Acyclic Schiff Base Research Articles

Synthesis, Characterization, Fluorescence and Antibacterial Activities Studies of Transition Metals Complexes with a Macro Acyclic Schiff Base Ligand

The reactions of the Schiff base 2,2’-[(2-hydroxypropane-1,3-diyl) bis-(imino-methane diyl)] bis-(4-bromophenol) (H3L), with metal transition ions (Mn(II), Ni(II), Cu(II), Zn(II), and Cd(II),) afforded one type of complex formulated as [M(HL)(H2O)2].nH2O. These compounds have been characterized by elemental analysis, UV–Vis, FTIR, 1H and 13C NMR spectroscopies, molar conductivity and room temperature magnetic measurements. The structure of nickel (II) complex has been determined by X-ray crystallography. The complex crystallizes in the orthorhombic space group Pnma with a = 7.7702(4) Å, b = 23.1921(15) Å, c = 10.6853(5) Å, V = 1925.57(15) Å3, Z = 8, R1 = 0.043 and wR2 = 0.107, Dcalc = 1.893 Mg m−3. The ligand acts in tetradentate fashion in its di-deprotonated form. Two coordinated water molecules complete the coordination sphere. The environment around the Ni(II) center is best described as an octahedral geometry. In the crystal structure of the Schiff base ligand, the existence of a strong intramolecular O-H•••O hydrogen bonding [O2W-H2W 0.80(3) Å, H2W •••O1 1.915(3) Å, O2W••• O1 2.6258(19) Å, O2W-H2W•••O1 148(3)°] and [O1W-H1W 0.73(3), H1W•••O1 2.15(4) Å, O1W•••O1 2.836(2)Å, O1W-H1W•••O1 156(4)°] are observed. Antibacterial activity study shows that the cadmium (II) complex is more active than the free ligand on.

Synthesis, characterization and sensing mechanism of a novel fluorescence probe for Fe(III) in semi-aqueous solution based on a Schiff base hexadentate receptor

A new acyclic Schiff base chemosensor L was synthesized by the one pot condensation reaction of 2-[3-(formyl phenoxy)2-hydroxypropoxy]benzaldehyde and 2-aminophenol in a 1:2 molar ratio and was characterized by elemental analysis, FTIR, 1H- and 13C NMR, and fluorescence spectroscopies. These studies were complemented with a thorough conformational study at the molecular mechanics and density functional theory (DFT) levels of theory to further elucidate the structure of the compound in solution. The chemosensor L displays high sensitivity and selectivity for Fe3+ in semi-aqueous (H2O-DMF, 1:1) solution, except in the presence of a significant amount of Ni2+, with the presence of Fe3+ being signaled through the total fluorescence quenching of the fluorophore when Fe3+ binds to the recognition unit. The synthesized ligand also shows high selectivity for Fe3+ compared to the metal ions Cu2+, Zn2+, Mg2+, Mn2+, Pb2+, Hg2+, Na+, Ba2+ and Cd2+, and reasonable selectivity in the presence of Ag+, Co2+ and Cr3+. The stoichiometry and structure of the complex formed between Fe3+ and the probe L were determined from a Job’s plot and DFT calculations, respectively. The complex was characterized as a high-spin 1:1 octahedral species, in which the ligand coordinates to the metal through the two ether oxygen atoms, two nitrogen atoms and two terminal hydroxyl groups. Time dependent (TD-DFT) calculations were performed to provide information on the type of mechanism causing the quenching of the fluorescence in the presence of Fe3+.

A highly potential acyclic Schiff base fluorescent turn on sensor for Zn2+ ions and colorimetric chemosensor for Zn2+, Cu2+ and Co2+ ions and its applicability in live cell imaging.

Herein, we report two acyclic Schiff base receptors CS-1 and CS-2 capable of being selective fluorescent turn on for Zn2+ions and colorimetric chemosensor for Zn2+, Cu2+, and Co2+ ions by showing a colour change from colourless to yellow in 1:1 ratio of acetonitrile and HEPES buffer (1:1, v/v, pH7.4) without the interference from other metal ions screened (Cd2+, Hg2+, Sn2+, Ni2+, Cr3+, Mn2+, Pb2+, Ba2+, Al3+, Ca2+, Mg2+, K+ and Na+). The fluorescence turn on enhancement towards Zn2+ ions is ascribed to PET blocking, suppression of -C=N- isomerisation, and the ESIPT process. The selectivity, competitivity and reversibility of the synthesised probes (CS-1 and CS-2) made them promising chemosensors for the detection of Zn2+, Cu2+, and Co2+ ions. The density functional theory (DFT) calculations have theoretically endorsed the colorimetric changes in the examined absorption spectra and binding mode of both CS-1/CS-2 with metals ions. In addition, 1H NMR titrations were also consistent with the recognition mechanism of Zn2+ ions with the CS-1/CS-2. Further, the Jobs plot analysis infers a 1:1 stoichiometric ratio for both evaluating receptors CS-1 and CS-2 with Zn2+, Cu2+ and Co2+ ions and was supported by DFT, NMR (only for Zn2+ ions), UV-Visible, and fluorescence spectroscopic studies. Moreover, the detection limits of CS-1 and CS-2 for Zn2+ ions were determined to be 7.69 and 5.35nM, respectively, which is less compared to the detection limit of Cu2+, Co2+ ions as well as the limit approved by the United State Environmental Protection Agency (US EPA). The probes CS-1 and CS-2 found to show high fluorescence quantum yields at pH=7 during the titration with Zn2+ as compared with other pHs (5-6 and 8-11). Gratifyingly, fluorescence microscopy imaging in HeLa cells revealed that the pair of receptors can be employed as an excellent fluorescent probe for the detection of Zn2+ions in living cells, indicating that this facile chemosensor has a huge potential in cellular imaging.

Mixed ligand Cu(II) complexes: Square pyramidal vs trigonal bipyramidal with the pyrrole-based dipodal ligand having hydrogen bond acceptors

The condensation between N,N-di(α-formylpyrrolyl-α-methyl)-N-methylamine LH2 and ethanolamine or picolylamine afforded the [1 + 2] acyclic Schiff base in an excellent yield. The reaction between LH2 and [Cu(OAc)2·H2O] yielded a bis(aqua)-bridged binuclear copper(II) complex [Cu{MeN(CH2–C4H2N–CHO)2-κN,N,N)}(μ-H2O)]21. The same product was obtained from the reaction between acyclic, cyclic or bicyclic Schiff base of LH2 and [Cu(OAc)2·H2O] or [CuCl2·2H2O] via hydrolysis of the Schiff-bases. Complex 1 readily reacts with diimines such as 2,2′-bipyridine (bipy), 1,10-phenanthroline (phen) and 2,9-dimethyl-1,10-phenanthroline (dmp) to give mixed ligand mononuclear Cu(II) complexes [Cu{MeN(CH2–C4H2N–CHO)2-κN,N,N)}(bipy)] 2, [Cu{MeN(CH2–C4H2N–CHO)2-κN,N,N)}(phen)] 3, and [Cu{MeN(CH2–C4H2N–CHO)2-κN,N,N)}(dmp)] 4 in very high yields. In all structures, L2− retains its original coordination mode and the geometry around the copper atom in 1, 2 or 3 is best described as a distorted square pyramidal (sp); on the other hand, the copper atom assumes a distorted trigonal bipyramidal (tbp) geometry with dmp in 4 owing to the steric bulk of methyl groups. DFT calculations gave the energy difference between sp and tbp geometries of different copper(II) complexes containing bipy and phen ligands bearing sterically encumbered substituents. As the steric bulk increases, tbp becomes the preferred geometry.

Construction of mononuclear macrocyclic and dinuclear acyclic Schiff base complexes via cadmium(II)–ion template: Synthesis, characterisation, and crystal structures

Abstract Using a metal template approach a series of mono and dinuclear cadmium(II) were synthesized by Schiff base condensation of a pendant armed dialdehyde, i.e. 2-[3-(2-formylphenoxy)-2-hydroxypropoxy] benzaldehyde (PL) with selection of different diamines, diethylenetriamine, dipropylenetriamine, 1,2-diaminopropane and 1,2-diaminoethane. Depending on the nature of the diaminoalkane spacers and metal ion, 1:1 (metal:ligand) macrocyclic (L1OH and L2OH) or 2:1 (metal:ligand) acylic (L3O− and L4O−) complexes of cadmium(II) were obtained. With the longer spacers diethylenetriamine and dipropylenetriamine ring closure around the cadmium ion was observed and [1+1] macrocyclic Schiff base ligands (L1OH and L2OH) were formed. With the shorter spacers 1,2-diaminopropane and 1,2-diaminoethane ring closure was not observed. Interestingly, the dialdehyde PL reacted with two molecules of diamine, forming intermediate product acyclic Schiff base [1+2] ligands (L3O− and L4O−) that are coordinated to two cadmium ions to form dinuclear complexes. Crystal structures indicated that the complex [CdL1(NO3)]. NO3 contains a hexadentate macrocyclic ligand and a bidentate NO3− anion with an eight-coordinated cadmium in distorted dodecahedron geometry. The molecular structures of the complexes [Cd2(L3O)(NO3)3(H2O)] and [Cd2(L4O)(NO3)3], on the other hand, exhibit of two seven-coordinated cadmium centers, which are bridged by the deprotonated hydroxyl group. The coordination geometries of the cadmium ions can be described as a capped trigonal prism and/or capped octahedron.

Synthesis, characterization and biomolecular interactions of Cu(II) and Ni(II) complexes of acyclic Schiff base ligand

Mononuclear copper(II) (1) and nickel(II) complexes (2) of acyclic Schiff base ligand, N,N′-bis(2-hydroxy-1-naphthyl)-1,4-bis(3-iminopropyl) piperazine (L) were synthesized and characterized. The molecular structure of the ligand was confirmed using single crystal X-ray diffraction analysis. The complexes displayed good binding abilities to bovine serum albumin protein (BSA). The binding interactions of complexes 1 and 2 with calf thymus DNA (CT-DNA) was investigated by absorption, fluorescence, circular dichroism spectral analysis and molecular docking studies. Complex 1 showed greater interaction with DNA than nickel(II) complex 2. The cleavage studies with pBR322 DNA showed efficient oxidative cleavage in the presence of 3-mercaptopropionicacid (MPA) and for hydrogen peroxide for complexes 1 and 2 respectively.

Syntheses, crystal structures and ESI-MS of mononuclear–dinuclear, trinuclear and dinuclear based one-dimensional copper(II)–s block metal ion complexes derived from a 3-ethoxysalicylaldehyde–diamine ligand

This paper presents the syntheses, crystal structures and electrospray ionization mass spectra (ESI-MS) of four copper(II)–s-block metal ion compounds of composition [{CuIILNaI(H2O)2}(CuIIL)](ClO4) (1), [(CuIIL)2CaII](ClO4)2·2CH3CN·H2O (2), [CuIILSrII(ClO4)2(H2O)]n (3) and [CuIILBaII(ClO4)2(H2O)]n (4), where H2L is the compartmental acyclic Schiff base ligand, obtained on [2+1] condensation of 3-ethoxysalicylaldehyde and trans-1,2-diaminocyclohexane. Compound 1 is a [2×1+1×1] cocrystal of one dinuclear [CuIILNaI(H2O)2]+ moiety and one mononuclear [CuIIL] moiety; the reason of cocrystallization is the hydrogen bonding interaction of a coordinated water molecule of the dinuclear unit with the O(phenoxo)2O(ethoxy)2 compartment of the mononuclear unit. [(CuIIL)2CaII](ClO4)2·2CH3CN·H2O (2) is a trinuclear, non-sandwiched compound where the second metal ion (CaII) is situated in between two O(phenoxo)2O(ethoxy)2 compartments of two [CuIIL] moieties. [CuIILSrII(ClO4)2(H2O)]n (3) and [CuIILBaII(ClO4)2(H2O)]n (4) are isomorphous and dinuclear CuIIMII (M=Sr or Ba) based one-dimensional systems, where polymerization takes place through the perchlorate ligands. A number of peaks are observed in the ESI-MS and those are well assigned. Although the compositions of 1, 2 and 3/4 are different, the ESI-MS of all the four compounds reveal the appearance of trinuclear, dinuclear and mononuclear ions. The peculiar/interesting aspects of the four compounds are discussed.

Sulfonated Schiff base dimeric and polymeric copper(II) complexes: Temperature dependent synthesis, crystal structure and catalytic alcohol oxidation studies

Temperature dependent synthesis and crystal structure of the dicopper(II) complex [Cu2(L-κONO′)2(μ-4,4′-bipy)(DMF)2] (1) and the dicopper(II) based coordination polymer [Cu2(μ-L-1κONO′:2κO)2(μ-4,4′-bipy)]n·nH2O·nDMF (2) derived from the acyclic Schiff base 2-[(2-hydroxy-3-methoxyphenyl)methylideneamino]benzenesulfonic acid (H2L) are described. Compounds 1 and 2 crystallize in monoclinic P21/n and P21/c systems, respectively. Crystal structure analysis reveals that the coordination polymer 2 consists of a dimeric building block which is comparable to the basic structure of 1. The compounds are isolated from the same reaction mixture but at different reaction temperatures and 1 can be converted into the coordination polymer 2. They were tested as catalysts for (both primary and secondary) alcohols oxidation. They show good catalytic activity for the solvent- and additive-free microwave (MW) assisted peroxidative (with tert-butylhydroperoxide) oxidation of cyclohexanol (up to 85% yield of cyclohexanone) after 30min of low power MW irradiation.

Synthesis of New Acyclic Schiff Base Oxovanadium(IV) Complexes and Their Electrochemical, Catecholase, and Antimicrobial Studies of Minimum Inhibitory Concentration

Catalytically active complexes containing [VO(IV)L] were synthesized by using Schiff base ligands L1–5 and vanadyl sulfate. Ligands L1–5 were obtained by the condensation of 5-methylsalicylaldehyde with diethylene triamine (L1), tris(2-aminoethyl)amine (L2), triethylene tetramine (L3), N,N-bis(3-aminopropyl)ethylenediamine (L4) and N,N- bis(aminopropyl) piperazine (L5). All the complexes were characterized by elemental and spectral analysis. ESR spectra for the mononuclear [VO(IV)L] complexes show eight lines, square pyramidal geometry. Room temperature magnetic moment for the complexes was around 1.73 B.M. Electrochemical and catalytic studies of the complexes were compared on the basis of chain length of the imine compartment. All the [VO(IV)L1–5] complexes were screened antibacterial activity of MIC.

Electrochemical sensing of phenolic compounds based on polymerized acyclic Schiff base modified glassy carbon electrode

Electrochemical sensing of phenolic compounds based on polymerized acyclic Schiff base modified glassy carbon electrode

Towards dipyrrins: oxidation and metalation of acyclic and macrocyclic Schiff-base dipyrromethanes.

Oxidation of acyclic Schiff-base dipyrromethanes cleanly results in dipyrrins, whereas the macrocyclic 'Pacman' analogues either decompose or form new dinuclear copper(ii) complexes that are inert to ligand oxidation; the unhindered hydrogen substituent at the meso-carbon allows new structural motifs to form.

Synthesis and characterization of chromium(III) Schiff base complexes: Antimicrobial activity and its electrocatalytic sensing ability of catechol

A series of acyclic Schiff base chromium(III) complexes were synthesized with the aid of microwave irradiation method. The complexes were characterized on the basis of elemental analysis, spectral analysis such as UV–Visible, Fourier transform infrared (FT-IR), nuclear magnetic resonance (NMR), electron paramagnetic resonance (EPR) spectroscopies and electrospray ionization (ESI) mass spectrometry. Electrochemical analysis of the complexes indicates the presence of chromium ion in +3 oxidation state. Cr (III) ion is stabilized by the tetradentate Schiff base ligand through its nitrogen and phenolic oxygen. From the spectral studies it is understood that the synthesized chromium(III) complexes exhibits octahedral geometry. Antimicrobial activity of chromium complexes was investigated towards the Gram positive and Gram negative bacteria. In the present work, an attempt was made to fabricate a new kind of modified electrode based on chromium Schiff base complexes for the detection of catechol at nanomolar level.

Design, synthesis and bioactivity of N-glycosyl-N'-(5-substituted phenyl-2-furoyl) hydrazide derivatives.

Condensation products of 5-substituted phenyl-2-furoyl hydrazide with different monosaccharides d-glucose, d-galactose,d-mannose, d-fucose and d-arabinose were prepared. The anomerization and cyclic-acyclic isomers were investigated by 1H NMR spectroscopy. The results showed that, except for the d-glucose derivatives, which were in the presence of β-anomeric forms, all derivatives were in an acyclic Schiff base form. Their antifungal and antitumor activities were studied. The bioassay results indicated that some title compounds showed superior effects over the commercial positive controls.

Exploration of heterometallic systems containing silver(I) in acyclic Schiff base ligands: Finite and infinite self-assemblies as a result of silver(I)–carbon bond and silver(I)⋯silver(I) interaction

The work in this report describes the syntheses and crystal structures of nine copper(II)–silver(I) compounds derived from some single-compartment N(imine)2O(phenoxo)2 or double-compartment N(imine)2O(phenoxo)2–O(phenoxo)2O(methoxy/ethoxy)2 acyclic Schiff base ligands. The nine compounds are [{CuII(ClO4)Lsal–enAgI}2{CuII(ClO4)Lsal–enAgI(H2O)}]n (1), [CuIILsal–pnAgI(ClO4)]n (2), [{CuIILsal–pnAgI(NO3)}2] (3), [(CuIILacpn–en)2AgI(MeCN)2](ClO4) (4), [{CuIILOMe–enAgI(NO3)}2] (5), [{CuIILOMe–pnAgI(NO3)}2] (6), [{CuIILOMe–pnAgI(NO3)}2]·2H2O (7), [{CuIILOEt–enAgI(NO3)}2] (8) and [{CuIILOEt–opAgI(MeOH)}2](ClO4)2 (9), where the superscripts in the ligand symbols mean the following: (i) sal, acpn, OMe and OEt indicate that the aldehyde counterpart is salicylaldehyde, 2-hydroxyacetophenone, 3-methoxysalicylaldehyde and 3-ethoxysalicylaldehyde, respectively; (ii) en, pn and op indicate that the diamine counterpart is ethylenediamine, 1,3-diaminopropane and o-phenylenediamine, respectively. Copper(II) in all these compounds occupies a N2O2 compartment and the two phenoxo oxygen atoms in all cases bridge one copper(II) and one silver(I) centers. Compound 4 is a trinuclear CuIIAgICuII system. Compounds 3 and 5–9 are dimer-of-dinuclear compounds, in which the dimerization takes place due to interdinuclear Cu–O(nitrate) and Ag⋯Ag interactions in 3, 5 and 6 and due to Ag–π (η1-/η2-) bonds in 7–9. Compounds 2 and 1 are one-dimensional coordination polymers due to Ag–π (η2-)/Ag–π (η3-) bonds. CSD search/analysis reveals some definite significant aspects in both the Ag–π and Ag⋯Ag bonded systems in the present investigation.

Synthesis and Characterization of Template Cr(III),Fe(III), Mn(II), Cd(II) and V(IV), Complexes Derived from 2,6- Diaminopyridine and 1,4-Dihydro-Quinoxalin-2,3-dione.

A new series of tetradentate N2O2 acyclic complexes of type (M(L)X2)Xn where M = Mn(II), Cd, Cr(III) and Fe(III); L is tetradentate acyclic Schiff base formed via condensation reaction, and X = Cl-, n=1 for M(III), have been prepared on the basis of condensation of 2,6-diaminopyridine and 1,4-dihydro-quinoxalin-2, 3-dione by template method. The complexes are formulated as: (M(L)Cl)Cl where M=Cr, Fe(III),(MLCl2),MII=Mn, Cd(II) and (VOL)SO4 on the basis of elemental analyses,molar conductance and other spectral data. The organic moiety formed up on template condensation behaves as tetradentate N2O2 system through the two azomethine nitrogen atoms of -C=N- and the participation of O atoms of -C=O in 2- position of pyrazine ring. However, the pyridine nitrogen atom does not take part in coordination as confirmed by FTIR,UV-Visible and H NMR spectroscopy data. The newly template metal complexes have characterized with the help of various spectral techniques H NMR,13C NMR, F.T.I.R, elemental analyses, electronic spectra, molar conductivity measurements and magnetic susceptibilities. The octahedral geometry has been proposed for Cr(III),Fe(III), Mn (II) and Cd(II) while vanadyl complex was square pyramid configuration respectively. Keywords: Template complex, Quinoxaline-3, 2-dione, Schiff bases.

Synthesis, spectral characterization and X-ray crystal structure of Fe(III) and Co(III) complexes with an acyclic Schiff base ligand

Two complexes of composition [Co(HL)2]·ClO4·CH3OH (1) and [Fe2L3]·0.38H2O (2) (H2L=2-((2-(2-hydroxybenzylamino)ethylamino)methyl)phenol) have been synthesized and their structures have been characterized. The mononuclear cobalt complex 1 shows the metal ion Co(III) in an octahedral environment, being coordinated to two ligand molecules in a N4O2 core, remaining one of the two hydroxyl phenol groups of each ligand not deprotonated and uncoordinated. Instead, complex 2 is dinuclear, and each of the two metal centers is coordinated by one molecule ligand and other ligand molecule acts as bridge between the two metal centers, resulting a distorted N4O2 octahedral environment for each Fe(III) ion. In this case the two hydroxyl phenol groups of the ligand molecules are deprotonated and coordinated. Variable-temperature solid-state magnetic studies have been performed for compound 2.

Synthesis and spectroscopic studies of dinuclear Schiff base and its transition metal complexes with Cr(III), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) ions

An acyclic Schiff base ligand containing N2O3 donor atoms was synthesized by the condensation reaction of 2,6-diformyl-4-ter-butylphenol and 4-aminoantipyrine. The synthesized ligand and complexes of the metal ions [CrIII, FeIII, CoII,NiII,CuII and ZnII] were characterized by 1HNMR, 13CNMR, mass spectrometry, UV/visible, FTIR, atomic absorption, elemental analysis (C.H.N.), molar conductivitym and magnetic susceptibility measurements. A binuclear complex was obtained through phenolic oxygen acting as a bridge between two metal ions.

Pentadentate N2O3 Schiff Base Complexes of Rare Earth Metals

Acyclic Schiff base ligand containing N2O3 donor atoms was synthesized by the reaction of 2,6 – diformyl – 4 – ter-butylphenol and 4 – aminoantipyrine in 1:2 molar ratio. The synthesized ligand (H1L) and Ln(III) complexes [Ln= LaIII, CeIII and GdIII] were characterized by1HN.M.R., 13CN.M.R., mass spectrometry, UV /Visible, FTIR, Elemental analysis (C.H.N.), Magnetic susceptibility and Molar conductivity measurements. A seven coordinated complex obtained through N2O3 and two chloride atoms coordinated to metal ions.

Spectral, Electrochemical, Fluorescence, Kinetic and Anti-microbial Studies of Acyclic Schiff-base Gadolinium(III) Complexes

Centre for Advanced Studies in Botany, University of Madras, Guindy Maraimalai Campus, Chennai 600 025, IndiaReceived June 5, 2012, Accepted August 1, 2012A new series of acyclic mononuclear gadolinium(III) complexes have been prepared by Schiff-base con-densation derived from 5-methylsalicylaldehyde, diethylenetriamine, tris(2-aminoethyl) amine, triethylene-tetramine, N,N-bis(3-aminopropyl)ethylene diamine, N,N-bis(aminopropyl) piperazine, and gadolinium nitrate.All the complexes were characterized by elemental and spectral analyses. Electronic spectra of the complexesshow azomethine (CH=N) within the range of 410-420 nm. The fluorescence efficiency of Gd(III) ion in thecavity was completely quenched by the higher chain length ligands. Electrochemical studies of the complexesshow irreversible one electron reduction process around −2.15 to −1.60 V The reduction potential ofgadolinium(III) complexes shifts towards anodic directions respectively upon increasing the chain length. Thecatalytic activity of the gadolinium(III) complexes on the hydrolysis of 4-nitrophenylphosphate was determin-ed. All gadolinium(III) complexes were screened for antibacterial activity. Key Words : Schiff-base ligands, Gadolinium(III) complexes, Fluorescence, Kinetic, Anti-microbialIntroductionIn the past decade, a great attention has been devoted tothe design and the synthesis of macrocyclic ligands and theirlanthanide complexes are a fascinating area of research,owing to their importance in basic and applied chemistry. Inparticular, acyclic Schiff bases have successfully been pro-posed as excellent systems in the formation of mono, homo,hetero nuclear lanthanide complexes.

Synthesis, spectroscopic characterization and crystal structure of novel NNNN-donor μ-bis(bidentate) tetraaza acyclic Schiff base ligands

Novel NNNN-donor μ-bis(bidentate) tetraaza acyclic Schiff base ligands with different substituents (CF3, N(CH3)2 or OH groups) were synthesized by the condensation reaction of triethylenetetramine with 4-substituted benzaldehydes. Triethylenetetramine tris(4-trifluoromethylbenzylidene) (TTFMB), triethylenetetramine tris(4-dimethylaminobenzylidene) (TTDMB) and triethylenetetramine tris(2,4-dihydroxybenzylidene) (TTDHB) were formed as N4 donor ligands. The formation of a five-membered imidazolidine ring from the ethylenediamine backbone as a spacer-cumbridging unit gives rise to a new type of imidazolidine ligand. The structure of the TTFMB and TTDMB were determined by single crystal X-ray crystallography. The synthesized ligands have been characterized on the basis of the results of cyclic voltammetry (CV) and spectroscopic studies viz. FT-IR spectroscopy (FT-IR), mass spectroscopy (MS) and UV–Vis spectroscopy (UV–Vis).