Solvent- and Temperature-Controlled In Situ Ligand Reactions Mediated by CuII and 3'-[(E)-{[(1S,2S)-2-Aminocyclohexyl]imino}methyl]-4'-hydroxy-4-biphenylcarboxlic Acid

Three new compounds, CuL, CuL', and Cu2O2L''2 (H2L=3'-[(E)-{[(1S,2S)-2-aminocyclohexyl]imino}methyl]-4'-hydroxy-4-biphenylcarboxlic acid, H2L'=3'-[(E)-{[(1S,2S)-2-aminocyclohexyl]imino}methyl]-4'-hydroxy-5'-nitro-4-biphenylcarboxlic acid, H2L''=3'-(N,N-dimethylamino methyl)-4'-hydroxy-4-biphenylcarboxlic acid), were selectively synthesized through a controlled in situ ligand reaction system mediated by copper(II) nitrate and H2L. Selective nitration was achieved by using different solvent mixtures under relatively mild conditions, and an interesting and economical reductive amination system in DMF/EtOH/H2O was also found. All crystal structures were determined by single-crystal X-ray diffraction analysis. Both CuL and CuL' display chiral 1D chain structures, whereas Cu2O2L''2 possesses a structure with 13x16 angstrom channels and a free volume of 41.4?%. The possible mechanisms involved in this in situ ligand-controlled reaction system are discussed in detail.