Cyclometalated palladium(II) metallomesogens with Schiff bases and N-benzoyl thiourea derivatives as co-ligands

Cyclometalated palladium(II) metallomesogens with Schiff bases and N-benzoyl thiourea derivatives as co-ligands

Publication Type:

Journal Article

Source:

Journal of Molecular Liquids, Volume 233, p.45-51 (2017)

ISBN:

0167-7322

Abstract:

<p>Two series of cyclometalated palladium(II) complexes based on Schiff bases and N-benzoylthiourea (BTU) ligands having four alkoxy groups at their periphery, with different number of carbon atoms, have been designed and prepared. The liquid crystalline behavior of these palladium(II) complexes was investigated by a combination of polarized optical microscopy (POM), differential scanning calorimetry (DSC) and powder X-ray diffraction while their thermal stability was studied by thermogravimetric analysis (TGA). The palladium(II) complexes are thermally stable on a broad temperature range up to 230 degrees C showing, depending on the alkoxy chain length, either monotropic or, for longest alkyl chain, enantiotropic smectic A and C phases. The luminescent properties of palladium(II) complexes were reported. These complexes show a yellow-orange solid-state emission at room temperature with two emission maxima at lambda(max) around 580 and 650 nm, respectively, with a shoulder around 710 nm, when the samples are irradiated in the 330-380 nm range. (C) 2017 Elsevier B.V. All rights reserved.</p>