Di-aqua-bridged dinuclear Cu(II) isonicotinate adducts using 2,2′-bipyridine and 1,10-phenanthroline

• Published in: Polyhedron 2015-09, Vol.97, p.182-187
• Main Authors: Thatipamula, Krishna Chary, Bhargavi, G., Rajasekharan, M.V.
• Format: Article
• Language: English
• Subjects: Bpy; Copper(II); Isonicotinic acid; Magnetic properties; Phen
• ISSN: 0277-5387
• DOI: 10.1016/j.poly.2015.05.027

Isonicotinic acid (L) complexes with Cu(II) in zwitter-ion form to produce weakly ferromagnetically coupled diaquo-bridged dicopper(II) complexes which give triplet state EPR spectra. [Display omitted] Two new diaquo-bridged dicopper(II) complexes are obtained by reacting Cu(II) nitrate with isonicotinic acid and either 2,2′-bipyridine (bpy) or 1,10-phenanthroline (phen). They are formulated as [Cu2(μ-OH2)2(L)2(INH)2(NO3)2](NO3)2 where L=bpy (1), phen (2) and INH=zwitterion of isonicotinic acid. Both the complexes were characterized by single crystal X-ray diffraction analysis, variable temperature magnetic susceptibility measurements and EPR spectroscopy. The complexes consist a dinuclear cation, [Cu(OH2)2Cu]+4 at its core in which the water molecules function as unsymmetrical bridges between Cu(II) octahedra in the equatorial–axial mode. The variable temperature (3–300K) magnetic susceptibility measurements suggest weak ferromagnetic coupling in the dicopper(II) cation with 2J=3.52 and 1.80cm−1 respectively for 1 and 2. Both compounds give triplet state EPR with similar zero-field splitting parameter, D=0.034cm−1 for 1 and 0.038cm−1 for 2.