catena-Poly[[[(2,2′-bipyridine-κ2 N,N′)cobalt(II)]-μ-(E)-3,3′-(but-2-ene-2,3-diyl)dibenzoato-κ4 O,O′:O′′,O′′′] hemihydrate]

The title coordination polymer, {[Co(C18H14O4)(C10H8N2)]·0.5H2O}n, features a helical polymeric chain that runs along the b axis. The Co atoms are chelated by the carboxylate groups of two 3,3′-(but-2-ene-2,3-diyl)dibenzoate ligands and the N atoms of a 2,2′-bipyridine ligand. The lattice water molecule is disordered about a center of inversion and is connected to the chain by an O—H⋯O hydrogen bond. The CoII atom shows a distorted octahedral coordination.


Related literature
For a review of the adducts of metal carboxylates with 2,2 0bipyridine-like ligands, see: Ye et al. (2005). For details of the synthesis, see: McMurry (1989).
layers or even linear chains through the formation of adducts with 2,2'-bipyridine like ligands; the molecular architectures of such adducts of metal carboxylates with such α,α'-dimine ligands have been reviewed (Ye et al., 2005).
We have synthesized (E)-3,3'-(but-2-ene-2,3-diyl)dibenzoic acid in a multi-step synthesis for use in another research projecttheme; we have used this rigid dicarboxylic acid to form a coordination polymer as no derivatives of this acid have been reported. The dicarboxylate ion of the coordination polymer, [Co(C 10 H 8 N 2 )(C 18 H 14 O 4 ) . 0.5H 2 O] n (Scheme I, Fig. 1), has its carboxyl -CO 2 ends each chelating a 2,2'-bipyridine chelated Co II atom to generate a helical polymeric chain that runs along the b-axis of the monoclinic unit cell (Fig. 2). The Co II atom shows octahedral coordination. The lattice water molecule is disordered about a center-of-inversion and is connected to the chain by an O-H···O hydrogen bond (Table 1). Experimental 2,3-Bis-(3-bromophenyl)-2-butene was synthesized from the cross-coupling of 3-bromoacetophenone catalyzed by lowvalent titanium (McMurry, 1989).
2,3-Bis-(3-bromophenyl)-2-butene (17.3 g, 0.048 mol) was added to a solution of n-butyllithium (2.5 M in hexane, 40 ml, 0.10 mol) in ether (400 ml) at 200 K. The reaction was carried out under nitrogen. The mixture was warmed to room temperature and then stirred overnight. The reaction was quenched with water (100 ml) and the organic compounds were extracted with ether. The aqueous phase was adjusted to a pH of 1 by the addition of concentrated hydrochloric acid. The precipitate was collected, washed with ethyl acetate and dried to yield 3,3'-(but-2-ene-2,3-diyl)dibenzoic acid (yield 9.8 g, 70%) as a mixture of E and Z isomers.

Refinement
Carbon-bound H-atoms were placed in calculated positions (C-H 0.93 to 0.96 Å) and were included in the refinement in the riding model approximation, with U(H) set to 1.2 to 1.5U(C).
The water molecule lies near a center-of-inversion, and was assigned half site-occupancy. The H atoms were placed in a chemically sensible position on the basis of one hydrogen bonding interaction.  catena-Poly [[[(2,2'-bipyridine-κ 2 Crystal data [Co(C 18