Polyhdmn Vol. I. No. 3, pp. 30346, 1982 zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA Printed in Great Britain. 027743mwo3030u34so3.ao/o Per&mm Press Ltd. zyxwvutsrq THE PREPARATION AND COORDINATION CHEMISTRY OF 2,2’ : 6’,2”-TERPYRIDINE MACROCYCLES- EDWIN C. CONSTABLE and JACK LEWIS* UniversityChemicalLaboratory, LensfieldRoad, Cambridge CB2 IEW, England (Received 3 February1982) Ahstrati-A rangeof 6,6”disubstituted derivatives of 2,2’:6’,2”-terpyridine have been prepared with the intention of forming macrocyclesincorporating the 2,2’:6’,2”-terpyridyl moiety. A high yield route to 6,6”-bis(methyIhydraxino- 4’-phenyl-2,2’:6’,2”-terpyridine is described, and a numberof complexes of this novel pentadentate ligand have been prepared. Although complexes of the “classic” diimine ligands 2,2’-bipyridine (1) and l,lO-phenanthroline (2) have been known for many yearsLm3 it is only recently that such fragments have been incorporated into macrocyclesti. We have demonstrated that macrocycles of type 3 form transition metal complexes which exhibit unusual coor- dination geometries about the metal, and, with a view to extending these observations, we have embarked upon the synthesis of derivatives of 2,2’ : 6’,2”-terpyridine (4) suit- able for incorporation into such systems. 1 3 Our target molecule was a 6,6”-bishydraxino sub stituted compound, 4a, which was expected to condense with a 1,2-dicarbonyl compound to give a macrocycle of type 5, which has a similar donor set to macrocycle 3. We describe herein the synthesis of such derivatives using the Krohnke pyridiie synthesis,’ in which an a$- unsaturated carbonyl compound is condensed with an *Author to whom correspondence should be addressed. 4 4a Z=NRNHr 4b Z=CI,Y=H,X=Ph 4c Z=NHNH,,Y=H,X=Ph 4d Z=NMeNH,,Y=H,X=Ph 4e Z=NH,,Y=H,X=Ph 4f Z=Br,Y=Ph,X=H 4g Z=NMeNH,,Y=Ph,X=H MeyN JAN LN-4e zyxwvutsrqponmlkjihgfed /N N’ X’ %+ NN 1’ X A’ r 5 active methylene species in the presence of ammonium acetate to form a 1Jdiiydropyridine (Scheme 1). By adopting the strategy in which the methylene group is additionally activated by an N-pyridinium group (i.e. Scheme 1. 303