Presence of Jahn-Teller distortions in a novel six-coordinate Ag(II) complex: temperature dependent EPR, optical and magnetic susceptibility measurements

Single-crystal variable temperature EPR, optical and polycrystalline magnet ic susceptibility studies have been made on a novel six-coordinate Ag(II) c omplex. Temperature dependent EPR studies on pure single crystals of this c ompound reveal that dynamic Jahn-Teller distortion operates above 230 K, be tween 230 K and 120 K static Jahn-Teller distortion sets in and below 110 K there is evidence of exchange interaction. Crystal g values were obtained by least-squares fitting with the data obtained from the orientation depend ent EPR spectra of the undiluted single crystal of this complex at 300 K an d 77 K. From an optical study the Jahn-Teller stabilization energy is found to be similar to 2250 cm(-1). Comparison of Abs(max) values for other silv er(II) compounds enables us to conclude that the formal geometry of this co mplex is a tetragonally distorted octahedral. Infrared spectra of this comp lex were also recorded over a wide range of temperature. Magnetic susceptib ility measurements over a wide range of temperature on the powder sample of this compound reveal that the complex is antiferromagnetically coupled in the temperature range 5-40 K with 2J = 0.906 cm(-1), and above 40 K it is f erromagnetically coupled with 2J = +7.4 cm(-1). The effective magnetic mome nt (mu (eff)) of this complex has been compared with that of a series of ot her silver(II) complexes available in the literature. Finally, the spectral and magnetic data of this complex have been compared with those of a corre sponding isostructural and isomorphous copper(II) complex.