For questions relating to organic compounds which contain a bond between a carbon atom and a metal.
2
votes
0answers
23 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
39 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
85 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 ...
-1
votes
0answers
22 views
Why Iodide specially in sonogashira coupling and not other halides?
Q-Why iodide is specially better than other halides?, although if we are talking in terms of electron density on the adjacent carbon we will find that chloride for example is better in activating the ...
2
votes
1answer
200 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
25 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
88 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
158 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
70 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}$. But the given answer was ...
2
votes
1answer
82 views
One-pot synthesis of pyrazole [closed]
I am trying to follow a published paper. It is a one-pot synthesis of pyrazole from a ketone and and acid chloride via a diketone intermediate.
Here is the produre from the paper:
General Procedure:...
3
votes
0answers
183 views
Mechanism for reaction of an allene with the Grignard Reagent(RMgX)
How does the Grignard Reagent($\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.
5
votes
0answers
34 views
In situ preparation of organocopper compounds
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
239 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
140 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
73 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
112 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
41 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
219 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
177 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
762 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
75 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
293 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
80 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
326 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
863 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
25 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
59 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
319 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
81 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
65 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
28 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
602 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
317 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
472 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
257 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
176 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
928 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 ...
3
votes
0answers
49 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
645 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
106 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
536 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
96 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
88 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
35 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 ...
1
vote
1answer
7k views
Reduction of alkyl halides to alkanes
For all the three parts, only methane has been given as the product in my textbook.
In 1) and 2), according to the mechanism I wrote, I get both ethane and methane as products. I think both these ...
6
votes
0answers
322 views
Treatment of ketones with excess Tebbe reagent
The reaction in black below was presented in a set of lecture notes as an example of the use of the Tebbe reagent, however it's not immediately obvious (to me, at least) that the product should be the ...
5
votes
0answers
114 views
I found transition states (TS), but calculations aren't supported by experiment. Do I look for more TSs or somewhere else?
I'm using Gaussian to investigate a catalyst system.
Experimental evidence showed that one of three analogues (R = phenyl, Ph), yielded a benzosultam
when treated with 2,4,6-...
4
votes
0answers
50 views
Cycloaddition of Silyl Dienol Ethers with Sodium Bromodifluoroacetate: What's the scope?
I have recently came across this article "Copper(I)-Catalyzed [4 + 1] Cycloaddition of Silyl Dienol Ethers with Sodium Bromodifluoroacetate: Access to
β,β‐Difluorocyclopentanone Derivatives". (Org. ...
4
votes
0answers
302 views
Sodium Naphthalenide
The sodium fusion test done in the lab for the systematic identification of a given organic compound is basically fusing sodium metal in a fusion tube, and then adding the compound in a small quantity,...
