17 votes

Bonding between rings and iron atom in ferrocene

The "real" structure of ferrocene is an iron atom sandwiched between two flat, parallel, pentagonal C5H5 rings. The diagram above shows the atomic positions from a crystal structure but the ...
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Negative oxidation states of Si

I am not sure if Silane ($\ce{SiH_4}$) can really be considered. But there are silicides which silicon forms with strongly electropositive metals. In these compounds, silicon has a negative ...
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Are there any significant uses of the compound formed by magnesium and anthracene?

It seems like an idea of using magnesium anthracene systems for the $\ce{MgH2}$ production persisted since 1980s [1] till late 2000s, when new more efficient method with better scalability for ...
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12 votes
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Organic reaction of dry ice and Grignard reagent

You are correct. Grignard reagents $\ce{RMgX}$ (where $\ce{R}$ stands for some hydrocarbon group and $\ce{X}$ is a halogen, usually $\ce{Cl}$, $\ce{Br}$, or $\ce{I}$) react with carbon dioxide to ...
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Why can't the reaction of grignard reagent with carboxylic acid give a ketone?

Huy Ngo says it all. A Grignard reageant will react first with just about any hydrogen that has even a modicum of proton donation capability, before "resorting" to the slower nucleophilic ...
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What makes R-MgX a more reactive Grignard reagent than R-Cu?

The difference in electronegativity between copper (1.9) and magnesium (1.3) is the key difference. Since copper is more electronegative than magnesium its electronegativity is much closer to that ...
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Can ferrocene type sandwich compounds be made with fluorene?

Yes there are, many in fact. One of the examples is having a complex consisting of a fluorene molecule and of cp altogether with iron, described by Decken in Acta Cryst. E (doi: 10.1107/...
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10 votes
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Do organopolonium compounds exist?

As one might expect for an element with no long-lived isotopes, little is known about organopolonium compounds. What is known may be broadly divided into two categories [1,2; cited by Wikipedia]: ...
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10 votes

How does cyclopentadienyl anion act as reducing agent?

Disclaimer: None of this constitutes proof; it's just an informed guess. Any corrections with reputable sources are welcome. The simplest proposal seems to be single-electron transfer (SET) from $\ce{...
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What's wrong with using tin in medicinal chemistry?

Organotin compounds are rather toxic. They are also persistent in the environment and have a long biological half-life. The problem is that trialkyltin byproducts from your reaction are difficult to ...
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8 votes

Why do halogen-metal exchanges happen?

How Did Wittig Come to Discover Lithium-Halogen-Exchange? Georg Wittig, discoverer of the Wittig reaction, was studying the effect of ring strain on the strength of two neighboring carbons; by adding ...
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Role of Cu in Corey-House synthesis

Copper is used to avoid lithium-halogen exchange. Additional information on that reaction can be found in this discussion. Organolithiums will often, instead of acting as a nucleophile, form a new ...
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Is the term "heteroatom" reserved for exclusive elements?

The IUPAC Goldbook provides no 'official' definition of the term heteroatom,and as such you're somewhat free to use (and abuse) the term as you see fit. Since no IUPAC definition exists, it may be ...
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Triflate use in metathesis reactions

As a result of the -I effect of the trifluoromethyl group, triflate is a better nucleofuge than mesylate and tosylate. As compared to tosylate and nosylate, triflate is rather small. This might be ...
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Why do Grignard reagents react with epoxides but not THF?

The difference between THF and epoxides is perhapse bigger than you might think. Due to the three-membered-ring of an epoxide, a lot of energy is 'stored' in ring strain. This destabilizes the ...
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7 votes

Coordination number of carbon in methyllithium tetramer

TL; DR: coordination number of carbon atom in methyllithium tetramer is indeed 7, arising from 6 intramolecular interactions, as you suggested, and an extra bond with the lithium atom of the next ...
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7 votes

How to name this quintuply-bonded chromium dimer?

It was a great effort. However, in the proposed name bis[(μ-2,6-{[2,6-di(1-methylethyl)]diphenyl}phenyl-1κC1,2κC7)chromium](5 Cr—Cr) I can see several issues: In you point 12: Forcing the ...
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How does the Wurtz reaction produce alkynes?

@tox123: You have generated two radicals on the same carbon by a two-electron reductive α-elimination (1 --> 2). So far, so good. In other words, you have created a carbene (2). Carbenes can ...
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What is the mechanism of this reaction?

Nicco: Of course you can't "see it". If you were given the correct structure, the solution to your post would be straightforward. There should be a double bond in the lactam ring as shown in compound ...
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Why are tri-organotin chloride compounds so dangerous?

To get the gravity of how toxic organotin compounds can be, let us compare it with inorganic tin compounds. Most of the inorganotin compounds are non-toxic because of their low solubility and low ...
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6 votes

What is the chemical composition of the grignard reagent?

A Grignard reagent is an organomagnesium halide of the generic form $\ce{RMgX}$, where $\ce{R}$ is a hydrocarbon group and $\ce{X}$ is a halide, usually $\ce{Cl}$, $\ce{Br}$, or $\ce{I}$. These ...
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6 votes

Why do Organolithium or Grignard reagents act as nucleophiles and not as bases with aldehydes and ketones

Technically, you are comparing apples and oranges. Grignards and organolithium compounds are good nucleophiles (with the caveat permeakra highlighted) towards carbonyl groups. But they cannot attack ...
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6 votes

Inorganic chemistry reaction mechanisms

If this is in regard to mechanisms with organometallic complexes or coordination compounds, there are a set of specific mechanisms that are well defined. These are: Ligand dissociation / association ...
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  • 339
6 votes

Is there a reaction between ethanol and aluminum?

The reaction of aluminum and ethanol forms aluminum triethoxide, $\ce{ Al(OC2H5)3}$, but the reaction is fairly slow at room temperature, particularly if the aluminum is anodized. In the presence of ...
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6 votes

Why do the protons in pentacarbonylmethylmanganese show up at –0.21 ppm?

Unfortunately, you don't give an indication of what you expect the chemical shift for the -Me to be, other than higher than is observed. However, you are correct in your assumption; the π back ...
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Ketone/aldehyde synthesis from N-acylazetidines or aziridines

I think your suggestion about the stability of the tetrahedral intermediate is correct, but it's not that the tetrahedral intermediate itself has stability. I think it's because the collapse of the ...
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Why are 3 equivalents of organolithium needed in synthesis of ketone from carboxylic acid?

The text box you are quoting from (p 219) refers to this specific reaction. The compound in question possesses an α-hydroxyl group, which needs to be deprotonated too. Notice that three equivalents ...
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Effect of metal identity on CO bond length in carbonyl complexes

Let's look at the molecular orbital diagram calculated with JSmol. As you know, the principal effect is back-donation from the metal to the π-antibonding orbitals of the carbon monoxide. But not all ...
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5 votes

Do eta-4 benzene ligands participate in Diels Alder or other cycloadditions?

Coordinated benzene as a dienophile It would be logical to suggest that an η4-benzene ligand could behave as a dienophile. The reason why benzene is characteristically unreactive, both as a ...
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Where to find common inorganic/organometallic molecules?

I appreciate the suggestions but some digging found a few possibilities: As I mentioned in the question, there's the Cambridge Structural Database, which includes over 700,000 compounds (both organic ...
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