Analyzing Multiple Cobalt Complexes With Various Ligands And Explain The Ligand Field Transitions Of These Complexes Using Ultraviolet Visible

2072 Words Nov 4th, 2016 9 Pages
Objective

The purpose of the experiment is to synthesize multiple cobalt complexes with various ligands and explain the ligand field transitions of these complexes using Ultraviolet-Visible (UV-Vis) spectroscopy. The experiment provides insight into specific colors of certain molecular species and respective bonding information.

Introduction

Transition elements are defined by the IUPAC as atoms that have an incomplete d-subshell, most commonly referring to the d-block.1 When transition metals are not bonded to any other molecule, the d-orbitals are degenerate.2 However, when the metal starts bonding with other ligands, effects on the electrons attached to the metal are induced. Specifically, the d-orbitals split, obtain different energy levels, and become non-degenerate. How these d-orbitals split depend on the geometry of the compound formed, which is the basis of the Crystal Field Theory.2

At certain frequencies of electromagnetic radiation, electrons absorb the energy and get pushed to higher energy orbitals. The frequencies correspond to the energy difference between different orbitals. The energy difference between the non-degenerate d-orbitals correspond to the energy of radiation of the visible light spectrum.2

Color is due to absorbance by molecular bonds and many common bonds do not absorb in the visible spectrum. Thus, many organic compounds are colorless. It is important to note that a colorless substance describes the lack of color, whereas a clear…

Related Documents