The splitting pattern of the signals in aromatic region of the1H-NMR spectrum of 3 witnessed p-substituted [I' 7.60(2H, d, J = 9.2 Hz), 6.85 (2H, d, J = 8.8 Hz)] and 1,2-4-trisubstituted benzene ring
[I' 6.54 (1H, dd, J = 8.4, 2.0 Hz), 6.48 (1H, d, J = 8.4 Hz), 6.42 (1H, d, J = 2.0 Hz) systems in its structure, which were fully supported by the13C NMR spectrum of 3 (Table-1).
Summary: Organic scintillators are aromatic hydrocarbon compounds which contain benzene ring
structures interlinked in various ways
DVB was emulsified in the water easily and its benzene ring
had a conjugated effect with the benzene ring
of PS core which enhanced the compatibility between them, so DVB was a kind of excellent swelling agent for PS@PUB composite microspheres (Fig.
The stability of the benzene ring
and its tendency to take part in substitution reactions rather than addition reactions being one.
The IR (KBr disk) spectrum showed broad vibration at 3375 [cm.sup.-1] attributed to hydroxyl moiety (OH), sharp absorption at 1600 [cm.sup.-1] attributed to aromatic benzene ring
, strong absorption band at 2275 [cm.sup.-1] due to C-H stretching of saturated moiety, and absorption band at 1255 [cm.sup.-1] due to C-O stretching.
Because of the symmetry of the benzene ring
and the rotation of the benzene ring
around the C-X bond could be considered as free rotation, so the flexibility of polyimide only depends on the length of rigid chain and the valence angle of the C-X-C bond .
As stated earlier, the substituted benzene ring
at the end of the polypyridyl ligand has a large effect in determining the electronic and luminescence properties of the complex due to the lowest unoccupied molecular orbital (LUMO) location being centred on the polypyridyl ligand.
According to [sup.1]H NMR data, there exist four double-bond H signals including [[delta].sub.H] 7.46 (1H, d, J = 8.0), [[delta].sub.H] 7.33 (1H, d, J = 8.0), [[delta].sub.H] 7.08 (1H, t, J = 8.0), and [[delta].sub.H] 6.98 (1H, t, J = 8.0) in the low field, indicating the presence of ortho-disubstituted benzene ring
In the structure of compounds 5a, 5d, 5e, 5g, and 5j, the metasubstitution on the benzene ring
2 (Figure 2(b)) was modified to determine the contribution of this substitution to the antiproliferative activity.
The three additives were as follows: a C11 aromatic hydrocarbon called 4-tert-butyltoluene (TBT), NMA (a polar substance with a benzene ring
and amino group), and 2-Methyl-1,5-pentanediamine (also referred to as 2-methylpentamethylenediamine or C6 diamine, and abbreviated as MPD), which has no benzene ring
and two polar amino groups.
These factors include steric repulsion between the N[O.sub.2] groups, the formation of conjugated ions attracting the H atoms located at adjacent positions on the benzene ring
, the resistance of the conjugated [pi] orbitals to the rotation of the N[O.sub.2] groups, and the stress on the C-N bond caused by the repulsion of the N[O.sub.2] groups.
Naphthalene has two benzene ring
sharing two carbon atoms in the ortho position.