8.50–8.47 dd (2H Pyr);
7.60–7.52 m (2H Pyr);
7.13–7.06 m (4H Pyr)

U. Casellato et al. / Inorganica Chimica Acta 357 (2004) 4191–4207
4203
F1
F4
O
CH2
CH2
OH HN
CH2
CH2
N
N
O
O
Na+
OH
HN
CH2
CH2
O
F3
F2
[M+Na]+ m/z= 625
- 122 (-F1= C7H9N2)
- 122 (-F2= C7H9N2)
625
503
381
- 30 (-F3= CH2O)
351
255
- 126 (-F4= C5H11O2Na)
Scheme 5. Fragmentation pathway of H2RM
.
Na(HRD) ꢀ H2O.
Well
formed
crystals
of
Na(HRD) ꢀ H2O, suitable for an X-ray diffractometric
investigation, were grown from methanol. Fig. 1 shows
an ORTEP drawing of the structure. In this complex the
asymmetric unit consists of one [1+1] macrocyclic mol-
ecule of the ligand coordinated to a sodium ion by five
oxygen atoms present in the ligand. The coordination
geometry of the metal can be described as a pentagonal
pyramid with the sodium atom occupying the vertex.
This constraints the whole molecule to assume a butterfly
like shape with the wings, constituted by the two benzene
rings, forming a dihedral angle of 48.9°. Surprisingly the
sodium ion does not form other bonds or contacts, so it
appears empty on the opposite side with respect to the
ligand. The oxygen atoms form a plane (maximum and
Fig. 2. Shape of the coordination polyhedron generated by the sodium
and oxygen atoms.
and H2R makes the preparation of transition metal
complexes highly feasible. They have been prepared by
condensation of the formyl and amine precursors in the
presence of these metal ions as templating agents or by
reaction of the preformed ligand with the appropriate
metal ion.
ꢀ
minimum deviations are 0.1 and 0.02 A, respectively),
ꢀ
from which the sodium atom displaces of 0.79 A.
The neutralisation of the positive charge present on
the sodium atom is reached by a negative charge dis-
tributed on the O(1) and O(2) atoms. The Na–O dis-
H2LA–H2LD react with equimolecular amounts of
, , ) or
Ni2þ Co2þ
M(CH3COO)2 ꢀ nH2O (M ¼ Cu2þ
ꢀ
ꢀ
tances are 2.565(6) A for O(2) and 2.620(7) A for O(1),
respectively, very shorter than the other Na–O(etheric)
Mn(CH3COO)3 ꢀ 2H2O in refluxing alcoholic solution to
form, respectively, M(L) ꢀ nH2O and Mn(L)(CH3
COO) ꢀ nH2O. The same copper(II) and nickel(II) com-
plexes have been obtained also by template procedure
[18].
ꢀ
bond distances (2.904 A mean). The bond angle O(1)–
Na–O(2) is very large, (107°), with respect to all other
angles to the sodium ion that are comprised between
57.2° and 59.2°. The conformation of the torsion angles
O(3)–C(20)–C(21)–O(4) and O(4)–C(22)–C(23)–O(5) are
gꢁ and gþ, identical to N(3)–C(12)–C(11)–N(2) and
N(2)–C(9)–C(8)–N(1), respectively. The coordination
polyhedron generated by sodium and the oxygen atoms
is reported in Fig. 2.
The similar reaction of the preformed ligand H2LE
with the appropriate copper(II) or nickel(II) acetate
hydrate or the condensation of equimolar amount of
3,30-(3-oxapentane-1,5-diyldioxy)bis(2-hydroxybenzalde-
hyde) with 1,5-diamino-3-aza(dodecyl)pentane in the
presence of the same metal salt gives rise to the com-
plexes M(H2LE)(CH3COO)2 ꢀ nH2O. In the nickel(II)
complex the magnetic moment (leff ¼ 2:30 BM) sug-
gests the metal ion has probably an octahedral envi-
ronment with the acetate groups acting as monodentate
ligands.
3.4. Mononuclear complexes
The presence of a Schiff base site or of its reduced
analogue in the prepared cyclic and acyclic ligands H2L

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U. Casellato et al. / Inorganica Chimica Acta 357 (2004) 4191–4207
Copper(II), nickel(II) and manganese(III) acetate re-
These complexes are all paramagnetic: for the
nickel(II) complex the magnetic moment (3.0 BM), sug-
gests an octahedral configuration about the central metal
ion; similarly for the cobalt (II) complex a magnetic
moment of 3.6 BM and a d–d band at 617 nm in the
electronic spectrum in CHCl3 support a strongly dis-
torted configuration about the cobalt(II) ion in contrast
with the parent Schiff base complex, where a square
planar coordination was found. For Mn(RA)(CH3COO)-
2H2O a magnetic moment of 5.9 BM was found; possibly
a pentacoordination occurs. Finally for Cu(RA) a mag-
netic moment of 1.8 BM was found. The electronic
spectrum in CHCl3 evidences three bands at 343, 400 and
614 nm, this last d–d band suggesting a square pyramidal
pentacoordination.
act with the acyclic Schiff base H2LI in alcoholic solu-
tion and in a 1:1 molar ratio to give rise to M(LI) (M ¼
Cu2þ, Ni2þ) and Mn(LI)(CH3COO) ꢀ H2O. On the con-
trary cobalt (II)acetate forms Co(H2LI)(CH3COO)2.
The IR spectra of M(LI) show a strong band at 1618–
1631 cmꢁ1 due to m(C@N), while no bands due to ace-
tate groups have been detected. Ni(LI) is diamagnetic
while the magnetic moment of the copper complex is 1.9
BM; the electronic spectra in CHCl3, in addition to
band at 423 and 450 nm, show d–d bands at 556 nm for
nickel(II) complex and at 564 nm for copper(II) one.
These magnetic and electronic data agree with a square
planar configuration about nickel(II) and copper(II).
1
The H NMR spectrum in CDCl3 of Ni(LI) shows a
singlet at 8.54 ppm due to iminic protons, two doublets
of doublets at 7.95–7.91 ppm and 7.81–7.77 ppm due to
aromatic protons, a triplet at 7.63–7.55 ppm due to the
remaining aromatic protons. Also peaks at 5.34–5.24
ppm (ArOCH2), at 4.73 ppm (CNCH2) and at 2.71 ppm
(CH3) due to aliphatic protons are present.
The acyclic complexes Ni(RI) ꢀ 3H2O, Cu(RI) ꢀ 2H2O,
Ni(H2RI)(CH3COO)2, Co(H2RI)(CH3COO)2 ꢀ 2H2O,
Mn(RI)(CH3COO) ꢀ H2O and Cu(RL) ꢀ H2O have been
prepared with a procedure similar to that above re-
ported. The acetate groups may be eliminated by adding
to the prepared complexes or to the preparation solution
an equimolar amount of tetrabutyl-ammonium hy-
droxide, [N(Bu)4](OH). By this procedure, for instance,
Cu(RI) ꢀ H2O, Ni(RI) ꢀ 3H2O and Cu(RL) ꢀ H2O have
been conveniently prepared. Again IR bands at 3244–
3215 cmꢁ1 due to m(N–H) have been observed with a
shift of 50–70 cmꢁ1 with respect to the free ligand in
consequence of coordination. The acetate groups, where
present, show IR absorption at 1583–1566 cmꢁ1
In the IR spectra of Co(H2LI)(CH3COO)2 and
Mn(LI)(CH3COO) ꢀ H2O in addition to the band at
1624–1640 cmꢁ1 due to m(C@N), the bands due to car-
boxylate groups at 1577–1553 cmꢁ1
m
asym(COO) and at
1392–1393 cmꢁ1
msym(COO) have been detected.
Co(H2LI)(CH3COO)2 shows a magnetic moment of 3.20
BM in agreement with a severe distortion from the
planarity towards an octahedral coordination about the
central metal ion, in agreement with the electronic
spectrum where a d–d band at 610 nm is observed.
Analogously [Ni(LL)] and [Cu(LL)] have been syn-
thesized by reaction of H2LL with the appropriate metal
acetate in methanol. When these reactions are carried
out in MeOH/CHCl3 the complexes contain also a
molecule of solvent chloroform. The IR spectra show
the m(C@N) at 1630 and 1639 cmꢁ1, respectively. Mag-
netic data at room temperature (leff ¼ 3:0 BM) evidence
an octahedral coordination about the nickel(II) ion,
corroborated by the solid state electronic spectra where
d–d bands at 540 nm and 770 nm have been detected.
The reduced macrocycle H2RA forms, when reacted
with Cu(CH3COO)2 ꢀ H2O or Mn(CH3COO)3 ꢀ 2H2O in a
CHCl3/MeOH and in a 1:1 molar ratio, respectively,
Cu(RA)2H2O and Mn(RA)(CH3COO) ꢀ 2H2O. Using the
same experimental conditions Ni(CH3COO)2 ꢀ 4H2O and
Co(CH3COO)2 ꢀ 4H2O give rise to Ni(H2RA)(CH3COO)2
and Co(H2RA)(CH3COO)2.
m
asym(COO) and at 1410–1393 cmꢁ1
msym(COO). The
magnetic moment of cobalt(II) (3.6 BM, 3.0 and 3.5
BM) and nickel(II) complexes suggest an octahedral
coordination about the central metal ion. For
Cu(RI) ꢀ 2H2O a square pyramidal configuration about
the central metal ion may be proposed on the basis of
a d–d band at 610 nm in its electronic spectrum in
CHCl3. Moreover a magnetic moment of 1.9 and 1.73
BM was found, respectively, for Cu(RI) ꢀ 2H2O and
Cu(RL) ꢀ H2O.
It must be noted that an analogous reaction of
H2RI with NiCl2 ꢀ 6H2O gives rise to Ni(H2RI)
(Cl)2 ꢀ H2O as confirmed also by an electron micros-
copy and EDX investigation, which evidences the ho-
mogeneity of the prepared complexes and the correct
Ni:Cl ¼ 1:2 ratio.
Thus, according to the above reported physico-
chemical data, the transition metal ion invariantly oc-
cupies the Schiff base site in the mononuclear cyclic
complexes. These complexes in turn contain a free and
adjustable ‘‘crown-ether-like’’ coordination chamber
and can be used as ‘‘ligands’’ towards appropriate hard
metal ions giving rise to pure positional isomers. It is
well known, for example, the ability of crown-ethers to
bind selectively alkali ions, strongly depending on the
dimension and on the denticity of the coordination
moiety [40,41].
In the prepared complexes the IR spectra show bands
at 3216–3272 cmꢁ1 due to m(N–H) with a shift of 20–75
cmꢁ1 with respect to the free ligands. In the complexes
containing acetate groups an intense band at 1589–1576
cmꢁ1
cmꢁ1
m
m
asym(COO) and a less intense one at 1408–1383
sym(COO) are also observed, suggesting that
also in these complexes the acetate act as monodentate
ligands.

U. Casellato et al. / Inorganica Chimica Acta 357 (2004) 4191–4207
4205
3.5. Heterodinuclear complexes
paramagnetic (leff ¼ 3:1–3:5 BM). The presence of the
different donor set N2XO2 causes a different coordina-
tion geometry, possibly octahedral, about the nickel(II)
ion.
As above reported the prepared mononuclear tran-
sition metal complexes contain a free crown-ether like
coordination chamber; hence they can be conveniently
used as ligands for further complexation reactions. In
particular, taking into consideration that sodium ion
prefers the crown-ether site, as ascertained also by the
X-ray structure of Na(HRD) ꢀ H2O, the transition metal
complexes can be proposed as receptors for the recog-
nition of Naþ. Similarly the sodium(I) complexes can be
used as receptors for transition metal ions. The final
products are in both cases the same d,s-heterodinuclear
complexes, where the transition metal ion occupies the
Schiff base site and the sodium ion the crown-ether
moiety, independently from the shape of the coordina-
tion chambers.
The availability of the [1+1] cyclic functionalized
bases
sodium
Schiff
Na(H2LG) ꢀ H2O
and
Na(H2LH) ꢀ H2O, obtained from the condensation of the
appropriate diformyl- and -amine precursors in the
presence of NaOH, allows the formation of the related
complexes NiNa(LG) ꢀ H2O or NiNa(LH) ꢀ H2O by re-
action of these sodium macrocyles with nickel(II) ace-
tate in a 1:1 molar ratio. A template procedure affords
the same complexes.
The strong IR bands at 1635 and 1636 cmꢁ1, present
in Na(H2LH) ꢀ H2O and Na(H2LH) ꢀ H2O, attributed to
t
asymCOO, are shifted to 1614 and 1613 cmꢁ1 in the
related heterodinuclear NiNa complexes, in conse-
quence of the coordination of the transition metal ion
into the N2O2 Schiff base site. Ir data suggest that the
carboxylate ion is also involved in the coordination.
Solid state magnetic susceptibility (leff ¼ 2:7–2:8 BM)
and UV–Vis measurements (d–d bonds at 540–550 mm
and 630 mm) suggest octahedral coordination about the
central metal ion in these NiNa complexes.
Thus by reaction of equimolar amount of the cyclic
and acyclic Schiff base (also prepared in situ) with the
appropriate transition metal acetate in the presence of
two equivalents of NaOH, the heterodinuclear complexes
MNa(L)(CH3COO) ꢀ nH2O (M ¼ Cu2þ, Ni2þ, Co2þ) and
MnNa(L)(CH3COO)2 ꢀ nH2O (H2L ¼ H2LAꢀ ꢀ ꢀH2LD [18]
and H2LF, H2LI, H2LLH2LM) have been obtained. The
same complexes can be prepared by the template con-
densation of the appropriate precursors in the presence of
M(CH3COO)2 ꢀ nH2O and NaOH.
The nickel(II)–sodium complex NiNa(L)(CH3COO)
derived from the functionalised acyclic Schiff bases
H2LL and H2LM, prepared by same procedure above
reported, deserves further considerations. In these li-
gands the outer Schiff base chamber present a open
N4O2 donor set and hence may induce a different co-
ordination geometry about nickel(II) with respect to the
acyclic ligand H2LI. Their IR spectrum shows bands at
These reactions give rise to the designed hetero-
dinuclear complexes in high yield and in one pot owing
to the above mentioned high selectivity of the two sites
of the ligands, respectively, for the d transition metal ion
and the sodium ion and hence to the impossibility to
give rise to scrambling or migration reactions.
1623 and 1636 cmꢁ1 m(C@N), at 1603 cmꢁ1
masym(COO)
sym(COO). The magnetic moment
The same complexes have been obtained when the
preformed mononuclear transition metal complexes are
reacted with sodium acetate or when the reaction of the
acyclic sodium complex, Na(HL) ꢀ nH2O with the ap-
propriate polyamine in the presence of the derived
transition metal salt was carried out. The formation of
the heterodinuclear complexes is corroborated by SEM
and EDS investigations: for all the prepared complexes
a M:Na ¼ 1:1 ratio was found.
and at 1404 cmꢁ1
m
found (leff ¼ 3:1 BM) suggests an octahedral coordi-
nation about the central metal ion.
The
infrared
spectra
of
MNa(HLN) ꢀ H2O
(M ¼ Cu2þ,Ni2þ), prepared by the reaction of
Na(H3LN) ꢀ H2O with the appropriate metal acetate in
methanol, show a shift of the m(C@N) and masym(COO),
in consequence of the coordination of the transition
metal ion into the Schiff base moiety, respectively, from
1655 and 1611 cmꢁ1 in the sodium derivative to 1644
and 1601 cmꢁ1 in the CuNa complex and to 1639 and
1600 cmꢁ1 in the NiNa complex. The non planarity
about the nickel(II) ion is confirmed by the magnetic
moment (leff ¼ 3:6 BM) which supports an octahedral
coordination about the central metal ion.
In the infrared spectra of these complexes strong
absorption at 1639–1619 cmꢁ1 m(C@N), at 1604-1580
cmꢁ1 asym(COO) and at 1406–1313 cmꢁ1
m msym(COO)
have been observed.
The magnetic moments of the Schiff base complexes
where H2L ¼ H2LA and H2LI (0.3–0.4 BM for NiNa,
2.2–2.8 BM for CoNa and 1.8 BM for CuNa) show that
the square planar N2O2 coordination about the transi-
tion metal ion is maintained upon Naþ complexation.
The electronic spectra parallel those of the mononuclear
analogues.
On the contrary the nickel complexes, derived from
the cyclic Schiff bases where R ¼ (CH2CH2)2NCH3,
(CH2CH2)2N(CH2)11CH3 (Scheme 2) are strongly
Analogously
the
heterodinuclear
complexes
MNa(R)(CH3COO) ꢀ nH2O or MnNa(R)(CH3COO)2 ꢀ n
H2O have been obtained by reaction of the reduced
macrocycles H2R with the appropriate metal acetate
hydrate in the presence of NaOH in a molar ratio 1:1:2.
Again the obtainment of the designed complexes was
verified also by SEM-EDS analysis which shows a
1:1 ¼ M:Na ratio for all the prepared samples.

4206
U. Casellato et al. / Inorganica Chimica Acta 357 (2004) 4191–4207
The IR bands at 3283–3226 cmꢁ1 due to m(NH), at
References
1560–1589 cmꢁ1
m
m
asym(COO) and at 1278–1421 cmꢁ1
sym(COO) corroborate the proposed formulation. The
[1] S. Tamburini, P.A. Vigato, Coord. Chem. Rev., in press.
[2] V. Alexander, Coord. Chem. Rev. 95 (1995) 273.
[3] D.E. Fenton, M. Okawa, Ber/Recueil 130 (1997) 433.
[4] P. Guerriero, S. Tamburini, P.A. Vigato, Coord. Chem. Rev 139
(1995) 17.
magnetic moment of the paramagnetic nickel(II) com-
plexes (leff ¼ 2:2–3:5 BM) suggest an octahedral coor-
dination about the central metal ion, corroborated by
the absorption at 555–560 and 750 nm in their electron
spectra.
[5] P. Guerriero, P.A. Vigato, D.E. Fenton, P.C. Hellier, Acta Chem.
Scand. 46 (1992) 1025.
[6] O. Kahn, in: A.G. Sikes (Ed.), Advances in inorganic Chemistry,
vol. 43, Academic Press, San Diego, 1995, p. 179.
[7] P. Zanello, S. Tamburini, P.A. Vigato, G.A. Mazzocchin, Coord.
Chem. Rev. 77 (1987) 65.
For the copper(II) complexes a d–d band in their
electronic spectra at ffi606 or 680–690 nm coordinated
by spectra at 555, 560 and 750 nm in the electronic
spectra suggests a square pyramidal coordination. The
magnetic moments for these complexes are 1.80–1.92
BM. For the cobalt(II) complexes with H2RA and H2RI
the magnetic moment (leff ¼ 2:6 BM and leff ¼ 2:1
BM) and the UV–Vis d–d band, respectively, at 639 and
596 nm, seem to suggest a strongly distorted square
planar configuration for the latter complex. Also for
NiNa(RI)(CH3COO) the magnetic moment of 3.5 B.M.
suggest an octrahedral environment about the central
metal ion. For the manganese(III)–sodium complexes
magnetic moments in the range 4.7–5.0 BM were found,
suggesting a high spin manganese(III) in a pentacoor-
dinate or octahedral coordination.
[8] K.D. Karlin, Y. Gultnek, in: S.Y. Lippared (Ed.), Progress in
Inorganic Chemistry, vol. 35, Wiley, New York, 1987, p. 19.
[9] J.C.G. Bunzli, C. Piguet, Chem. Rev. 102 (2002) 1987.
[10] (a) R. Menif, A.E. Martell, P.J. Squattrito, A. Clearfield, Inorg.
Chem. 27 (1990) 472;
(b) D. Kong, J. Reibenspies, J. Mao, A. Clearfield, A.E. Martell,
Inorg. Chim. Acta 342 (2003) 158.
[11] (a) R.D. Willet, D. Gatteschi, O. Kahn, Magneto-Structural
Correlations in Exchange Coupled Systems, NATO, ASI Series,
Riedel, Dordrecht, 1983;
(b) O. Kahn, Acc. Chem. Res. 33 (2000) 647.
[12] S. Schindler, Eur. J. Inorg. Chem. (2000) 2311.
[13] (a) P. Molenveld, J.F.J. Engbersen, D. Reinhoudt, Chem. Soc.
Rev. 29 (2000) 75;
(b) N.V. Kaminskaia, C. He, S.J. Lippard, Inorg. Chem. 39 (2000)
3365.
In conclusion the preparation of a series of largely
asymmetric acyclic and cyclic compartmental Schiff
bases and their related reduced analogues together with
the study of the ability of the two adjacent chambers to
give rise to different metal ion recognition processes,
allow to obtain pure positional mononuclear or hetero-
dinuclear isomers.
[14] H. Okawa, H. Furutachi, D.E. Fenton, Coord. Chem. Rev. 174
(1998) 51.
[15] M. D’Alpaos, S. Tamburini, P. Tomasin, P.A. Vigato, P. Traldi,
Rapid Commun. Mass Spectrom. 11 (1997) 1909.
[16] (a) N. Brianese, U. Casellato, S. Tamburini, P. Tomasin, P.A.
Vigato, Inorg. Chim. Acta 293 (1999) 178;
(b) U. Casellato, S. Tamburini, P. Tomasin, P.A. Vigato, Inorg.
Chim. Acta 262 (1997) 117.
Thus the enhanced selectivity of the Schiff base site
(or of the reduced amine analogue) toward transition
metal ions (i.e., copper(II), nickel(II), cobalt(II), man-
ganese(III)) and of the crown-ether like chamber for
alkali metal ions (i.e., sodium (I)) allows the formation
of the same heterodinuclear complexes containing d
and s metal ions in one pot, under a variety of exper-
imental different procedures. These processes open in-
teresting possibilities in the design and synthesis of
molecular devices and sensors. Unfortunately these
systems are not very soluble and stable in water. The
insertion of appropriate functionalities inside the co-
ordination moiety or at the periphery of these ligands
could confer the appropriate physico-chemical proper-
ties to these complexes. Preliminary investigations are
very promising.
[17] M. Botta, U. Casellato, C. Scalco, S. Tamburini, P. Tomasin, P.A.
Vigato, S. Aime, A. Barge, Chem. Eur. J. 8 (2002) 3917.
[18] A. Cassol, P. Di Bernardo, P.L. Zanonato, S. Tamburini, P.
Tomasin, P.A. Vigato, Supramol. Chem. 13 (2001) 469.
[19] U. Casellato, S. Tamburini, P. Tomasin, P.A. Vigato, S. Aime, M.
Botta, Inorg. Chem. 38 (1999) 2906.
[20] A. Caneschi, L. Sorace, U. Casellato, P. Tomasin, S. Tamburini,
P.A. Vigato, Eur. J. Inorg. Chem., accepted for publication.
[21] D.J. White, M. Laing, H. Muller, S. Parsons, S. Coles, P.A.
Tasker, Chem. Commun. (1999) 2077.
[22] D.M. Rudkevich, W.T.S. Huch, F.C.J.M. van Veggel, D.N.
Reinhoudt, in: L. Fabbrizzi, A. Poggi (Eds.),Transition Metals in
Supramolecular Chemistry, NATO ASI Series, vol. 448 1994, p.
329.
[23] W.F. Nijenhuis, A.R. van Doorn, W. Verboom, A.M. Reichwein,
F. de Jong, D.N. Reinhoudt, J. Am. Chem. Soc. 113 (1991) 3607.
[24] A.M. Reichwein, W. Verboom, S. Harkema, A.L. Spek, D.N.
Reinhoudt, J. Chem. Soc. Perkin Trans. (1994) 1167.
[25] D.M. Rudkevich, W.P.R.V. Stauthamer, W. Verboom, J.F.J.
Engebersen, S. Harkema, D.N. Reinhoudt, J. Am. Chem. Soc. 114
(1992) 9671.
[26] D.M. Rudkevich, W. Verboom, Z. Brzozka, M.J. Palys, W.P.R.V.
Stauthamer, G.J. Van Hummel, S.M. Franken, S. Harkema, J.F.J.
Engbersen, D.N. Reinhoudt, J. Am. Chem. Soc. 116 (1994) 4341.
[27] D.M. Rudkevich, Z. Brzozka, M. Palys, H.C. Visser, W.
Verboom, D.N. Reinhoudt, Angew. Chem. Int. Ed. Engl. 33
(1994) 467.
Acknowledgements
We thank Mr. A. Aguiari, Mrs. A. Moresco and Mrs.
O. Biolo for experimental assistance.
We are also indebted to MIUR-FIRB (project code
RBNE019H9K) for financial support.
[28] D.M. Rudkevich, W. Verboom, D.N. Reinhoudt, J. Org. Chem.
59 (1994) 3683.

U. Casellato et al. / Inorganica Chimica Acta 357 (2004) 4191–4207
4207
[29] D.M. Rudkevich, J.D. Mercer-Chalmers, W. Verboom, R. Ung-
aro, F. de Jong, D.N. Reinhoudt, J. Am. Chem. Soc. 117 (1995)
6124.
(b) SHELXL-93 G.M. Sheldrick, Program for Crystal Structure
€
€
Refinement, University of Gottingen, Gottingen, Germany, 1993.
[35] P. Guerriero, P.A. Vigato, B. Burtet-Fabris, Inorg. Chim. Acta
164 (1989) 155.
[30] D.D. Perrin, W.L. Armarego, D.R. Perrin, in: Purification of
Laboratory Chemicals, second ed., Pergomon Press, Oxford,
1982.
[36] P.P. Morgan, J.M. Beynon, R.M. Bateman, B.M. Green, Int. J.
Mass Spectrom. Ion Phys 28 (1978) 171.
[31] C.J. Van Staveren, J. Van Eerden, F.C.J.M. Van Veggel, S.
Harkema, D.N. Reinhoudt, J. Am. Chem. Soc. 110 (1988) 4994.
[32] F.C.J.M. Van Veggel, M. Bos, S. Harkema, W. Verboom, D.N.
Reinhoudt, Angew. Chem. Int. Edn. Engl. 28 (1989) 746.
[33] F.C.J.M. Van Veggel, M. Boss, S. Harkema, H. van de Bovenk-
amp, W. Verboom, J. Reedijk, D.N. Reinhoudt, J. Org. Chem. 56
(1991) 225.
[37] M. Barber, R.S. Bordoli, R.D. Sedgwick, A.M. Taylor, J. Chem.
Soc. Chem. Commun. 7 (1981) 171.
[38] C.J. Connor, E. Sinn, E.J. Cukauskas, B.S. Deaver, Inorg. Chim.
Acta 32 (1979) 29.
[39] C.J. Connor, in: S.J. Lippard (Ed.), Progress In Inorganic
Chemistry, 29, Wiley, New York, 1982, p. 203.
[40] Y. Inoue, G.W. Gokel (Eds.), Cation Binding by Macrocycles,
Marcel Dekker, New York, 1992.
[34] (a) SHELX-86G.M. Sheldrick, C. Kruger, R. Goddard (Eds.),
Crystallographic Computing 3, Oxford University Press, London,
1985, p. 175;
[41] S.R. Cooper (Ed.), Crown Compounds: Toward Future Applica-
tions, VCH Publishers, New York, 1992.