The UV spectra of compounds 2 and 4

The UV spectra of compounds 2 and 4 investigated cannot be
interpreted in terms of the azo structure of the types (A and B)
but evidently they appear compatible with the indicated hydrazone
structure (C). The presence of diazonium coupling products
of 1 and 3, apparently exclusively, in the hydrazone form can be
explained by a smaller degree of resonance stabilization of the
azo forms (A and B). The six-membered hydrogen-bonded ring
structure in the hydrazone form, as in (C), would also undoubtedly
enhance its relative stability [21], since the color of an azodye
depends on the structure of the diazotizable amines. It is clear that,
these dyes exhibit three absorption bands, of these, the medium
and high wavelength bands seem to be affected by the nature of
the polar substituent in the arylazo group and the low wavelength
band is unaffected. Table 1 shows that, both electron withdrawing
and electron donating groups cause the absorption to occur at
higher wavelengths A “C N” linkage was reported to have properties
especially analogous to those of an ethylenic linkage [22].
Hence, an electronic effect of a substituent on the aromatic nucleus
of the arylazo moiety will be transmitted to the whole conjugate
system through –P conjugation, exerting a considerable influence
upon the conjugation bands A and B. Table 1 also shows that, the
presence of electron donating or electron withdrawing groups has
not brought about any marked increase or decrease in max in the
visible region and log ε has nearly remained constant. This does
point towards the hydrazone structure (C) where the resonance
in the diazo components is minimal, owing to steric factors. The
1H NMR spectra of arylazo derivatives 2a–d and 4a–f showed asinglet signal at ı 88 ppm corresponding to NH proton. The downfield
shift of the former occurs because the nearby azo group has
a deshielding effect [23]. Compound 2a–d showed a doublet at ı
865 ppm corresponding to -proton (C-6) in pyridine ring, while
compounds 4a–f showed two doublets (AB system) due to - and
-protons of the pyridine ring at  855 and 721 ppm, respectively.
Also, the 1H NMR spectra of arylazo derivatives revealed a multiplet
at ı 691–745 ppm corresponding to the aromatic protons

ผลลัพธ์ (อังกฤษ) 2:

The UV Spectra of compounds 2 and 4 Investigated Can Not be
interpreted in terms of azo The structure of The types (A and B)
but evidently they appear compatible with The indicated hydrazone
structure (C). The Presence of diazonium coupling products
of 1 and 3, apparently exclusively, in The hydrazone Form Can be
explained by a smaller Degree of resonance Stabilization of The
azo forms (A and B). The Six-membered hydrogen-Bonded ring
structure in The hydrazone Form, As in (C), would also undoubtedly
ENHANCE ITS relative stability [21], since The color of an Azodye
depends on The structure of The Diazotizable Amines. It is clear that,
these Three Dyes exhibit absorption bands, of these, The Medium
and High wavelength bands SEEM to be affected by The Nature of
The Polar Substituent in Arylazo The Group and The Low wavelength
band is unaffected. Table 1 Shows that, Both Electron withdrawing
and Electron donating groups Cause The absorption to occur at
Higher wavelengths A "CN" linkage was Reported to Have Properties
especially analogous to those of an Ethylenic linkage [22].
Hence, an Electronic Effect of a Substituent. on The Aromatic Nucleus
of The Arylazo moiety Will be transmitted to The Whole Conjugate
System Through? -P conjugation, exerting a considerable influence
upon bands A and B. The conjugation Table 1 also Shows that, The
Presence of Electron Electron donating or withdrawing groups has.
Not Marked increase or decrease in any brought About? MAX in The
Visible and log epsilon region has remained Nearly Constant. This does
Point towards The hydrazone structure (C) Where The resonance
in The Diazo components is Minimal, owing to steric factors. The
1H NMR Spectra of Arylazo Derivatives 2a and 4a-D-F showed Asinglet ı Signal at 88 PPM corresponding to NH Proton. The Downfield
Shift of The Former occurs nearby azo Because The Group has
a Deshielding Effect [23]. Compound 2a-D showed a doublet at ı
corresponding to 865 PPM? -proton (C-6) in pyridine ring, while
compounds 4a-F showed Two doublets (AB System) Due to? - and
? -protons of The pyridine ring at. ? PPM 855 and 721, respectively.
Also, The 1H NMR Spectra of Derivatives Arylazo Revealed a multiplet
at from 691 to 745 PPM corresponding to ı The Aromatic protons.

ผลลัพธ์ (อังกฤษ) 3:

The UV spectra of compounds 2 and 4 investigated cannot be
interpreted in terms of the azo structure of the types (A and. B)
but evidently they appear compatible with the indicated hydrazone
structure (C). The presence of diazonium coupling products
of 1, and 3 apparently. Exclusively in the, hydrazone form can be
explained by a smaller degree of resonance stabilization of the
azo forms (A and. B).The six-membered hydrogen-bonded ring
structure in the, hydrazone form as in (C), would also undoubtedly
enhance its relative. Stability [21], since the color of an azodye
depends on the structure of the diazotizable amines. It is clear that
these,, Dyes exhibit three bands absorption, these of, medium the
and high wavelength bands seem to be affected by the nature of
.The polar substituent in the arylazo group and the low wavelength
band is unaffected. Table 1 shows that both electron,, Withdrawing
and electron donating groups cause the absorption to occur at
higher wavelengths A "C N linkage was reported." To have properties
especially analogous to those of an ethylenic linkage [22].
Hence an electronic, effect of a substituent. On the aromatic nucleus
.Of the arylazo moiety will be transmitted to the whole conjugate
system through  - P conjugation exerting a, considerable. Influence
upon the conjugation bands A and B. Table 1 also, shows that the
presence of electron donating or electron withdrawing. Groups has
not brought about any marked increase or decrease in  Max in the
visible region and log ε has nearly remained. Constant. This does
.Point towards the hydrazone structure (C) where the resonance
in the diazo components, is minimal owing to steric factors.? The
1H NMR spectra of arylazo derivatives 2A - D and 4A - f showed asinglet signal at ı 88 ppm corresponding to NH proton. The. Downfield
shift of the former occurs because the nearby azo group has
a Deshielding effect [23]. Compound 2A - D showed a. Doublet at ı
.865 ppm corresponding to  - proton (C-6), in pyridine ring while
compounds 4A - f showed two doublets (AB system) due to  -. And
 - protons of the pyridine ring at  855 and, 721 ppm respectively.
Also the 1H, NMR spectra of arylazo derivatives revealed. A multiplet
at ı 691 - 745 ppm corresponding to the aromatic protons.