M2 Lecture 9/10 Flashcards
22. Identify and draw isomers for TM complexes, including structural isomers (coordination, linkage, ionization) and stereoisomers (geometric and optical). includes using wedge and dash notation (28 cards)
What complexes can exhibit fac-mer isomerism?
a) linear
b) tetrahedral
c) square planar
d) octahedral
ONLY d) octahedral
polydentate ligands
good chelating agents - help bind up or isolate metal by making 2 or more connections to it
What complexes can exhibit cis-trans isomerism?
a) linear
b) tetrahedral
c) square planar
d) octahedral
ONLY c) square planar and d) octahedral
geometric isomers
same formula, different arrangement of atoms
cis-trans
fac and mer
cis-
2 ligands are on the same side
trans-
2 ligands are on the opp side
stereoisomers
isomers with the same atoms, same connectivity (what’s bonded to what)
there are 2 kinds of isomers - geometric and optical/chidral isomers
Optical/chiral siomers (aka enantiomers)
Same arrangement of atoms, but not the same molecule. MUST BE 3D molecules.
Chiral
Non-superimposable mirror images. No mirror planes within the molecule.
What complexes can exhibit optical/chiral isomerism?
a) linear
b) tetrahedral
c) square planar
d) octahedral
ONLY b) tetrahedral and d) octahedral because they are 3d molecules
fac-
3 atoms of the same species are 90* apart from one another // facial
mer-
3 atoms form a T shaped. along the edges almost.
Optical isomers
Similar physical properties (boiling point, solubility, etc) but interact diff with polarized light. Molecules do not line up.
If a molecule has a mirror plane, it most likely is not:
a) cis
c) fac
d) mer
e) chiral
f) optical
e) chiral
Structural isomer
complexes with the same atoms but different connectivitity. 3 kinds: Linkage isomers, ionization isomers, and coordination isomers
Linkage isomer
same ligand, bonded through different atoms
(ex: M-N-O2 vs M-O-N-O)
What is the minimum amounts that a ligand must have in a linkage isomer?
2
Ionization isomers
a ligand and the counter ion switch places. [ABC]D == [ABD]C
Coordination isomers
different center metal, same coordination environment (same ligands and geometry). but technically not the same atom
(ex: [Ni(OH2)6]^2+ == [Co(OH2)6]^2+
Do all polyatomic ligands do linkage isomerisms?
no, if the ligands (ex: CN) has a formal charge, the e- density will be higher in one area, making it less likely that the central metal will bond with a different atom (C or N).
Will [Ni(CO)4] do linkage isomerism? If not, which one will always bind to the central metal?
No because C has a formal charge of -1 and O has a formal charge of +1. Because C has the negative formal charge, C has more electrons despite being more electropositive and will bind to the metal.
On the spectrochemical species, how can you tell that a ligand can do linkage isomerism? Which one is the bonding ligand atom?
Any ligands that have an atom that is underlined. The underlined atom is the bonding ligand atom.
Is a chiral isomer a:
a) geometric isomer
b) enantimer
c) structural isomer
b) enantimer
Is a linkage isomer a:
a) geometric isomer
b) enantimer
c) structural isomer
c) structural isomer
