Spectral, structural elucidation and coordination abilities of Co(II) and Mn(II) coordination entities of 2,6,11,15-tetraoxa-9,17-diaza-1,7,10,16-(1,2)-tetrabenzenacyclooctadecaphan-8,17-diene

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Molecular and biomolecular spectroscopy, 2011-09, Vol.79 (5), p.1042-1049
• Main Authors: Rajiv, Kumar, Rajni, Johar
• Format: Article
• Language: English
• Subjects: 1H and 13C NMR; Antimicrobial; Coordination entities (CEs); EPR; Molecular modeling
• ISSN: 1386-1425
• DOI: 10.1016/j.saa.2011.04.017

Designing tactics were tailored and followed by synthetic and formulation methodologies to prepare 2,6,11,15-tetraoxa-9,17-diaza-1,7,10,16-(1,2)-tetrabenzena-cyclooctadecaphan-8,17-diene. Spectral techniques (MS, infrared, 1H NMR, 13C NMR, electronic and EPR), physiochemical measurements (elemental analysis, molar conductance and magnetic susceptibility), electrochemistry (cyclic voltammetry) and classical mechanics (molecular modeling) were employed for structural elucidation of Co(II) and Mn(II) coordination entities having N 2O 4 chromophore. Inhibiting potential (antifungal screened against Aspergillus flavus) showed enhanced antimicrobial properties of CEs as compared to ligand. Molecular modeling was employed to find out different molecular features along with their stabilization energies. [Display omitted] ► Binding abilities of donor atom(s) [O, S and N (nucleophile)] forced metal ion(s) to adopt different coordination geometries. ► 1H NMR and 13C NMR spectra study evidence new azomethine (–CH N–) linkage. ► Identification of antifungal character because of inhibits enzymatic activity. ► Coordination shortens for the N(38)–Co(39) due to the presence of hydrogen in azomethine (–CH N–). ► Macrocycles used as selective host for a wide variety of guest molecules and metal ion(s). Designing tactics were tailored and followed by synthetic and formulation methodologies to prepare 2,6,11,15-tetraoxa-9,17-diaza-1,7,10,16-(1,2)-tetrabenzenacyclooctadecaphan-8,17-diene. Spectral techniques (MS, infrared, 1H NMR, 13C NMR, electronic and EPR), physiochemical measurements (elemental analysis, molar conductance and magnetic susceptibility), electrochemistry (cyclic voltammetry) and classical mechanics (molecular modeling) were employed for structural elucidation of Co(II) and Mn(II) coordination entities having N 2O 4 chromophore. Comparative spectral analysis revealed legating nature of N 2O 4 donor macrocycle and confirmed host/guest connectivity between ligand and metal(s). Mass spectrometry (MS) determined 1:1 stoichiometry in CEs. Further electrochemical study confirmed change in oxidation and reduction patterns of CEs. Inhibiting potential (antifungal screened against Aspergillus flavus) showed enhanced antimicrobial properties of CEs as compared to ligand. Molecular modeling was employed to find out different molecular features along with their stabilization energies.