Synthesis and characterization of dendrimeric bridged salen/saloph complexes and investigation of their magnetic and thermal behaviors

Article abstract of DOI:10.1002/hlca.200900294

Eight new multinuclear Fe^III and Cr^III complexes involving the tetradentate Schiff bases N,N′-bis(salicylidene) ethylenediamine (salenH₂) or N,N′-bis(salicylidene)benzene-1,2- diamine (salophH₂) and the two new ligands 4,4′,4″, 4?,4′?,4″?-[1,3,5-triazine-2,4, 6-triyltris(nitrilomethylidyne-4,1-phenyleneoxy-1,3,5-triazine-6,2, 4-triyldiimino)]hexakis[benzoic acid] (4) or 5,5′,5″,5?, 5′?,5″?-[1,3,5-triazine-2,4,6- triyltris(nitrilomethylidyne-4,1-phenyleneoxy-1,3,5-triazine-6,2,4-triyldiimino) ]hexakis[benzene-1,3-dicarboxylic acid] (5) were synthesized (Schemes 1 and 2) and characterized by means of ¹H-NMR and FT-IR spectroscopy, elemental analysis, LC/MS analysis, AAS (atomic-absorption spectrum) analysis, thermal analyses, and magnetic-susceptibility measurements. The complexes can also be characterized as low-spin distorted-octahedral Fe^III and Cr^III complexes bridged by carboxylato moieties.

Full text of DOI:10.1002/hlca.200900294

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Helvetica Chimica Acta – Vol. 93 (2010)
Synthesis and Characterization of Dendrimeric Bridged Salen/Saloph
Complexes and Investigation of Their Magnetic and Thermal Behaviors
by Ziya Erdem KoÅ* and S¸aban Uysal
Selcuk University, Faculty of Science, Department of Chemistry, 42075-Konya, Turkey
(phone: þ 90-536-2263303; e-mail: zerdemkoc@gmail.com)
Eight new multinuclear FeIII and CrIII complexes involving the tetradentate Schiff bases N,N’-
bis(salicylidene)ethylenediamine (salenH2) or N,N’-bis(salicylidene)benzene-1,2-diamine (salophH2)
and the two new ligands 4,4’,4’’,4’’’,4’’’’,4’’’’’-[1,3,5-triazine-2,4,6-triyltris(nitrilomethylidyne-4,1-phenyl-
eneoxy-1,3,5-triazine-6,2,4-triyldiimino)]hexakis[benzoic acid] (4) or 5,5’,5’’,5’’’,5’’’’,5’’’’’-[1,3,5-triazine-
2,4,6-triyltris(nitrilomethylidyne-4,1-phenyleneoxy-1,3,5-triazine-6,2,4-triyldiimino)]hexakis[benzene-
1
1,3-dicarboxylic acid] (5) were synthesized (Schemes 1 and 2) and characterized by means of H-NMR
and FT-IR spectroscopy, elemental analysis, LC/MS analysis, AAS (atomic-absorption spectrum)
analysis, thermal analyses, and magnetic-susceptibility measurements. The complexes can also be
characterized as low-spin distorted-octahedral FeIII and CrIII complexes bridged by carboxylato moieties.
Introduction. – An important class of compounds having anticancer, antitumor,
antiviral, and antifungal activities consists of substituted s-triazine (¼1,3,5-triazine)
derivatives. These compounds have been used in the treatment of depression and hence
gained considerable significance. They are valuable bases for estrogen-receptor
modulators [1] and also used as bridging agents to synthesize herbicides and in the
production of drugs or polymers [2].
We now report the synthesis and characterization of dendrimeric Schiff bases
including six or twelve carboxylic acid groups as new templates. The reaction of
melamine (¼1,3,5-triazine-2,4,6-triamine) with 4-hydroxybenzaldehyde in benzene
gave the desired tris(nitrilomethylidyne) and triphenolic moieties in a single step [3].
The phenolic OH groups [4][5] were then modified with trimeric cyanuric chloride
(¼2,4,6-trichloro-1,3,5-triazine) as a single-directional linker [6 – 10], followed by
treatment with 4-aminobenzoic acid or 5-aminoisophthalic acid [11 – 20] to give the
mentioned new dendrimeric Schiff bases which we call ꢀoxy-Schiff basesꢁ (cf. [4][5]).
The magnetochemical properties of the m-oxo-bridged complexes [{Fe(salen)}2O]
[(salenH2 ¼ N,N’-bis(salicylidene)ethylenediamine) ¼ 2,2’-[ethane-1,2-diylbis(nitrilo-
methylidyne)]bis[phenol]] and [{Fe(saloph)}2O] [(salophH2 ¼ N,N’-bis(salicylidene)-
benzene-1,2-diamine) ¼ 2,2’-[1,2-phenylenebis(nitrilomethylidyne)]bis[phenol]] and
their X-ray studies have widely been presented in the literature [21 – 24]. Kessel and
Hendrickson [25] have studied Schiff-base complexes of FeIII incorporating p-quinone
bridges. The reaction of [{Fe(salen)}2O] with carboxylic acids have been reported by
Wollmann and Hendrickson [26]. They used trichloroacetic, trifluoroacetic, salicylic,
and picric acids, and characterized the prepared complexes as dimers of the
ꢂ 2010 Verlag Helvetica Chimica Acta AG, Zꢃrich

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composition [Fe(salen)X]2, where X is the monoanion of the appropriate acid. The
complexes [{Fe(salen)}2L] and [{Fe(saloph)}2L] (where L ¼ terephthalato(2ꢀ),
fumarato(2ꢀ), oxalato(2ꢀ), and succinato(2ꢀ)) have also been prepared [21]. The
crystal and molecular structure of [{Fe(salen)}2ter] (H2ter¼ terephthalic acid) have
been reported [21]. Other complexes of composition [{Fe(salen)}2L] (where L ¼
glutarato(2ꢀ), adipato(2ꢀ), pimelato(2ꢀ), suberato(2ꢀ), and dithiooxamidato(2ꢀ))
were prepared by Smekal et al. [27].
Therefore, in the present study, we aimed at the synthesis of other dendrimeric
hexa- and dodecacarboxylato bridges and to present their presumed influence on the
magnetic behavior of the prepared complexes. We were also interested in dendrimeric
hexa- and dodecanuclear systems formed by means of carboxylato bridges because
some interesting work dealing with this kind of bridge and associated data has been
reported [28 – 32].
Result and Discussion. – The 4,4’,4’’-[1,3,5-triazine-2,4,6-triyltris(nitrilomethylidy-
ne)]tris[phenol] (2) was prepared in nearly quantitative yield from melamine (1) and
3 equiv. of 4-hydroxybenzaldehyde (Scheme 1, Table 1). Afterward, 2 was treated with
cyanuric chloride at 0 – 58, and the structural formula of the produced N2,N4,N6-tris{{4-
[(4,6-dichloro-1,3,5-triazin-2-yl)oxy]phenyl}methylene}-1,3,5-triazine-2,4,6-triamine
1
(3) was verified by elemental analysis (Table 1), H-NMR, FT-IR, and MS data. The
reaction of 3 with 4-aminobenzoic acid or 5-aminoisophthalic acid (¼ 5-aminobenzene-
1,3-dicarboxylic acid) at reflux temperature readily furnished the dendrimeric ꢀoxy-
Schiff basesꢁ 4 or 5, respectively, containing six or twelves COOH groups.
The tripodal ꢀoxy-Schiff baseꢁ 2 was characterized by its elemental analysis, thermal
1
analyses, H-NMR, FT-IR, AAS (atomic-absorption spectrum), and MS data. To
establish the structure of 2, the 1H-NMR spectra were recorded in (D6)DMSO
[33][34]. Thus the signals at d(H) 9.77 (s) correspond to three N¼CH groups and that
at d(H) 6.08 (s) to three OH groups. The data also showed that three directional
linkages to the melamine moiety are present in 2. In addition, when 3 equiv. of cyanuric
chloride were added to 2, the phenolic OH signal at d 6.08 disappeared. Elemental
analysis (Table 1), 1H-NMR, FT-IR, and MS data of the product 3 from 2 and cyanuric
chloride established that each OH group of 2 had reacted with cyanuric acid. This was
confirmed by Fujiwaraꢁs test [7]. Moreover, when 6 equiv. of 4-aminobenzoic acid or 5-
aminoisophthalic acid were added to 3, the NH2 signals at d(H) 5.90 of the former and
at d(H) 5.19 of the later shifted to d(H) 4.55 or 4.75 (NH of 4 or 5, resp.). The
1H-NMR spectrum of 4 and 5 showed signals at d(H) 13.92 – 13.96 and 10.03 – 10.05
corresponding to the carboxylic OH and ꢀoxy-Schiff baseꢁ N¼CH resonances,
1
respectively. Moreover, the H-NMR spectrum of 5 was similar to that of 4, thus
establishing their structures. The new ligands 4 and 5 are soluble in common organic
solvents.
The synthetic strategy for preparing dendrimeric hexa- or dodecanuclear complexes
consists of the use of a complex as a ꢀligandꢁ containing a potential donor group
(COOꢀ) capable of coordinating with another ligand. We chose [{Fe(salen) or
(saloph)}2O] and [{Cr(salen) or (saloph)}2O] as ꢀligand complexꢁ 6 because it can
coordinate with another ligand [35 – 37]. Thus, the dendrimeric hexa- or dodecanuclear
complexes 7 – 14 with bridging carboxylato groups to the Fe and Cr centers were

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obtained from 6 and the ligands 4 or 5 (Scheme 2). All compounds 7 – 14 are stable at
room temperature in the solid state, and their elemental analyses (Table 1) were in
agreement with the proposed structures. The results showed that 7 – 14 are hexa- or
dodecanuclear complexes. They are only soluble in organic solvents such as DMSO and
DMF, and insoluble in H2O.
In the IR spectra of the free ligands 4 and 5, the vibrations of the azomethine C¼N,
triazine C¼N, and CꢀOꢀC of the free ligands 4 and 5 were observed at 1618 – 1605,
1574 – 1560, and 1375 – 1359 cmꢀ1, respectively [38][39]. In the complexes 7 – 14, these
bands were shifted to lower frequencies, which indicated that the N- and O-atoms of the
dendrimeric ꢀoxy-Schiff-baseꢁ ligands 4 and 5 are coordinated with the ꢀligand
complexesꢁ 6. In the free ligands 4 and 5, the bands at 3258 – 3234 or 3425 –
3427 cmꢀ1 were assigned to the carboxylic OH or NH group vibrations, respectively
[10][28]. In the complexes 7 – 14, the OH bands of the COOH groups were missing,
thus evidencing chelation of the O-atom to the metal [21][28][30][31][35 – 37]. These
results were consistent with previous studies; especially in [21][28][31] is reported that
the carboxylic OH bands disappeared as a result of chelation of the carboxylato
O-atom to the metal. In the complexes 7 – 14, the bands in the ranges of 544 – 532
and 478 – 468 cmꢀ1 were attributed to the MꢀN and MꢀO stretching modes
[30 – 33].
The magnetic moments of the complexes 7 – 14 given in Table 1 were measured at
room temperature. On the basis of spectral evidence, these dendrimeric low-spin FeIII
and CrIII complexes have a hexanuclear or dodecanuclear structure in which the low-
spin FeIII and CrIII cations have an approximately octahedral environment. The
magnetic behavior of these low-spin FeIII and CrIII complexes is in accordance with the
proposed hexanuclear or dodecanuclear structures; their magnetic moments estab-
lished their paramagnetic property, the magnetic susceptibility value per atom being
1.65 – 1.70 B.M. and 3.75 – 3.90 B.M., respectively. It is seen that the [{Fe(salen) or
(saloph)}2O] and [{Cr(salen) or (saloph)}2O] containing compounds 7 – 14 are
represented by the electronic structure t2g5eg0 and t2g3eg0. The magnetic data for the
dendrimeric Fe- and Cr-complexes were in accordance with the low-spin d5 and d3
metal ion in an octahedral structure, respectively. This conclusion is supported by the
results of the elemental analyses suggesting that the dendrimeric complexes 7 – 14 have
also an octahedral structure [21][28 – 32].
The ligands 4 and 5 and complexes 7, 10, 12, and 13 were also thermally investigated,
and their plausible degradation schemes are presented in Table 2 [40][41]. It is well
known that there is a strong relation between the temperature range for the
dehydration process and the binding mode of the H2O molecules of the respective
metal complexes. The elimination of H2O took place in a single-step process attributed
to the release of the hydrating H2O molecules of 7 · x H2O, 10 · x H2O, 12 · x H2O, and
13 · x H2O (in the range of 60 – 1358). Thermal decomposition of the anhydrous
[{Fe(salen) or (saloph)}2O] and [{Cr(salen) or (saloph)}2O] complexes left from the
ligands 4 and 5 started in the range of 290 – 3908 and was completed in the range 565 –
6508. The final decomposition products were metal oxides and triazine ring. The observed
weight losses for all ligands and complexes were consistent with the calculated values.
The LC/MS data of all compounds 2 – 5 and 7 – 14 given in the Exper. Part confirm
their relative molecular mass Mr (Table 1).

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Table 2. Decomposition Steps with the Temperature Range and Weight Loss for Ligands 4 and 5 and
Complexes 7, 10, 12, and 13a)
Molecular formula
C75H51N21O15
Temp. range [8]
Weight loss, found (calc.) [%]
Fragment
4
5
65 – 125
300 – 375
18.12 (17.00)
37.71 (39.60)
21.33 (20.82)
31.62 (30.17)
31.42 (33.64)
18.41 (17.68)
7.76 (7.50)
15.03 (14.37)
55.42 (54.62)
7.31 (6.99)
21.88 (21.16)
51.78 (50.71)
10.18 (9.24)
18.27 (17.65)
61.45 (59.13)
8.92 (8.32)
CO2, H2
N2, H2O
N2, C2H2
CO2, H2
N2, H2O
N2, C2H2
H2O, CO2
N2, C2H4
CO2, N2, H2, C6H6
CO2, H2O
N2, C6H6, C2H4
CO2, N2, H2, C6H6
CO2, H2O
N2, C6H6, C2H4
CO2, N2, H2, C6H6
H2O, CO2
C81H51N21O27
60 – 120
220 – 315
317 – 390
60 – 130
200 – 310
335 – 450
60 – 125
225 – 325
335 – 455
60 – 122
210 – 295
315 – 410
60 – 135
7
C171H141Fe6N33O27
C195H141Cr6N33O27
C321H231Fe12N45O51
C273H231Cr12N45O51
10
12
13
215 – 320
325 – 445
27.01 (25.17)
55.48 (53.56)
N2, C2H4
CO2, N2, H2, C6H6
a) The final thermal decomposition products are metal oxides.
Conclusions. – In this study, the novel tri-directional Schiff bases 2 – 5, derived from
melamine and cyanuric chloride were synthesized. The synthetic strategy for the
preparation of the hexa- and dodecanuclear complexes 7 – 14 involved a ꢀligand
complexꢁ that contains a potential donor group (COOꢀ) capable of coordinating to
another ligand. We chose [{Fe(salen or saloph)}2O] and [{Cr(salen or Saloph)}2O] as
ꢀligand complexesꢁ because their central Fe- or Cr-atom can coordinate to the ligands 4
and 5 via the carboxylate anions derived from the latter. The structures of the
complexes 7 – 14 were characterized by means of elemental analysis, 1H-NMR and FT-
IR spectroscopy, thermal analyses, LC/MS analysis, and magnetic susceptibility
measurements. The magnetic data for these hexa- and dodecanuclear complexes were
consistent with an octahedral environment of the d5 and d3 metal ion.
Experimental Part
1. General. All chemicals were purchased from Aldrich. Vacuum drying in a Vacucell 22 MMM-
Medcenter Einrichtungen GmbH. Flash chromatography (FC): CombiFlashꢄ chromatography. M.p.:
Bꢂchi-SMP-20 melting point apparatus. IR Spectra: Perkin-Elmer-1600 FT-IR spectrophotometer; KBr
1
discs; ˜n in cmꢀ1. H-NMR Spectra: Bruker-200 spectrometer in (D6)DMSO; d in ppm rel. to Me4Si as
internal standard, J in Hz. MS: Varian-MAT-711 spectrometer; in m/z (rel. %). LC/MS: in m/z.
Elemental analyses: Carlo-Erba-1106 elemental analyzer; metal contents in complexes were determined
with a Unicam-929 atomic absorption spectrometer.
Thermal analyses: Shimadzu-DTA-50 and TG-50-H instruments; 10 mg samples under dry N2;
heating rates 108/min, from 22 – 7508. Magnetic susceptibilities: Sheerwood-Scientific-MX-Gouy
magnetic susceptibility apparatus; measurements by the Gouy method with Hg[Co(SCN)4] as calibrant;

Helvetica Chimica Acta – Vol. 93 (2010)
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pffiffiffiffiffiffi
calculation of the effective magnetic moment meff per metal atom from meff ¼ 2:84 cMT B:M:, where cM is
the molar susceptibility.
2. ꢀLigand Complexesꢁ. [{Fe(salen) or (saloph)}2O] and [{Cr(salen) or (saloph)}2O] were prepared by
adding conc. NH3 soln. to a stirred hot EtOH solns. of [Fe(salen) or (saloph)Cl] and [Cr(salen) or
(saloph)Cl], resp., until it became alkaline [21][35 – 37].
3. 4,4’,4’’-[1,3,5-Triazine-2,4,6-triyltris(nitrilomethylidyne)]tris[phenol] (2). Melamine (1; 5 mmol,
0.63 g) was suspended in benzene (10 ml), and a suspension of 4-hydroxybenzaldehyde (1.83 g, 15 mmol)
in benzene (25 ml) was added by stirring. The mixture was boiled under reflux for 5 h, and the pink
powder formed was dried under vacuum [3]. The obtained mixture was purified by FC (CombiFlashꢃ,
AcOEt/hexane 1:4): 2 (ca. quant). FT-IR: 3338 (OH), 2842 (CH), 1615 (CH¼N), 1565 (triazine C¼N).
1H-NMR ((D6)DMSO): 9.77 (s, 3 H); 7.76, 7.73 (2d, J ¼ 0.028, 6 H); 6.93 – 6.90 (d, J ¼ 0.028, 6 H); 6.08 (s,
3 H). LC/MS: 438 ꢁ 2.
4. N2,N4,N6-Tris{{4-[4,6-dichloro-1,3,5-triazin-2-yl)oxy]phenyl}methylene}-1,3,5-triazine-2,4,6-tri-
amine (3). A cyanuric chloride (2.76 g, 15 mmol) soln. in acetone (100 ml) was added dropwise to a
soln. of 2 (2.19 g, 5 mmol) and NaOH (0.6 g, 15 mmol) in H2O (50 ml) at 0 – 58, while stirring. The
mixture was stirred vigorously for 3 h at 0 – 58 and then for 2 h at 15 – 208. At these stages, Fujiwaraꢁs test
[7] for dichlorotriazine was positive. The temp. was allowed to increase to 258 and maintained at 25 – 308.
The pale white solid was filtered and washed with cold H2O, then with EtOH. The obtained mixture was
purified by FC (CombiFlashꢃ, AcOEt/hexane 1:4), and the recrystallized from acetone: 3 (3.09 g, 70%).
FT-IR: 2847 (CH), 1618 (CH¼N), 1574 (triazine C¼N), 1366 (CꢀOꢀC), 845 (CꢀCl). 1H-NMR
((D6)DMSO): 10.03 (s, 3 H); 8.05 – 8.01 (d, J ¼ 0.42, 6 H); 7.56, 7.52 (2 d, J ¼ 0.42, 6 H). LC/MS: 882 ꢁ 2.
5. 4,4’,4’’,4’’’,4’’’’,4’’’’’-[1,3,5-Triazine-2,4,6-triyltris(nitrilomethylidyne-4,1-phenyleneoxy-1,3,5-triazine-
6,2,4-triyldiimino)]hexakis[benzoic Acid] (4) or 5,5’,5’’,5’’’,5’’’’,5’’’’’-[1,3,5-Triazine-2,4,6-triyltris(nitrilo-
methylidyne-4,1-phenyleneoxy-1,3,5-triazine-6,2,4-triyldiimino)]hexakis[benzene-1,3-dicarboxylic Acid]
(5). A soln. of 3 (0.88 g, 1 mmol) in acetone (50 ml) was added dropwise to deionized (100 ml) H2O
cooled in an ice bath (0 – 58), under vigorous stirring. 4-Aminobenzoic acid (0.82 g, 6 mmol) or 5-
aminoisophthalic acid (1.09 g, 6 mmol), resp., and sat. Na2CO3 soln. (0.636 g, 6 mmol) in deionized H2O
were added. The mixture was stirred for 3 h while being cooled in the ice bath and then boiled under
reflux for 10 h. The dirty white or grey powder formed was dried under vacuum and subjected to FC
(CombiFlashꢃ, AcOEt/hexane 1:4): 4 (1.00 g, 68%) or 5 (1.05 g, 60%).
Data of 4: FT-IR: 3421 (NH), 3155 (OH), 2835 (CH), 1690 (C¼O), 1605 (CH¼N), 1560 (triazine
C¼N), 1405 (COOꢀ), 1359 (COC). 1H-NMR ((D6)DMSO): 13.92 (br. s, 6 H); 10.03 (s, 3 H); 7.88, 6.67
(d, 24 H); 7.43, 6.87 (d, 12 H); 4.55 (d, 6 H). LC/MS: 1486 ꢁ 2.
Data of 5: FT-IR: 3425 (NH), 3165 (OH), 2840 (CH), 1692 (C¼O), 1615 (CH¼N), 1573 (triazine
C¼N), 1408 (COOꢀ), 1372 (COC). 1H-NMR ((D6)DMSO): 13.96 (br. s, 12 H); 10.05 (s, 3 H); 8.25 (s,
6 H); 7.68 (d, 12 H); 6.82 (d, 6 H); 7.45 (d, 6 H); 4.75 (d, 6 H). LC/MS: 1750 ꢁ 2.
6. Hexakis{{2,2’-{ethane-1,2-diylbis[(nitrilo-kN)methylidyne]}bis[phenolato-kO]}(2ꢀ)}- and Hexa-
kis{{2,2’-{1,2-phenylenebis[(nitrilo-kN)methylidyne]}bis[phenolato-kO]}(2ꢀ)}{m6-{4,4’,4’’,4’’’,4’’’’,4’’’’’-
[1,3,5-triazine-2,4,6-triyltris(nitrilomethylidyne-4,1-phenyleneoxy-1,3,5-triazine-6,2,4-triyldiimino)]hexa-
kis[benzoato-kO1 :kO1’:kO1’’:kO1’’’:kO1’’’’:kO1’’’’’)}}hexairon (7 and 8, resp.) or Hexakis{{2,2’-{ethane-
1,2-diylbis[(nitrilo-kN)methylidyne]}bis[phenolato-kO]}(2ꢀ)}- and Hexakis{{1,2’-{2,2-phenylenebis-
[(nitrilo-kN)methylidyne]}bis[phenolato-kO]}(2ꢀ)}{m6-{4,4’,4’’,4’’’,4’’’’,4’’’’’-[1,3,5-triazine-2,4,6-triyltris-
(nitrilomethylidyne-4,1-phenyleneoxy-1,3,5-triazine-6,2,4-triyldiimino)]hexakis[benzoato-kO1 :kO1’:kO1’’:
kO1’’’:kO1’’’’:kO1’’’’’)}}hexachromium (9 and 10, resp.) [{Fe(salen) or (saloph)}2O] (1.98 g, 3 mmol; or
2.27 g, 3 mmol) or [{Cr(salen) or (saloph)}2O] (1.96 g, 3 mmol; or 2.25 g, 3 mmol) was suspended in hot
EtOH (50 ml), and a soln. of 4 (1.49 g, 1 mmol) in EtOH was added under stirring. The mixture was
boiled under reflux for 4 h, and the solid formed was dried under vacuum. The obtained mixtures were
purified by FC (CombiFlashꢃ, MeOH/hexane 1:4): 7 (2.33 g, 68%), 8 (2.41 g, 65%), 9 (1.87 g, 55%), or
10 (2.18 g, 59%).
Data of 7 and 9: FT-IR: 3425 (NH), 2895 (CH2), 2837 (CH), 1540 – 1617 (CH¼N), 1580 (triazine
C¼N), 1385 (COOꢀ), 1369 (COC), 534 (MꢀN), 468 (MꢀO). LC/MS: 3425 ꢁ 2 (7); 3402 ꢁ 2 (9).
Data of 8 and 10: FT-IR: 3423 (NH), 2847 (CH), 1545 – 1627 (CH¼N), 1587 (triazine, C¼N), 1382
(COOꢀ), 1372 (COC), 544 (MꢀN), 478 (MꢀO). LC/MS: 3713 ꢁ 2 (8); 3690 ꢁ 2 (10).

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7. Dodecakis{{2,2’-{ethane-1,2-diylbis[(nitrilo-kN)methylidyne]}bis[phenolato-kO]}(2ꢀ)}- and Do-
decakis{{2,2’{1,2-phenylenebis[(nitrilo-kN)methylidyne]}bis[phenolato-kO]}(2ꢀ)}{m12-{5,5’,5’’,5’’’,5’’’’,5’’’’’-
[1,3,5-triazine-2,4,6-triyltris(nitrilomethylidyne-4,1-phenyleneoxy-1,3,5-triazine-6,2,4-triyldiimino)]hexa-
kis[benzene-1,3-dicarboxylato(2ꢀ)-kO1 :kO1’:kO1’’:kO1’’’:kO1’’’’:kO1’’’’’:kO3 :kO3’:kO3’’:kO3’’’:kO3’’’’:
kO3’’’’’]}}dodecairon (11 and 12, resp.) or Dodecakis{{2,2’-{ethane-1,2-diylbis[(nitrilo-kN)methylidyne]}-
bis[phenolato-kO]}(2ꢀ)}- and Dodecakis{{2,2’{1,2-phenylenebis[(nitrilo-kN)methylidyne]}bis[phenola-
to-kO]}(2ꢀ)}{m12-{5,5’,5’’,5’’’,5’’’’,5’’’’’-[1,3,5-triazine-2,4,6-triyltris(nitrilomethylidyne-4,1-phenyleneoxy-
1,3,5-triazine-6,2,4-triyldiimino)]hexakis[benzene-1,3-dicarboxylato(2 ꢀ)-kO1 :kO1’:kO1’’:kO1’’’:kO1’’’’:
kO1’’’’’:kO3 :kO3’:kO3’’:kO3’’’:kO3’’’’:kO3’’’’’]}}dodecachromium (13 and 14, resp.). [{Fe(salen) or
(saloph)}2O] (3.96 g, 6 mmol; or 4.54 g, 6 mmol) or [{Cr(salen) or (saloph)}2O] (3.92 g, 6 mmol; or
4.49 g, 6 mmol) was suspended in hot EtOH (100 ml), and a soln. of 5 (1.75 g, 1 mmol) in EtOH was
added by stirring. The mixture was boiled under reflux for 4 h, and the solid formed was dried under
vacuum. The obtained mixtures were purified by FC (CombiFlashꢃ, MeOH/hexane 1:4): 11 (3.83 g,
68%), 12 (4.47 g, 72%), 13 (3.46 g, 62%), or 14 (4.13 g, 67%).
Data of 11 and 13: FT-IR: 3427 (NH), 2892 (CH2), 2838 (CH), 1542 – 1615 (CH¼N), 1583 (triazine
C¼N), 1381 (COOꢀ), 1371 (COC), 532 (MꢀN), 470 (MꢀO). LC/MS: 5628 ꢁ 2 (11); 5582 ꢁ 2 (13).
Data of 12 and 14: FT-IR: 3424 (NH), 2840 (CH), 15456 – 1617 (CH¼N), 1588 (triazine C¼N),
1384 (COOꢀ), 1375 (COC), 538 (MꢀN), 476 (MꢀO). LC/MS: 6204 ꢁ 2 (12); 6158 ꢁ 2 (14).
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Received August 10, 2009