Ajax K. Mohamed

Macrocyclic complexes of transition metals with divalent polyaza units

A new series of 14–16-membered hexaazamacrocyclic complexes [ML1X2] and [ML2X2] (M = CoII, NiII, CuII and ZnII; X = Cl or NO3) have been synthesized by template condensation of phenylenediamine, primary diamines and formaldehyde solution 35% in MeOH and have been characterized by i.r., 1H-n.m.r., e.p.r., and u.v. spectroscopy as well as by magnetic susceptibility and conductivity measurements. An octahedral geometry has been suggested for all the complexes.

Metal ion directed synthesis of 14–16 membered tetraimine macrocyclic complexes

A new series of 14–16 membered tetraazatetraimine macrocyclic complexes [ML1X2]-[ML3X2] [M=CoII, NiII and ZnII] and [CuL1]X2-[CuL3]X2 [X=Cl or NO3] have been synthesized by the template condensation of dibenzoylmethane with primary diamines in MeOH. The complexes were characterized by elemental analysis, i.r, 1H-n.m.r., e.p.r. and u.v-vis spectroscopy, as well as by conductivity and magnetic susceptibility measurements. The copper complexes exhibit square planar geometry, whereas an octahedral geometry is suggested for all other complexes.

Tetraamide macrocyclic complexes of transition metals with ligands derived from hydrazine

Succinic acid or phthalic acid react with hydrazine hydrate and formaldehyde in the presence of metal ions to give the macrocyclic complexes [ML1Cl2] or [ML2Cl2][M = FeII, CoII, NiII, CuII and ZnII]. The resulting cyclization has been identified, on the basis of i.r. and 1H-n.m.r. studies. The coordination of amide groups through nitrogen and the overall geometry of the complexes have been assigned on data obtained from elemental analyses i.r., u.v.-vis., magnetic moments, e.p.r and conductivity studies. All the complexes exhibit an octahedral geometry, except copper which is square planar, where the amide group coordinates through nitrogen, and are air stable. The observed low molar conductivity values suggest the non-ionic nature of all the compounds.

PREPARATION AND STRUCTURAL CHARACTERIZATION OF 14-16-MEMBERED PENDENT ARM MACROCYCLIC COMPLEXES OF TRANSITION METAL IONS

Abstract Template condensation reaction of ethylenediamine or propylenediamine, formaldehyde and benzidine in 1:2:1 molar ratio in methanol medium resulted in the formation of a new series of pendent arm hexaazamacrocyclic complexes of the type [ML 1 Cl 2 ] or [ML 2 Cl 2 ] (M II = Fe II , Co II , Ni II ,Cu II and Zn II ). These polycrystalline compounds are soluble in DMSO and have been characterized by IR, 1 H NMR, EPR and electronic spectral studies, and conductivity and magnetic susceptibility measurements. An octahedral geometry is suggested for all the complexes, where two coordination sites are occupied by chloride ions and the other four by secondary amines.

TRANSITION METAL COMPLEXES OF 16-18-MEMBERED TETRAAZAMACROCYCLES BEARING POLYAMIDE GROUPS

Abstract A new series of 16–18-membered tetraazamacrocyclic complexes [ML 1 Cl 2 ][ML 4 CL 2 ] [MFe (II) , Co (II) , Ni (II) and Zn (II) and [CuL 1 ]Cl 2 -[CuL 4 ]Cl 2 have been prepared via the template condensation reaction of o-aminobenzoic acid with phthalic or glutaric acid and 1,2-diaminoethane or 1,3-diaminopropane. These complexes have been characterized by IR, 1 H NMR, EPR and electronic spectral studies, and conductivity and magnetic susceptibility measurements. A square-planar geometry has been assigned for copper whereas the other metals exhibit octahedral configurations.

Transition metal complexes of 13–14-membered tetraazamacrocycles: Synthesis and characterization

Abstract A new series of 13–14-membered tetraazamacrocyclic complexes [ML1]X2-[ML2]X2 [M = NiII and CuII, X = Cl or NO3] and [ML1X2]-[ML2X2] [M = MnII, CoII and ZnII, X = Cl or NO3] have been synthesized by template condensation reaction of o-bromoaniline, 2,4-pentanedione and primary diamines in methanol solution and have been characterized through IR, 1H NMR, EPR and electronic spectral studies, conductivity and magnetic susceptibility measurements. An octahedral geometry has been suggested for the manganese, cobalt and zinc complexes, while square planar geometry is proposed for the nickel and copper complexes.

SELF-CONDENSATION OF ORTHO-AMINOBENZOIC ACID IN THE PRESENCE OF METAL IONS

Abstract The self-condensation reaction of o-aminobenzoic acid in the presence of metal ions resulted in the preparation of a novel series of tetraazamacrocyclic complexes bearing amide groups. These complexes were characterized by elemental analysis, IR, 1H NMR, EPR and electronic spectral studies, conductivity and magnetic susceptibility measurements. Except for the complex of copper(II), which is square planar, all the other complexes have octahedral structures.

Metal Complexes of 22-Niembered Mononuclear Tetraimine-Tetraamide Macrocycles: Synthesis and Characterization

Abstract Template condensation reaction of succinic acid or phthalic acid with hydrazine hydrate and 2,4-pentanedione resulted in the formuation of a new series of 22-membered tetraiminetetraamide macrocyclic complexes: dichloro/dinitrato (8, 11, 19, 22-tetraone-3, 5, 14, 16-tetramethyl-1, 2, 6, 7, 12, 13, 17, 18-octaazacyclodocosane-2, 5, 13, 16-tetraene)metal(II), [ML1X2] [M = Mn(II), Co(II), Ni(II) and Zn(II); X = CI or NO3]; (8, 11, 19, 22-tetraone-3, 5, 14, 16-tetramethyl-1, 2, 6, 7, 12, 13, 17, 18-octaazacyclodocosane-2, 5, 13, 16-tetraene)copper(II) dichloride/dinitrate [CuL1]X2; dichloro/dinitrato(9, 10, 20, 21-d ibenzo-8, 11, 19, 22-tetraone-3, 5, 14, 16-tetramethyl-1, 2, 6, 7, 12, 13, 17, 18-octaazacyclodocosane-2, 5, 13, 16-tetraene)metal(II), [ML2X2] [M = Mn(II), Co(II), Ni(II) and Zn(II); X = CI or NO3) and (9, 10, 20, 21-dibenzo-8, 11, 19, 22-tetraone-3, 5, 14, 16-tetramethyl, 2, 6, 7, 12, 13, 17, 18-octaazacyclodocosane-2, 5, 13, 16-tetraene)copper(II) dichloride/dinitrate, [CuL2]X2. These complexes have been characterized by IR, 1H NMR, EPR and electronic spectral studies, conductivity and magnetic susceptibility measurements. An octahedral geometry has been suggested for the manganese, cobalt, nickel and zinc complexes, while a square-planar geometry is proposed for the copper complexes. All complexes are stable to air.

Synthesis and electrochemical studies of a new series of pendantarmed hexaazamacrocyclic transition metal complexes

SummaryThe synthesis of a new series of 14- and 16-membered hexaazamacrocyclic complexes has been achieved by the template condensation of ethylenediamine or 1,3-propylenediamine with formaldehyde and acetamide in a 1∶2∶1 molar ratio in the presence of metal chlorides. Octahedral structural formulae for selective metal complexes are proposed on the basis of physico-chemical and spectroscopic data. The redox behaviour in DMSO solution of the CuII complexes has been studied by cyclic voltammetry.

Synthesis and Spectroscopic Studies of Bis(Macrocyclic) Dimetal(II) Complexes Based on 14–18 Membered Pentaaza Units

Abstract Bis (macrocyclic) binuclear transition metal complexes [M2LC14] [M = Fe(II), Co(II), Ni(II), Cu(II) and Zn(II); L = L1-L6, have been synthesised by the template condensation reaction of ethylenediamine or l,3-diaminopropane with formaldehyde, benzidine and acetylacetone or dibenzoyl methane or phthalaldehyde in 4:4:1:2:2 molar ratio. All prepared complexes have been characterized by elemental analyses, IR, 1H NMR, EPR and UV/VIS and conductivity data as well as magnetic susceptibility measurements. An octahedral geometry is suggested for all complexes.