10.22376/ijpbs.2019.10.1.p1-12 Volume 4 Issue 3 2013 (July - September) 1,4-Bis(1-piperidineethyl)piperazine tetradentate N lessThan sub greaterThan 4 lessThan /sub greaterThan type of ligand synthesized from piperazine and 1-(2-chloroethyl)piperidine HCl. The Cu(II), Pd(II), Fe(III) and Mn(II) complexes of ligand N lessThan sub greaterThan 4 lessThan /sub greaterThan were synthesized by taking 1:1 ration of M:N lessThan sub greaterThan 4 lessThan /sub greaterThan . The ligand and complexes have been characterized by elemental analyses, lessThan sup greaterThan 1 lessThan /sup greaterThan H-NMR, FT-IR, UV-Vis., spectroscopic techniques and mass spectrometric studies. The magnetic moment measurements and conductance measurements were carried out on all the complexes. The elemental analyses shows that the complexes obtained have the composition of [Cu(N lessThan sub greaterThan 4 lessThan /sub greaterThan )](PF lessThan sub greaterThan 6 lessThan /sub greaterThan ) lessThan sub greaterThan 2 lessThan /sub greaterThan , [Pd(N lessThan sub greaterThan 4 lessThan /sub greaterThan )](PF lessThan sub greaterThan 6 lessThan /sub greaterThan ) lessThan sub greaterThan 2, lessThan /sub greaterThan [Fe(N lessThan sub greaterThan 4 lessThan /sub greaterThan )Cl lessThan sub greaterThan 2 lessThan /sub greaterThan ]PF lessThan sub greaterThan 6 lessThan /sub greaterThan and [Mn(N lessThan sub greaterThan 4 lessThan /sub greaterThan )Cl lessThan sub greaterThan 2 lessThan /sub greaterThan ]. The spectroscopic data revealed, square planar geometries for Cu(II), Pd(II) and octahedral geometries for the Fe(III), Mn(II) complexes and the ligand acts as tetradentate N lessThan sub greaterThan 4 lessThan /sub greaterThan donor. The ligand and all complexes were screened for their antibacterial activity against bacterial species lessThan i greaterThan Enterococcus faecalis lessThan /i greaterThan , lessThan i greaterThan Staphylococcus aureus, Escherichia coli as well as fungi Streptococcus mutans, Candida albicans, Aspergillus fumigatus. The activity data revealed that the metal complexes are to be more potent antibacterials lessThan /i greaterThan in comparison to lessThan i greaterThan parent ligand. lessThan /i greaterThan KRISHNA MURTHY.P, N.VENKATASUBBA NAIDU AND P.RAGHAVENDRA KUMAR 1,4-Bis(piperidineethyl)piperazine, N4 tetradentate ligand, Cu(ІІ), Pd(ІІ), Fe(ІІІ) and Mn(ІІ), antimicrobial activity. 947-956