Examples of functional group in the following topics:
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- Functional groups are atoms or small groups of atoms (two to four) that exhibit a characteristic reactivity when treated with certain reagents.
- A particular functional group will almost always display its characteristic chemical behavior when it is present in a compound.
- Because of their importance in understanding organic chemistry, functional groups have characteristic names that often carry over in the naming of individual compounds incorporating specific groups.
- In the following table the atoms of each functional group are colored red and the characteristic IUPAC nomenclature suffix that denotes some (but not all) functional groups is also colored.
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- Functional groups also play an important part in organic compound nomenclature; combining the names of the functional groups with the names of the parent alkanes provides a way to distinguish compounds.
- Functional groups play a significant role in directing and controlling organic reactions.
- Functionalization refers to the addition of functional groups to a compound by chemical synthesis.
- Alcohols are a common functional group (-OH).
- Define the term "functional group" as it applies to organic molecules
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- Functional groups are atoms or small groups of atoms (usually two to four) that exhibit a characteristic reactivity when treated with certain reagents.
- A particular functional group will almost always display its characteristic chemical behavior when it is present in a compound.
- Because of this, the discussion of organic reactions is often organized according to functional groups.
- The following table summarizes the general chemical behavior of the common functional groups.
- For reference, the alkanes provide a background of behavior in the absence of more localized functional groups.
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- Other functional group combinations with the carbonyl group can be prepared from carboxylic acids, and are usually treated as related derivatives.
- Although nitriles do not have a carbonyl group, they are included here because the functional carbon atoms all have the same oxidation state.
- Functional groups of this kind are found in many kinds of natural products.
- Some examples are shown below with the functional group colored red.
- Penicillin G has two amide functions, one of which is a β-lactam.
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- Detailed information about the infrared absorptions observed for various bonded atoms and groups is usually presented in tabular form.
- The following table provides a collection of such data for the most common functional groups.
- Infrared absorption data for some functional groups not listed in the preceding table are given below.
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- The carboxyl functional group that characterizes the carboxylic acids is unusual in that it is composed of two functional groups described earlier in this text.
- As may be seen in the formula below, the carboxyl group is made up of a hydroxyl group bonded to a carbonyl group.
- Other combinations of functional groups were described previously, and significant changes in chemical behavior as a result of group interactions were described (e.g. phenol & aniline).
- In this case, the change in chemical and physical properties resulting from the interaction of the hydroxyl and carbonyl group are so profound that the combination is customarily treated as a distinct and different functional group.
- For this group of compounds one such phrase is: "Oh My Such Good Apple Pie".
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- In the IUPAC system of nomenclature, functional groups are normally designated in one of two ways.
- For the mono-functional alcohols, this common system consists of naming the alkyl group followed by the word alcohol.
- Many functional groups have a characteristic suffix designator, and only one such suffix (other than "ene" and "yne") may be used in a name.
- When the hydroxyl functional group is present together with a function of higher nomenclature priority, it must be cited and located by the prefix hydroxy and an appropriate number.
- Compounds incorporating a C–S–H functional group are named thiols or mercaptans.
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- The functional group of the alcohols is the hydroxyl group, –OH.
- Unlike the alkyl halides, this group has two reactive covalent bonds, the C–O bond and the O–H bond.
- Consequently, the covalent bonds of this functional group are polarized so that oxygen is electron rich and both carbon and hydrogen are electrophilic, as shown in the drawing below.
- Indeed, the dipolar nature of the O–H bond is such that alcohols are much stronger acids than alkanes (by roughly 1030 times), and nearly that much stronger than ethers (oxygen substituted alkanes that do not have an O–H group).
- The most reactive site in an alcohol molecule is the hydroxyl group, despite the fact that the O–H bond strength is significantly greater than that of the C–C, C–H and C–O bonds, demonstrating again the difference between thermodynamic and chemical stability.
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- Aldehydes and ketones are organic compounds which incorporate a carbonyl functional group, C=O.
- In cyclic ketones the carbonyl group is assigned position #1, and this number is not cited in the name, unless more than one carbonyl group is present.
- The atom adjacent to the function is alpha, the next removed is beta and so on.
- The other functional groups are treated as substituents.
- The generic name for such groups is acyl.
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- If these same functional groups are attached to an acyl group (RCO–) their properties are substantially changed, and they are designated as carboxylic acid derivatives.
- Carboxylic acids have a hydroxyl group bonded to an acyl group, and their functional derivatives are prepared by replacement of the hydroxyl group with substituents, such as halo, alkoxyl, amino and acyloxy.
- Some examples of these functional derivatives were displayed earlier.
- The last nine entries in the above table cannot function as hydrogen bond donors, so hydrogen bonded dimers and aggregates are not possible.
- The relatively high boiling points of equivalent 3º-amides and nitriles are probably due to the high polarity of these functions.