Studies on Pentakisantipyrine Copper(II) Perchlorate

Abstract

Five coordinated antipyrine (A) complex of copper(II) perchlorate, [CuA5](ClO4)2 has been prepared. Both the electric conductivity and the cryoscopic determination of molecular weight in nitrobenzene solution show that the complex dissociates into three ions. Differential thermal analysis gives one peak at about 285°C owing to the explosion of the complex. Infrared spectrum reveals the presence of both strongly and weakly coordinated antipyrine molecules in the complex. The complex in 1,2-dichloroethane absorbs at 16130 (ε=51) cm 15630 (ε=53) and 14500 (ε=56) cm1. These d-d transitions with comparatively high intensities suggest C4v symmetry for the complex ion [CuA5]2+. A square pyramidal structure with four antipyrine molecules in the square plane at normal Cu-O bond distance and one antipyrine occupying the axial position with an elongated Cu-O bond, is assigned to the complex ion.

Cadmium and tin complexes of Schiff-base ligands

“…A common feature of all these spectra is that between 3500 and 3100 cm À1 they possess several bands, which are ascribed to (OH) of hydroxymethyl group and H 2 O, along with the (NH2) vibrations. The (NH) , which in spectra of free PLSC and PLTSC has been observed by Gopalakrishnan et al [147] at 3150 cm À1 , Agarwal et al [148], and Raman et al [149], is missing from spectra of singly deprotonated ligands. This also holds for (NH) from the pyridine ring, which in spectra of free ligands and complexes involving monoanionic ligands is observed at 2850 cm À1 ; this is absent from the spectra of complexes with dianionic form of ligands.…”

Coordination Modes of a Schiff Base Derived from Substituted 2‐Aminothiazole with Chromium(III), Manganese(II), Iron(II), Cobalt(II), Nickel(II) and Copper(II) Metal Ions: Synthesis, Spectroscopic and Antimicrobial Studies

“…In recent years, nitrogen heterocyclic compounds have gained importance on account of their varied types of biological activities [20][21][22] pyrazole derivatives have been reported to possess antidiuretic 23 , antihelminthic 24 , hypoglycaemic, fungicidal, antituberculotic 25 , antineoplastic 26 and antifertility 27 activities.…”

Complexes of Co(II), Ni(II), and Zn(II) with pyrazolone ligands

“…A large number of compounds of this ligand have been shown to be unidentate and oxygen coordinated from infrared (i.r.) spectral studies (1)(2)(3)(4)(5); a variety of coordination geometries are encountered.…”