Presentation on theme: "ORGANIC FUNCTIONAL GROUPS AND NOMENCLATURE. ALKYL GROUPS An alkyl group is an unbranched alkane with a hydrogen atom removed from the terminal, or end,"— Presentation transcript:
ORGANIC FUNCTIONAL GROUPS AND NOMENCLATURE
ALKYL GROUPS An alkyl group is an unbranched alkane with a hydrogen atom removed from the terminal, or end, carbon. To name the alkyl group, replace the – ane ending of the unbranched alkane with –yl. Thus, if you take one hydrogen from CH 4, it becomes CH 3, and the name changes from methane to methyl.
Alkane Molecular Formula Structural Formula Alkyl Molecular Formula MethaneCH 4 MethylCH 3 EthaneC2H6C2H6 CH 3 EthylC2H5C2H5 PropaneC3H8C3H8 CH 3 CH 2 CH 3 PropylC3H7C3H7 ButaneC 4 H 10 CH 3 (CH 2 ) 2 CH 3 ButylC4H9C4H9 PentaneC 5 H 12 CH 3 (CH 2 ) 3 CH 3 PentylC 5 H 11 HexaneC 6 H 14 CH 3 (CH 2 ) 4 CH 3 HexylC 6 H 13 HeptaneC 7 H 16 CH 3 (CH 2 ) 5 CH 3 HeptylC 7 H 15 OktaneC 8 H 18 CH 3 (CH 2 ) 6 CH 3 OktylC 8 H 17 NonaneC 9 H 20 CH 3 (CH 2 ) 7 CH 3 NonylC 9 H 19 DekaneC 10 H 22 CH 3 (CH 2 ) 8 CH 3 DekylC 10 H 21 UndekaneC 11 H 24 CH 3 (CH 2 ) 9 CH 3 UndekylC 11 H 23 DodekaneC 12 H 26 CH 3 (CH 2 ) 10 CH 3 DodekylC 12 H 25 NAMES OF ALKANES and ALKYL GROUPS
ALKYL GROUPS ANIMATION
Carbon atoms are classified as primary, secondary, tertiary, or quaternary based on the number of non-hyrogen groups attached to the sp 3 carbon. The hydrogen atoms attached to these carbon atoms are given the same designation.
Primary,secondary and tertiary carbon atoms Organic compounds often contain functional groups bonded on to different types of carbon chains. These can often be usefully distinguished using the terms primary,secondary and tertiary. Primary means that the carbonthat the functional group is joined to is bonded to only one other carbon atom Secondary means that it is bondedto two other carbon atoms Tertiary three other carbon atoms.
METYL,ETHYL and PROPYL GROUPS
DRAWING PROPYL GROUPS IN A VARIETY OF ORIENTATIONS
TRIVIAL(COMMON) AND IUPAC NAMES OF COMMON ALKYL GROUPS
PENTYL GROUPS There are eight different pentyl groups (-C 5 H 11 ), but only four of these have trivial names. These four are shown above.
ALKYL GROUP Note that an alkyl group (C n H 2n+1, like an alkane with one H removed) can be represented by R. Thus alcohols (which contain the hydroxyl group OH) can be represented as ROH. Similarly the benzene ring can be represented as so that phenol (a benzene ring with an OH attached) is represented as
ALKENYL GROUP An alkenyl group is a hydrocarbon group formed when a hydrogen atom is removed from an alkene group. Alkenyl compounds are named by replacing the -e from the parent alkene's name with -yl. H 2 C=CH- (ethenyl or commonly known as vinyl). The parent alkene was H 2 C=CH 2, ethene.
ALKYNYL GROUP An alkynyl group is a hydrocarbon group formed when a hydrogen atom is removed from an alkyne group. Alkenyl compounds are named by replacing the -e from the parent alkyne's name with -yl. ethynyl group, H C C derived from ethyne, H C C H is also called ethynyl radical.
AROMATICS (ARENES) Arenes are cyclic hydrocarbons that contain three single bonds and three double bonds conjugated in a six-carbon ring. Arenes are usually derived from benzene. Another commonly used name for arenes is aromatic hydrocarbons. Arenes are cyclic hydrocarbons with alternating single and double bonds. Aromatic hydrocarbons are arenes based on benzene.
BENZENE DERIVATIVES The nomenclature of substituted benzene ring compounds is less systematic than that of the alkanes, alkenes and alkynes. A few mono-substituted compounds are named by using a group name as a prefix to "benzene", as shown by the combined names listed below. A majority of these compounds, however, are referred to by singular names that are unique. There is no simple alternative to memorization in mastering these names.
ARYL GROUP aryl group, in chemistry, group of atoms derived from benzene or from a benzene derivative by removing one hydrogen that is bonded to the benzene ring. The simplest aryl group is phenyl, C 6 H 5 ; it is derived from benzene.
ALKYL, ALKENYL, ALKYNYL and ARYL GROUPS HydrocarbonsGroups after one hydrogen removed Name of the Group FormulaName of the Compound Name of the Group FormulaName of the Substituent AlkaneCH 4 MethaneAlkylCH 3 –Methyl C2H6C2H6 EthaneC 2 H 5 –Etihyl CyclohexaneCyclohexyl AlkeneCH 2 = CH 2 EteneAlkenylCH 2 = CH –Ethenyl(Vinyl) – CH = CH – CH 3 1-Propenyl CH 2 = CH – CH 3 Propene CH 2 = CH – CH 2 –2-Propenyl (Allyl) Alkyne CH EthyneAlkynyl CH C – Ethynyl CH C – CH 3 Propyne CH C – CH 2 – Propynyl AreneBenzeneArylPhenyl TolueneBenzyl Naphtalinenaphthyl CH 3 CH 2
FORMATION OF ALKANES AND ARENES Alkyl, Alkenyl, Alkynyl and Aryl groups are not stable enough to exist as alone. Their tendency is to join other groups and this bonding tendency is the basis of synthetic organic chemistry. When alkyl groups join with each other alkanes will form: CH 3 -CH 3 CH 3 CH 2 -CH 2 CH 3 CH 3 CH 2 - CH 2 CH 2 CH 3 Ethane Butane Pentane When alkyl groups joined to aryl groups arenes will form. When we are naming arenes (aromatic hydrocarbons) first the name of alkyl group is said then the word benzene is added: Methylbenzene ( Toluene ) Ethylbenzene CH 3 C2H5C2H5
FORMATION OF POLYCYCLIC ARENES When aryl groups join to each other polycyclic arenes (polycyclic aromatic hydrocarbons) will form.These compounds are named by using their common names. Anthracene Naphtaline
FORMATION OF ALKENES When alkyl groups join to alkenyl groups alkenes will form. 2- propenyl (CH 2 = CH – CH 2 -) and methyl ( CH 3 -) groups join 1- butene will form: CH 2 = CH – CH 2 – CH 3 When we are naming alkenes according to IUPAC (Systematic Naming) rules number the carbons in the chain so that the double bond would be between the carbons with the lowest designated number CH 2 = CH – CH 2 – CH 3 When writing the name of the compound: 1.first the lower number of the carbon atom which makes the double bond is written then 2.a hyphene (-) is drawn and 3.finally the name of the alkene corresponding to the parent chain( the longest continuous chain of carbons that have the double bond) is written CH 2 = CH – CH 2 – CH 3 CH 3 - CH=CH - CH 3 1- butene 2- butene
FORMATION OF ALKYNES When alkyl groups join to alkynyl groups alkynes will form. For example: ethyl (C 2 H 5 -) and propynyl (CH C – CH 2 -) groups joined to each other 1-pentyne will form: CH C – CH 2 – CH 2 – CH 3
NAMING ALKYNES 1. Identify the longest continuous chain of carbon atoms that contains the carbon-carbon triple bond. The parent name of the alkyne comes from the IUPAC name for the alkane of the same number of carbon atoms, except the - ane ending is changed to - yne to signify the presence of a triple bond. Thus, if the longest continuous chain of carbon atoms containing a triple bond has five atoms, the compound is pentyne. 2. Number the carbon atoms of the longest continuous chain, starting at the end closest to the triple bond. Thus, is numbered from right to left, placing the triple bond between the second and third carbon atoms of the chain. (Numbering the chain from left to right incorrectly places the triple bond between the third and fourth carbons of the chain.)
Naming Alkynes 3. The position of the triple bond is indicated by placing the lower of the pair of numbers assigned to the triple- bonded carbon atoms in front of the name of the alkyne. Thus the compound shown in rule 2 is 2- pentyne. 4. The location and name of any substituent atom or group is indicated. For example, the compound is 5-chloro-2-hexyne.
ALKYL HALIDES AND ALCOHOLS When halogens and alkyl groups join to each other alkyl halides will form. In the functional groups table - I we can see ethyl bromide as an example of an alkyl halide. Similarly when hydroxide and alkyl groups join to each other alcohols will form. In the functional groups table - I we can see propyl alcohol or propanol (C 3 H 7 - OH) as a combination of a propyl (C 3 H 7 -) and hydroxide (- OH) groups.When we are naming alcohols in common naming syste,first the name of alkyl group is written than the family name alcohol is added.
FUNCTIONAL GROUPS Alkyl groups can also join with halogens and other atoms or atom groups to form organic ompounds other than hydrocarbons. Groups that are joined to alkyl grous which have tendency to react chemically are called Functional Groups. Functional groups will be represented in a table in the next two slides. The R, R',R 1,R 2,R 3 and R 4 written as bold represent different alkyl groups. But R not written as bold are generally represent alkyl groups and in some special cases it may be hydrogen,H.
Functional Groups in Compounds Family Name General FormulaFormula of the Compund as an Example Name of the Compound R Alkane R H or R R CH 3 – CH 3 Ethene C = C Alkene R 2 R 1 HC = CH R 3 R 4 CH 3 CH 2 CH = CHCH 2 CH 3 3-hexene C C Alkyne R 1 C C R 2 C 2 H 5 – C C – CH 3 2-pentyne AreneMethyl benzene (Toluene) X (-F, -Cl, Br, -I) Alkyl Halide R – XC 2 H 5 – BrEthyl bromide OH AlcoholR – OHC 3 H 7 – OHPropyl alcohol (propanol) O EtherR – O – R'CH 3 – O – CH 3 Dimethyl ether AldehydeAcetaldehyde KetonePropanone (dimethyl ketone) R CH 3 O CH O CHR O CH O C O CR'R'R O C NAMES AND FORMULAS OF COMMON FUNCTIONAL GROUPS AND DERIVED COMPOUNDS - I
Functional Groups in Compounds Family NameGeneral FormulaFormula of the Compund as an Example Name of the Compound carboxylic acidPropanoik acid AminePropylamine Nitro alkaneNitromethane C N Nitrile R C NCH 3 C N Ethanenitrile EsterEthyl ethanoate Amideacetamide (Ethanamide) Acyl halideacetyl chloride O COH O C R O CC2H5C2H5 H NH H NHR H NC3H7C3H7 H O NO O NOR O NCH 3 O O CC2H5C2H5 OCH 3 O CO O CORR'R' O CN H H O CNRH H O CCH 3 N H H O C Cl O CX O CXR NAMES AND FORMULAS OF COMMON FUNCTIONAL GROUPS AND DERIVED COMPOUNDS - II
LEARNING CHECK 1.Draw the stuructural formula and write the name of the compound made of ethyl(-C 2 H 5 ) and butenyl(CH 2 = CH – CH 2 – CH 2 -) grops. 2.Draw the stuructural formula of 2- pentene. 3.Draw the stuructural formula of isobutyl chloride. 4.Write the IUPAC name of the structure: CH 3 – CH 2 – C C – C 2 H 5 5.Draw the stuructural formula and then write the name of the compound when the alkyl group 1,1-Dimethylethyl and hydroxyl group (- OH) join to each other. CCH 3
PHYSICAL PROPERTIES OF HETEROATOMIC ORGANIC COMPOUNDS Heteroatomic groups like hydroxide (- OH), formyl(- CHO) and caboxyl(-COOH) can join to alkyl groups. The physical properties of these heteroatomic compounds are different than that of hydrocarbons having the same number of carbon atoms. Due to changes in intermolecular forces based on mass,volume and polarity changes) physical properties will change. Alcohols,aldehydes and carboylic acids have higher melting and boiling points than alkyl halides having the same number of carbon atoms due to addition of hydrogen bonding to dipole-dipole interactions.(Remember hydrogen bonding is stronger interaction than dipole-dipole forces.)
LEARNING CHECK Namem.p (ºC) b.p (ºC) Butane Butanol Etoxyethane (Dimethyl ether) Butylamine Try to explain the differences in melting and boiling points of the compounds in the given table by comparing their intermolecular forces.
PHYSICAL PROPERTIES OF HETEROATOMIC ORGANIC COMPOUNDS When heteroatomic groups like hydroxide (- OH), and caboxyl (- COOH) join to alkyl groups solubility in water will increase since these hydrophilic groups are polar. Hydrofobic group Hydrophilic group CH 3 - CH 2 - CH 2 - OH propopyl alcohol Hydrofobic group Hydrophilic group CH 3 - CH 2 - CH 2 - COOH butanoic acid On the other hand hydrocarbons having the same number of carbon atoms with alcohols and carboxylic acids do not dissolve in water since hydrophobes are nonpolar molecules.
CHEMICAL PROPERTIES OF HETEROATOMIC ORGANIC COMPOUNDS When heteroatoms are joined to alkyl groups chemical reactivity will be greater than the hydrocarbons having the same number of carbon atoms. Saturated hydrocabons(Alkanes) can only give substitution and combustion reactions. Alkenes and Alkynes are more reactive than alkanes due to existance of pi bonding.So they can also give addition reactions. Heteroatomic organic compounds can give other types of reactions due to polar character of heteroatomic part.
CHEMICAL PROPERTIES OF HETEROATOMIC ORGANIC COMPOUNDS Funcional groups can be cations and anions in chemical reactions. Acetyl group in the compound H 3 C – CO – Cl act as a cation since acetyl chloride molecule is polar. Cl is partial negative and C is partial positive. In the compound Li – CH 3 methyl group act as an anion,since methyl lithium molecule is polar. CH 3 is partial negative and Li is partial positive. Li + + CH 3 - LiCH 3 Lithium Methyl Methyl lithium cation anion O C + CH 3 Cl Acetyl cation Chlorine anion O CCH 3 Cl Acetyl chloride
CHEMICAL PROPERTIES OF HETEROATOMIC ORGANIC COMPOUNDS In the polar compound Methyl fluoride (Fluoromethane) CH 3 F methyl group act as a cation and fluorine act as an anion. CH F - CH 3 F Methyl Fluorine Methyl fluoride cation anion
NAMING OF DIOLS AND TRIOLS Diols, hydroxyaldehydes, hydroxyketones,dicarbonyls,hydroxyacids,ketoacids and dicarboxylic acids are the examples of organic compunds having more than one functional groups. Diols (glycols) have two hydroxide (-OH) groups but triols (glycerine) have three hydroxide groups. When naming these compounds the longest continuous chain having hydroxide groups is chosen and numbering should start from the end closer to hydroxide group. After writing the numbers of carbon atoms bonded to hydroxide groups a hyphen is drawn and then the name of the hydrocarbon is written according to the number of carbon atoms in the longest chain. Finally the word diol or triol is added if the molecule has two or three hydroxide groups respectively. CH 2 OH 2 1 1,2-Ethanediol (Glycol) CH 2 OH 3 2 1,2,3-Propanetriol (Glycerine) CHOH CH 2 OH 1
NAMING OF HYDROXYALDEHYDES AND HYDROXYKETONES Hdroxyaldehdes and hdroxyketones have both hydroxide (- OH) and carbonyl( C=O ) groups. When naming these compunds the carbon atom having the double bonded should be located to the lowest possible number. 3-Hydroxybutanal CHCH 3 OH 1 2 CH 2 3 C O H 4 4-Hydroxy-4-methyll-pentane- 2-on (Diaceton alcohol) CCH 3 O 1 2 CH 2 3 COH 4 CH 3 5
NAMING OF DICARBONYL COMPOUNDS Dicarbonyl compounds are dialdehydes,aldehyde-ketone and diketones. When naming these compounds the longest chain is numbered in such away that the carbonyl group should be located to the lowest possible number. After writing the numbers of carbon atoms bonded to oxygen atoms a hyphen is drawn and then the name of the hydrocarbon is written according to the number of carbon atoms in the longest chain. Finally do not forget to add the suffixes - dione,- trione,- dial and – trial depending on the the type and number of functional groups. –al suffix will be used for aldehyde and -one suffix will be used for ketone. 2,4-Pentandione Acetylacetone CCH 3 O 1 2 CH 2 3 CCH 3 4 O 5 1,4-Butanedial Succinindialdehy de CH O 3 1 CH 2 2 CH 4 O
NAMING OF KETOACIDS Ketoacids are the carbonyl group containing carboxylic acids. When naming these compounds the longest chain is numbered in such a way that the carboxylic acid should be located to the lowest possible number. Carbonyl group is defined by oxo- (=O) prefix. Write the name of the hydrocarbon according to the number of carbon atoms in the longest chain and then add the suffix –oic acid. O CCH 3 COOH 2-Oxopropanoic acid Pirüvik asi 4 O CCH 3 CH 2 3-Oxobutanoic acid Acetoacetic acid COOH 3 21
NAMING OF HYDROXYACIDS Hydroxy acids are the compounds having both hydroxyl(-OH) and carboxyl (-COOH) groups. When naming these compounds the longest chain is numbered in such a way that the carboxylic acid should be located to the lowest possible number. After writing the number of carbon atom which is bonded to hydroxyl group a hyphene is added. Then hydroxy prefix is written, the name of the hydrocarbon according to the number of carbon atoms in the longest chain and the suffix –oic acid is added. COOH 2-Hydroxypropanoic acid Lactic acid COHH CHH H COOH 2,3-Dihydroxyibutanedioic acid Tartaric acid COHH CH COOH Hydroxybutanedioic acid Malic acid COHH CH 2 COOH
NAMING OF DICARBOXYLICACIDS Dicarboxylic acids are the compounds having two carboxyl groups in their molecules. When naming them, write the name of the hydrocarbon according to the number of carbon atoms in the longest chain and then add the suffix –dioic acid. Ethanedioic acid Oxalic acid COH O C O Butanedioic acid Succinic acid COH O C O CH 2
CONDENSED STRUCTURAL FORMULAS Chemical structures may be written in more compact forms, particularly when showing organic molecules. In condensed structural formulas, many or even all of the covalent bonds may be left out, with subscripts indicating the number of identical groups attached to a particular atom. Two varieties of condensed structural formula, both showing butane:
SKELETAL ( BOND-LINE ) FORMULA Another shorthand structural diagram is the skeletal formula (also known as a bond-line formula or carbon skeleton diagram). In skeletal formulae, carbon atoms are not signified by the symbol C but by the vertices of the lines. Hydrogen atoms bonded to carbon are not shown they can be inferred by counting the number of bonds to a particular carbon atom each carbon is assumed to have four bonds in total, so any bonds not shown are, by implication, to hydrogen atoms. A skeletal diagram of butane:
SKELETAL ( BOND-LINE ) FORMULA For example, in the image below, the skeletal formula of hexane is shown. The carbon atom labelled C 1 has only one bond shown to it, so there must also be three hydrogens bonded to it, in order to make its total number of bonds four. The carbon atom labelled C 3 has two bonds to other carbons and is therefore bonded to two hydrogen atoms as well.
BALL-AND-STICK MODEL A ball-and-stick model of the actual molecular structure of hexane, as determined by X-ray crystallography, is shown for comparison, in which carbon atoms are depicted as black balls and hydrogen atoms as white ones.
COMPARISON OF DIFFERENT MODELS Shown below for comparison are a ball-and-stick model of the actual three-dimensional structure of the ethanol molecule in the gas phase (determined by microwave spectroscopy, left), the Lewis structure (centre) and the skeletal formula (right).
Bazı organik bileşiklerin iskelet (çizgi-bağ) formülleri Name of the compound Molecular formula Stuructural Formula Bond-Line Formulas IsohexaneC 6 H 14 Ethyl acetate (Ethyl ethanoate) CH 3 CO 2 C 2 CH 5 AcetophenoneC 6 H 6 COCH 3 NeopentaneC 5 H 12 CH 3 CH CH 2 CH 3 O CH 2 CH 3 C O C O C O O O BOND-LINE FORMULAS OF SOME ORGANIC COMPOUNDS
LEARNING CHECK 1.Name the following compounds represented by the bond- line formulas: 2.Draw the stuructural formulas of the following compounds and then write their bond-line formulas: a) ethyl ethanoate b) 1- aminobutane c) 2- chloro- 4 - methylheptane OH