Synthesis and Crystal Structure of a New Glycinato Copper Compound

1 INTRODUCTION Amino acids (AA) are some of the most important biological ligands, and metal ions are known to par- ticipate in a variety of biological reactions, therefore, research on the coordination behavior of metal-ami- no acid complexes is one of the most essential ele- ments of chemical biology[1, 2]. For over three deca- des their structures have been of considerable inte- rest and importance in coordination chemistry[2, 3]. Studies of these relatively simple complexes may en- ha…     

The cis/trans isomerization of Cu(II)-bis-(glycinato) complex in solution: a computer aided multifrequency EPR and DFT/PCM calculation study

In this paper the Cu(II)-bis-(glycinato) complex has been analysed in solution by applying a combined approach of multifrequency EPR and DFT/PCM calculations. The accuracy in the determination of magnetic parameters has been reached by the use of a unique simulation program (COSMOS) for the whole range of temperatures analysed and by the error analysis. A change in magnetic parameters was envisaged in the 243-253 K range of temperature, and was interpreted in terms of stabilization, near the freezing point of the solution, of one of the isomers of the complex. A DFT/PCM computational model was crucial in assigning, on the basis of the experimental superhyperfine interaction value, the isomer to the trans form.     

COORDINATION COMPOUNDS OF LANTHANIDE PERCHLORATES WITH PYRAZINEAMIDE

Abstract

Lanthanide perchlorate complexes of the type [Ln(pyaH)₄] (ClO₄)₃ where Ln=Pr, Nd, Sm, Eu, Tb and Lu, and pyaH is pyrazinamide have been isolated. The compounds were characterized by chemical analyses, molar conductance, vibrational spectra, and electronic absorption and emission spectra. The vibrational spectra and molar conductances indicate that the perchlorate groups are ionic and that pyaH acts a bidentate ligand. The oscillator strengths of the transitions of the Nd(III) complex were determined in terms of the Judd-Ofelt theory. It was possible to use the modified Judd-Ofelt parameters, τλ, for the evaluation of the spectral intensities. In addition, a group-theoretical analysis of the emission spectrum indicates an effective site symmetry D₂ for the Eu(III) complex between 77° K and 10° K.