AV-Portal 3.23.3 (4dfb8a34932102951b25870966c61d06d6b97156)

Lecture 03: Ring Size Conjugation, Electron-Withdrawing Groups

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Lecture 03: Ring Size Conjugation, Electron-Withdrawing Groups
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This is a graduate course in organic spectroscopy, focusing on modern methods used in structure determination of organic molecules. Topics include mass spectrometry; ultraviolet, chiroptical, infrared, and nuclear magnetic resonance spectroscopy.
Ionenbindung Deformation (mechanics) Chain (unit) Heterocyclic compound Maid Set (abstract data type) Molecule Lecture/Conference Lactitol Nanoparticle Process (computing) Waterfall Hydrocarboxylierung Chemical element Stickstoffatom Hydrogen bond Carbon (fiber) Infrarot-Spektrum Carbonylverbindungen Cyclin-dependent kinase Solution Alcohol Electronic cigarette Emission spectrum Hydrogen Mineral oil Functional group Chemical compound Zunderbeständigkeit Carboxylierung Soil
Waterfall Chemical formula Ovalbumin Deformation (mechanics) Chloroform Hydrogen bond Highway Addressable Remote Transducer Protocol Solution Emission spectrum Vietnamese people Hydrogen Human subject research System on a chip Functional group Chemical compound Ausgangsgestein Chemical structure Salt
Kohlenstoff-14 Deformation (mechanics) Oxygenierung Wursthülle Molecule Sample (material) Electron Ageing Cell (biology) Sea level Halogen Chemical formula Elektrostatische Wechselwirkung Stickstoffatom Doppelbindung Reaktionsgleichung Chloroform Hydrogen bond Carbon (fiber) Carbonylverbindungen River source Solution Alcohol Emission spectrum Water Hydrogen Drop (liquid) Computer animation Yield (engineering) Functional group Azo coupling Chemical compound Chemical structure Cobaltoxide
Deformation (mechanics) Ionenbindung Meat Growth medium Wursthülle Ice Ageing Shear strength Lecture/Conference Hyperpolarisierung Dipol <1,3-> Salt Area Vimentin Stickstoffatom Hydrogen bond Carbon (fiber) Lightning Solution Alcohol Electronic cigarette Hydrogen Computer animation Yield (engineering) Azo coupling Chemical compound Salt Chemical structure Screening (medicine)
Ionenbindung Blood vessel Chemische Verschiebung Resonance (chemistry) Hydroxyl Operon Wursthülle Columbia Records Ammonium Molecule Solvent Ageing Shear strength Sodium hydroxide Lecture/Conference Phenylalanine Common land Honduras Conjugated system Ovalbumin Organische Chemie Vimentin Chloroform Hydrogen bond Carbon (fiber) Mutilation Solution Chemical reaction Alcohol Electronic cigarette Emission spectrum Sodium Hydrogen Acid Bicarbonate Functional group Sodium carbonate Chemical compound Pharmaceutical drug Chemical structure Base (chemistry) Carboxylierung Extract
Ionenbindung Deformation (mechanics) Sunscreen Aromaticity Molecule Nitroverbindungen Dreifachbindung Zeitverschiebung Tidal race Shear strength Lecture/Conference Stickstoffatom Doppelbindung Carbon (fiber) Heck-Reaktion Ampicillin Computer animation Functional group Azo coupling Chemical compound Can (band) Chemical structure Cobaltoxide Carboxylierung Base (chemistry) Chewing gum Stuffing
Cyanide Sense District Deformation (mechanics) Spectrometer Wursthülle Alkene Dreifachbindung Chemische Synthese Shear strength Lecture/Conference Common land Chemical element Naturstoff Stickstoffatom Doppelbindung Octane rating Walking Carbon (fiber) Adamantane Chemical reaction River source Solution Emission spectrum Combine harvester Functional group Azo coupling Wound Carboxylierung Cobaltoxide Chewing gum Pain
Deformation (mechanics) Toluene Proline Hydroxyl Stereoselektive Synthese Methylgruppe Molecule Meeting/Interview Isomer Benzene Mass spectrometry Setzen <Verfahrenstechnik> Metal Patent Hydrogen bond Topicity Carbon (fiber) Law enforcement Heck-Reaktion Ice Hydrogen Combine harvester Spectroscopy Functional group Azo coupling Chemical compound Polymer Cobaltoxide
that I wanted to do was discussed nitrogen containing compounds and again when I want to continue with is the idea of being able to recognize some patterns pick out important classes of compounds and probably get mastery of maybe 2 dozen 2 dozen different categories of compounds will also take a look at the end that a few more specialized examples and see some things that you can tell what I R in just a few neat neat things in ways that can talk to you but let's start with some basic nitrogen containing compounds so am intends to continue our discussion of carbonyl groups we talked about the hammered carbon your band and we said of all the common functional groups of all the common carbonyl compounds maids have the the lowest carbon he'll stretching frequency at 1650 the 1690 sometimes this is referred to as the enemy is 1 band 2 see in a moment what the ended to vendors now what's interesting is you often end up looking for things in pairs looking for sets of data that point in a particular direction with IR spectroscopy so the other thing for primary and secondary and that is and that's where you have either 2 hydrogen sir 1 hydrogen on the nitrogen is you're going to have an 8 stretching frequencies so the primary Ahmed it is primary and compounds where you have an H 2 groups have to an 8 stretches In by now you should all know what are those makes stretches in terms of the the symmetric and asymmetric In their frequencies gonna depend obviously it's going to be I think everyone by now knows that that region above 3 thousand is worried that all wages in any beaches and so forth it's gonna fall in that general region and heads just like carboxyl against since the very prone to hydrogen bonding and so often you'll see different behavior with different states so for a primary In solution In all say died you know the words not super concentrated so you don't have a lot of hydrogen bonding those bands show up at about 35 20 In about 30 400 remember my emphasis really has been on the reading spectra in other words looking at the spectrum and seeing patterns here and so when I look I sort of look at that region below 3 thousand and I'd be seeing abandon these bonds tend to be kind of broad not as broad as your typical alcohol bans but certainly not as sharp as the CHP and hydrogen bonding weekends the NH stretch and so In the solid-state there's certainly hydrogen even when you grind up your molecules with KBR grind them with new job grind them with mineral oil to make a mall the molecules are still in particles and Micron in sizes so forth all hydrogen bonded together so and solid (left parenthesis hydrogen bonded then shift to lower frequencies typically broaden out all say about 35 50 about 33 52 and 31 80 and the pattern changes a little bit of trying to graft things on the same scale here so now we fall below 30 500 the band's typically typically become a little bit broader sales see this kind of like an alcohol stretch over here becoming becoming broader so just like we talked about carboxyl like answered particularly particularly primary and and like tails conform these hydrogen-bonding ring structures and quite prone to doing so and the reason so primary elements are more prone to doing this and as a reluctance on the reason is that by the time you get to secondary admitted that is where you have 1 are justified nitrogen typically the hydrogen prefers to be trains to the carbonyl group so it doesn't set itself up as nicely for forming ring structures you can still form chains but they don't don't and to performers extensively
secondary emits also have an innings stretch so again tried to overrun the other black Ford this a secondary In typical you're talking about mandates stretch from about 30 400 about 30 500 and if you're hydrogen bonds were how about 3 thousand about 30 300 this hydrogen so in addition to these parents which recall the innate stretch bands as I said if you will also have for primary and secondary ambient who called the Emad to ban the army to vendors NHK and enact typically is on the order of about 1500 to about 6 1650 In fall on top of the armored wondering how this you wouldn't see it alright I'd like to help us get in the habit of the pattern recognition on the and start to see the differences in these classes of compounds just so you get good at seeing what's what's out there so let me pass out I've got some handouts here send these down will look at a few spectrum you might need more send to and the extras back there so this might be might also be a nice Nice time for it will mean a better question here so we're on the subject of an we know we know we haven't here problem here this was taken taken from a book problems says we have a compound with the molecular formula C 6 H 13 and know that it contains a few people it's a good figure out the structure they won't have an idea this the the user of the group so a methylene group that's situation the church and this is we used up used up 1st so what we what we do with this so as it is it's so we have to expect here we have 1 inspector in chloroform solution and I'll tell you it's a concentrated spectrum sold so this is notice these
numbers here so we have 1 number at 34 100 In another number at 33 100 so clearly clearly we have at least 1 hydrogen bonding at least something NRA nature's hydrogen bond and they don't look quite like that so is its primary
assumes SEC it's gotta be a it's gotta be a
secondary and and so what we do with the
structure of so H 3 monitored Beutel In like cell nor the other way and we With this level of information we can tell tell the difference between In fact in fact this structure is the is the first one year now there is 1 question the outfit so we have so this is to repeal laws it's a secondary ended this is our free and aged this is hydrogen bonded so typically you'll be working with like a fiver 10 Percent solution of so many of the molecules are monomeric and you see a band for the 8 stretch about 30 400 you're also going to have some cases in which the molecules are hydrogen bonded together like so either to form 2 were more molecules and so the hydrogen bonded and 8 stretch is going to be the 1 at about the point numbers for primary and maybe there will be different in size usually the 1 that's that's the higher wave numbers is slightly longer and 1 hot OK so great question so what experiment could we do with this sample in chloroform to determine whether the band 33 100 was associated with hydrogen bonded on her for diluted and what would you expect to see the decrease in the 33 100 or more specifically both bands would have cost decrease because of his diluted by the relative intensity of the band 33 based on the spectrum alone if we if if I look at this pattern here I'd say Well this clearly doesn't look like a monomeric primary and as I said you'd expect about 30 I thought that 3 thousand 520 and about 30 400 and pride as a look like a hydrogen bonded primary amid 1st of all the standard 30 300 usually hold it high and it's a little bit narrower members said typically 31 80 but if you saw my stature sort of broad like an alcohol were basically spend about 300 ways so you might or might not be able to do this with pattern recognition I mean this is as you see more of these spectra you get you get better and better now it's happening here in the solid state is your only having the hydrogen bonded band so you're you're seeing just the hydrogen bonded and age other thoughts and questions the surveillance all of these bills shoulder right here now the people on the the peak which spectrum of the peak at the shoulder that's on there probably different states of hydrogen bonding probably some With more hydrogen bonds for example you can have a bifurcated hydrogen bond so it may be something like that it's something clearly that's characteristic solid-state now we're dealing with again this is what I was saying for the this sort of pedagogy of spectroscopy were dealing with a relatively small molecule here it's only got 6 carbon atoms by the time you get a bigger molecules the relative intensity of urine nature's relative to for example your ch is is going to be less and this is where I said KBR is really bad because you typically it's hard to get out every last bit of water it doesn't matter so much for a molecule of this size but if you're dealing with a molecule say the size of strict knocking on your going to have almost no almost 10 times let's say 5 times the carbon too nitrogen ratio of carbon emigration so that each can be a lot smaller you really don't have trouble trouble seeing it OK the 1 other thing I I wanted to to bring up with just about problem-solving strategies on and I presume everyone seen this but it's worth it worth bringing up the the idea so this molecule was seen sex age 13 NO In the 1st thing that you want to think about when you're asking What's this compound is the and saturation number and you can do that mathematically in other words how many double bonds and rings around that's incredibly useful piece of information fact molecular formula is probably the most useful information that you can get for starting with the compound followed by what functional groups are in it which is why we're starting the course with aspect so there are a couple of ways you can do it honestly I never do it the way I am about to at the saturation numbers the number of carbons minus the number of hydrogen is over minus the number of halogen over 2 I hate formulas I don't even keep formulas in my head plus the number of nitrogen is over 2 plus 1 if you plugged in right that 6 minus 13 over to plus 1 over 2 plus 1 is equal to 1 which is 0 1 double bond carbonyl group I never do things this way basically the way I think about it is if a molecule has 6 carbons in it if it were and allocating it would be C 6 H 14 if it has intelligence and it they just count as hydrogen so in other words C 6 H 14 is saturated C 6 H 13 CL was saturated oxygen is don't count toward on saturation number Salford's don't count toward on saturation number nitrogen's you need 1 more adamant in their 1 more hydrogen in there to complete the balance in other words an Al Qaim would have a formula C 6 H 14 if I go ahead and add a nitrogen it would have to be seized 6 age 15 and then I simply look and say OK it's aged 13 so there's 1 degree upon saturation so that's how I think about and saturation number but then immediately you're saying Wait a 2nd we've got a carbon Eolande here it can't be electing him it can't be a ring compounds for example we only have 1 1 degree upon centuries I thought Sir questions at this point Our why is the lower here had the hydrogen bonding so the hydrogen bonding ends up weakening the carbon yield it's kind of what's kind of counterintuitive on hydrogen bonding is you can think of hydrogen bonding as being an electrostatic phenomenon primarily by that I mean you think about your dealt the positive on the nitrogen and you're dealt the negative on the oxygen and your pulling electrons away from the double bomb you're weakening the double bottom in forming a hydrogen bomb informing electrostatic interactions then you think about the NH stretching frequency you have electrons on the oxygen those electrons are pushing the NH electrons toward the nitrogen knew weakening the nitrogen hydrogen bonds so that stretching frequency drops to a lower number all right so
let's see let's do it another class of nitrogen containing compounds and you notice for the Ahmed's particularly in the solid-state the stretch is a little different than alcohol sure you I'll show you an alcohol in case you haven't seen it in just a moment but alcohols tend to be less lumpy then hydrogen bonded and it's in the solid state they tend to be pretty ugly Art let's take a look at it means so the means there similar to Amazon's "quotation mark but we the newest obviously you don't have a carbon yield but in other words you have innate stretches you have NH bands but the bonds or this heavily polarized and when you have less polarization of the bond you have less change in dipole moment right the carbon Eolanda nitrogen very electron withdrawing so that increases the change in dipole moment it gives you a stronger stronger band so primary means are in H 2 you'd see 2 bands are symmetric and asymmetric stretch the asymmetric typically has about 35 free end about 34 for the symmetric stretch know words in other words the city rain-free here not hydrogen bonding the means don't hydrogen-bond nearly as much as it bids are alcohols sewing solution you're not going to see them hydrogen bonded in the solid state during the meaning the pure liquid for example Sam which is a film between Salt points you will so we need a mean typically you'd have about 30 400 In about 30 300 the 2nd area means far too when age now you don't have the couple vibrations so you see 1 band slightly lower in frequency let's say approximately 33 50 2 of 33 to so when you're looking at data like this you're not necessarily gonna have something screen to you this is definitely in main but what you're gonna have a this is definitely in a minute but you're going to be getting pieces of evidence and saying Wait a 2nd the data's .period again in this direction a red flag is going up this seems to be consistent with an animated cos I'm seeing a carbon ended and in an age structure to an 8 stretches and then you start to look for other data or you perform additional experiments let me give you an example here on the media you in so I wanted to just put contrast here so I've taken both Amin here and I'll tell you what these are this time this is Beutel Amin and this is Putin when viewed on the morning of June 1 when you all and you'll see some differences so here's what we see for a typical alcohol 0 8 strength they're both meat the hydrogen about the alcohol is hydrogen bonded Strong too broad and again in terms of pattern recognition you sort of see coming up and 30 500 and going down by about 3 thousand you mean is weaker In this case
because it's neat and
because its primary we are seeing at hydrogen I'll tell you this secondary means are often really hard to see the often very weakened by the time you get to a molecule that's that has more carbon unless the mean and that they end up being darn hard to say what's frustrating with secondary means primary means to but secondary means in particular is often Indiana more spectrum particularly in chloroform solution it's really hard to see that in each of the NH band in the Indiana more spectrum so it can be really vexing and if you're working so for your morals and you know you have a mean Coslet saved carried out a reaction everything else is consistent the mess that is consistent you'll end up saying Oh my goodness and not seeing the inmates are the NH resonance Indiana mom not seeing an innate stretching the eye on you might have to look really hard for the animal you might want to dissolve Indian vessel which tends to be the solvent that avoids exchange the answer questions so let's take ammonium salts if carboxyl like acids are the ugliest ugliest thing say ammonium salts are even uglier carboxyl against and 2 pounds ammonium salts Bulldogs so ammonium salts the NIH is just you large and misshapen is really the only way the only way to describe it and again here's my very simple-minded view all of of an IR spectrum I'll put in a market in 2000 here because of the drawing upon them in the 2nd so for ammonium salts the NIH some talking like Goran age 3 plus 4 of course you can have you could have just like a secondary ammonium salt but basically at about 30 to 100 things come on and you know you might see some ch is poking out and then will come down and that's 2 thousand 225 500 so here you start to inflected about 30 to 100 and of course then you'll have you know whatever else you have spectrum but it basically let's say about 30 to 100 to 2 thousand were 20 500 very broad very ugly so long reason that that this is so important to keep in mind is 1 very common laboratory operation is to isolate mean by liquid liquid extraction if you're teaching staff more organic chemistry you're probably doing at making a free basis from a hydrochloride Salter taking in enemy into an acid lighter and then taking it back and it's very easy you even in a research project to end up getting yourself and think you made a free base people often use a sodium by Bykov which is just the bicarbonate or the conjugate acid for Bykov is just managed to to an ammonium group so it's not a great way to free and in a much better off with sodium hydroxide a sodium carbonate but I've seen this happen to people where they still get us a product that they say might mean doesn't dissolve in anything it doesn't dissolve in organic solvents that dissolving I stripped it down your isolated I precipitated it as not dissolving its because Timonium ammonium group and that's something I'd be hard to tell by animal respect trust the people knew exactly where to look you might say of the adjacent methylene is often chemical shift by a few tenths of a ppm but no I or spectrum where you see something like this it's like Oh my God you know clearly my compound is used talking to me like a show you an example and this is this is a cool 1 the people of this last last nite the I'm not the guy included this in the handouts citing the need to give a separate handouts no no no no no need to send a few more than year medicine is what puts you right in the he went on to great question so the question the question that was just ask is if you have for talking about a primary Amin what's going to happen if we have we changed the group here To like a hydroxyl mean it should be pretty similar because the first-order approximation your reduced mass is going to be the same for year-end age bonds and your bond strength will be very similar so you're rude came over a new term in your harmonic oscillator is going to be similar for specialized compounds like this this is a great place to look things up if you really needed to know the exact frequency the book you have the Pracha book is really good for looking at specialized compounds at the end of today's class or give you some general principles of where to look for things because there's a lot of a lot of overlap there other words basically it doesn't change that much Harrell Adam Taff hydrogen bond we saw all over alcohols are carboxyl like acids are animated sir means all in their general region between about 3 thousand and about 30 500 but if you needed something more subtle you could are right so the example that I picked here is phenylalanine so are it's a phenylalanine if you look at your if you look at your soft organic chemistry
texts I think you'll see that's the structure of phenylalanine but you'll also you'll also see CIA not surprisingly since the PKK of a carboxyl against it is about 5 and the PKK have an ammonium group is about to that you have an equilibrium that lies essentially completely to the right a tour this winter ion we would like and it might be hard to see this by some other other method but you've got this really really typically ugly pattern where starting at about 30 to 100 year coming through this swampy region here for all the different hydrogen bonded states and in this case coming down at about 2 hours
search really really talking to us the Luxor questions alright I wanna
take a couple of other nitrogen containing compounds and then maybe maybe talk about a few other things nite trails FAA carbon triple bond in Nike trails always surprises me because I expect the carbon nitrogen bond to be highly polarized I expected it to be stronger than it really is the position ends up being very precise it's about 20 to 50 wave numbers doesn't vary a whole heck of a lot so it stands out it's in that region between 2000 and all about 20 700 where you don't normally see a lot of stuff it's and typically it's weak to moderate In intensity in other words if you've got a big molecule and you have a nite trail functionality and it you'll still a but there and it'll be recognizable and shop there won't be a big band like a carbon your state another class of compounds will take nitro compounds so already known to were aromatic nitro compound I'll just drawn broader nitro groups so we typically see 2 bands associated with the nitro compound associated with the DNO stretch about 1500 to 1600 and about 13 hundred they tend to be strong the 1 in 1502 1600 tends to build stronger 1 are the 2 bands symmetric facing even know I'm writing 1 resident structure that doesn't mean there's 1 nitrogen oxygen double bond 1 nitrogen oxygen single bond the 2 equal residents structures contributing contributing both equally and so it 1 and a half months of peace the asymmetric stretch is always hiring frequency just a higher energy structure same same question it's about race by way of Coleraine glitzy let's see what you can do with ideas here so what do you think about carboxyl what you think we'd see for those along the way see mean frequency because indeed it is and that's the way we more single vine factored in fact it's 1 and 1 and a half fond character for exactly exactly the same reason and sniper groups and remember you reduce mass means you have a square root terms so if you're dropping Europe bond strength to 1 and a half times last year frequency is not going to be 1 and a half times lower it's going to be like near 1 . 2 times lower ,comma against you think it's safer 2 the 2 are 1 of the many many things to do 2 for exactly exactly the same reason so in other words you'll see about 1652 about 15 54 on asymmetric stretch in about 13 about 1400 Smith stretch and again if you're thinking thinking back to this issue of making a free base then if you're dealing with a carboxyl against senior program dating it you're saying all my carboxyl against citizen dissolving in any
Salvatore doesn't dissolve and chloroform solution I get that Matamoros spectrum of it why not it might be that you have a carboxyl later on and even if few dissolve Indiana so you probably are sense is often don't see carboxyl against Sadr's Indiana you're going to not be able to really tell by in a more spectroscopy but you take an IRA spectrum sideline no I should see a carbon for carboxyl aghast and about 17 hundred just a hair above 1700 I'm not seeing it all yeah I see this funny banded about 1600 and say I got my carboxyl against this impregnated so again this is a case for higher religion really shines obviously we can't talk about every functional group known to man and a few research project focuses on a particular functional groups of your research project for example were to focus on making I cyanide say in some of the marine natural products you would probably go to practice and look up where the ISO cyanide functional groups showed up and then when you're carrying out the strategic reaction to produce a group you able to lock in the I R but at the same time for reading and earlier spectrum you can make some generalizations so here again is my wounds steps I'll just put it my remarks at the key places I like it a lot we've already talked about this region here for NH In OH wage the region here from about 2 thousand 2 23 300 is an unusual region if you see anything other than a little bit of C O 2 from breathing in the specter and the spectrometer you probably should have your head perk up because you have many triple bonds in this region so even tho I don't know where an ISO 9 trail function shows up I would expect it to be in that region you also have are cumulated double bonds accumulated means for you have to double bonds connected to the same Adam resort carbon-dioxide showing up in that region another common functional group that's often used in synthetic chemistry on Aleem show up in that region as well I can't name every double bond but double bonds in general have about the same strength you're dealing with typically elements like carbon nitrogen oxygen and all of those elements will give you a similar reduced mass so this region from 1800 to 1300 has many double bonds in other words your carbon Neil stretches are there but also if you're doing a project with a means that would be be the 1st place you'd expect to look for in means if you're doing a project with Nitro so groups that would be the 1st place I'd expect a look for Nitro subgroups we've seen carbon-carbon double bonds In the region as well hurry and get a mention in a couple of more more specialized pieces of information just as examples of things you can see with IRS prospered so aromatics you have a combination bands involving the carbon are ratings at about 16 15 in 2000 those brands a week they tend to be a little bit on the facts side they often show up in patterns you'll also when you can the diagnostic by tearing things have out of plane bands ch bins at about 675 to about 900 and I'll just show you patterns that had been documented it is this
I think this is part can you check whether this is the last page in your hand out 2 more pages greater foreign so the next to the last page in the so for example fennel groups Avery comment and you'll see this pattern of 4 lines here and you'll also see so this is your your combination and this is you're out of a plane this pattern you'll see they look very different than a carbon stretch their much weaker you'll see this come up in a couple of your homework problems in the four-page she's 1 of the homework problems says identify the functional groups present in the carbon hydrogen oxygen containing molecules 1 of the molecules that you will encounter there is Ethyl benzene or toluene and think accessible and and you will see this pattern there another the problem you have which would be an interesting 1 is on polymers and you'll see this pattern show up along with some other things in that problem on on identifying on identifying polymers so you can pick out different substitution patterns you could for example pick out what were those Eileen verses matters Eileen paraxylene based on the on the patents here are let's see couple of other special topics here 1 thing that's really cool and again this will come back to that homework problem on polymers sofa CH 3 groups there is a very very sharp band at 1375 that's a ch bandits the asymmetric band for methyl groups and remember how I talked about coupling if you have to methyl groups together you get a couple of vibration so in an ice of pro ball broke In nicer probable group were jammed I methyl group you will see 2 bands 1 at 13 70 1 at 13 90 student coupled ch fans symmetric and asymmetric types of things that actually help you in determining some of your polymers apart the last thing I'll just show you for the heck of it because it's on the last page of the handouts and I think I'll wrap up on I are just 1 more 1 more special topic the type of thing so hydrogen when it's enforced can be really really strong and so on here we have the need I R a spectra of 2 different isomers of worthwhile hydroxy metal bands away to methyl Solis a and of the meta isomer and the 1 thing that I thought was kind of cool is the difference between the 2 OH group said the OH stretches at 31 90 and the author of compound in its 33 70 in the matter compound so these are of hydrogen bonded over wages by India tho compounds you have enforcement of hydrogen bonding through an intramolecular hydrogen bond and that intramolecular hydrogen bond is really strong so you end up being even lower In frequency then the matter compound would just have intermolecular hydrogen bonding all right but I think that's what I want to say about IRA spectroscopy will pick up next time talking about mass spectrometry and will spend 3 lectures will start by talking of bewildered about the theory and instrumentation and in
some of the concepts