Transcript Transition metal chemistry

Review of variable valence
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Transition metal ions have variable oxidation
state
Electron configurations
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4s23dn with some exceptions
Isomerism – same atoms, different
arrangement
Constitutional and stereo
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Constitutional
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Different connections between the atoms
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Linkage isomers (choice of linkage atom)
Ionization isomers (different anion bonding)
Stereoisomers
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Same connections but different spatial
arrangements
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Diastereoisomers (geometric isomers)
Enantiomers (handedness)
Linkage isomers
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The nitrite ion can use either the O or the N atom as the ligand
since both have non-bonding pairs.
Indicate linkage in the name:
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Nitro (NO2) links through N
Nitrito (ONO) links through O
Obvious influence on physical properties
Ionization isomers
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Different anions are linked to the central atom
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In one, the free anion is SO42In the second, the free anion is Br-
CoNH  Br SO
CoNH  SO Br
3 5
3 5
4
4
Diastereo (geometric) isomers
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Same attachments but different arrangement
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Cis- and trans- (analogous to bonding in alkenes)
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Influences physical properties through different polarity
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Example with square planar: opposite or side-by-side
Octahedral complex
Not all complexes qualify for
geometric isomers
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Square planar –
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ML2X2 (cis and trans)
ML3X (none)
Tetrahedral – none with any composition
Octahedral –
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ML4X2 (cis and trans)
ML3X3
ML5X (none)
More than two ligands…
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ML2XY or ML4XY can also have cis and trans
isomers
Isomers or equal?
What hands are these…?
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Apparently all same connections and yet…
Enantiomers are molecules or ions that form
mirror images of each other
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Tetrahedral C atoms with four different groups
Hands are enantiomers.
They possess chirality
Molecules that have no handedness are achiral
Testing for chirality
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Presence of planes of symmetry – achiral
Absence of plane of symmetry – chiral
Handedness in complexes with
bidentate ligands
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How many diastereoisomers and enantiomers are
there of Co(en)2Cl2+?
Getting a complex?
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Which are chiral?
Which are achiral?
What are the enantiomers?