.J. Indian Chern. Soc., Vol. 84, December 2007, pp. 1202-1204 Synthesis and spectroscopic studies of Crill, Fe 1 1I and Coli complexes of hexaazamacrocycles R.N. Prasad*, Mala Mathur and Ashish Upadhyay Department of Chemistry, University of Rajasthan, Jaipur-302 004, Rajasthan, India E-mail: rnp_l949@yahoo.co.in Manuscript received 20 February 2007, revised 13 September 2007, accepted 20 September 2007 Abstract: Complexes of the type [ML[(N0 3 ) 3 and [CoL](N0 3 ) 2 [where M = Cr 111 , Fe 111 and L= macrocyclic ligands L 1 , L 2 or L 3 ] have been synthesized by template method involving 2 : 2 cyclocondensation of a-diketones with 1,5-diamino-3-azapcntanc. These complexes have been characterized by elemental analyses, conductances, magnetic moments, IR and electronic spectra. Keywords : Macrocyclic complexes, transition metal complexes, magnetic moments, electronic spectra. 2,6-Diaminopyridine has been commonly used to synthesize polyazamacrocyclic complexes e.g. those of Co 11 , Ni 11 and Cu 11 with macrocycles derived from 2,6- diaminopyridine and a-diketones 1 such as 2,3-butanedione or P-diketones 2 such as acetylacetone or benzoylacetone. Co 11 , Ni 11 , Cu 11 and Zn 11 complexes of unsymmetrical N 4 and N 5 macrocycles have been synthesized by the template reaction of polyamine such as diethylenetriamine with a- aminobenzoic acid and haloalkanes 3 .4. However, complexes of N 6 macrocycles derived from diethylenetriamine and a-diketones have not been reported so far. Hence, we report herein the synthesis and characterization of Cr 111 , Fe 111 and Co 11 complexes of hexaazamacrocycles derived from I ,5-diamino-3- azapentane and a-diketones. R I R 2 \ I c-c <"II "') HZ_N N5 11 // c-c I \ R 2 R I Rl L 1 CH, L2 Clis L 3 p-CH 3 C 6 H 4 R2 11-C,H 7 C2Hs p-CH 3 C 6 H 4 Fig. I. Macrocyclic ligands Results and discussion 1202 Co(N0 3 ) 2 .6Hp with I ,5-diamino-3-azapentane and 4,4'- dimethylbenzil, 3,4-hexanedione or 2,3-hexanedione in I : 2 : 2 molar ratios result in the formation of hexaazamacrocyclic complexes according to the general Scheme 1. All the complexes are insoluble in methanol, carbon tetrachloride, acetonitrile and nitrobenzene but are soluble in DMSO. M(N03)k.xH20 + 2R 1 COCOR 2 +2H2N(CH2)2NH(CH 2 ) 2 NH 2 t(x+4)H,O R 1 = CH 3 ; R 2 = CH 2 CH 2 CH 3 L' R I = C2Hs ; R2 = C2Hs L2 R I = p-CH3C6H4 ; R 2 = p-CH3C6H4 L3 M k X Cr 3 9 Fe 3 9 Co 2 6 Scheme 1. Synthesis of hexaazamacrocyclic complexes. Molar conductances : Molar conductances of the macrocyclic complexes are given in Table 1. Complexes