STUDIES ON SOME NEW METAL COMPLEXES OF IMIDES

Abstract

Unlike the other nitrogen bearing compounds those containing the anIno,the amldo and the imldo groups possess the distinctive feature of giving biuret reaction with metal. Korenman1 hat listed thirteen klndt of compounds all of them aliphatic vhich give thlt reaction. According to him the tpeoiflo grouping of atom within theto compounds responsible for the biuret reaction are *;JH.C0.S.C0.ffl!a in biurets,*HHC ( iNH ) M CO*!JHt In dicyanodiaaidlne, >NC ( I N ) NC ( t m ) NH« in blguanidet, >10 I J*C ( INH ) in 2l*phanyl-if ( **amino bentyl )»ben«amidine,and n i CMC ( f NH ) m» In dieyanodlamldes. These groups have In common the ability to form six membered Internal complexes of the type »-C-8*C*I*a- when M is a metal ion and n an Integer*, itill other groupings capable of this reaction,e.g*, •MH*C*C*CONHa In malonaraldes and H t C*C*00J1Ha in cyanoacetamide and its derivatives can be generalised in the form 8V4WWMML * Thus the atomic groutings,capable of giving the biuret reaction faH under two type** <D S«C*X»C*N*Mll of which there are twelve variations and (11) Mn*;.-C*X*C*N of which there is one variation* X is either C or N and 2 is either H or 0. The number and distribution of jnultiplt bonds within the ring is responsible for a given variation 2 but doet not effect the ability of the compound to give the biuret reaction* riur*t reason of afflItQ ft0^ ajMtii- Metaltsdno acid amide complexet have bean reported by Siting and Yang8* The amino acld*amidet gave purple colouration with coi per in the absence of alkali. Thlt behaviour wss considered to be because of their ready enollsatton* the cuprlc Ion being coordinated with four nitrogen atoms of two mol*culet of acld*amldes* The analysis confirms the loss of one hydrogen atom by each molecule of the acld-amlde as In the case of glycine and alanine. 'luret, reaction of diacld amidesI* Rising and coworkersstudied the reaction of diacld amides with copper in the presence of alkali and shovod that there mutt be two hydrogen atoms In each aiolocule of the amide for salt formation and one or more amino nitrogen atoms for complex ion formation* They also observed that an increase In the number of carbon or nitrogen atoms separating the amide groups (separation factor) ,also weakens the strength of the amide as acids so that salt formation is ultimately hindered* Mono and symmetrical dlaikyl oxamides give the reactIon.while unsyametrlcal and trialkyl oxamides do not give* Malik and coworkers* studied polaro^rarhically the biuret reaction of m&lonamide* The polaro prof nic data gave evidence that two moleculet of the amide took 3 part in the complex formation with one atom of oopper* On Li batIs,the structural formula or the complex was given est CO 31 "SSL CO CHa :u CHa 00 H MH 9Q Motal*lmlde comtaexosi* Comparatively little attention has bean paid to stuly the metal imide complexes on account of their hydroiysable nature. The few investigations reported in the existing literature deal with the isolat ion of the complexes,their chemical analysis and measure ments of magnetic susceptibilities. Systematic investiga* tions on the nature mf these eoetpounds,their composition, structure and stability ( as evidenced by various physlco* chemical techniques) have not been taken up as yet and offer scope for further studies. Before this Is taken up It will be worthwhile to briefly survey the work already done on these complexes. Mary M« Tilting* prepared BaOu sucelnlmlde complex (BaCuCt*H»*S«0a ) which wat brownish red in colour. Hexahydrate copper sucelnlmlde complex (Cu(HC*0aH« )6HaO* was prepared by the action of metallic copper with mercuric acetate and a paste of mercuric sucelnlmlde. *he structure was confirmed by chemical analysis. Some gold complexes of sucelnlmlde have also been reported*. Seshadrl and Rao* 4 isolated Ii2 mercury complexes of suocinimide and rhthollmido with ethyl alcohol* ^Ivo Cambit had given a long lift of the magnetlo propertlet of potassium salts of palladium complexes of sucelnlmlde and phthaiimldef and methyl and ethyl amine salts of nickel complexes of fhthaliralde and tetra methyl succinlmide. Magneto-chomieal studies on the copper* nickel and cobalt complexes derived from lmldet have also boon reported In the literature. Recently Blllraan and obert Chernln,# has reported the use of sulfonamide derivative for direct titration of copper* Bom sulfonamide derivatives heve bean used In chromatographic determination of lead and copperM. Non-aqueous titrations of sulfonamidet(potentiometric and sp<sctrophotometrlo) '* and conductometrio titrations of imldes with lithium hydroxide in ammonioal medium1- have also been cited in the literature* irom the above turvey it it evident that compre hensive studies incorporating various worth luvestigatlng aspects of metal Imide reactions are completely lacking* To achieve this investigations were planned with the following aims In vlewt 1 ) choice of new llgands falling under the category of lmldet. ii) selectIon of reactions based on biuret and nonbiuret reaction mechanisms. 5 111) study of the reactions in tolutiont both in the aqueous and the nonaqueous medial studies in non-aqueous medium were especially undertaken in view of the hydrolysable nature of certain metal imide complexes. The preparation and properties of the newly prepared lmldet are given in Chapter I,Part II* Biuret and non*bluret reactions*- The foUowing laides were chosen for carrying out reactions with metals* Known imidesi succiniraldo,3-nitrophthall»idefsa©charl . Kewly synthesised imidesi bensofur 2-yl carboxomide ?J*p*toiuene sulphonyl.cyrld*2«yl carboxomide #*p*toluenc •alphaayla Fe(til) ,Cu(ID ,#1(11} ,Co(II) were found to give biuret reactions with 3-nitroj:hthallmlde,sucelnlmlde, bensofur-r-yl ecrboxos-ida F-r-tcluone sulphonyl,pyrId 2-yl carboxomide :i-p-toluene sulphonyl* lon*bturet reactions were observed with CedID 9 CodD ,Si(ID fFe(III) with 3-nltrophthalimlde,sucelnlml de and saccharin. The reactions in the solution phase were studied both by sp€ctrophotometrlc and electro-chemical methods. Measurementt in polar organic solvetits were possible. Although the suitability of ; U-metrlc measurements in non-aqueous medium has not been extensively Investi gated,there Is no orer riding reason why acidity scale analogous with the pi scale should not be set up for any 6 solvent* The compounds.wherever possible,were isolated and their T.a* spectra and magnetic behaviour ttudled.