Theoretical study of some pyrazole derivatives and rare earth metal complexes

The theoretical study of some pyrazole derivatives and rare earth metal complexes was carried out. The equilibrium geometry of eight structures and modelling fragments was found by ab initio method (Hf/6-31G HF/3-21G for Sc). The coordinational type of ligand was determined for a fragment of scandium complex taken as an example. After optimization, the Sc-O bond length was 2.17 Angstrom, and the Sc-N bond length was 2.98 Angstrom. So, the ligands examined were monodentate in complexes of transition metals with a carbonyl oxygen atom as the donor atom. Based on II. and III structure calculations, the amidopyrine (Amy) geometry was estimated. Force constants, vibrational frequencies and scale factors of some pyrazole derivatives and transition metal complexes were calculated. The results obtained were used for the assignment of experimental vibrational frequencies. (C) 1998 Elsevier Science B.V. All rights reserved.