Organometallic Chemistry - University of KwaZulu-Natal

Organometallic Chemistry - University of KwaZulu-Natal

CHEM310 INORGANIC CHEMISTRY Part 3 ORGANOMETALLIC CHEMISTRY 1. Introduction (types and rationale) 2. Molecular orbital (bonding) of CO, arrangement in space or ligand types (hapticity) 3. 16 and 18 electron rule (learning to count) 4. Synthesis, steric effects and reactivity - Wilkinsons catalyst (part 1) 5. Characterisation IR nmr etc. 6. Applications (oxidative addition b elimination) What is organometallic chemistry? Chemistry: structures, bonding and properties of molecules. Organometallic compounds: containing direct metal-carbon bonds. Either s or p bonds can occur Main group: (AlMe3)2

Structures s bonds and 3c-2e (or even 4c-2e) bonds Chem 210 Synthesis the first M-C bond Reactivity nucleophilic and basic auxiliaries in organic synthesis source of organic groups for transition metals

Strong preference for s-donor groups but Cp is often p-bound (deceptively like with transition metals) Cp2Mg Cp2Fe Electropositive metals: often 3c-2e or 4c-2e hydrides/alkyls (Me3Al)2 (MeLi)4 As a Nucleophile Addition to polar C=X bonds (C=O, C=N, CN)

R M R + O OM Substitution at sp2 carbon (often via addition) OR' R M + O R

OR' R - MOR' OM O Substitution at sp3 carbon does occur but is far less easy and often has a multistep mechanism Substitution at other elements: often easy for polar M-X bonds (Si-Cl, B-OMe)

Me MeMgBr + B(OMe)3 BrMg B(OMe)2 OMe MeOMgBr + MeB(OMe)2 Me3B As a base More prominent in polar solvents think of free R - acting as base Elimination H + RH + MX

R M X mechanism can be more complex than this Metallation H R M Me2N M + RH Me2N chelate effect more important than inductive effect! b-hydrogen transfer Al

H O Al O H mainly for Al: for more electropositive elements, deprotonation and nucleophilic attack are faster for less electropositive elements, often no reaction Chemistry: structures, bonding and properties of molecules. Transition metal compounds Me Me Me

W Me Me CO OC Fe Ph PPh3 Cl Ru CF2 PPh3 CO Fe CO

Me Cl OC CO C RO W MeLi OR OR PhMgBr Some compounds do not contain metal-carbon bond, but they are usually included in the field of organometallic chemistry. They include:

Metal hydride complexes, e.g. H Et3P Pt PEt3 Ph3P H2 Cl PPh3 H Ru H Phosphine complexes, e.g. PPh3 Ph3P

Rh PPh3 Cl 2+ N N PPh3 N2-complexes, e.g. NH3 H 3N H3N NH3

Ru N N NH3 Ph2P Ph2P PPh2 Mo PPh2 N N Ph3P PPh3 Cl Ru Cl PPh3 Exercise. Which of the following compounds is an organometallic compound? NH3

OCH 3 a) CH3O Ti Cl H3 N OCH 3 OCH 3 - Cl c) b) Pt

CH2 d) O CH2 Li Pt O O Li Me NH3

NH3 O Cl e) Cu 2+ Ph Me Li Me Me OC

Li P CO CO O Co C Co CO CO f) OC Co O C Co OC OC P Ph In general, metals in organometallic compounds include: main group metals

transition metals f-block metals In this course, transition metals are our main concern. A brief history of organometallic chemistry 1) Organometallic Chemistry has really been around for millions of years Naturally occurring Cobalimins contain Co C bonds Vitamin B12 2) Zeises Salt synthesized in 1827 = K[Pt(C 2H4)Cl3] H2O Confirmed to have H2C=CH2 as a ligand in 1868 Structure not fully known until 1975 3) Ni(CO)4 synthesized in 1890

4) Grignard Reagents (XMgR) synthesized about 1900 Accidentally produced while trying to make other compounds Utility to Organic Synthesis recognized early on 5) Ferrocene synthesized in 1951 Modern Organometallic Chemistry begins with this discovery (Paulson and Miller) 1952 Fischer and Wilkinson Nobel -Prize Winners related to the area: Victor Grignard and Paul Sabatier (1912) Grignard reagent K. Ziegler, G. Natta (1963) Zieglar-Natta catalyst E. O. Fisher, G. Wilkinson (1973) Sandwich compounds K. B. Sharpless, R. Noyori (2001) Hydrogenation and oxidation Yves Chauvin, Robert H. Grubbs, Richard R. Schrock (2005) Metalcatalyzed alkene metathesis

Common organometallic ligands M H M M M M CO CS C M M

M M C CNR NO M M M M M C N2 PR3

M M H H M M H X M M C M

C Why organometallic chemistry ? a). From practical point of view: * OMC are useful for chemical synthesis, especially catalytic processes, e.g. In production of fine chemicals In production of chemicals in large-scale reactions could not be achieved traditionally OBn + RO RO Ar N Mo CMe2Ph

H OBn I CN + Ph Ph + NEt3 Pd(PPh3)3 CN Ph Ph + HNEt3I * Organometallic chemistry is related to material sciences. e.g. Organometallic Polymers

PBu3 Pt C C PBu3 C C PBu3 Pt n C C PBu3 Small organometallic compounds: Precursors to films for coating (MOCVD) (h3-C3H5)2Pd -----> CH3CC-Au-CNMe ----->

Luminescent materials Pd film Au film C C n * Biological Science. Organometallic chemistry may help us to understand some enzyme-catalyzed reactions. e.g. B12 catalyzed reactions. H R R H b). From academic point of view:

* Organometallic compounds display many unexpected behaviorsdiscover new chemistry- new structures H3N: M M M M C C C M C

M e.g. M C C New reactions, reagents, catalysts, e.g. Ziegler-Natta catalyst, Wilkinson catalyst Reppe reaction, Schwartz's reagent Sharpless epoxidation, Tebbe's reagent M H H M

H SiR3 Types of bonds possible from Ligands Language: All bonds are coordination or coordinative Remember that all of these bonds are weaker than normal organic bonds (they are dative bonds) Simple ligands e.g. CH3-, Cl-, H2 give s bonds systems are different e.g. CO is a s donor and p acceptor Bridging ligands can occur two metals Metal-metal bonds occur and are called d bonds they are weak and are a result of d-d orbital overlap 18 Electron Rule (Sidgwick, 1927) OM chemistry gives rise to many stable complexes - how can we tell by a simple method Every element has a certain number of valence orbitals: 1 { 1s } for H

4 { ns, 3np } for main group elements 9 { ns, 3np, 5(n-1)d } for transition metals s dxy px dxz py dyz pz dx2-y2 dz2

Therefore, every element wants to be surrounded by 2/8/18 electrons For main-group metals (8-e), this leads to the standard Lewis structure rules For transition metals, we get the 18-electron rule Structures which have this preferred count are called electron-precise Every orbital wants to be used", i.e. contribute to binding an electron pair The strength of the preference for electron-precise structures depends on the position of the element in the periodic table For early transition metals, 18-e is often unattainable for steric reasons the required number of ligands would not fit

For later transition metals, 16-e is often quite stable (square-planar d8 complexes) Addition of 2e- from 5th ligand converts complex to 5 CN 18e- , marginally more stable Predicting reactivity 14 e - C2H4 (C2H4)2PdCl2 16 e CO dissociative (C2H4)PdCl2 CO ? (C2H4)2(CO)PdCl2

associative 18 e Most likely associative (C2H4)(CO)PdCl2 - C2H4 16 e Predicting reactivity 16 e - CO 18 e Cr(CO)6 MeCN dissociative

Cr(CO)5 MeCN ? Cr(CO)5(MeCN) 18 e Cr(CO)6(MeCN) associative 20 e (Sterics!) Most likely dissociative - CO N.B. How do you know a fragment forms a covalent or a dative bond?

Chemists are "sloppy" in writing structures. A "line" can mean a covalent bond, a dative bond, recognise/understand the bonding first Use analogies ("PPh3 is similar to NH3"). Rewrite the structure properly before you start counting. Cl PPh3 Cl Pd covalent bond 1e dative

bond "bond" to the allyl fragment PPh3 Pd 2e 3e Pd = Cl = P = allyl = 10 1 2 3

+ e-count 16 "Covalent" count: (ionic method also useful) 1. Number of valence electrons of central atom. from periodic table 2. Correct for charge, if any but only if the charge belongs to that atom! 3. Count 1 e for every covalent bond to another atom. 4. Count 2 e for every dative bond from another atom. no electrons for dative bonds to another atom! 5. Delocalized carbon fragments: usually 1 e per C (hapticity) 6. Three- and four-center bonds need special treatment 7. Add everything N.B. Covalent Model: 18 = (# metal electrons + # ligand electrons) - complex charge The number of metal electrons equals it's row number (i.e., Ti = 4e, Cr = 6 e, Ni = 10 e) Hapto (h) Number (hapticity)

For some molecules the molecular formula provides insufficient information with which to classify the metal carbon interactions The hapto number (h) gives the number of carbon (conjugated) atoms bound to the metal It normally, but not necessarily, gives the number of electrons contributed by the ligand We will describe to methods of counting electrons but we will employ only one for the duration of this module The two methods compared: some examples N.B. like oxidation state assignments, electron counting is a formalism and does not necessarily reflect the distribution of electrons in the molecule useful though Some ligands donate the same number of electrons Number of d-electrons and donation of the other ligands

can differ Now we will look at practical examples on the black board Does it look reasonable ? Remember when counting: Odd electron counts are rare In reactions you nearly always go from even to even (or odd to odd), and from n to n-2, n or n+2. Electrons dont just appear or disappear

The optimal count is 2/8/18 e. 16-e also occurs frequently, other counts are much more rare. Exceptions to the 18 Electron Rule ZrCl2(C5H5)2 Zr(4) + [2 x Cl(1)] + [2 x C5H5(5)] =16 TaCl2Me3 Ta(5) + [2+ x Cl(1)] + [3 x M(1)] =10 WMe6 W(6) + [6 x Me(1)] =12 Pt(PPh3)3 Pt(10) + [3 x PPh3(2)] =16 IrCl(CO)(PPh3)2 Ir(9) + Cl(1) + CO(2) + [2 x PPh3(2)] =16 What features do these complexes possess? Early transition metals (Zr, Ta, W) Several bulky ligands (PPh3) Square planar d8 e.g. Pt(II), Ir(I) -donor ligands (Me) Alkyl ligands: Transition metal alkyl complexes important for catalysts e.g. olefin polymerization and hydroformylation thermodynamic

Problem is their weak kinetic stability (Thermally fine: M-C bond dissociation energies are typically 40-60 kcal/ mol with 20-70 kcal/mol) Simple alkyls are sigma donors, that can be considered to donate one or two electrons to the metal center depending on which electron counting formalism you use Synthesis of Metal Alkyl Complexes 1. Metathetical exchange using a carbon nucleophile (R-). Common reagents are RLi, RMgX (or R2Mg), ZnR2, AlR3, BR3, and PbR4. Much of this alkylation chemistry can be understood with Pearson's "hardsoft" principles 2. Metal-centered nucleophiles (i.e. using R + as a reagent) Typical examples are a metal anion and alkyl halide (or pseudohalogen). for example: NaFp + RX Fp-R + NaX [Fp = Cp(CO) 2Fe]

3. Oxidative Addition. This requires a covalently unsaturated, low-valent complex (16 e- or less). A classic example: 4. Insertion- To form an alkyl, this usually involves an olefin insertion. The simplest generic example is the insertion of ethylene into an M-X bond, i.e. M-X + CH2CH2 M-CH2CH2-X Carbonyl Complexes Bonding of CO Electron donation of the lone pair on carbon s This electron donation makes the metal more electron rich - compensate for this increased electron density, a filled metal d-orbital may interact with the empty p* orbital on the carbonyl ligand p-backbonding or pbackdonation or synergistic

bonding Similar for alkenes, acetylenes, phosphines, and dihydrogen. What stabilizes CO complexes is MC bonding The lower the formal charge on the metal ion the more willing it is to donate electrons to the orbitals of the CO Thus, metal ions with higher formal charges, e.g. Fe(II) form CO complexes with much greater difficulty than do zero-valent metal ions For example Cr(O) and Ni(O), or negatively charged metal ions such as V(-I) In general to get a feeling for stability examine the charges on the metals Syntheses of metal carbonyls Metal carbonyls can be made in a variety of ways. For Ni and Fe, the homoleptic or binary metal carbonyls can be made by the direct interaction with the metal (Equation 1). In other cases, a reduction of a metal precursor in the presence of CO (or using CO as the reductant) is used (Equations 2-3). Carbon monoxide also reacts with various metal complexes, most typically

filling a vacant coordination site (Equation 4) or performing a ligand substitution reactions (Equation 5) Occasionally, CO ligands are derived from the reaction of a coordinated ligand through a deinsertion reaction (Equation 6) Synthesis of carbonyl complexes Direct reaction of the metal Not practical for all metals due to need for harsh conditions (high P and T) Ni + 4CO Ni(CO)4 Fe + 5CO Fe(CO)5 Reductive carbonylation Useful when very aggressive conditions would be required for direct reaction of metal and CO Wide variety of reducing agents can be used CrCl3+ Al + 6CO AlCl3 + Cr(CO)6 3Ru(acac)3 + H2 + 12CO Ru3(CO)12 + N.B. From the carbonyl complex we can synthesize other derivatives Main characterization methods:

Xray diffraction (static) structure bonding NMR structure en dynamic behaviour EA assessment of purity (calculations) Useful on occasion: IR MS EPR Not used much: GC LC IR spectra and metal-carbon bonds The CO stretching frequency of the coordinated CO is very informative Recall that the stronger a bond gets, the higher its stretching

frequency M=C=O (C=O is a double bond) canonical structure Lower the CO stretching frequency as compared to the M-CO structure (triple bond) Note: CO for free CO is 2041 cm-1) [Ti(CO)6]2- [V(CO)6]- [Cr(CO)6] [Mn(CO)6]+ [Fe(CO)6]2+ CO 1748 1858 1984 increasing M=C double bonding 2094 2204 cm-1

decreasing M=C double bonding Bridging versus terminal carbonyls Bridging CO groups can be regarded as having a double bond C=O group, as compared to a terminal CO, which is more like a triple bond: ~ double bond ~ triple bond M M-CO terminal carbonyl (~ 1850-2125 cm-1) C=O M bridging carbonyl (~1700-1860 cm-1)

Bridging CO between 1700 and 2200 cm-1 the C=O group in a bridging carbonyl is more like the C=O in a ketone, which typically has C=O = 1750 cm-1 Bridging versus terminal carbonyls in [Fe2(CO)9] O OC OC Fe OC CO

C Fe C C O CO CO O terminal carbonyls bridging carbonyls Summary 1. As the CO bridges more metal centers its stretching frequency drops same for all p ligands More back donation

2. As the metal center becomes increasingly electron rich the stretching frequency drops Alkene ligands Dewar-Chatt-Duncanson model The greater the electron density back-donated into the p* orbital on the alkene, the greater the reduction in the C=C bond order Stability of alkene complexes also depends on steric factors as well An empirical ordering of relative stability would be: tetrasubstituted < trisubstituted < trans-disubstituted < cisdisubstituted < monosubstituted < ethylene Alkyne ligands: Similar to alkenes Alkynes tend to be more

electropositive-bind more tightly to a transition metal than alkenes -alkynes will often displace alkenes Difference is 2 or 4 electron donor sigma-type fashion (A) as we did for alkenes, including a pi-backbond (B) The orthogonal set can also bind in a pi-type fashion using an orthogonal metal d-orbital (C) The back-donation to the antibonding orbital (D) is a delta-bond-the degree of overlap is quite small - contribution of D to the bonding of alkynes is minimal The net effect p-donation - alkynes are usually non-linear in TM complexes Resonance depict the bonding of an alkyne. I is the metallacyclopropene resonance form

Support for this versus a simple two electron donor, II, can be inferred from the C-C bond distance as well the RC-C-R angles III generally does not contribute to the bonding of alkyne complexes. Ally ligands: Allyl ligands are ambidentate ligands that can bind in both a monohapto and trihapto form The trihapto form can be expressed as a number of difference resonance forms as shown here for an unsubstituted allyl ligand: Important applications Dihydrogen Ligands: Metal is more electropositive than hydrogen Hydrogen acts as a two electron sigma donor to the metal center. The complex is an arrested intermediate in the oxidative addition of dihydrogen How does this affect the oxidation state of the meta? Dihydrogen complexes Bonding is simple a 3C-2electron bond. H2 - neutral two electron sigma donor

One could also describe a back-donation of electrons from a filled metal orbital to the sigma-* orbital on the dihydrogen Electronic Attributes of Phosphines Like that of carbonyls As electron-withdrawing sigma-donating capacity decreases At the same time, the energy of the p-acceptor (sigma-*) on phosphorous is lowered in energy, providing an increase in backbonding ability. Therefore, range of each capabilities tuning rough ordering -CO stretching frequency indicator- low CO stretching frequency- greater backbonding to M Experiments such as this permit us to come up with the following empirical ordering: Cone Angle (Tolman) Steric hindrance: A cone angle of 180 degrees effectively protects (or covers) one half of the coordination sphere of the metal complex Phosphine Ligand

Cone Angle PH3 87o PF3 104o P(OMe)3 107o PMe3 118o PMe2Ph

122o PEt3 132o PPh3 145o PCy3 170o P(t-Bu)3 182o P(mesityl)3

212o You would expect a dissociation event to occur first before any other reaction -steric bulk (rate is first order -increasing size) This will also have an effect on activity for catalysts N.B. flat can slide past each other For example Wilkinson's catalyst (more later) Has a profound effect on the reactivity! Reaction chemistry of complexes Three general forms: 1. Reactions involving the gain and loss of ligands a. Ligand Dissoc. and Assoc. (Bala) b. Oxidative Addition c. Reductive Elimination d. Nucleophillic displacement

2. Reactions involving modifications of the ligand a. Insertion b. Carbonyl insertion (alkyl migration) c. Hydride elimination (equilibrium) 3. Catalytic processes by the complexes Wilkinson, Monsanto Carbon-carbon bond formation (Heck etc.) a) Ligand dissociation/association (Bala) Electron count changes by -/+ 2 No change in oxidation state Dissociation easiest if ligand stable on its own (CO, olefin, phosphine, Cl-, ...)

Steric factors important M Br M + Br- b) Oxidative Addition Basic reaction: LnM + X Y

X LnM Y Electron count changes by +/- 2 (assuming the reactant was not yet coordinated) Oxidation state changes by +/- 2 Mechanism may be complicated The new M-X and M-Y bonds are formed using: the electron pair of the X-Y bond one metal-centered lone pair One reaction multiple mechanisms Concerted addition, mostly with non-polar X-Y bonds H2, silanes, alkanes, O2, ... Arene C-H bonds more reactive than alkane C-H bonds (!) LnM +

X Y X LnM Y A Intermediate A is a s-complex Reaction may stop here if metal-centered lone pairs are not readily available Final product expected to have cis X,Y groups X LnM Y

Stepwise addition, with polar X-Y bonds HX, R3SnX, acyl and allyl halides, ... low-valent, electron-rich metal fragment (Ir I, Pd(0), ...) X LnM X Y LnM X Y B Metal initially acts as nucleophile Coordinative unsaturation less important Ionic intermediate (B) Final geometry (cis or trans) not easy to predict Radical mechanism is also possible LnM Y

Cis or trans products depends on the mechanism H2 H OC Ir Et3P Cl H OC Et3P PEt3 Ir Cl HI

OC Et3P Ir(I) Ir Cl PEt3 H Ir(III) cis PEt3 Ir(III) I cis

CH3 PEt3 CH3Br OC Et3P Ir Cl Br trans Ir(III) c) Reductive elimination This is the reverse of oxidative addition - Expect cis elimination Rate depends strongly on types of groups to be eliminated. Usually easy for:

H + alkyl / aryl / acyl H 1s orbital shape, c.f. insertion alkyl + acyl participation of acyl p-system SiR3 + alkyl etc Often slow for: alkoxide + alkyl halide + alkyl thermodynamic reasons? We will do a number of examples of this reaction Relative rates of reductive elimination L CH3

Pd L L -L Ph3P Pd Ph3P MePh2P P Ph Pd Ph

P CH3 CH3 MePh2P Ph solv Rate Constant (s-1) Complex Ph Pd + solv

CH3 CH3 Pd CH3 CH3 CH3 CH3 RE CH3 T(oC) 1.04 x 10-3 60

9.62 x 10-5 60 4.78 x 10-7 80 Most crowded is the fastest reaction LPd(solv) + CH3 CH3 Special case: Nucleophilic Attack on a Coordinated CO acyl anion Fisher carbene This is Fischer carbene It has a metal carbon double bond

Such species can be made for relatively electronegative metal centers N.B. mid to late TMs Fischer carbenes are susceptible to nucleophilic attack at the carbon Fischer carbenes act effectively as donors and p acceptors The empty antibonding M=C orbital is primarily on the carbon making it susceptible to attack by nucleophiles Other type is called a Shrock carbene (alkylidene) Characteristic Fischer-type Schrock-type Typical metal (Ox. State) Middle to late T.M. Fe(0), Mo(0) Cr(0)

Early T.M. Ti(IV), Ta(V) Substituents attached to carbene carbon At least one highly electronegative heteroatom H or alkyl Typical other ligands Good p acceptors Good s and p donors

Electron count 18 10-18 Nucleophilic displacement Ligand displacement can be described as nucleophilic substitutions O.M. complexes with negative charges can behave as nucleophiles in displacement reactions Iron tetracarbonyl (anion) is very useful O R R' R'X ]2- [Fe(CO)4

RX [ R O O2 Fe(CO)4]- R O X2 H+ R X R R H

CO O [ R O Fe(CO)4 ]- H+ R H O X OH

Modifications of the ligand a) Insertion reactions Migratory insertion! The ligands involved must be cis - Electron count changes by -/+ 2 No change in oxidation state If at a metal centre you have a s-bound group (hydride, alkyl, aryl) a ligand containing a p-system (olefin, alkyne, CO) the s-bound group can migrate to the p-system 1. CO, RNC (isonitriles): 1,1-insertion 2. Olefins: 1,2-insertion, b-elimination R R M M CO 1,1

O R M M 1,2 R 1,1 Insertion The s-bound group migrates to the p-system if you only see the result, it looks like the p-system has inserted into the M-X bond, hence the name insertion To emphasize that it is actually (mostly) the X group that moves, we use the term migratory insertion (Both possible tutorial) The reverse of insertion is called elimination Insertion reduces the electron count, elimination increases it

Neither insertion nor elimination causes a change in oxidation state a- elimination can release the new substrate or compound In a 1,1-insertion, metal and X group "move" to the same atom of the inserting substrate. The metal-bound substrate atom increases its valence Me M M CO O Me Me M

M SO2 S Me O O CO, isonitriles (RNC) and SO2 often undergo 1,1-insertion 1,2 insertion (olefins) Insertion of an olefin in a metal-alkyl bond produces a new alkyl Thus, the reaction leads to oligomers or polymers of the olefin polyethene (polythene) polypropene Standard Cossee mechanism R

M M R M R M R Why do olefins polymerise? Driving force: conversion of a p-bond into a s-bond One C=C bond: 150 kcal/mol Two C-C bonds: 285 = 170 kcal/mol Energy release: about 20 kcal per mole of monomer (independent of mechanism) Many polymerization mechanisms Radical (ethene, dienes, styrene, acrylates) Cationic (styrene, isobutene) Anionic (styrene, dienes, acrylates)

Transition-metal catalyzed (a-olefins, dienes, styrene) b Hydride elimination (usually by b hydrogens) Many transition metal alkyls are unstable (the reverse of insertion) the metal carbon bond is weak compared to a metal hydrogen Bond Alkyl groups with hydrogen tend to undergo elimination M -CH2-CH3 M - H + CH2=CH2 Two examples A four-center transition state in which the hydride is transferred to the metal An important prerequisite for beta-hydride elimination is the presence of an open coordination site on the metal complex - no open site is available - displace a ligand metal complex will usually have less than 18 electrons, otherwise a 20 electron olefin-hydride would be the immediate product. To prevent beta-elimination from taking place, one can use alkyls that: Do not contain beta-hydrogens Are oriented so that the beta position can not access the metal center Would give an unstable alkene as the product Catalysis (homogeneous)

Reduction of alkenes etc. The size of the substrate has an effect on the rate of reaction Same reaction different catalyst Alternative starting material The Monsanto acetic acid process Methanol - reacted with carbon monoxide in the presence of a catalyst to afford acetic acid Insertion of carbon monoxide into the C-O bond of methanol The catalyst system - iodide and rhodium Iodide promotes the conversion of methanol to methyl iodide, Methyl iodide - the catalytic cycle begins: 1. Oxidative addition of methyl iodide to [Rh(CO) 2I2]2. Coordination and insertion of CO - intermediate 18-electron acyl complex 3. Can then undergo reductive elimination to yield acetyl iodide and regenerate our catalyst Catvia Process

Wacker process (identify the steps) Identify the steps

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