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Polymeric versus monomeric and tetrahedral versus octahedral coordination in zinc(ii) pyridine complexes

2001; Royal Society of Chemistry; Volume: 3; Issue: 23 Linguagem: Inglês

10.1039/b103378f

1466-8033

Chunhua Hu, Ulli Englert,

Crystallography and molecular interactions

The first one-dimensional chain polymers of the type [Zn(μ-Cl)2py]∞ (py⊕=⊕3,5-dichloropyridine and 3,5-dibromopyridine) were synthesized by reaction of the 3,5-dihalopyridines with ZnCl2. In the resulting linear coordination polymer octahedral zinc(II) centres are linked in an edge-sharing fashion by halogen bridges in their pseudo-equatorial plane. In contrast to these findings the analogous reaction between ZnBr2 and the 3,5-dihalopyridines results in the formation of mononuclear tetrahedral complexes. Both of the zinc dihalides react with 3,4,5-trichloropyridine with formation of isotypic molecular crystals which show relatively short halogen⋯halogen contacts; their projections along the [001] direction exhibit a remarkable similarity to those of the chain polymers. From ZnX2 (X⊕=⊕Cl, Br) and 4,4′-bipyridyl (bpy) a zigzag chain coordination polymer of composition [ZnX2(μ-bpy)]∞ was obtained.