Interplay between Resonance-Assisted Hydrogen Bonding and Coordination in Sulfo-Functionalized Arylhydrazones of Active Methylene Compounds

The interaction of sodium(I) and copper(II) with sodium (E,Z)-2-[2-(1-cyano-2-methoxy-2-oxoethylidene)hydrazinyl]benzenesulfonate (NaHL1), sodium 4-[2-(2,4-dioxopentan-3-ylidene)hydrazinyl]benzenesulfonate (NaHL2), and sodium 2-[2-(2,4-dioxopentan-3-ylidene)hydrazinyl]benzenesulfonate (NaHL3) is studied on the basis of competition between intra- and intermolecular hydrogen bonding and coordination. The interplay between such interactions provides an unprecedented strategy towards an easy ((E,Z)E or Z) isomeric resolution of NaHL1 to give the new coordination polymers [Na(H2O)2(μ-HL1)]n (1) (E form) and [Na2(H2O)4(μ-HL1)2]n⋅nH2O (2) (Z form). It is also applied to the synthesis of the new compounds [Cu(H2O)6](HL2)2⋅4 H2O (3) and [Cu(A)L3]⋅H2O (4) (A=2-(pyridin-2-yl)ethanol). The intra- and intermolecular structural relevance of hydrogen bonding is detailed by X-ray diffraction.