Rac-aqua(4-methyl-oxazolidine-4-carboxylato)(nitrato)(1,10-phenanthroline) copper(II), the aldol condensation product of formaldehyde with the D- and L-(alaninato) aqua(1,10-phenanthroline) copper(II) nitrate

摘要

The d- and l-enantiomers of the ternary complex [Cu(phen)(ala)(H2O)]NO3 [phen = 1,10-phenanthroline; ala = alanine; l-enantiomer (1a); d-enantiomer (1b)] both undergo an aldol-type condensation with formaldehyde under mild acidic conditions to yield racemic rac-[Cu(phen)(4MeOCA)(H2O)(NO3)] (2) (4MeOCA = 4-methyl-oxazolidine-4-carboxylate). The precursors and the products were characterized by circular dichroism, FTIR, UV-Vis, fluorescence spectroscopy, molar conductivity and electrospray ionization mass spectrometry. The racemic nature of the product was established by X-ray crystallography . In the crystal structure, the copper atom has a tetragonally elongated octahedral geometry in which the water and an oxygen atom of a nitrate group are mutually trans. A possible mechanism for the racemization of the ligand is proposed.