Crystal structures of (2,2'-bipyridyl-κ²N,N')bis[N,N-bis(2-hydroxyethyl)dithiocarbamato-κ²S,S']zinc dihydrate and (2,2'-bipyridyl-κ²N,N')bis[N-(2-hydroxyethyl)-N-isopropyldithiocarbamato-κ²S,S']zinc.

The common feature of the title compounds, [Zn(C5H10NO2S2)2(C10H8N2)]-- 2H2O, (I), and [Zn(C6H12NOS2)2(C10H8N2)], (II), is the location of the Znn atoms on a twofold rotation axis. Further, each ZnII atom is chelated by two symmetry-equivalent and symmetrically coordinating dithiocarbamate ligands and a 2,20-bipyridine ligand. The resulting N2S4 coordination geometry is based on a highly distorted octahedron in each case. In the molecular packing of (I), supramolecular ladders mediated by O--H···O hydrogen bonding are found whereby the uprights are defined by {···HO(water)···HO(hydroxy)···}n chains parallel to the a axis and with the rungs defined by 'Zn[S2CN(CH2CH2)2]2'. The water molecules connect the ladders into a supramolecular layer parallel to the ab plane via water-O--H···S and pyridyl-C--H···O(water) interactions, with the connections between layers being of the type pyridyl-C--H···S. In (II), supramolecular layers parallel to the ab plane are sustained by hydroxy-O -- H···S hydrogen bonds with connections between layers being of the type pyridyl-C--H···S. [ABSTRACT FROM AUTHOR]