Organo Metallic Intro
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Transcript of Organo Metallic Intro
Organometallic Chemistry. 1
What are organometallic compounds?What do organometallic compounds do?What organometallic chemistry will you do?
http://www.wikipedia.comhttp://www.webelements.comhttp://www.3dchem.com/table.asp
Organometallic compounds have M-C bonds
• In reality, other M compounds without M-C bonds are considered “organometallic” if they can form M-C bonds
Image credits
Organometallic Chemistry. 1
What do organometallic compounds do?What are organometallic compounds?
What organometallic chemistry will you do?
To see more:http://www.3dchem.com/table.asp
Ru3(CO)12
Ru2(cot)(CO)6
Grubb’s catalyst,famous for olefin metathesis RuCl2Pcy3(=CHPh)
What the *@&#%&s happened here???
Organometallic Chemistry. 1
What do organometallic compounds do?What are organometallic compounds?
What organometallic chemistry will you do?
• Use some important ligands
• Do some key reaction types
• Learn some fundamental concepts
Organometallic Chemistry. Ligands
Prototypical
Carbon Monoxide, COCarbonyl ligands
Why prototypical
Metal carbonyls are frequent starting materials
Metal carbonyls are known for most transition metals
Metal carbonyls are reactive — labile — CO is easily substituted
Metal carbonyls are easily studied by IR and provide information on structure, symmetry, electron density changes at metal
CO lost as gas is swept from system, pushes reaction forward
Organometallic Chemistry. Metal Carbonyls
Metal carbonyls are known for most transition metals
To see more:http://www.3dchem.com/table.asp
Fe3(CO)12Fe2(CO)9Fe(CO)5
Mo(CO)6 Ni(CO)4 Co4(CO)12
[Rh12(m12-Sn)(CO)27]4- one-step synthesis of [Pt38(CO)44]2- dianion from [PtCl6]2- potassium salt.
Organometallic Chemistry. Metal Carbonyls
Metal carbonyls clusters are big!
COMPOSITION PER CAPSULE :Iron (as iron carbonyl USP) 100mgVitamin B9 (Folic acid BP) 1,5mgVitamin B12 (Cyanocobalamine USP) 15µgVitamin C (Ascorbic acid USP) 75mgZinc (as sulfate BP) 22,5mgExcipients for one capsule.
EXCIPIENTS WITH KNOWN EFFECT :None.
PROPERTIES :Antianemic preparation with iron and folic acid.This association with Vitamin B12 and Zinc participate in the haemoglobin synthesis process.
Ferronyl (iron carbonyl)
Also:www.ferralet.com/Patient_Information/Index.aspx
Organometallic Chemistry. Metal Carbonyls
Metal carbonyls as vitamins??!!!
Organometallic Chemistry. Metal Carbonyls
Bonding in Metal carbonyls understood with MOT
Catomic orbitals
Oatomic orbitals
COmolecular orbitals
sigma bonding =donation from HOMO on C
pi bonding =donation from M to LUMO on C
Organometallic Chemistry. Concepts.1
Predicting structure
18 electron Rule or Effective Atomic Number (EAN) Rule
“a stable organometallic compound has 18 valence electrons at the metal”
Examples
Organometallic Chemistry. Concepts.1
Predicting structure
18 electron Rule or Effective Atomic Number (EAN) Rule
“a stable organometallic compound has 18 valence electrons at the metal”
Examples
And so for Ni0??Ni(CO)4
Organometallic Chemistry. Concepts.1
18 electron Rule or Effective Atomic Number (EAN) Rule
Meet some new ligands
:PPh3
:PR3
MeCN, thf, MeOH (donor solvents)
“diphos” or “dppe” = Ph2P:(CH2)2P:Ph2
:X-, :Cl-, :Br-, :OH-, :SR-
Mo(CO)5(PPh3)
Organometallic Chemistry. Concepts.1
18 electron Rule or Effective Atomic Number (EAN) Rule
Can you think of other possible ligands for organometallics?
Organometallic Chemistry. Reactions.1
Ligand Subsitution
Metal carbonyls are frequent starting materials becausemetal carbonyls are reactive — labile — CO is easily substituted
Mo(CO)6 + energy “Mo(CO)5” + CO(g)
Mo(CO)5 + L Mo(CO)5L
Predicting reactivity: use Concept 1.
18 electron Rule or Effective Atomic Number (EAN) Rule
“a stable organometallic compound has 18 valence electrons at the metal”
Organometallic Chemistry. Reactions.1
Carbonyl Substitution can be Thermal or Photolytic
Photolysis excites one electron to an antibonding orbital, and one M-C bond is broken
Mo(CO)6 + hnenergy “Mo(CO)5” + CO(g)
monosubstituted Mo(CO)5 + L Mo(CO)5L
Mo(CO)6 + heat energy “Mo(CO)3” + 3 CO(g)
trisubstituted Mo(CO)3 + 3 L Mo(CO)3L3
Thermolosis adds enough energy to break several M-C, and causes molecule to lose as many CO’s as is favorable
Organometallic Chemistry. Reactions.2
Oxidative Addition
Recognized by two characteristics:• increase of M oxidation state, Mn+ M(n+2)+
• increase in number of coordinated atoms— coordination number, CN
Fe(CO)5 + Cl2 Fe(CO)4Cl2 + CO(g)
Fe0(CO)5 + Cl2 Fe2+(CO)4Cl2 + CO(g)
CN = 5 CN = 6
Organometallic Chemistry. Reactions.2
Oxidative Addition
Does it obey the 18 e- Rule?
Fe0(CO)5 + Cl2 Fe2+(CO)4Cl2 + CO(g)
Organometallic Chemistry. Do it!!
This week’s reactions
Reaction A: Mo0(CO)6 + diphos ? + n CO(g)
Reaction B: product of A + I2 ? + n’ CO(g)
What do these reactions make? How can we tell? Ideas?
Organometallic Chemistry. Do it!!
This week’s reactions
Reaction A: Mo0(CO)6 + diphos ? + n CO(g)
Reaction B: product of A + I2 ? + n’ CO(g)
Reaction Conditions
(1) anaerobic reaction—WHY?—How?
(2) Rxn A is heated—why?
Organometallic Chemistry. Do it!!
Prep for this week’s reactions
Reaction A: Mo0(CO)6 + diphos ? + n CO(g)
Reaction B: product of A + I2 ? + n’ CO(g)
Preparation(1) clean and dry 200 3-necked flask.
(2) clean and dry stir bar
(3) anaerobic set-up: what do you know?
(4) use heating mantle
(5) ppt with hexanes
(6) filter with Hirsch funnel (what’s that?)