CIRCULAR-DICHROISM STUDIES OF CO(II), NI(II) AND CU(II) COMPLEXES OF ANTIBIOTIC (-AMPICILLIN FORMED IN SOLUTION())

Circular dichrosim studies show that (+)-Ampicillin, a broad spectrum beta-lactam antibiotic, forms soluble complexes with Co(II), Ni(II) an d Cu(II) ions in aqueous solution. Complexation of these metal ions wi th (+)-ampicillin ((+)-amp) is indicated by appearance of Co bands in crystal field region. In solution, complexes of composition [M((+)-amp )(2)](2+) are formed at pH 6.5-8.0 which have 2-3 Cotton bands in 14,7 06-23,697 cm(-1) region. The CD band ellipticity is linearly increased with concentration of the components under optimum conditions between 0.002-1.0 mol L(-1). The Cotton bands in these systems are interprett ed in terms: of electronic excitations to unidimensional levels arisin g due to lower symmetry of these complex ions.