Results of a theoretical study of the electronic properties of polymeric sy
stems [M(C2X4)](n), With M= Ni, CU, Zn and X= O, S, Se, are presented. The
calculations were carried through using a first-principles density-function
al method (DFT-LMTO full-potential). We analyze the effects of varying the
torsion angle between adjacent unit cells including its influence on the me
tal-ligand orbital overlap. The frontier orbitals depend strongly on the li
gand, and the conductivity of the systems is predicted to be very dependent
on the oxidation state of the metal (i.e., also on the presence of counter
ions). The Fermi level depends on X as well as on M.