A rare diiodo-L-tyrosine copper(II) complexes – Crystal and molecular structure of materials stabilized by weak interactions

Abstract

The problem in formation of 3,5-diiodo-L-tyrosinato (L-I2Tyr) various metal ion complexes as a crystals is generated by the low solubility of iodo-L-tyrosinato derivatives (as ligands) in pure aqueous solution. However, two inorganic–organic hybrid l-I2Tyr copper(II) complexes i.e. [CuCl(L-I2TyrOH)(phen)]∙2H2O (1) and [Cu(l-I2TyrOH)(H2O)(phen)](NO3) (2) with l-I2TyrOH were isolated in acid aqueous/methanol medium. In crystals 1 and 2, the monomeric distorted square planar pyramidal copper(II) coordination is stabilized by weak intramolecular π···π stacking, copper(II)···π and π···I non-covalent interactions. The connection of adjacent 2D layers into 3D supramolecular network is realised by weak π···π contacts in 1, while in 2 the 3D architecture is stabilized by weak CH···π interaction as well as π···π contacts. The complexes are also characterized by infrared and Raman spectroscopies (FT-IR, FT-Raman), X- and Q-band electron paramagnetic resonance spectroscopy (EPR), electronic spectroscopy (NIR-Vis-UV), magnetic method, and theoretical calculation.