Ch.23 - Transition Metals and Coordination Chemistry
Chapter 23, Problem 46
Complete the exercises below. Determine if each of the following metal complexes is chiral and therefore has an optical isomer: c. octahedral cis-[V(en)₂ClBr].

1
Identify the geometry of the complex: The complex is octahedral, which means it has six ligands arranged around the central metal ion in an octahedral shape.
Examine the ligands: The complex contains two ethylenediamine (en) ligands, one chloride (Cl) ligand, and one bromide (Br) ligand.
Determine the arrangement of ligands: In a cis configuration, the two identical ligands (in this case, the two en ligands) are adjacent to each other.
Check for chirality: A complex is chiral if it cannot be superimposed on its mirror image. In octahedral complexes, chirality often arises when there are bidentate ligands like en that create an asymmetrical arrangement.
Conclude about optical isomerism: If the complex is chiral, it will have non-superimposable mirror images, known as optical isomers.
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Chirality
Chirality refers to the geometric property of a molecule that makes it non-superimposable on its mirror image, much like left and right hands. A chiral molecule typically has an asymmetric carbon atom, but in coordination complexes, chirality can arise from the arrangement of ligands around a central metal atom. Understanding chirality is essential for determining whether a complex can exist in two optical isomers.
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Chirality
Octahedral Geometry
Octahedral geometry is a common arrangement in coordination chemistry where a central metal atom is surrounded by six ligands at the corners of an octahedron. The spatial arrangement of these ligands can lead to different isomeric forms, including cis and trans configurations. In the case of the complex cis-[V(en)₂ClBr], the specific arrangement of the ligands is crucial for assessing its chirality.
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Electron Geometry
Optical Isomers
Optical isomers, or enantiomers, are pairs of chiral molecules that are mirror images of each other and cannot be superimposed. These isomers exhibit different optical activities, meaning they rotate plane-polarized light in opposite directions. The presence of optical isomers in a metal complex indicates chirality, which is determined by the arrangement of ligands and the overall symmetry of the complex.
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Types of Isomers
Related Practice