1-(4- Bromo -1-hydroxynaphthalen-2-yl)-ethan-1-one was prepared by refluxing 4- bromonaphthalen-1-ol with glacial acetic acid in presence of fused ZnCl2. By condensing 1-(4- bromo -1-hydroxynaphthalen-2- yl)-ethan-1-ones with 4- methoxy benzaldehyde, to prepared by 1-(4- bromo -1- hydroxynaphthalen-2-yl)-3-(4-methoxy phenyl)-prop-2-en-1-one were synthesized.1-(4- bromo -1- hydroxynaphthalen-2-yl)-3-(4-methoxy phenyl)-prop-2-en-1-one, urea and concentrated HCl in DMF were added and refluxed. Cool and pour in crushed ice. Treat it with cold NH4OH solution to obtain titled compounds. The compounds thus synthesized have been characterized by physical and spectral data. All of these titled synthesized compounds have been screened for antimicrobial study and are found to possess excellent antimicrobial activities.

The good activity of drug is depending upon its stability constant i.e. proton ligand stability constant and metal ligand stability constant. If the stability constant is fairly very good then it should use as a good and effective medicine .In content to this in present work the proton ligand stability constant and metal ligand stability constant of fluro substituted chalconeimines L5 = 2-Hydroxy naphthalene 4-dimethyl aniline 4- fluro chalconeimine [FN] are studied with highly reactive transition metal like (Cu (II), Co(II),Cr(II) and Fe(III)). The 70% dioxane water solvent system used in the present investigation. The presence of –OH group confirmed by using of 0.1 M ionic strength. The transition metal (Cu (II),Co (II),Cr(II)and Fe(III)) used and the ligand form 1:1 and 1:2 complex with all values of log k1 and log k2 positive.