Synthesis, crystal structure determination, and spectroscopic characterization of [2,13-dibenzyl-5,16-diethyl-2,6,13,17-tetraazatricyclo(16.4.0.07,12)docosane] copper(II) dinitrate.

A novel metal complex, [Cu(Lb)](NO3)2 [Lb = 2,13-dibenzyl-5,16-diethyl-2,6,13,17-tetraazatricyclo(16.4.0.07,12)docosane], was synthesized and characterized by single-crystal X-ray diffraction as well as other spectroscopic techniques. Structural analysis revealed that the copper(II) ion has an approximately square planar arrangement with stable trans -III configuration of the macrocyclic ligand. The Cu-N(tertiary) distance (2.0860 (14) Å) is greater than the Cu-N(secondary) distance (2.0229 (15) Å), which may be attributed to the steric effect of the benzyl group attached to the tertiary N atom. The nitrate anion and complex cation are linked by hydrogen bonds and weak Cu...O interactions. The metal complex showed strong blue luminescence when excited in the 355-391 nm region, and both blue as well as green emissions when excited in the 438-460 nm range. [ABSTRACT FROM AUTHOR]