Problem 44
Question
The compound(s) that exhibit(s) geometrical isomerism is (are) (a) \(\left[\mathrm{Pt}(\mathrm{en}) \mathrm{Cl}_{2}\right]\) (b) \(\left[\mathrm{Pt}(\mathrm{en})_{2}\right] \mathrm{Cl}_{2}\) (c) \(\left[\mathrm{Pt}(\mathrm{en})_{2} \mathrm{Cl}_{2}\right] \mathrm{Cl}_{2}\) (d) \(\left[\mathrm{Pt}\left(\mathrm{NH}_{3}\right)_{2} \mathrm{Cl}_{2}\right]\)
Step-by-Step Solution
Verified Answer
Compounds (a), (c), and (d) exhibit geometrical isomerism.
1Step 1: Understand Geometrical Isomerism
Geometrical isomerism, often known as cis-trans isomerism, occurs in complexes where the ligands can adopt different spatial arrangements around the central metal atom. This typically happens in square planar and octahedral complexes.
2Step 2: Analyze Each Option
We need to analyze each given platinum complex to see if they can exhibit geometric isomerism. This generally occurs when there are at least two identical ligands and the structure allows them to be positioned cis or trans to each other.
3Step 3: Examine Option (a)
The complex \([\text{Pt(en)Cl}_2]\) is square planar but the 'en' ligand is bidentate, occupying two positions. The two Cl ligands can be on adjacent corners (cis) or opposite corners (trans), thus this compound can exhibit geometrical isomerism.
4Step 4: Examine Option (b)
The complex \([\text{Pt(en)}_2]\text{Cl}_2\) has only 'en' (ethylenediamine) as bidentate ligands, and no other types of ligands to create cis-trans isomerism. So, this compound does not exhibit geometrical isomerism.
5Step 5: Examine Option (c)
In \([\text{Pt(en)}_2\text{Cl}_2]\text{Cl}_2\), the coordination [\text{Pt(en)}_2\text{Cl}_2] involves bidentate 'en' and Cl ligands, still arranged octahedrally. Here, all positions are occupied without any cis-trans configuration. Therefore, this complex can exhibit geometrical isomerism as Cl can be adjacent or opposite.
6Step 6: Examine Option (d)
The complex \([\text{Pt}( ext{NH}_3)_2 ext{Cl}_2]\) is square planar, having similar ligands (\text{NH}_3\ and Cl). The Cl ligands can be adjacent (cis) or opposite (trans), thus allowing it to exhibit geometrical isomerism.
7Step 7: Conclusion
Based on the analyses, compounds (a) \([\text{Pt(en)Cl}_2]\), (c) \([\text{Pt(en)}_2\text{Cl}_2]\text{Cl}_2\), and (d) \([\text{Pt}( ext{NH}_3)_2 ext{Cl}_2]\) have the potential to show geometrical isomerism due to the spatial arrangement of similar ligands.
Key Concepts
Square Planar ComplexesBidentate LigandsCis-Trans Isomerism
Square Planar Complexes
In chemistry, square planar complexes are a specific type of coordination compound. They have a central metal atom surrounded by ligands positioned at the corners of a square. These complexes are prevalent with certain metals, such as platinum and palladium.
The interesting aspect of square planar complexes is their ability to exhibit geometrical isomerism, particularly cis-trans isomerism. This occurs because the ligands can be situated either next to each other (cis) or opposite (trans) each other.
In essence, for a complex to be square planar, the coordination number is often four. This refers to the number of atoms, ions, or molecules bonded to the central atom. In these configurations, the spatial arrangement allows for varying arrangements of ligands, thus leading to different isomers which can have distinct properties.
The interesting aspect of square planar complexes is their ability to exhibit geometrical isomerism, particularly cis-trans isomerism. This occurs because the ligands can be situated either next to each other (cis) or opposite (trans) each other.
In essence, for a complex to be square planar, the coordination number is often four. This refers to the number of atoms, ions, or molecules bonded to the central atom. In these configurations, the spatial arrangement allows for varying arrangements of ligands, thus leading to different isomers which can have distinct properties.
Bidentate Ligands
Bidentate ligands are a fascinating type of ligand in coordination chemistry. The term "bidentate" signifies that these ligands can form two bonds with the central metal atom. This ability is due to the presence of two donor atoms that can simultaneously attach to the metal center.
A common example of a bidentate ligand is ethylenediamine, also abbreviated as "en." This ligand can coordinate twice to a central metal, creating more stable complexes.
Bidentate ligands are crucial because they influence the geometric and chemical properties of the resulting complex. In terms of geometric isomerism, bidentate ligands can limit the number of possible isomers, as they inherently occupy more space around the metal center than a monodentate ligand. These ligands can thus affect the overall stability and shape of the complex, contributing to the distinct spatial arrangements characteristic of geometric isomerism.
A common example of a bidentate ligand is ethylenediamine, also abbreviated as "en." This ligand can coordinate twice to a central metal, creating more stable complexes.
Bidentate ligands are crucial because they influence the geometric and chemical properties of the resulting complex. In terms of geometric isomerism, bidentate ligands can limit the number of possible isomers, as they inherently occupy more space around the metal center than a monodentate ligand. These ligands can thus affect the overall stability and shape of the complex, contributing to the distinct spatial arrangements characteristic of geometric isomerism.
Cis-Trans Isomerism
Cis-trans isomerism is a form of geometrical isomerism seen in coordination compounds, strongly associated with square planar and octahedral complexes. In these isomers, the relative positioning of the same ligands around the central metal atom can change, leading to different physical and chemical properties.
In the context of square planar complexes, cis-trans isomerism arises when two ligands of the same type can either be adjacent (cis) or opposite (trans) to each other. This is especially significant because these differing spatial arrangements can have notable effects. For example, they can affect the compound's color, reactivity, and biological activity.
In the context of square planar complexes, cis-trans isomerism arises when two ligands of the same type can either be adjacent (cis) or opposite (trans) to each other. This is especially significant because these differing spatial arrangements can have notable effects. For example, they can affect the compound's color, reactivity, and biological activity.
- Cis isomers have ligands next to each other, often resulting in different properties than trans isomers.
- Trans isomers, with ligands on opposite sides, typically exhibit differing behaviors, such as solubility or interaction with biological molecules.
Other exercises in this chapter
Problem 43
The pair(s) of coordination complexes/ions exhibiting the same kind of isomerism is(are) (a) \(\left[\mathrm{Cr}\left(\mathrm{NH}_{3}\right)_{5} \mathrm{Cl}\rig
View solution Problem 43
Among the following metal carbonyls, the C-O bond order is lowest in (a) \(\left[\mathrm{Mn}(\mathrm{CO})_{6}\right]^{+}\) (b) \(\left[\mathrm{Fe}(\mathrm{CO})_
View solution Problem 44
\(\mathrm{Ag}^{+}+\mathrm{NH}_{3} \rightleftharpoons\left[\mathrm{Ag}\left(\mathrm{NH}_{3}\right)\right]^{+} ; k_{1}=6.8 \times 10^{-3}\) \(\left[\mathrm{Ag}\le
View solution Problem 45
Statement-1 : The geometrical isomers of the complex \(\left[M\left(\mathrm{NH}_{3}\right)_{4} \mathrm{Cl}_{2}\right]\) are optically inactive. Statement-2 : Bo
View solution