Crystal structures, magnetic and dielectric features of two new isostructural one-dimensional platinum-bis-dithiolene molecular solids.

Two new one-dimensional (1-D) molecular solids, [CH 2 = CH-BzPy][Pt(mnt) 2 ] ( 1 ) and [CH 2 = CH-BzPy-d 5 ][Pt(mnt) 2 ] ( 2 ) where CH 2 = CH-BzPy-d 5 + = 1- N -(4-vinylbenzyl) pyridinium-d 5 and mnt 2− = maleonitriledithiolate, were synthesized and characterized. A structural phase transition undergoes with T C ≈ 335 K in the crystals of 1 and 2 , which were confirmed by variable-temperature magnetic susceptibility and DSC measurements. Crystals of 1 and 2 are isostructural in both high- and low-temperature phases. Besides the strong similarity in crystal structures, they show quite analogous magnetic and dielectric features. Above T C , the magnetic behavior is failed to follow the S = ½ Heisenberg linear chain model; below T C , a spin gap is opened for 1 and 2 . The thermally-assisted dielectric relaxation occurs above ca. 280 K for 1 and 2 , and this relaxation process is related to the dipole motion of the disordered CH 2 CH groups in the cation under an ac electrical field. [ABSTRACT FROM AUTHOR]