title: Salen, reduced salen and N-alkylated salen type compounds: spectral characterization, theoretical investigation and biological studies.
abstract: Salen [2,2'-{propane-1,3-diylbis[nitrilo(E)methylylidene]}bis(6-methoxyphenol)], reduced salen [(2,2'-[propane-1,3-diylbis(iminomethylene))]bis(6-methoxyphenol)] and N-alkylated salen [diethyl-2,2'-(propane-1,3-diylbis((2-hydroxy-3-methoxybenzyl) azanediyl))diacetate] compounds have been synthesized and characterized by IR, (1)H NMR, (13)C NMR and UV-vis. spectroscopy. Molecular geometry of the title compounds in the ground state has been optimized by density functional method (B3LYP) with 6-31 G basis set. Vibrational frequencies of the compounds were computed and compared with the experimental values. Tautomeric stability study of salen inferred that the enolimine form is more stable than its ketoenamine form in gas phase. The spectral behavior of salen in polar and nonpolar solvents was examined demonstrate the positive solvatochromism. The synthesized compounds have been studied with respect to their binding to calf thymus DNA showed that there were interactions between the compounds and DNA through a groove binding mode. Furthermore, the DNA cleavage activity of the compounds has been investigated by gel electrophoresis. The antioxidant properties of compounds were evaluated by DPPH method. The N-alkylated compound has a higher DPPH free radical scavenging activity. The antimicrobial activity was investigated on various gram positive and gram negative bacteria.
authors.affiliation: Chemistry Research Centre, National Engineering College, KR Nagar, Kovilpatti 628 503, Thoothukudi District, Tamil Nadu, India.
authors.forename: P
authors.initials: P
authors.lastname: Jeslin Kanaga Inba
authors.forename: B
authors.initials: B
authors.lastname: Annaraj
authors.forename: S
authors.initials: S
authors.lastname: Thalamuthu
authors.forename: M A
authors.initials: MA
authors.lastname: Neelakantan
mesh_terms: D000042:Absorption; D000478:Alkylation; D000818:Animals; D000890:Anti-Infective Agents / Q000494:pharmacology; D001419:Bacteria / Q000187:drug effects; D001713:Biphenyl Compounds / Q000737:chemistry; D002417:Cattle; D004247:DNA / Q000378:metabolism; D003851:Deoxyribonucleases / Q000378:metabolism; D004583:Electrons; D005029:Ethylenediamines / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D008826:Microbial Sensitivity Tests; D008958:Models, Molecular; D008968:Molecular Conformation; D010084:Oxidation-Reduction; D010851:Picrates / Q000737:chemistry; D011789:Quantum Theory; D012996:Solutions; D012997:Solvents / Q000737:chemistry; D013055:Spectrophotometry, Infrared; D013056:Spectrophotometry, Ultraviolet; D013816:Thermodynamics; D014732:Vibration
chemical_list: D000890:Anti-Infective Agents; D001713:Biphenyl Compounds; D005029:Ethylenediamines; D010851:Picrates; D012996:Solutions; D012997:Solvents; D004247:DNA; C427203:calf thymus DNA; C011452:disalicylaldehyde ethylenediamine; C004931:1,1-diphenyl-2-picrylhydrazyl; D003851:Deoxyribonucleases