EFN-313 Lífræn efnafræði 11. kafli

“The most important hypothesis in all of biology…is that everything that animals do, atoms do. In other words, there is nothing that living things do that cannot be understood from the point of view that they are made of atoms acting according to the laws of physics.” Richard Feynman (1918-1988)

Lífræn efni byggjast öll á kolefni C, CO, CO2 og CO3 teljast ólífræn Önnur C sambönd kallast lífræn Annaðhvort sameindir eða sameindajónir Óendanlega mörg lífræn efni til, á öllum formum með mismunandi eiginleika.

C-atóm eru einstök Mynda óskautað samgild tengi við Vetni Mynda samgild tengi sín á milli og mynda langar keðjur Mynda samgild tengi við aðra málmleysingja t.d. P,O,N,S og halogena C-C og C-H tengi eru óskautuð (nonpolar)

Raun lögun etan sameindar Fjögur sp3 hybridised orbitals mynda ferflötung sp3 hybridised orbitals frá 2 C atómum geta skarast og myndað C-C σ-tengi Each sp3 orbital contributes one electron to form C-C [C..C] C-C s bond

sp3 svigrúmablanda (rafeindir) flýr eins langt frá kjarnanum og hægt er og tengist í þær áttir.

s bonds: symmetrical about the bond axis Carbon sp3 orbitals can overlap with Hydrogen 1s orbitals to form Carbon-Hydrogen s bonds Each sp3 orbital contributes one electron; each s orbital contributes one electron to form C-H [C..H] s bonds: symmetrical about the bond axis

Bond Dissociation Energy C-C N-N O-O Bond Dissociation Energy (kJ mol-1) 348 163 157 Carbon-Carbon bonds: especially Sterk samgild tengi Kolefni: Einstakt, myndar catenate [Keðjur] Forms molecules composed of C-C bonds Línulaga/Linear Greinótt/Branched Hring/Cyclic

Organic molecules = Carbon-based molecules Organic chemistry = Chemistry of carbon-based molecules Some properties of organic molecules Stability: composed of stable C-C covalent bonds Defined molecular structures Defined three-dimensional shapes

Organic chemicals are universal Biological matter Plants Animals Microbes Geological matter Fossil Fuels Other Organic Chemicals Atmospheric and cosmic matter Manufactured products

Biological organic chemicals Natural fibres Antibiotics Fermentation products Natural flavours Natural fragrances Plant & microbial products Bio-matter Sugars Proteins Fats & oils Vitamins DNA & RNA Wood Natural rubber Essential oils

Organic chemicals in manufactured products Imaging agents Medicines Veterinary medicines Disinfectants Bio-active products Herbicides Antiseptics Pesticides Fertilizers Fungicides Plant growth hormones

Organic chemicals in manufactured products Plastics Coatings & lacquers Fibres & clothings Paper Materials Films Packaging Wound dressings Medical implants

Organic chemicals in manufactured products Fibre Fats & Oils Vitamins Sugars Foods Flavourings Dietary supplements Anti-oxidants Colourants Methanol/Ethanol “Petrol” “Diesel” Fuels Peat/Turf Coal LPG Natural gas

Organic chemicals in manufactured products Miscellaneous Lubricants Cosmetics Fragrances Pigments Dyes Inks Adhesives Explosives Detergents Surfactants Emulsifiers Coolants Photographic agents Anti-scalants Forensic chemicals Liquid crystal displays

Hydrocarbons - Kolvetni Kolvetni eru einföldustu lífrænu efnin Kolvetni eru gerð úr Kolefni og Vetni Kolvetni þar sem öll tengi milli atóma eru einföld kallast ALKANar Öll eintengi eru sigmatengi (σ-bonds) og um þau frjás snúningur. Einföldustu: CH4, C2H6, C3H8

Um kolvetni Mettað kolvetni (Saturated hydrocarbon): Kolvetni eingöngu með eintengi Alkane: Mettuð kolvetni þar sem kolefnin raða sér í opna keðju. Aliphatic hydrocarbon: Annað nafn á alkan

Hydrocarbons

Bygging Lögun Ferflötungslaga Öll horn tengja um 109.5°

Drawing Alkanes Nokkrar aðferðir við að teikna byggingu Endi og horn eru kolefnisatóm (line-angle)

IUPAC International Union of Pure and Applied Chemistry Látum nægja að læra utanað upp í 10 en allt ofar þarf að kannast við. Sjá annars töflu 11.1 í bók.

Línulaga - Beinkeðjualkanar Nafn # Kolefni Byggingaformúla Methane 1 CH4 Ethane 2 CH3CH3 Propane 3 CH3CH2CH3 Butane 4 CH3CH2CH2CH3 Pentane 5 CH3CH2CH2CH2CH3 The names of organic compounds are determined by the IUPAC rules (International Union of Pure and Applied Chemistry). The stem of the name states the number of carbon atoms in the carbon chain of the compounds. The suffix, in this case –ane, indicates the alkane family.

IUPAC NAMES Hexane 6 CH3CH2CH2CH2CH2CH3 Nafn # C-atóma Byggingaformúla Hexane 6 CH3CH2CH2CH2CH2CH3 Heptane 7 CH3CH2CH2CH2CH2CH2CH3 Octane 8 CH3CH2CH2CH2CH2CH2CH2CH3 Nonane 9 CH3 CH2 CH2CH2CH2CH2CH2CH2CH3 Decane 10 CH3CH2CH2CH2CH2CH2CH2CH2CH2CH3

Dæmi A. Hver er byggingaformúla… H H H H H C C C C H B. Hver er mólikúlformúlan? C. Hvert er nafnið?

Lausn A. CH3CH2CH2CH3 B. C4H10 C. butane

Nafnakerfi - IUPAC Forskeyti/Prefix segir fjölda C-atóma

Nöfn: Greinóttra alkana Finndu lengstu kolefniskeðjuna. Númera keðjuna, byrja þaðan sem styst er í fyrstu hliðargrein. Nefnið hliðarhópa og notið númer á C sem staðsetningu. Raðið hliðarhópum (substituents) í stafrófsröð. Notið di-, tri-, ef sami hópur kemur oft fyrir. =>

Lengsta keðjan Fjöldi kolefnisatóma í lengstu keðju ræður orðstofni/Nafni Ef það eru tvær keðjur jafnlangar velst sú keðja sem hefur fleiri hliðarhópa. =>

Númera C -atóm Byrjið við endann næst fyrsta hliðarhóp. Ef tveir hl.hópar eru jafn langt frá skoðið þá aðra hópa. 1 2 3 4 5 6 7 =>

Nöfn hliðarhópa – ALKYL hópar CH3-, methyl CH3CH2-, ethyl CH3CH2CH2-, n-propyl CH3CH2CH2CH2-, n-butyl =>

Alphabetize Raðið í stafrófsröð. Ignore di-, tri-, í stafrófsröðinni. 3-ethyl-2,6-dimethylheptane =>

Flóknari hliðarhópar Ef greinin er greinótt, númerið C in frá tengi við aðalkeðju. Nefnið og númerið hliðarkeðju í hliðarkeðju. Setjið sviga utanum flókna hliðarhópinn. 1 2 3 1-methyl-3-(1,2-dimethylpropyl)cyclohexane =>

Nomenclature - IUPAC Parent name: the longest carbon chain Substituent: a group bonded to the parent chain alkyl group: a substituent derived by removal of a hydrogen from an alkane; given the symbol R-

Nomenclature - IUPAC 1.The name of a saturated hydrocarbon with an unbranched chain consists of a prefix and suffix 2. The parent chain is the longest chain of carbon atoms 3. Each substituent is given a name and a number 4. If there is one substituent, number the chain from the end that gives it the lower number

Nomenclature - IUPAC 5. If there are two or more identical substituents, number the chain from the end that gives the lower number to the substituent encountered first indicate the number of times the substituent appears by a prefix di-, tri-, tetra-, etc. use commas to separate position numbers

Nomenclature - IUPAC 6. If there are two or more different substituents, list them in alphabetical order number from the end of the chain that gives the substituent encountered first the lower number

Nomenclature - IUPAC 7. The prefixes di-, tri-, tetra-, etc. are not included in alphabetization alphabetize the names of substituents first and then insert these prefixes

Nomenclature - IUPAC Alkyl groups

Nomenclature - Common The number of carbons in the alkane determines the name all alkanes with four carbons are butanes, those with five carbons are pentanes, etc. iso- indicates the chain terminates in -CH(CH3)2; neo- that it terminates in -C(CH3)3

Propyl Groups H H n-propyl isopropyl A primary carbon A secondary carbon =>

Butyl Groups H H n-butyl sec-butyl A primary carbon A secondary carbon =>

Isobutyl Groups H H isobutyl tert-butyl A tertiary carbon => A primary carbon

Alkyl Groups Branches on carbon chains H H C CH3 methyl H H H C C CH3CH2 ethyl An alkyl group is composed of one or more carbon atoms attached to a carbon chain. An alkyl group is derived from an alkane by removing one hydrogen. The ending –ane of the alkane is changed to –yl. The carbon branch from methane is the methyl group. The carbon branch from ethane is the ethyl group.

Branched Alkanes CH3 CH3CHCH3 methyl groups CH3 CH3 CH3CHCH2CHCH3 In the structural formula of an alkane, the alkyl group is typically attached vertically above or below the carbon chain.

Naming Branched Alkanes CH3 methyl branch CH3CH2CH2CHCH2CH3 6 5 4 3 2 1 Count A branched-chain alkane is named by indicating the attached groups on the longest carbon chain. In this example, the longest carbon chain has 6 carbon atoms.

Naming Branched Alkanes CH3 methyl branch CH3CH2CH2CHCH2CH3 6 5 4 3 2 1 Count 3-Methylhexane on third C CH3 six carbon chain group The chain is numbered to give the side group or methyl group a location on carbon 3 in the chain.

Naming Summary 1. Count the C’s in the longest chain 2. Name each attached group 3 Count the longest carbon chain to give the first attached group the smallest number 4. Name and locate each group

Dæmi A. CH3 CH3 CH3CHCH2CHCH3 B. CH3 CH3 CH3CH2CHCH2CCH2CH3 CH3

Svör A. CH3 CH3 CH3CHCH2CHCH3 2,4-dimethylpentane B. CH3 CH3 CH3CH2CHCH2CCH2CH3 CH3 3,3,5-trimethylheptane

Dæmi Write a condensed structure for A. 3,4-dimethylheptane B. 2,2-dimethyloctane

Solution Alk5 A. 3,4-dimethylheptane CH3 CH3CH2CHCHCH2CH2CH3 CH3 2,2-dimethyloctane CH3 CH3CCH2CH2CH2CH2CH2CH3

Constitutional/structural Isomerism Byggingaisomerur: Efni með sömu mólikúlformúlu en ólíka byggingaformúlu t.d.: C4H10

Byggingaisomerur 11.6 Eru þetta byggingaisomerur? Finndu lengstu keðjuna Númerið að fyrsta hliðarhóp Berið saman lengd og greinar

Constitutional Isomerism World population is about 6,000,000,000

Learning Check Alk6 Write 3 isomers of C5H12 and name each.

Solution Alk6 CH3 CH3CH2CH2CH2CH3 pentane CH3CHCH2CH3 2-methylbutane CH3CCH3 2,2-dimethylpropane

Dæmi Write a condensed structure for A. 3,4-dimethylheptane B. 2,2-dimethyloctane

Svör A. 3,4-dimethylheptane CH3 CH3CH2CHCHCH2CH2CH3 CH3 2,2-dimethyloctane CH3 CH3CCH2CH2CH2CH2CH2CH3

Dæmi Write 3 isomers of C5H12 and name each.

Svör CH3 CH3CH2CH2CH2CH3 pentane CH3CHCH2CH3 2-methylbutane CH3CCH3 2,2-dimethylpropane

Cycloalkanes Hringmyndanir (CH2 groups) Formula: CnH2n Óskautaðir og óleysanlegir í vatni eins og alkanar Bræðslu, suðumörk og flestir eiginleikar svipaðir og hjá samsvarandi alkönum =>

Nafnakerfi Sykloalkanar eru venjulega orðstofninn Hringur á hvorki upphaf né endi – en sé hliðarhópur þarf að númera…. Raða í stafrófsröð. Stöku sinnum finnast cyklo sem hliðarhópar eins og syklopentyl. =>

Cycloalkanes Hringir með 5 og 6 C algengastir Structure and nomenclature if two substituents, number from the substituent of lower alphabetical order if three or more substituents, number to give them the lowest set of numbers and then list substituents in alphabetical order

Cycloalkanes Teiknaðir Lína er C-C bond Horn og lína þýðir C

Cycloalkanes Example: name these cycloalkanes

Bicycloalkanes Bicycloalkane: an alkane that contains two rings that share two carbons Bicyclo[4.4.0]decane (Decalin) Bicyclo[4.3.0]nonane (Hydrindane) Bicyclo[2.2.1]heptane (Norbornane)

Bicycloalkanes Nomenclature parent is the alkane of the same number of carbons as are in the rings number from a bridgehead, along longest bridge back to the bridgehead, then along the next longest bridge, etc. show the lengths of bridges in brackets, from longest to shortest

Chair Conformer =>

Boat Conformer =>

Conformational Energy =>

Axial and Equatorial Positions =>

Monosubstituted Cyclohexanes =>

1,3-Diaxial Interactions =>

Disubstituted Cyclohexanes =>

Cycloalkanes Cyclopropane CH2 CH2 CH2 Cyclobutane CH2 CH2 The is a group of alkanes that have a cyclic structure. These cycloalkanes contain a carbon chain that is in a ring. Each cycloalkane has a formula that is 2C less than the corresponding alkane. For example, propane is C3H8 whereas cyclopropane ic C3H6. Butane is C4H10 and cyclobutane is C4H10. The names of the cyclic structures use the prefix cyclo in from of the alkane name for the carbon chain.

More Cycloalkanes Cyclopentane CH2 CH2 CH2 CH2 CH2 Cyclohexane CH2

Naming Cycloalkanes with Side Groups Number of Naming side groups One Side group name goes in front of the cycloalkane name. Two Number the ring in the direction that gives the lowest numbers to the side groups.

Cycloalkanes with Side Groups

Dæmi

Lausn

Chapter 11.8 Alkenes and Alkynes Geometric Isomers / rúmísomerur Alkena Alken hefur C=C tvítengi Alkýn hefur CC

Mettuð/Saturated og ómettuð/Unsaturated Mettuð kolvetni hafa mesta mögulega fjölda vetnisatóma. CnH2n+2 fyrir alkan Ómettuð kolvetni hafa færri vetnisatóm en mettuð Ómettuð kolvetni hafa tví eða þrítengi milli C atóma Milli tví og þrítengja er enginn snúningur

ALKEN C=C tvítengi Endar á EN H2C=CH2 ethen (ethylen) H2C=CH-CH3 propen (propylen) cyclohexen

Alkyn Carbon-carbon triple bonds Endar á -yn HCCH ethyn (acetylen) HCC-CH3 propyn Alken mun algengari en alkyn

Nafnakerfi alken/alkyn Þegar keðja hefur 4 eða fleiri C, þá númera keðju þaðan sem styst er í tvítengi án tillits til alkýl hliðarhópa. 1 2 3 4 CH2=CHCH2CH3 1-buten eða But-1-en CH3CH=CHCH3 2-buten eða But-2-en CH3CHCHCH3 2-butyn eða But-2-yn

Dæmi Ritið nöfn þessara efna: A. CH3CH2CCCH3 CH3 B. CH3C=CHCH3 C.

Lausn IUPAC nöfnin eru: A. CH3CH2CH=CHCH3 2-pentyne CH3 B. CH3C=CHCH3 C. 3-methyl-2-butene 3-methylcyclopentene

Þar sem engin snúningur er um tvítengi geta myndast rúmísomerur (geometric isomers) Rúmisomerur geta myndast ef keðja er 4C eða lengri. Rúmisomerur myndast á C no. 2 eða ofar Sömu megin úr tvítengi er CIS Sitthvoru megin úr tvítengi er Trans

Cis and Trans Isomers Efnið er 2-buten Cis/trans eru mögulegar CH3 CH3 CH3 CH = CH CH = CH cis trans CH3

Cis/trans Cis/trans isomerur hafa mikil áhrif á lögun sameinda Náttúran notar oftast Cis í lífverum og allar fitusýrur í náttúrunni eru Cis Cis og trans hafa líka ólík bræðslu og suðumörk

Trans fitusýrur - ómettaðar

Sömu ómettuðu – CIS

12.8 Alkenar och Alkynar π orkumeira, Léttara brjóta - hvargjarnara  Stöðugra, orkulægra óhvarfgjarnt

Nafnareglur Liknar det för alkaner –en -yn 1. Namnge den kolkedja som innehåller längsta kedja med dubbel trippel bindning 2. Numrera kedjan från den ände som ger dubbel trippel bindning lägst siffra. 3. Placera siffra och namnet på substituenter framför alken-alkyn namn 2-etyl-1-buten

Hefur efnið tvo tvíbindinga kallast það DÍEN Cykloalkanar, þar er talið yfir tvíbinding til hliðarhóps Hefur efnið tvo tvíbindinga kallast það DÍEN Hexatrien Butadien

Cis-trans isomer stereoisomeri,cis-trans Almennt er trans stöðugra

Cis-trans isomer Cis och trans isomeri kräver att de grupper som binder till kolet är OLIKA

11.9 Aromatic Compounds Aromatic compounds innihalda benzene. Benzene C6H6 has 6 C atoms and 6 H Atoms Two possible ring structures show benzene.

Benzene Structure The structures for benzene are also written as one formula with a circle within the ring to represented the alternating double bonds. Benzene structure

Aromatic Compounds in Nature and Health Many aromatic compounds are common in nature and in medicine.

Naming Aromatic Compounds Aromatar hafa Bensen sem orðstofn og hliðarhópar settir fyrir fram. (stundum!!!!). methylbenzene chlorobenzene

Þegar bensen er tvískipt (tveir hliðarhópar) er hringur númeraður þannig að hóparnir fái sem lægst númer. Forskeytin ortho (1,2), meta (1,3-) and para (1,4-) eru einnig notuð.

Aromatar hafa verslunarnöfn (common name). Ef tvískipt, þá oft með ortho-, meta-, para-.

Dæmi Select the names for each structure: 1. Chlorocyclohexane 2. Chlorobenzene 3. 1-chlorobenzene 1. Meta-methyltoluene 2. Meta-dimethylbenzene 3. 1,3-dimethylbenzene

Svör Select the names for each structure: 2. Chlorobenzene 1. Meta-methyltoluene 2. Meta-dimethylbenzene 3. 1,3-dimethylbenzene

Dæmi Ritið byggingaformúlur: A. 1,3-dichlorobenzene B. Ortho-chlorotoluene

Svör Byggingaformúlurnar: A. 1,3-dichlorobenzene B. Ortho-chlorotoluene

Learning Check Alk11 Identify the organic family for each:

Solution Alk11 Identify the organic family for each: alkane cycloalkane aromatic

Fused Benzene Rings

Carcinogens Fused ring of benzene cause cancer Contain four or more fused rings Present in tobacco smoke, auto exhaust, and burned food The more a person smokes, the greater the risk of developing cancer

Unsaturated Fatty Acids Fatty acids in vegetable oils are omega-6 acids (the first double bond occurs at carbon 6 counting from the methyl group) A common omega-6 acid is linoleic acid CH3CH2CH2CH2CH2CH=CHCH2CH=CH(CH2)7COOH 6 linoleic acid, a fatty acid

Trans Fats In vegetable oils, the unsaturated fats usually contain cis double bonds. During hydrogenation, some cis double bonds are converted to trans double bonds (more stable) causing a change in the fatty acid structure If a label states “partially” or “fully hydrogenated”, the fats contain trans fatty acids.

Trans Fats In the US, it is estimated that 2-4% of our total Calories is in the form of trans fatty acid. trans fatty acids behave like saturated fatty acids in the body. Several studies reported that trans fatty acids raise LDL-cholesterol. Some studies also report that trans fatty acid lower HDL-cholesterol The trans fatty acids controversy will continue to be debated.

Fats and Atheroschlerosis Inuit people of Alaska have a high fat diet and high blood cholesterol levels, but a very low occurrence of atherosclerosis and heart attacks. Fat in the Intuit diet was primarily from fish such as salmon, tuna and herring rather than from land animals (as in the American diet).

Omega-3 Fatty Acids Fatty acids in the fish oils are mostly the omega-3 type (first double bond occurs at the third carbon counting from the methyl group). linolenic acid 18 carbon atoms CH3CH2CH=CHCH2CH=CHCH2CH=CH(CH2)7COOH  eicosapentaenoic acid (EPA) 20 carbon atoms CH3CH2(CH=CHCH2)5(CH2)2COOH

Atherosclerosis Plaques of cholesterol adhere to the walls of the blood vessels Blood pressure rises as blood squeezes through smaller blood vessels Blood clots may form Omega-3 fatty acids decrease the “sticking” of blood platelets (fewer blood clots) Omega-3 fatty acids can increase bleeding time

Learning Check HA6 (1) Ture or (2) False A. ____ There are more unsaturated fats in vegetable oils. B. ____ Vegetable oils have more omega-3 oils than found in fish. C. ____ Hydrogenation of oils converts some cis-double bonds to trans- double bonds. D. ____ Animal fats have more saturated fats.

Solution HA6 (1) True or (2) False A. _T__ There are more unsaturated fats in vegetable oils. B. _F__ Vegetable oils have more omega-3 oils than found in fish. C. _T__ Hydrogenation of oils converts some cis-double bonds to trans- double bonds. D. _T__ Animal fats have more saturated fats.