142
A. Reyes-Arellano et al. / Journal of Molecular Structure 655 (2003) 141–148
We have recently reported [17] the synthesis of
added dropwise at ambient temperature. The mixture
˚
wasstirredfor30 min,5 Amolecularsieves(previously
various substituted N,N-bis(benzylidene)ethylenedia-
mines, which were co-crystallized with meso-1,2-
diphenyl-1,2-ethanediol. It was observed that not all
bisimines formed a complex. Therefore, it seems that
the presence of an aromatic ring in the bisimine
structure (indeed aldimines form complexes but
ketimines do not), coupled to a negligible steric
hindrance are factors (among others) that determine
the complexation process.
dried at 110 8C during 72 h, cooled and kept for 12 h at
room temperature under N2 atmosphere) were added
andthemixturewas intermittentlyshaken. Themixture
was then filtered, the molecular sieves washed with
CH2Cl2 and the solvent removed under vacuum. The
remaining residue was purified by crystallization and
then dried under high vacuum. All reactions were
performed under a nitrogen atmosphere.
As a continuation of our research in this field, an
studyoftheinfluenceofthenitrogroupinbisimineswas
undertaken. Thus N,N-bis(3-nitrobenzylidene)ethyle-
nediamine (1) and N.N-bis(4-nitrobenzylidene) ethy-
lenediamine (2) were synthesized and treated with
meso-hydrobenzoin. Here we present our results.
2.2. N,N-bis(3-nitrobenzylidene)ethylenediamine 1
Colorless crystals, mp 158–160 8C, yield 87.6%
IR (KBr) 3085, 2931, 1647, 1525, 1351, 813 cm21
1H NMR (DMSOd6–CDCl3, 2:1) d ¼ 8.49 (s, 2H,
3
HCyN), 8.41 (s, 2H, H-2), 8.19 (d, J ¼ 8.0 Hz, 2H,
H-6), 8.04 (d, 3J ¼ 8.0 Hz, 2H, H-4), 7.61 (t,
3J ¼ 8.0 Hz, 2H, H-5), 3.70 (s, 4H, CH2CyN). 13C
NMR (DMSOd6–CDCl3, 2:1) d ¼ 159.9 (CyN),
148.3 (Cipso NO2), 137.5 Cipso CyN) 133.9 (C-2),
129.6 (C-4), 124.8 (C-6), 122.3 (C-5), 61.0 (NyC–
CH2). MS (70 eV) m/z (%) 326 (2) [Mþ], 178 (100)
[Mþ –(O2NC6H3 þ HCN)], 163 (33) O2NC6H4-
CHyNyCH2], 161 (89) [O2NC6H4CNCH], 117 (74)
[C6H4CHyNyCH2], 90 (82) [C6H4CH þ H].
2. Experimental
Melting points were determined on an electro-
thermal melting point apparatus and are uncorrected.
Infrared spectra were recorded on a Perkin–Elmer
1
599-B spectrophotometer. H NMR and 13C NMR
spectra were recorded with a JEOL DELTA-GSX-270
1
spectrometer equipped with a 5 mm probe. H NMR
spectra were recorded at 270.05 MHz (spectral width
2700 Hz, acquisition time 1.516 s, pulse width 458, 32
scans, recycle delay 2 s). 13C NMR spectra were
recorded at 67.80 MHz (spectral width 12224.9 Hz
acquisition time 1.34 s, pulse width 308, 128 scans,
recycle delay 0.8 s). The chemical shifts are refer-
enced to internal (CH3)4Si (d1H ¼ 0, d13C ¼ 0). The
electron ionization (EI) mass spectra (70 eV) were
recorded using a Hewlett Packard HP-5998A spec-
trometer. The X-ray diffraction analysis of the
supramolecule was obtained on an Enraf–Nonius
CAD-4 diffractometer and the X-ray diffraction
analysis of the N,N-bis(4-nitrobenzylidene) ethylene-
diamine (2) was performed on an automatic Siemens
diffractometer. Elemental analysis was performed by
M-H-W Laboratories (Phoenix, AZ, USA).
2.3. N.N-bis-(4-nitrobenzylidene) ethylenediamine 2
Pale yellow crystals, mp 197–199 8C, yield
82.0%.
IR (KBr) n ¼ 3100, 3073, 2910, 2855, 1645 CyN),
1602, 1519 y 1339 (NO2), 854 cm21
1H NMR (DMSO-d6) d ¼ 8.45 (s, 2H, HC ¼ N),
8.05 (AA0BB0, 8H,), 4.05 (s, 4H, CH2–N).
13C NMR (DMSO-d6) d ¼ 160.0 (CyN), 148.5
(Cipso NO2), 141.0 (CipsoCyN), 128.4 (Cortho
CyN), 123.4 (Cortho NO2), 61.0 (NyC–C H2). MS
(70 eV) m/z (%) ¼ 326 (2) [Mþ], 178 (100) [Mþ–
(O2NC6H3 þ HCN)], 163 (34) [O2NC6H4-
CHyNyCH2], 149 (55) [O2NC6H4CNH], 117 (64)
[C6H4CHyNyCH2], 90 (70) [C6H4CH þ H].
2.1. Synthesis of bisimines
2.3.1. Supramolecule I
Equimolar quantities of N,N-bis(3-nitrobenzylide-
ne)ethylenediamine and meso-hydrobenzoin were
dissolved in ethyl acetate and kept in a hexane
atmosphere at room temperature. After 48 h
2.1.1. General procedure
Toasolutionofnitroarylaldehydeinanh.CH2Cl2,an
equimolar solution of ethylenediamine in CH2Cl2 was