The electronic absorption spectrum of copper ammine complexes

 

1. (i) Draw the electron distribution in the d orbitals of an octahedral Cu(II) complex and show the electronic transition responsible for the absorptions observed.

2. (ii) Assign the transition you observe for each complex and give the value of Δ (in cm-1).

1.2 1 0.8 0.6 0.4 0.2 0 450 Visible absorption spectra of Cu(II) complexes Cu (HO)2(NH3)4 500 550 [Cu (HO)6]+ [Cu (HO)5(NH3)]+ [Cu (H2O)4(NH3)2]+ [Cu (H2O)3(NH3)3]+ [Cu (H2O)2(NH3)4]+ Cu (HO)3(NH3)3 Cu (HO)4(NH3)2 600 650 Wavelength peak 811.0 nm 760.5 nm 688.0 nm 645.0 nm nm 602.5 nm 700 Absorbance 0.916 0.396 750 0.340 0.674 1.069 Cu (HO)6 Cu (HO)5(NH3) 800 850 900