Synthesis, crystal structure, spectroscopic, fluorescent, thermal properties and EPR spectra of doped Cu2+ ions in [Cd(sac)2(H2O)2(meim)2] single crystal

The crystal structures of the six-coordinate complexes [Cd(sac)2(H2O)2(meim)2] (complex 1) formed by reaction of 4-methylimidazole(meim) with [Cd(sac)2(H2O)4]·2H2O (saccharinate = sac), was synthesized and characterized by elemental analysis, infrared (IR) and electron paramagnetic resonance (EPR) spectroscopy, thermal analysis and X-ray single crystal diffraction. X-ray diffraction analysis revealed that complex 1 crystallized in the monoclinic crystal system with space group P21/c. The Cd(II) center was six-coordinated with four nitrogen atoms from two sac and two 4-meim ligands, two oxygen atoms from two aqua ligands. Spectral and thermal analysis data for complex 1 was in agreement with the crystal structures. In addition complex 1 displayed blue fluorescent emission in the solid state at room temperature. Single crystal EPR spectra at room temperature are resolved and have exhibited that two different Cu2+ complexes were located in different chemical environments which contained two magnetically nonequivalent Cu2+ sites. In low temperature EPR spectra down to 110 °C did show no considerable change. At higher temperatures, however, both thermo gravimetric analyses (TGA) and EPR spectra showed detectable changes around 140 °C; the causes and the mechanisms of changes are discussed.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► The crystal structure of the synthesized [Cd(sac)2(H2O)2(meim)2] (complex 1) was determined. ► Spectral and thermal analysis data of complex 1 was agreed with the crystal structure. ► Magnetic properties of complex 1 and its structural change occurred with temperature were studied with EPR spectroscopy. ► Both TGA and EPR spectra was found discoverable changes around 140 °C.