SN1, SN2 Reaction and Walden Inversion

Aces to Ingold involve in at which liate the numbers of moleculen suity if there watient. rato of redend while the members" whose conncentrats on in mate, determing stop. athe reaction. However there are in which reagent no effect on order change some action excess so having conn, here the reagent counted in the molecularity but Independent to order of reaction The SN credations are studied by modularity of the reaction as! Rate & substrato ] (Ni] Bimolecular (SN²) Rate & substrate ] Unimalicular (SNI) Bimolecular Nucleophiler substitution Reaction (SN2) In SN² reactions the nucleophile sttack to the carbon stone of substrats just opposite side to the leaving group It is due to the repulsion same change. The C-Ne hond forming start the and at same rate the C-L Bond Istart breaking I st means the breaking of old band K forming of neve hond takes place sinultaneously incoming nucliophile dimensch its as it provide electron in informing C-Nu bohd L gaining the The charge the At the same time the nucleofung -tve bonding electrons of changsond time both have equal partial exist as far as as possible. of the reaction which is sthout lived and readily. three bonds are fully plome at 1200 fully and the at any so at -ve charge It is the T.S very highly reactive y Convented into product in which the in the same spopes of 50% one abbre the covalent Compare a wheel while the two bonds barthal & lic perpendiculas wheel 2 one fust below the wheel at 100° to each other. The co-ordinate of reaction energy content can be given graphically The real three dimensional arrangement of groups in space i the stewo Chemistry & it is of two types namely geometrical Isomeriem and optical. loomerism ( enantiomerism) of SN 2 Hughes & Ingold reac The given by In both types of storeschemical configu -ration of subitrate the tone dult following two become reverse in which can be beroved by experimental studie: F (a) The geometrical arrangement of subebate and the rewise arkangement! I given by cyclohexane Single the since hydrialyes of the substrati Aaving bonded but in peroducts Mestricted bond estation due to closed seibstats having -configuration the product should also be circonfiguration bind whe-veasn but practically the product sbtained configuration just reverte stenchchemical formation of bansproduct exclusively in the above reaction attack of issoming nucleophile become from the opporets side to the same the formed configurated it alronde showe cist-alrohde should of the SN² reaction carried out in optically. optically active substreets there should also be opposite config found in product. for ex'-" broma ethane the hydrolysie of 1-phenyl-broma doom 1-phenye ethanol which also have the reverse stereochemical arrange ment The reaction can be giver A front (same) side attack As front 8 Rear (opposite) side attach experiment again pure that The above is the attack of takes place from the reas side of nucleofuge which form the alcohol the configuration of of Pereveerse sotation Tin which Ibonded groups reverse and it is also prown as Walden Inversion Ive Walden Inversion Stereochemically WI. in the cabover waction Original tetrahedral as can be explained the dextro-rotator Attacked by areas start forming bonding. side and start the same breaker and ot leaving group start by thoithdrawing the pond in substrate c- the t's where tetrahedral lost and 3. covalent bonds convert into planes 120° since there is and with kubstrate a total repulsion the incoming a covalent form carbon farthest nucleofuge. During thes process Inew tetahedral bond from the the nucleopsite Stant ta to the starting and product become Which is Substrate opposite tetrahedral with opposite optical rotation. This inversion of tetrahedral is termed as W.I The w I also prown as umbrella e Envert out against the umbrella effect which force of wind.