Isomerism in 1D coordination polymers of Cu(II) complexes of N-(2-hydroxybenzyl)-L-valine:: Influence of solvent and coordination sphere on the conformation

The reaction of the deprotonated N-(2-hydroxybenzyl)-L-valine ligand ("Sval") with Cu(II) salts afforded [Cu-2(Sval)(2)(H2O)(3)](n), 1, which has a 1D coordination polymeric structure cross-linked by strong hydrogen bonds to give 2D hydrogen-bonded coordination polymer in the solid state. Compound 1 can lose all the water molecules bonded to Cu(II) below 110 degreesC. However, recrystallization from aqueous solution of anhydrous 1 gave a supramolecular isomer, [Cu-2(Sval)(2)(H2O)](n).2nH(2)O, 2. Interestingly, the thermal dehydration behavior of 2 is very similar to that of 1. Pseudo-supramolecular isomeric compounds Of [Cu-2(Sval)(2)(H2O)](n).0.5nC(3)H(7)OH, 3, and [Cu-4(Sval)(4)(H2O)(2)(C4H9OH)](n).nC(4)H(9)OH, 4, were obtained when anhydrous 1 was recrystallized from 2-proponal and 1-butanol, respectively.