Draw all geometrical isomers of Pt(CN)2 Br2(H2 O)2. Which of these isomers has an optical isomer

Draw all geometrical isomers of Pt(CN)2 Br2(H2 O)2. Which of...

Key Concepts

Coordination Chemistry

This concept involves the study of complexes in which a central metal atom (or ion) binds to surrounding molecules or ions (ligands) through coordinate covalent bonds. The arrangement, type, and number of ligands determine the properties and reactivity of the complex, and understanding these interactions is essential for predicting and rationalizing the complex’s behavior in various chemical environments.

Octahedral Geometry

Octahedral geometry is characterized by six ligands symmetrically arranged around a central metal atom at the vertices of an octahedron. This arrangement is common in coordination compounds, and its high symmetry gives rise to numerous possible isomeric forms when different types of ligands are present, influencing the complex’s physical and chemical properties.

Geometrical Isomerism

Geometrical isomerism in coordination compounds arises when ligands can be arranged in different spatial orientations relative to the central metal ion, such as in cis or trans positions, or in facial and meridional arrangements. This concept is crucial for understanding how the positions of ligands affect the overall structure, bonding, and reactivity of the complex.

Optical Isomerism and Chirality

Optical isomerism occurs when a molecule or complex is chiral, meaning that it lacks an internal plane of symmetry and exists as non-superimposable mirror images (enantiomers). In coordination complexes, specific arrangements of ligands can create chiral centers, leading to optical isomers that rotate plane-polarized light differently, a phenomenon important in fields such as catalysis and molecular recognition.

Transcript

00:02 Draw all geometrical isomers of this complex which of these isomers has an optical isomers.

00:11 Draw the various optical isomers.

00:14 So first we have to recall that what is geometrical isomers.

00:20 We know that two types of geometrical isomers are possible, cis and trans.

00:26 When same ligands are next to each other, then we can say that it is cis isomer in case of geometrical isomer.

00:38 And when same ligands are arranged across from each other, then we will say it is trans isomer.

00:45 And what is the meaning of optical isomers? optical isomers should not have any kind of symmetry, like a plane of symmetry or center of symmetry.

01:01 And one more important thing, that optical isomers mirror image should be non -superimposable mirror image and by this they can rotate the plane of polarized light so these are optical isomers now we are drawing one by one all the isomers so first we are making the cis isomer and both are actually optically active two cis isomers are possible and both are optically active so we have to make their mirror images also so first one is platinum at the center four bonds are making this square planar and this is octahedral complex so one should be above the plane other should be below the and all are cis that means 2 cn at cis position 2 br at cis position and 2 water molecules are also at cis position so we can draw latinum 1 cn here second cn here third cn 3rd can be a water molecule o h2, o h2 should be cis and all are at cis br and br.

03:13 Angle is 90 degree.

03:16 So this is how we can make the first structure, that is cis structure.

03:21 And the second structure is also, second can be a first we are drawing the mirror image.

03:32 So this is the composition actually this should be separated.

03:36 This part and the mirror image of this should be here platinum at the center one two three four one is above the plane other one is below the plane so cn is here one cn should be here one water molecule should be here second water molecule is here one vr and bum one bear.

04:20 So this is the mirror image and these are non -superimposable mirror images and that is why they are optically active.

04:28 These isomers are optically active.

04:31 So this is one isomer.

04:40 This should be the second is.

04:48 Now in the next case, since second isomer is also possible, one is datinum at the center one two three four all are in the same plane one is above the plane other one is below the plane so here this isomer should have one c in here and one cn must be here and here water molecule and here it should be br and one b r must be here one br must be here one b or and one water molecule must be here.

05:48 So look at the position of each one.

05:51 All are cis water molecule and water molecule, 90 degree angle and cn and cn is also 90 degree angle.

06:00 And here one is below the plane and in the same plane br.

06:06 Here also angle is 90 degree.

06:08 But this isomer is different from the first one and it's mirror image.

06:14 We can draw here the mirror image.

06:19 Letting them at the center...

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