Organoheterobimetallic complexes derived from bis(1-ethoxycarbonyl)-1-cyanoethylene-2,2-dithiolatometalate(II) ion: synthesis and properties

A complex salt [NEt4]2[Cu(ecda)2] and six organoheterobimetallic complexes [Bu2Sn][Cu(ecda)2], [Ph3Sn]2[Ni(ecda)2] and [PhHg]2[M(ecda)2] (M=Ni(II), Cu(II), Zn(II) or Cd(II); ecda2−=1-ethoxycarbonyl-1-cyanoethylene-2,2-dithiolate) have been prepared. Their characterization relies on analysis, spectroscopic methods, magnetic and conductivity measurements and cyclic voltammetric studies. The diamagnetic compounds [PhHg]2[Cu(ecda)2] and [Bu2Sn][Cu(ecda)2] are strongly antiferromagnetically coupled. Unshifted and unbroadened nature of 1H-NMR signals show that [PhHg]2[Cu(ecda)2] remains diamagnetic in solution while [PhHg]2[Ni(ecda)2], which is paramagnetic in the solid state becomes square planar-diamagnetic in solution. In the case of [Bu2Sn][Cu(ecda)2] the peak broadening shows absence of Cu–Cu interaction due to paramagnetic nature of the compound in solution. All the products exhibited σrt in the range of 10−10–10−9 S cm−1. Except [Bu2Sn][Cu(ecda)2], [PhHg]2[Cu(ecda)2] and [Ph3Sn]2[Ni(ecda)2], which show semi conducting behaviour in the range of 293–343 K, the remaining compounds are electrically insulating over the above temperature range.