Effect of α–Cyclodextrin on 4-Nitro Benzoic Acid And 3, 5-Dinitro Benzoic Acid

The absorption fluorescence FT-IR and SEM charcecteristics of 4- nitro benzoic acid (4–NBA) and 3,5-dinitrobenzoic acid (3,5–DNBA) have been investigated for different concentration of α–Cyclodextrin ( α-CD). The inclusion processes are discussed based on absorption, emission, FT – IR spectroscopy and SEM studies. The absorption and emission studies show that carbonyl group is deeply entrapped in the α-Cyclodextrin cavity and NO2 group is entrapped in the upper rim of the α-Cyclodextrin. The higher formation constant value for 4-NBA proves that 4-NBA included deeply in the α-Cyclodextrin cavity than 3, 5-DNBA. Lower formation constant value suggest that Intramolecular hydrogen bonding and steric hindrance are present in 3, 5-DNBA. Change in the IR frequency shows that both 4-NBA and 3, 5-DNBA are included in the α-Cyclodextrin cavity. Benesi – Hildebrand plot confirmed that 1:1 stoichiometric ratio was present in the inclusion complex. SEM study cleared shows the morphological difference in the inclusion complex