New experimental and theoretical studies of two series of tripods based on pyrazole

New comparative experimental and theoretical studies of two isomeric series of tripods based on pyrazole rings were investigated. Tripods were characterized by the presence of two types of connecting junctions N-C-N (1, 3) and N-C-C (2, 4). Melting points, IR, NMR and MS spectra of ligands 1-4 were examined. All geometrical parameters were computed using density functional theory method (B3LYP) with 6-311+G (2d,p) as basis set. The nature of junctions between the aniline N-atom and the pyrazole rings influence considerably the melting points, chemical shifts, fragmentation pattern, bond angles and orientations between pyrazolic rings. However, the junction modes produce small variations on the bond lengths in side arms.