Sonochemical synthesis, characterization, thermal and semiconducting behavior of nano-sized azidopentaamminecobalt(III) complexes containing anion, CrO42- or Cr2O72.

New nano-sized cobalt(III) coordination complexes, [Co(NH3)5N3]CrO4 (1N) and [Co(NH3)5N3]Cr2O7 (2N) were synthesized using an innovative sonochemical methodology based on reaction between [Co(NH3)5N3]Cl2 and potassium salt of CrO42- or Cr2O72- in aqueous medium. These complexes were also compared with their respective bulks which were synthesized under identical conditions in the absence of sonicaion. All the complexes were characterized by elemental analysis and spectroscopic techniques (UV-visible and IR). Morphology and particle size of nano-sized complexes was determined by SEM and Zeta-sizer respectively. TGA was used for comparative thermal stability and XRD to identify the phase difference between nano structures and bulk complexes. Furthermore, the electrical property was investigated and all complexes were found to be electrical semiconducting materials and 2N shows better result than others. The single crystals X-ray structure study of new [Co(NH3)5N3]Cr2O7 revealed the presence of discrete ions, [Co(NH3)5N3]2+ and Cr2O72-, crystallizes in monoclinic, space group Pc, with R=0.0636 in the solid state.

Sonochemical synthesis, characterization, antimicrobial activity and textile dyeing behavior of nano-sized cobalt(III) complexes.

Using ultrasonic irradiations, nano-sized cobalt(III) coordination complexes, [Co(NH3)6]Cl3·2H2O (A), [Co(en)3]Cl3·3H2O (B) (en-ethylenediamine) and [Co(dien)2]Cl3·3.5H2O (C) (dien-diethylenetriamine) were synthesized. These complexes were characterized by spectroscopic studies like IR, UV/Visible and NMR. Morphology of these complexes was determined by SEM and particle size with the help of TEM & Zeta-sizer. The comparative thermal stability along with phase difference between nano structures and their respective bulk complexes has been studied by thermal gravimetric analysis (TGA) and X-ray powder diffraction (XRD) study respectively. The dyeing behavior of nano-sized Co(III) complexes and their respective bulks has also been studied (using both exhaust and pad dyeing methods) on cotton and wool fabrics and results shown rationalized dyeing behavior. All these complexes were further tested for antimicrobial activity (against B. subtilis, E. coli, K. pneumoniae, F. oxysporum and A. alternate) and it was observed that nano sized complexes enhanced the activity further.