Indian Journ al of Ch emistry Vo l. 43, February 2004, pp. 320- 322 Tetraazamacrocycles of manganese and iron metals: Synthesis, spectroscopic characterization and biological evaluation As hu Chaudhary, Nidhi Bansal, Nighat Fahmi & R V S in gh* Depa rt ment of cl lemistry, _U ni vers it y of Rajasthan, Ja ipur 302004, Indi a Ema il : kudiwnl@dat a in fo sys.net Received 4 Decell/ ber 2002; revised 17 No vell/ ber 2003 A new se ri es of 14 to 20 membered tetraa zamacrocycl ic co m- pl exes of the type [M( Ma c")CI 2 ], where, M = Fe(lI) and Mn ( ll ), have been synth es ized by the template co nde nsa ti on of 1,2- phenylenediamine with dic arboxyl ic acids (malon ic , succinic, glutaric and adipic). The compounds have bee n characte ri zed by elemental analysis, IR, el ec tro ni c, .17 Fe mossbaur, magne ti c mo- me nt , conduc ti v it y, mass and X-ray spectral studies . Th e se studies show that the co mpounds are monomers hav in g an octahedral geometry. All the compl exe s have been screen ed aga in st seve ral fun gi and bacteria and the results have bee n di scu ssed. Th e chemistry of macro cyc lic co mpl exes ha s rece ived much attention in rece nt yea rs o n acco unt of its vari- OLI S applica ti ons in bioinorga ni c che mi stry I. Co nsid- era bl e attrac ti on in metal co mpl exes w ith tetraazamacrocy clic li gands has been fo ll owed by extensive work on metal co ntro ll ed template synthesis of macrocyclic species. Macrocyc li c co mpl exes of transition metals having both oxo and aza groups in a li ga nd are we ll know n for th e li ga nds hav in g di oxo te t- raza, tetraoxoo ct aaza and tetr aoxo tetraaza moie ti es. Th ese complexes of nitrogen donor li ga nds have b ee n s tu died in deta il , on a cco unt of their interesting stereoc he mi stry and wide prac ti ca l utilit /· 3 . In co n- nec ti on with previous inves ti gations on th e coo rdi- nating properties of tetraazamacrocyc les 4 and in order to isolate new transition metal co mplexes with poten- ti al antimicrobial properties we h ave studied on th e synthe ti c, spectrosco pi c and bi oc he mi ca l aspects of tetraazamacrocy li c co mplexes of Fe(l!) and Mn(ll ) derived from I,2-phenylenediamin e with di ca rb oxy li c ac ids. Experimental The chemicals including malonic acid, succinic acid, gluta ri c acid, adipic acid (F luka), 1,2- pheny lenediamine ( E. Merck), FeC I 2 .4H 2 0 and MnCI 2 .4H 2 0 ( BOH ) were u sed as obta in ed. Synthesis of complexes The reaction was carried out in I : 2:2 molar ratios. Metal chloride (5 mmol) was dissolved in methanol (25 mL) and coo led in an ice bath. To th is so lution taken in a magne ti cally stirred 100 mL round bottom fl ask was a dd ed I,2-ph enylene diam ine (co rrespond- ing to metal chloride) in methanol (25 mL ). The reac- ti on was fo ll owed by the addition of dica rboxy li c acid (co rresponding to th e metal chlo ri de) in Me OH (25 mL). Th e resulting mi xture was s ti rred for 24-25 hrs. Th e solid product wa s isolated by filteration, repea t- edly washed with the sa me so lvent and dried ill va cuo (yield 37%). Th e co mp o und was recrystallized in benzene and dr ied aga in ill vac ll o. Nitroge n and c hl orine we re estimated by Kjelda hl 's and Volhard's method respec ti vely. Iron and manga - nese were estimated gravimetri ca ll y. Conduc ti vi ty measurements we re made with a Systronic (Model 305) condu c ti vity brid ge in dry dimethylformamide. Molecular we ights we re determined by the Rast cam- phor me th od. Th e IR spectra of the solid sa mples were reco rded as KBr di scs on a Nicolet Magna FTIR-550 spec trophotomete r. Ele ctronic spectra in dim ethylsulphoxide we re recorded, in the range 200- 600 nm us in g methanol as the so lvent on a UV-1 60A Shimad zu spectrophotometer. X-ray powder diffrac- ti on spectra of the co mpound was obtained on a Phil- ips (Model p,W. 1840) a utom a ti c diffr actometer us in g Fe( Ka ) target with Mg filte r. Th e wavelength used was 1.937 3A and th e re fl ections from 5-65°C were reco rded, Th e mass spec tra of the com pounds were reco rded on a JE OL FX 102/D A-6000 mass spec - trometer/data system using Argo n/Xenon (6 KY, 10 mA) as the FAB gas . m-Nit robenzyl alcohol was used as the matr ix . Results and discussion A ll the co mpl exes are coloured so li ds and soluble in most of the orga ni c solvents like methanol, ben- zene, di c hl oro methane tetrahyd rofur a n, dimethy l- for mamide and dimethylsulphoxide, Their molec ul ar weight determina ti ons sh owed them to be monomer ic in nature. Th eir non-electrolytic nature wa s co nfirmed by low molar co nductan ce va lues 11 -20 ohm-I em] mol-I, Physica l properties and analy ti cal data of th e co mplexes are given in Table I,