Perpendicular interpenetration of independent square grid sheets. Synthesis and structural properties of [Co(NCS)(2)(Py2L)(2)](n) (Py2L=trans-1,2-bis(4-pyridyl)ethylene, 1,2-bis(4-pyridyl)ethane)

Abstract

Novel coordination polymers of general form [Co(NCS)(2)(Py2L)(2)](n) (Py2L=trans-1,2-bis(4-pyridyl) ethylene (bpee), 1; 1,2-bis(4-pyridyl)ethane (bpea), 2) have been synthesized by slow diffusion of aqueous solution of Co(NCS)(2) with ethanolic solution of appropriate spacer ligand, Py2L, in a mole ratio of 1:2. X-ray analyses on both 1 and 2 have provided similar unit and infinite structures with space group Ibam. The local geometry around the cobalt(II) atoms is an octahedral arrangement with two NCS groups in trans position (N-Co-N, 180.0 degrees (1); 180.0 degrees (2)) and four pyridine units in propeller fashion. Each spacer ligand connects two cobalt(II) ions defining the edges of a [Co(II)](4) rhombus. The most fascinating feature is the occurrence of perpendicular interwoven of independent square grid sheets: this is, one molecular network is perpendicularly interpenetrated through the centers of the [Co(II)](4) rhombuses of another independent network with all of the cobalt(II) atoms in a coplanar sheet. The physicochemical properties of the present unique structures were studied.