Ethyl ester of DNS, 3,5-dinitro ethylsalicylate, was prepared according to both of the described proceures [12] and the described procedures [13] using ethyl salicylate instead of methyl salicylate, the products were identical in spectral analysis as well as physical propertie, pale yellow solid compounds, δ = 1.3 (t, CH₃ ester), 4.2 (q, CH₂ ester), 8.4 - 8.6 (m, CH aromatic), m.p. 73˚C, crystallized from ethanol-water 1:1 v/v. The purity was tested by thin layer chromatography (TLC).

Ethyl 3,5-dinitrosalicylate (1) (1 mmole) is dissolved in 10 ml boiled absolute ethanol and ethylenediamine (4 mmole) is added, the mixture was boiled for five minutes. The yellow solid product formed (2) was filtered out, dried and recrystallized from water. Yellow solid, m.p 192˚C, Scheme 1.

A saturated DMF-water, dimethylformamide-water, solvent mixture of 2-Aminoethanaminium 2-(ethoxycarbonyl)-4,6-dinitrophenolate salt (AED) was stirred for half an hour and filtered through quantitative whatmann 41 grade filter paper, the clear solution was kept undisturbed in a clean environment for one week.

Following the same procedures have been described by Miller and a recently published work [10] [14] [15] [16] [17] .

The ¹H and ¹³C NMR spectra of 2-Aminoethanaminium 2-(ethoxycarbonyl)-4,6-dinitrophenolate (AED) were recorded using the BRUKER AC 400MHz spectrophotometer with TMS as the internal reference standard and DMSO as a solvent.

δ = 1.3 (t, CH₃ ester), 4.2 (q, CH₂ ester), 3.7 (s, CH₂ adjacent N H 3 + ), 7.8 (s, ⁺NH₃), 8.4 - 8.6 (m, CH aromatic), 2.7 (s, CH₂ adjacent NH₂), 2.9 (s, NH₂), ¹³C NMR in DMSO, 14.15 ppm for CH₃ ester carbon, 60.01 ppm for CH₂ ester carbon, 165.15 ppm for C=O ester, 36.66 ppm for CH₂ ethylenediamine carbon, 123.78 - 139.98 ppm for aromatic carbons and 167.17 ppm for aromatic carbon attached to ester group.

The title crystal shows eight proton signals indicating the presence of eight different proton environments in the aminium crystal. The broad hump appearing at δ 7.8 ppm is assigned to the highly deshielded N H 3 + protons. The intense singlet signal appearing at δ 8.4 - 8.6 ppm has been assigned to aromatic protons. The intense signal at 3.7 ppm is assigned to the methylene group beside the highly shielded aminium group and another signal appeared at 2.7 ppm for methylene adjacent to the free amino group.

The characteristic vibrational frequencies of the functional groups of the aminium salt are identified from the fourier transform infrared (FT-IR) spectrum recorded in the range of 4000 - 400 cm⁻¹ employing Shimadzu Affinity 1S FT-IR spectrometer. The formation of charge transfer complex during the acid-base interaction of ethylenediamine with ethyl 3,5-dinitrosalicylate is strongly evidenced through the realization of important bands in the complex salt. The absorption at 3194 cm⁻¹ is due to the +N-H stretching vibration. The absorption band at 3060 cm⁻¹ corresponds to aromatic C-H asymmetric stretching vibration. The broad absorption bands in the region 3400 to 3600 cm⁻¹ are due to NH₂ asymmetric and symmetric stretching vibration. The absorptions at 1535 and 1359 cm⁻¹ confirm the asymmetric and symmetric stretching vibrations of NO₂ group respectively. The C=O stretching vibration is observed at 1680 cm⁻¹.

A yellow chip crystal having approximate dimensions of 0.500 × 0.300 × 0.300 mm was mounted on a glass fiber. All measurements were made on a Rigaku SCX mini diffractometer using graphite monochromated Mo-Kα radiation. The crystal-to-detector distance was 52.00 mm.

The crystal structure analyses reveal it is crystallized in monoclinic crystal structure with centrosymmetric space group C2/c and the unit cell parameters are a = 15.289(2) Å, b = 20.755(3) Å and c = 20.545(3) Å. The crystal structure has been already deposited in Cambridge Crystallographic Data Center coded CCDC 1441586, Figure 1 represents the molecular ORTEP diagram for the aminium salt [14] .

Some of the crystal data are listed (Table 1).

The optical transmission spectrum of the aminium salt was recorded in the region 400 - 1000 nm employing a Shimadzu 1061 UV-Vis spectrophotometer in

solution using DMSO as the solvent. The percentage of transmittance was around 100 in the region between 460 and 1000 nm. Hence, this crystal can be used for the suitable optical applications due to its wide transparency range in the part of visible region above 460 nm.

TG/DTA analysis, the sample is analyzed between 25˚C - 600˚C at a heating rate 10 K/min in nitrogen atmosphere. The DTA reveals exactly same changes shown by the TGA. From thermo gravimetric curve it is inferred that the material decomposes immediately after melting into gaseous products. The material exhibits sharp weight loss at 192.47˚C and below this temperature no significant weight loss. The endothermic peak appears at 190.97˚C in DTA corresponds to the melting point of the compound and another sharp exothermic peak at 268.84˚C may be attributed to decomposition temperature of the aminium salt.