Superbase

Some things are very strong.

They love to grab tiny bits. These tiny bits are called protons. We call these strong things superbases.

People have used them since 1850. They help us build new things. Some are made of metal. Others are made of parts with nitrogen.

You can make a new superbase by mixing two bases. This makes a new, strong tool. It is a neat trick! It is very useful in science.

Some chemicals are very strong. They have a high affinity for protons. An affinity is a strong pull or attraction. These strong chemicals are called superbases.

People have used them since the 1850s. They help scientists make new things.

There are different kinds of superbases. Organic superbases are one kind. They are mostly made of nitrogen. Nitrogen helps them grab protons. Some of these use groups called amidines or guanidines.

Another kind is organometallic. These use metals. One example is lithium diisopropylamide.

You can also make a superbase by mixing. You can mix two bases to make a new one. This new tool has its own special traits. This is how the Schlosser base is made. It mixes two parts together. This makes it more reactive than the parts alone. There are also inorganic superbases. These are often salt-like. They do not dissolve in liquids. Their surfaces are very reactive. This makes them useful for science.

A superbase is a special kind of chemical compound. It has a very high affinity for protons. An affinity is a strong pull or attraction. These chemicals are very important in organic synthesis. This is the way scientists build new molecules. They have been using superbases since the 1850s. These tools help researchers explore new ideas in science.

There are different ways these chemicals work. Organic superbases are often made of nitrogen. The nitrogen acts as a proton acceptor. This means it grabs protons with great strength. Some organic types include amidines and guanidines. Other types include phosphazenes and phosphanes. Some of these are called proton sponges. They catch protons just like a sponge catches water.

Scientists can also make superbases by mixing things. This can create a new kind of reactive species. This does not mean the new base is stronger. It means the mixture has new properties. One famous example is the Schlosser base. It is a mix of n-butyllithium and potassium tert-butoxide. These two parts form a mixed group. This group is more reactive than the single parts.

Some superbases use metals in their structure. These are called organometallic superbases. One example is lithium diisopropylamide, or LDA. Other examples include organomagnesium compounds. These are often called Grignard reagents. You can also make them by swapping a metal for a hydrogen. This happens on atoms like oxygen or nitrogen. These metal-based tools are usually very strong nucleophiles.

There are also inorganic superbases to learn about. These are usually salt-like compounds. They often have small and highly charged anions. Examples include lithium hydride and sodium hydride. These materials do not dissolve in liquids. However, their surfaces are very reactive. Scientists use them in a thick liquid called a slurry. Quantum-chemical calculations suggest caesium oxide might be the strongest base.

A superbase is a chemical compound with a very high affinity for protons. In chemistry, an affinity is a strong attraction or pull. This means superbases are extremely effective at grabbing and holding onto protons. They are of great theoretical interest to researchers. They are also potentially valuable tools in organic synthesis. Organic synthesis is the process of building new organic molecules. Scientists have been describing and using superbases since the 1850s.

There are several ways to define a superbase. The International Union of Pure and Applied Chemistry, or IUPAC, calls a superbase a compound with very high basicity. A common example is lithium diisopropylamide, often called LDA. Many scientists group superbases into two broad categories: organic and organometallic. Others define them by comparing them to a specific molecule called proton sponge. Proton sponge is 1,8-bis(dimethylamino)naphthalene. To be a superbase by this definition, a species must have a higher absolute proton affinity than proton sponge. It must also have a higher intrinsic gas phase basicity. The absolute proton affinity of proton sponge is 245.3 kcal/mol. Its intrinsic gas phase basicity is 239 kcal/mol.

Organic superbases are mostly charge-neutral species. These molecules often contain nitrogen. In these compounds, the nitrogen acts as a proton acceptor. This means the nitrogen atom is the part that grabs the proton. Common organic superbases include amidines and guanidines. They also include phosphazenes and phosphanes. Some organic compounds act as proton chelators. These are called aromatic proton sponges or bispidines. Multicyclic polyamines like DABCO might also be included in this group. Even though they have huge proton affinity, some organic superbases show low nucleophilicity. Nucleophilicity is a measure of how much a species seeks out positive charges.

Organometallic superbases are another important group. These involve metals and organic groups. Some are called Lochmann–Schlosser superbases. These result from combining alkali metal alkoxides with organolithium reagents. One famous example is the Schlosser base. This is a mixture of n-butyllithium and potassium tert-butoxide. When these two are mixed, they form a mixed aggregate. This aggregate is more reactive than either reagent used by itself. You can also create these by exchanging a reactive metal for a hydrogen on a heteroatom. This can happen on atoms like oxygen or nitrogen. Metal amides, such as lithium diisopropylamide, are one example. Organolithium and organomagnesium compounds, known as Grignard reagents, are also examples. Unlike many organic superbases, organometallic superbases are generally strong nucleophiles.

Some scientists define superbases by how they are made. Caubère defines a superbase as a base resulting from mixing two or more bases. This mixing leads to new basic species with inherent new properties. This definition does not mean the new base is thermodynamically or kinetically stronger than the original bases. Instead, it means a new reagent is created by combining different characteristics. This creates a tool that behaves in ways the single bases could not.

Inorganic superbases exist as well. These are typically salt-like compounds. They feature small and highly charged anions. Examples include lithium hydride, potassium hydride, and sodium hydride. These inorganic superbases are usually insoluble in liquids. However, the surfaces of these materials are highly reactive. Because of this, scientists often use them in a thick mixture called a slurry. This allows the reactive surfaces to interact with other chemicals during synthesis.

Superbases play a major role in many chemical fields. They are frequently used in organocatalysis. This is a way to speed up chemical reactions using organic molecules. They are also essential for creating complex structures in organic synthesis. Even the strength of these bases can be studied through advanced math. Quantum-chemical calculations suggest that caesium oxide might be the strongest base. This shows how much there is still to learn about these powerful tools.