Synthesis and crystal structures of ZnCl2 and CdCl2 containing helical coordination polymers derived from a flexible bis(pyridylurea) ligand.

A flexible bis(pyridylurea) ligand, 1,1′-[oxybis(2,1-phenylene)] bis(3-pyridin-3-ylurea) (L), has been synthesized and characterized. The interaction of L with ZnCl 2 and CdCl 2 has been investigated. In the structure of {[ZnLCl 2 ]·2DMF} n ( 1 ), the flexible ligands bridge the Zn II centers to form 1D helical chains with a pitch of 9.743 Å. The P and M helical chains are arranged equally, and the whole complex 1 is racemic. In the structure of [CdLCl 2 (DMF)] n ( 2 ), the flexible ligands bridge Cd II centers to form one-dimensional P and M helical chain structures in a similar manner. Then the chlorine atoms act as bridges in bidentate modes linking the P helical chain with M helical chain to form a 1D looped chain coordination polymer. [ABSTRACT FROM AUTHOR]