For questions relating to organic compounds which contain a bond between a carbon atom and a metal.
-1
votes
0answers
6 views
M-C bond dissociation energy in transition metals [closed]
Why for the main group elements, the M-C bond energy decreases for the heavier congeners in a group but the trend is opposite for the transition metals?
2
votes
0answers
14 views
How to calculate the magnetic exchange coupling in a charged radical complex?
I have a neutral complex with two magnetic centers. For this case it is easy to calculate the exchange coupling as the broken symmetry state is converged properly. But when I am making the complex ...
2
votes
0answers
24 views
What makes dimethylmercury ((CH3)2Hg) so penetrative through latex and human skin?
I've read the story of Karen Wetterhahn and how she was poisoned and died from two drops of dimethylmercury that accidentally fell on her latex glove, and I was wondering what is the chemical ...
4
votes
1answer
51 views
Is it possible to have a ferrocenol?
I'm specifically talking about having a hydroxy- group on the ferrocene ring.
Is it simply impossible because the ring is anionic?
I haven't seen any hydroxyferrocene molecules available online. (...
0
votes
0answers
12 views
Is the Dewar-Chatt-Duncason model limited to bonding between only alkenes and a metal?
Most of what I have read states that the DCD model only consists of the alkene and the metal. Can only alkenes (C=C) bond with a metal pi complex in context of the DCD model? Or does the DCD model ...
2
votes
1answer
33 views
How do we know cyclopentadienylmolybdenum tricarbonyl occurs as a dimer?
Cyclopentadienylmolybdenum tricarbonyl, $\ce{MoC8H5O3}$, dimerizes to form the cyclopentadienylmolybednum tricarbonyl dimer, $\ce{(MoC8H5O3)2}$.
$\hspace{3cm}$
How was it discovered that it does ...
3
votes
0answers
50 views
Do Sodium Alkynides react with esters in the same way that Grignard reagents do?
We know that Sodium alkynides react with aldehydes and ketones like Grignard reagents. But do they behave the same way with esters?
9
votes
1answer
100 views
How can the solid state structure of cyclopentadienyllithium be explained?
In the solid state, LiCp adopts a polymeric multidecker structure where Li atoms are sandwiched between two Cp rings (shown in this diagram from Organometallics 1997, 16 (17), 3855–3858):
If we ...
2
votes
1answer
465 views
How to electron count bridging ligands?
Although I am okay with rationalising bridging halides and $\mu$-2 CO I can't seem to figure out others, including $\mu$-2 hydride, CN- and NO.
When considering the electron count of bridging ligands,...
1
vote
0answers
33 views
What does unactivated, activated and deactivated aryl chloride means in cross-coupling reactions?
When I read this literature https://pubs.acs.org/doi/pdf/10.1021/jo990408i, it used unactivated aryl chloride for Buchwald-Hartwig amination.
What does unactivated, activated and deactivated aryl ...
10
votes
1answer
171 views
Mechanism of lithium-halogen exchange of primary alkyl iodide
On Clayden's page 190 this reaction is given for preparation of organometallics:
What is the mechanism of this reaction? I expected the "almost carboanion" part of the $\ce{t-BuLi}$ to attack as a ...
5
votes
2answers
190 views
How does the Wurtz reaction produce alkynes?
Wikipedia mentions that alkynes can be produced from geminal dihalides through the Wurtz reaction. However, I am unsure of the reaction mechanism for this reaction. I have not been able to find any ...
2
votes
1answer
71 views
What is the product of magnesium reacting with carbon?
$$\ce{Mg + C -> X}$$
$$\ce{X + H2O -> Y}$$
Determine unknowns X and Y.
Now the problem is I think the answer should be $\ce{X=MgC2}$ and $ \ce{Y=C2H2 + Mg(OH)2}$. But the given answer was ...
2
votes
1answer
83 views
One-pot synthesis of pyrazole [closed]
I am trying to follow a published paper. It is a one-pot synthesis of pyrazole from a ketone and and acid chloride via a diketone intermediate.
Here is the produre from the paper:
General Procedure:...
3
votes
0answers
203 views
Mechanism for reaction of an allene with the Grignard Reagent(RMgX)
How does the Grignard Reagent($\ce{RMgX}$) react with an allene $\ce{CH_2=C=CH_2}$ and what are the products formed?
This is exactly what I tried to do.
Any help will be appreciated.
6
votes
0answers
43 views
How can organocuprates generated with catalytic Cu(I) be competitive in 1,4-addition to an enone?
Organocoppper compounds (e.g. $\ce{LiCuR_2}$) are often prepared from an organolithium or Grignard reagent when a soften nucleophile is needed, such as for a conjugate addition to an $\alpha,\beta$-...
4
votes
1answer
267 views
Why are 3 equivalents of organolithium needed in synthesis of ketone from carboxylic acid?
For the reaction of a carboxylic acid and organolithium reagents to synthesise a ketone, Clayden's, on p 219, mentions:
Notice that three equivalents of organolithium are needed in this reaction: ...
-1
votes
1answer
174 views
electron counting for transition metal-oxo ligand compound
Using donor-pair method, how many electrons would an oxo ($O^{2-}$) ligand contribute? I cannot decide if it is 2 or 4.
3
votes
1answer
91 views
Is associative ligand exchange possible with octahedral complexes?
Can associative ligand exchange produce an octahedral intermediate as long as the initial complex has 16 electrons (unsaturated)?
Not sure. all I ever see is a square planar turning into a trigonal ...
13
votes
1answer
117 views
Mechanism of a Gold catalyzed organometallic reaction: Confusion regarding the last step
I needed to draw the reaction mechanism for this reaction:
So, after consulting some literature I drew this mechanism:
But, I am not sure about the last step. Does the $\ce{H+}$ just substitute the $...
1
vote
0answers
45 views
Looking for a low boiling point solvent for MAPI precursors (Lead Iodide (II) and Methylammonium Iodide) [closed]
Things I have thought of till now:
Acetonitrile with HI additive
Acetonitrile with DMSO additive
The problem with the first would be that HI is in an around 55% aqueous solution and water doesn't ...
17
votes
1answer
239 views
How to name this quintuply-bonded chromium dimer?
Depicted below is a chromium compound with a metal–metal quintuple bond. It boasts two identical bridging ligands, derivatives of 1,3-diphenylbenzene. The aim of this question is to figure out
the ...
2
votes
0answers
219 views
C-O bond strength in metal carbonyls [duplicate]
The metal carbonyls (and similar organometallic compounds) involve a combination of a $\sigma$-bond, a $\pi$-bond and backbonding. The bond strengths under consideration are the metal-carbon bond and ...
14
votes
1answer
768 views
Are there any significant uses of the compound formed by magnesium and anthracene?
In an unusual reaction, magnesium reacts with anthracene in THF to form a grignard-like compound called, prosaically, magnesium anthracene:
I remember using it briefly in the 1980s. At the time there ...
1
vote
1answer
76 views
How to reconcile conflict between assumed oxidation state and the most stable multiplicity from electronic structure calculations?
Consider either of the small, neutral molecules containing two Zn atoms below. If I were to determine the oxidation state of Zn from this molecule, I would formally assume each Zn to be Zn(I) in order ...
3
votes
2answers
340 views
Which complex is the most stable?
Between $\ce{[Rh(Ph2PCH2PPh2)3]^{3+}}$ and $\ce{[Rh(Ph2PCH2CH2PPh2)3]^{3+}}$, which one is the most stable thermodynamically? I think it's about the size of the chelate ring effecting their stability, ...
7
votes
1answer
86 views
Ketone/aldehyde synthesis from N-acylazetidines or aziridines
A common principle in organic chemistry is to make sure the product is less reactive than the starting material, to prevent overreaction. So, for example, the treatment of an ester with a Grignard ...
0
votes
1answer
385 views
Chemical function of Mg and Conjugated bonds in Chlorophyll [closed]
This question has 3 parts, each related to the title.
In biochem, we were shown the chemical structure of chlorophyll. The light-absorbing head has many carbon-rings with alternating single and ...
1
vote
1answer
1k views
What's the explanation for the chelate effect? [duplicate]
I got that multidentate ligands form more stable coordination complexes than monodentate ligands, but why?
1
vote
0answers
26 views
Complexation of hydroxy chalcone oxime with metal [closed]
Does the complexation of 2-hydroxy chalcone oxime (below) with a metal require any catalyst? Is the complexation pH sensitive?
-1
votes
1answer
77 views
What is the systematic name of ammonium bisoxalato cuprate (II)? [closed]
What is the systematic name of ammonium bisoxalato cuprate(II)?
I already tried $\ce{(NH4)2[Cu(C2O4)2]^{2+}}$ but i am uncertain if that answer is correct.
6
votes
1answer
373 views
How are Grignard reagents stable in an ethereal solution? [duplicate]
I have heard of the leveling effect, which mentions that highly basic ions cannot exist in a solvent if it's acidity is high enough to be deprotonated by the base.
Considering that, check out the ...
2
votes
1answer
99 views
Why does a smaller bandgap correlate to increased absorption of visible light?
I am currently involved in a project on metal organic frameworks in my AP chemistry class, and specifically their applications in $\ce{CO2}$ reduction into formate. All the explanations we can find on ...
1
vote
2answers
68 views
Is it safe to lyophilize/Freeze-dry a chelated compound?
I have a compound that consists of a metal ion chelated by a linear organic structure with assorted moieties in aqueous medium. I'd like to dehydrate this mixture fully to get solid product, but ...
0
votes
0answers
31 views
Change in UV absorbance due to metal-complexation
In organometallic complexation, why is there a change in UV absorbance? Is it due to pi-pi* or n-pi*? According to some standard literatures metal complexes are formed due to sharing of electrons in d ...
8
votes
2answers
644 views
Is the term “heteroatom” reserved for exclusive elements?
From my experience, typically in organic chemistry, the implication of "hetero-atom" in some molecule is understood as B, N, O, S, P or a halogen -- or any nonmetallic element, perhaps.
If one ...
12
votes
1answer
342 views
Noyori hydrogenation and the Curtin–Hammett principle
My question is relating to how the Curtin–Hammett principle applies to homogeneous hydrogenation using chiral ligands.
Figure 0: An example of a quadrant diagram used as a mnemonic to predict the ...
1
vote
0answers
540 views
CO stretching frequency band in the IR spectrum for tetracarbonylnickel and tetracarbonylferrate(II)
A past exam question says:
With reference to the main bonding interactions between a transition
metal and a terminal $\ce{CO}$ ligand, explain whether you would expect to
observe a lower $\ce{...
0
votes
0answers
279 views
How to determine whether acid-base reactions of Grignard reagents will occur
I'm asked to say whether the following Grignard reactions will occur or not based on the pKa values of the chemical species involved:
I added the known pKa values (literature) under each species and ...
11
votes
1answer
189 views
Terminal Alkyne in Suzuki Coupling
I've done a very similar reaction to the one below but by TLC I observe only starting materials. It's super clear that nothing else is going on. Conditions: K3PO4, Pd(dppf)Cl2, dioxane/water, heat to ...
0
votes
0answers
1k views
Why is the carbonyl ligand (CO) a weak sigma donor? Why are the sigma donor and pi acceptor properties of CO synergistic?
I've read that CO ligands cannot have sigma donor interactions with metals without first having pi acceptor interactions first. Why is this the case? Why is the sigma donor interaction so weak? If its ...
7
votes
0answers
342 views
Why does magnesium prefer to insert into C–Br bonds over C–Cl bonds?
In the formation of a Grignard reagent from a compound possessing both bromine and chlorine, magnesium preferentially inserts into the C–Br bond over the C–Cl bond. For example, the formation of a ...
3
votes
0answers
53 views
Synthesis of a tungsten carbene bromide from [CpW(CO)3]-
I'm currently working through past test and exam papers in order to prepare for my organometallic test at the end of the month, but unfortunately I've gotten stuck on the following question.
Since I ...
1
vote
0answers
735 views
Why do heavy metals like mercury and lead have an affinity for sulfur or sulfur compounds?
Many of the heavy metals such as mercury, lead, thallium, cadmium, and arsenic exert toxic effects largely by binding to or otherwise interfering with organic sulfur compounds or groups in the body. ...
1
vote
0answers
117 views
Grignard Reagent R group [closed]
Can the R group of a Grignard reagent (RMgX) be an alkene?
Also what groups can't R be?
0
votes
1answer
630 views
Does 30% hydrogen peroxide eat away at platinum?
if I soaked a platinum dish with 30% hydrogen peroxide, will it eventually eat away at it?
0
votes
0answers
99 views
Wilkinson's catalyst: why this structure?
I wonder how the structure of Wilkinson's catalyst contributes to its catalytic properties. For example, what role do the phosphine ligands play? What properties make Rh the best TM centre?
Thank ...
6
votes
1answer
4k views
Why can't the reaction of grignard reagent with carboxylic acid give a ketone?
I understand that a Grignard reagent can act both as a base and a nucleophile.
It acts as a base in the presence of a proton source (eg: alcohols, amine, water, etc). But when reacting with a ketone ...
2
votes
0answers
92 views
Selectivity of olefin cross-metathesis reaction
I'm looking at the reaction shown below which uses a ruthenium catalyst:
I am confused because the ruthenium catalyst which is used in the reaction should be Z selective due to the features on the ...
4
votes
0answers
36 views
Are there any stable complexes where an (N-unsubstituted) imine is bound eta^2 to a (late) transition metal?
I've been looking for an example of a stable complex where a $\ce{C=N}$ is coordinated $\eta^2$ to a (late) transition metal, but could not find any. Do they exist at all?
For $\ce{C=C}$ there are ...
