Modern spectroscopic techniques in the characterization of Schiff base macrocyclic ligand and its complexes with transition metals

Mn(II), Co(II), Ni(II), and Cu(II) complexes with a new azamacrocyclic tetradentate [N(4)] ligand i.e. 2,3,9,10-tetraphenyl;l,4,8,11-tetraazacyclotetradeca;1,3,8,10-tetraene (L) have been synthesized and characterized by elemental analysis, molar conductance measurements, magnetic susceptibility measurements, mass, (1)HNMR, IR, electronic and EPR spectral studies. On the basis of their non-electrolytic nature, the probable formula of the complexes is proposed to be [M(L)X(2)], where M=Mn(II), Co(II), Ni(II), and Cu(II), X=Cl(-) and NO(3)(-), in dimethylformamide (DMF). All the complexes are of high-spin type and found to have six coordinated, octahedral geometry for Mn(II), Co(II), and Ni(II) complexes, and tetragonal for Cu(II) complexes. Macrocyclic ligand and its complexes have also been screened against pathogenic bacteria and fungi in vitro as growth inhibiting agent.     

Spectroscopic studies on Mn(II), Co(II), Ni(II), and Cu(II) complexes with N-donor tetradentate (N4) macrocyclic ligand derived from ethylcinnamate moiety

Manganese(II), cobalt(II), nickel(II), and copper(II) complexes are synthesized with a novel tetradentate ligand, viz. 1,5,9,13-tetraaza-6,14-dioxo-8,16-diphenylcyclohexadecane (L) and characterized by the elemental analysis, molar conductance measurements, magnetic susceptibility measurements, mass, 1H NMR, IR, electronic, and EPR spectral studies. The molar conductance measurements of the complexes in DMSO correspond to be nonelectrolyte nature for Mn(II), Co(II), and Cu(II) whereas 1:2 electrolytes for Ni(II) complexes. Thus, these complexes may be formulated as [M(L)X(2)] and [Ni(L)]X(2), respectively (where M = Mn(II), Co(II), and Cu(II) and X = Cl- and NO(3-)). On the basis of IR, electronic, and EPR spectral studies an octahedral geometry has been assigned for Mn(II) and Co(II) complexes, square-planar for Ni(II) whereas tetragonal for Cu(II) complexes. The ligand and its complexes were also evaluated against the growth of bacteria and pathogenic fungi in vitro.     

Spectroscopic approach in characterization of chromium(III), manganese(II), iron(III) and copper(II) complexes with a nitrogen donor tetradentate, 14-membered azamacrocyclic ligand

The complexes of Cr(III), Mn(II), Fe(III) and Cu(II) were synthesized with the macrocyclic ligand i.e. 2,3,9,10-tetraketo-1,4,8,11-tetraazacyclotetradecane. The ligand was prepared by the [2 + 2] condensation reaction of diethyloxalate and 1,3-diamino propane. These complexes were found to have the general composition M(L)X3 and M'(L)X2 [where M = Mn(II) and Cu(II), M' = Cr(III) and Fe(III), L = ligand (N4) and X = Cl-, NO3-, 1/2SO4(2-) and [CH3COO-]. The ligand and its transition metal complexes were characterized by the elemental analyses, molar conductance, magnetic susceptibility, mass, IR, electronic, and EPR spectral studies. On the basis of IR, electronic and EPR spectral studies an octahedral geometry has been assigned for Cr(III), Mn(II) and Fe(III) and a tetragonal geometry for Cu(II) complexes.     

Spectroscopic characterization of tetradentate macrocyclic ligand: its transition metal complexes

Manganese(II), cobalt(II), nickel(II) and copper(II) complexes are synthesized with a novel tetradentate ligand viz. 1,3,9,11-tetraaza-4,8,12,16-tetraoxo-2,6,10,14-tetrathiacyclohexadecane (L) and characterized by the elemental analysis, molar conductance measurements, magnetic susceptibility measurements, electron impact mass, 1H NMR, IR, electronic and EPR spectral studies. The molar conductance measurements of the complexes in DMSO correspond to be nonelectrolytic nature for Mn(II), Co(II) and Cu(II) while 1:2 electrolytes for Ni(II) complexes. Thus these complexes may be formulated as [M(L)X2] and [Ni(L)]X2 (where M: Mn(II), Co(II), and Cu(II) and X = Cl- and NO3-). On the basis of IR, electronic and EPR spectral studies an octahedral geometry has been assigned for Mn(II) and Co(II) complexes, square-planar for Ni(II) whereas tetragonal for Cu(II) complexes. The ligand and its complexes were also evaluated against the growth of bacteria and pathogenic fungi in vitro.     

Mass, EPR, IR and electronic spectroscopic studies on newly synthesized macrocyclic ligand and its transition metal complexes

Manganese(II), cobalt(II), nickel(II) and copper(II) complexes have been synthesized with a new tetradentate ligand viz. 1,3,7,9-tetraaza-2,4,8,10-tetraketo-6,12-diphenyl-cyclododecane (L) and characterized by the elemental analysis, molar conductance measurements, magnetic susceptibility measurements, mass, ¹H NMR, IR, electronic and EPR spectral studies. The molar conductance measurements of the complexes in DMF correspond to be nonelectrolytic nature for Mn(II), Co(II) and Cu(II) while 1:2 electrolytes for Ni(II) complexes. Thus, these complexes may be formulated as [M(L)X₂] and [Ni(L)]X₂ (where M = Mn(II), Co(II) and Cu(II) and X = Cl⁻ and NO₃⁻).On the basis of IR, electronic and EPR spectral studies an octahedral geometry has been assigned for Mn(II) and Co(II) complexes, square-planar for Ni(II) whereas tetragonal for Cu(II) complexes. The ligand and its complexes were also evaluated against the growth of bacteria and pathogenic fungi in vitro.     

Transition Metal Complexes of Dis(thiosemicarbazone): Synthesis and Spectral,and Antifungal Studies

Mn(II), Co(II), Ni(II), and Cu(II) complexes have been synthesized with benzil bis(thiosemicarbazone) (L) and characterized by elemental analyses, molar conductance measurements, magnetic susceptibility measurements, thermogravimetric studies, infrared (IR), electronic, and electron paramagnetic resonance (eEPR) spectral studies. The molar conductance measurements of the complexes in DMF correspond to the non-electrolytic nature of the complexes. Thus these complexes may be formulated as [M(L)X₂] (where M = Mn(II), Co(II), Ni(II), Cu(II) and X = Cl^? and NO₃ ^?). On the basis of IR, electronic, and EPR spectral studies, an octahedral geometry has been assigned for Mn(II), Co(II), and Ni(II) complexes, whereas a tetragonal geometry for the Cu(II) complexes is presumed. The free ligand and its metal complexes were tested against the phytopathogenic fungi (i.e., Rhizoctonia baticola, Alternaria alternata) in vitro.     

Synthesis and Antibacterial Activity of Metal Complexes of Cephalothin

The interactions of cephalothin (Hcephalo) with transition metal(II) ions and imidazole have been investigated. The complexes [M(cephalo)Cl], (where M=Mn(II), Co(II), Ni(II), Pd(II)) and [M(cephalo)(Im)Cl] (where M=Ni(II), Cu(II), Zn(II), Im=Imidazole) were obtained and characterized by physicochemical and spectroscopic methods. The IR and the ¹H-NMR spectra of the complexes suggest that the cephalothin behaves as a monoanionic tridentate ligand. They have been screened for antibacterial activity against several bacteria, and the results are compared with the activity of cephalothin.     

Physicochemical and Biological Characterization of Transition Metal Complexes with a Nitrogen Donor Tetra-dentate Novel Macrocyclic Ligand

A novel tetradentate nitrogen donor [N₄] macrocyclic ligand, i.e. 3,5,13,15,21,22-hexaaza-2,6,12,16-tetramethyl-4,14-dithia-tricyclo[15.3.1.1(7–11)]docosane-1(21),2,5,7,9,11(22),12,15,17,19-decaene, has been synthesized. Mn(II), Co(II), Ni(II) and Cu(II) complexes with this ligand have been prepared and subjected to elemental analyses, molar conductance measurements, magnetic susceptibility measurements, mass, ¹H-n.m.r. (Ligand), i.r., electronic, and e.p.r. spectral studies. On the basis of molar conductance the complexes may be formulated as [M(L)X₂] and [Ni(L)]X₂ [where M = Mn(II), Co(II) and Cu(II), and X = Cl⁻ and NO₃⁻] due to their nonelectrolytic nature in dimethylsulphoxide (DMSO). All the complexes are of the high spin type and are six coordinated. On the basis of i.r., electronic and e.p.r. spectral studies an octahedral geometry has been assigned to Mn(II) and Co(II), square planar for Ni(II) complexes, and tetragonal for Cu(II) complexes. The antimicrobial activities of the ligand and its complexes, as growth inhibiting agents, have been screened in vitro against several species of bacteria and plant pathogenic fungi.     

Complexation and Thermal Studies of Uric Acid with Some Divalent and Trivalent Metal Ions of Biological Interest in the Solid State

Nine new [metal uric acid] complexes [M(Ua) n ]°·XH 2 O have been synthesized. These complexes have been characterized by elemental analysis, X-ray diffraction (XRD), magnetic susceptibility ( w eff. ), FTIR spectra, thermal analysis (TG & DTA), and electronic spectra (UV/visible). Uric acid (HUa) coordinates as a bidentate ligand to Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Al(III), Cr(III) and Fe(III) through the protonated N-7 within the imidazole ring and O-6 within the pyrimidine ring. Uric acid forms neutral metal urate complexes with all the above metal ions. The quantitative compositions were determined as [M(Ua) 2 ·(H 2 O) 2 ]°·XH 2 O where M(II)=Mn, Fe, Co, Ni, Cu, Zn and X=2, 4, 2, 4, 2, 2, respectively. The M(II) complexes exhibit an isostructural octahedral coordination with N-7, O-6 of two uric acid ligand molecules, and O of two water molecules. Compositions were also determined as [M(Ua) 3 ]°·YH 2 O where M(III)=Al, Cr, Fe and Y=6, 3, 3 respectively. All the M(III) complexes form an isostructural octahedral coordination with N-7 and O-6 of three uric acid ligand molecules. Iron(III) complexes prepared with N 1 , N 3 and N 9 -methyl uric acid yielded brown complexes with a metal ligand ratio of 1 3, while N 7 -methyl uric acid did not yield a complex due to blockage of N-7 with a methyl group.     

Potentiometric, spectroscopic and thermal studies on the metal chelates of 1-(2-thiazolylazo)-2-naphthalenol

The synthesis and characterization of Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Pd(II) and UO2(II) chelates of 1-(2-thiazolylazo)-2-naphthalenol (TAN) were reported. The dissociation constants of the ligand and the stability constants of the metal complexes were calculated pH-metrically at 25 degrees C and 0.1 M ionic strength. The solid complexes were characterized by elemental and thermal analyses, molar conductance, IR, magnetic and diffuse reflectance spectra. The complexes were found to have the formulae [M(L)2] for M = Mn(II), Co(II), Ni(II), Zn(II) and Cd(II); [M(L)X].nH2O for M = Cu(II) (X = AcO, n = 3), Pd(II) (X = Cl, n = 0) and UO2(II) (X = NO3, n = 0), and [Fe(L)Cl2(H2O)].2H2O. The molar conductance data reveal that the chelates are non-electrolytes. IR spectra show that the ligand is coordinated to the metal ions in a terdentate manner with ONN donor sites of the naphthyl OH, azo N and thiazole N. An octahedral structure is proposed for Mn(II), Fe(III), Co(II), Ni(II), Zn(II), Cd(II) and UO2(II) complexes and a square planar structure for Cu(II) and Pd(II) complexes. The thermal behaviour of these chelates shows that water molecules (coordinated and hydrated) and anions are removed in two successive steps followed immediately by decomposition of the ligand molecule in the subsequent steps. The relative thermal stability of the chelates is evaluated. The final decomposition products are found to be the corresponding metal oxides. The thermodynamic activation parameters, such as E*, delta H*, delta S* and delta G* are calculated from the TG curves.     

Nine non-symmetric pyrazine-pyridine imide-based complexes: reversible redox and isolation of [M(II/III)(pypzca)2](0/+) when M = Co, Fe

The non-symmetric imide ligand Hpypzca (N-(2-pyrazylcarbonyl)-2-pyridinecarboxamide) has been deliberately synthesised and used to produce nine first row transition metal complexes: [M(II)(pypzca)(2)], M = Zn, Cu, Ni, Co, Fe; [M(III)(pypzca)(2)]Y, M = Co and Y = BF(4), M = Fe and Y = ClO(4); [Cu(II)(pypzca)(H(2)O)(2)]BF(4), [Mn(II)(pypzca)(Cl)(2)]HNEt(3). These are the first deliberately prepared complexes of a non-symmetric imide ligand. X-ray crystal structures of [Cu(II)(pypzca)(2)]·H(2)O, [Co(II)(pypzca)(2)], [Co(III)(pypzca)(2)]BF(4), [Cu(II)(pypzca)(H(2)O)(2)]BF(4)·H(2)O and [Mn(II)(pypzca)Cl(2)]HNEt(3) show that each of the (pypzca)(-) ligands binds in a meridional fashion via the N(3) donors. In the first three complexes, two such ligands are bound such that the 'spare' pyrazine nitrogen atoms are positioned approximately orthogonally to one another and also to the imide oxygen atoms. In MeCN the [M(II/III)(pypzca)(2)](0/+) complexes, where M = Ni, Co or Fe, exhibit one reversible metal based M(II/III) process and two distinct, quasi-reversible ligand based reduction processes, the latter also observed for M(II) = Zn. [Mn(II)(pypzca)Cl(2)]HNEt(3) displays a quasi-reversible oxidation process in MeCN, along with several irreversible processes. Both copper(II) complexes show only irreversible processes. Variable temperature magnetic measurements show that [Fe(III)(pypzca)(2)]ClO(4) undergoes a gradual spin crossover from partially high spin at 298 K (3.00 BM) to fully low spin at 2 K (1.96 BM), and that [Co(II)(pypzca)(2)] remains high spin from 298 to 4 K. All of the complexes are weakly coloured, other than [Fe(II)(pypzca)(2)] which is dark purple and absorbs strongly in the visible region.     

Synthesis,Spectral Studies and Bio‐activity of Some Ligand Bridged Polymeric Transition Metal Complexes of Acetone p‐Amino Acetophenone Isonicotinoyl Hydrazone

Ligand bridged polymeric complexes of the type [M(apainh)(H₂O)X] where, M=Mn(II), Co(II), Ni(II), Cu(II), and Zn(II); X=Cl₂ or SO₄; apainh=acetone p‐amino acetophenone isonicotinoyl hydrazone have been synthesized and characterized. The complexes are stable solids, insoluble in common organic solvents and are non‐electrolytes. Magnetic moments and electronic spectral studies suggest a spin‐free octahedral geometry for all Mn(II), Co(II), Ni(II), and Cu(II) complexes. IR spectra show tridentate nature of the ligand bonding through two >C?N and a >C?O groups. X‐ray powder diffraction parameters for some of the complexes correspond to orthorhombic and tetragonal crystal lattices. Thermal studies (TGA and DTA) of [Mn(apainh)(H₂O)SO₄] complex show multi‐step decomposition pattern of both an endothermic and exothermic nature. ESR data of Cu(II) chloride complex in solid state show an axial spectra, whereas, Cu(II) sulfate complex is isotropic in nature. The complexes show a significant antifungal activity against a number of pathogenic fungal species and antibacterial activity against Pseudomonas sp. and Clostridium sp. The metal complexes are more active than the ligand.     

Spectroscopic studies of transition metal complexes with a N-donor tetradentate(N4) 12-membered macrocylic ligand

Chromium(III), manganese(II), iron(III), cobalt(II), nickel(II), copper(II), ruthenium(III), iridium(III), palladium(II) and platinum(II) complexes were synthesized with a 12-membered 1,4,7,10-tetraazadodeca-5,6,11,12-tetraene macrocylic ligand (L) and characterized by elemental analysis, molar conductance, magnetic susceptibility, IR, electronic, EPR and M?ssbauer [Fe(III)] spectral studies. The molar conductance measurements of all the complexes in DMF solution correspond to non-electrolytic nature for M(L)Cl2 complexes [where M=Mn(II), Co(II), Ni(II), Cu(II)], 1:1 electrolytes for M'(L)Cl3 complexes [where M'=Cr(III), Fe(III), Ru(III) and Ir(III)] and 1:2 electrolytes for M'(L)Cl2 complexes [where M'=Pd(II) and Pt(II)]. Thus, the complexes may be formulated as [M(L)C1(2)], [M'(L)C1(2)]C1 and [M'(L)]C1(2), respectively [where L=ligand]. All complexes were of the high-spin type and found to have six-coordinate octahedral geometry except the Pd(II) and Pt(II) complexes which were four coordinate, square planar and diamagnetic.     

EPR, IR and electronic spectral studies on Mn(II), Co(II), Ni(II) and Cu(II) complexes with a new 22-membered azamacrocyclic [N4] ligand

The complexes of transition metal ions with an azamacrocyclic tetradentate nitrogen donor [N4] ligand viz. 2,6,12,16,21,22-hexaaza;3,5,13,15-tetramethyltricyclo[15.3.1.1(7-11)] docosa;1(21),2,5,7,9,11(22),12,15,17,19-decaene (L) have been synthesized. All the complexes were found to have general composition M(L)X2 [where M = manganese(II), cobalt(II), nickel(II) and copper(II) and X = Cl- & NO3-]. All the complexes are characterized by the elemental analysis, molar conductance measurements, magnetic susceptibility measurements, mass, 1H NMR, IR, electronic, EPR spectral and cyclic voltammetric studies. An octahedral geometry was assigned for Mn(II), Co(II) and Ni(II) complexes and tetragonal for Cu(II) complexes. The biological actions of the ligand and complexes have been screened in vitro against many bacteria and pathogenic fungi to study their comparative capacity to inhibit the growth.     

Synthesis and antibacterial activity of cephradine metal complexes

Cephradine (Hcephra) interacts with transition metal ions to give [Fe(cephra)Cl₂] and [M(cephra)Cl] complexes (M?=?Mn(II), Co(II), Ni(II), Cu(II) and Zn(II)) which were characterized by physicochemical and spectroscopic methods; a tetrahedral geometry is suggested for their structures where cephradine behaves as monoanionic tridentate ligand. The complexes have been screened for antibacterial activity against several bacteria, and the results showed that all metal complexes tested had lower antibiotic activity than the free ligand.     

Mn(II), Co(II), Ni(II) and Cu(II) complexes of a tertraaza macrocyclic ligand: Synthesis, characterization and biological screening

Manganese(II), cobalt(II), nickel(II) and copper(II) complexes with 1,5,11,15-tetraaza-21,22-dioxo-tricyclo [19,3,1,I^6,10]-5,10,15-20-dicosatetraene (L), as a new macrocyclicligand, have been synthesized with and characterized by elemental analysis, molar conductance measurements, magnetic susceptibility measurements, mass, IR, electronic and EPR spectral studies. The molar conductance measurements of the complexes in DMF correspond to non-electrolytic nature of Mn(II), Co(II) and Cu(II) complexes, while showing a 1:2 electrolyte for thew Ni(II) complexe. Thus, these complexes may be formulated as [M(L)X₂] and [Ni(L)]X₂ (where M = Mn(II), Co(II) and Cu(II) and X = Cl^- and NO₃ ^-). On the basis of IR, electronic and EPR spectral studies, an octahedral geometry has been assigned for Mn(II) and Co(II), a square planar for Ni(II) and tetragonal for Cu(II) complexes. In vitro ligand and its metal complexes were also screened against the growth of some fungal and bacterial species in order to assess their antimicrobial properties.     

Synthesis and characterization of self-assembled coordination polymers of N-diaminomethylene-4-(3-formyl-4-hydroxy-phenylazo)-benzenesulfonamide

The azo dye ligand N-diaminomethylene-4-(3-formyl-4-hydroxy-phenylazo)-benzenesulfonamide (HL) and Cu(II), Co(II), and Mn(II) coordination polymers were synthesized in addition to a non-polymeric Pd(II) complex. In all complexes, the ligand bonds to the metal ion through the formyl and α-hydroxy oxygen atoms. The sulfonamide oxygen also coordinates to the metal. The complexes are formulated as [ML₂] _n , where M?=?Cu(II), Co(II), and Mn(II), and [ML(Cl)(H₂O)], where M?=?Pd(II). On the basis of spectral studies and magnetic susceptibility measurements, an octahedral geometry was assigned to Co(II) and Mn(II) complexes, tetragonally elongated octahedral geometry for Cu(II) complex, while the Pd(II) complex was found to be square planar. Crystallization of Cu(II) complex from DMF afforded single crystals of general formula {[Cu(L)₂]?·?3DMF} _n (2). X-ray structural analysis of 2 revealed that each Cu(II) adopts elongated octahedral geometry affording 1-D chains. The chains are connected by hydrogen bonds, resulting in the formation of 2-D supramolecular assemblies. The crystal structure of HL has also been determined and discussed. Cyclic voltammetric behavior of the ligand and some complexes are also discussed.     

Spectral, magnetic and biological studies of 1,4-dibenzoyl-3-thiosemicarbazide complexes with some first row transition metal ions

The ligand 1,4-dibenzoyl-3-thiosemicarbazide (DBtsc) forms complexes [M(DBtsc-H)(SCN)] [M = Mn(II), Co(II) or Zn(II)], [M(DBtsc-H) (SCN)(H₂O)] [M = Ni(II) or Cu(II)], [M(DBtsc-H)Cl] [M = Co(II), Ni(II), Cu(II) or Zn(II)] and [Mn(DBtsc)Cl₂], which have been characterized by elemental analyses, magnetic susceptibility measurements, UV/Vis, IR,¹H and¹³C NMR and FAB mass spectral data. Room temperature ESR spectra of the Mn(II) and Cu(II) complexes yield <g> values, characteristic of tetrahedral and square planar complexes respectively. DBtsc and its soluble complexes have been screened against several bacteria, fungi and tumour cell lines.     

Spectral,physicochemical and biological characterization of 2,5,11,14,19,20-hexaaza-3,12-dimethyl-4,13-dipropyl-tricyclo [13.3.1.1(6-10)]cosane-1(19),2,4,6(20),7,9,11,13,15,17-decaene and its transition metal complexes

The synthesis of a tetradentate nitrogen donor macrocyclic ligand i.e. 2,5,11,14,19,20-hexaaza-3,12-dimethyl-4,13-dipropyl-tricyclo[13.3.1.1(6-10)]cosane-1(19),2,4,6(20),7,9,11,13,15,17-decaene and its complexes with manganese(II), cobalt(II), nickel(II) and copper(II) have been reported. The complexes were characterized by elemental analyses, molar conductance measurements, magnetic susceptibility measurements, mass, ¹H-n.m.r. (Ligand), i.r., electronic, and e.p.r. spectral studies. On the basis of molar conductance the complexes may be formulated as [M(L)X₂] [where M = Mn(II), Co(II), Ni(II) and Cu(II), and X = Cl⁻ & NO ₃⁻ ] due to their nonelectrolytic nature in dimethylformamide (DMF). All the complexes are of the high spin type and are six coordinated. On the basis of i.r., electronic and e.p.r. spectral studies an octahedral geometry has been deduced for Mn(II), Co(II) and Ni(II) complexes, and tetragonal geometry for Cu(II) complexes. The antimicrobial activities of the ligand and its complexes, as growth inhibiting agents, have been screened in vitro against several species of bacteria and plant pathogenic fungi.     

Modern spectroscopic and biological approach in the characterization of a novel 14-membered [N<Subscript>4</Subscript>] macrocyclic ligand and its transition metal complexes

A novel tetradentate nitrogen donor [N₄] macrocyclic ligand, i.e. 1,3,4,8,9,11-hexaaza-2,5,10,12-tetraoxo-7,14-diphenyl-cyclotetradecane (L), has been synthesized. Mn(II), Co(II), Ni(II) and Cu(II) complexes of this ligand have been prepared and subjected to elemental analyses, molar conductance measurements, magnetic susceptibility measurements, mass, ¹H-n.m.r. (Ligand), i.r., electronic, and e.p.r. spectral studies. On the basis of molar conductance the Mn(II), Co(II) and Cu(II) complexes may be formulated as [M(L)X₂] [where X = Cl⁻ & NO ₃ ⁻ ] due to their non-electrolytic nature in dimethylformamide (DMF). Whereas the Ni(II) complexes are 1:2 electrolytes and formulated as [Ni(L)]X₂. All the complexes are of the high spin type and are six/four coordinate. On the basis of i.r., electronic and e.p.r. spectral studies an octahedral geometry has been assigned to Mn(II) and Co(II), square planar for Ni(II) complexes, and tetragonal for Cu(II) complexes. The antimicrobial activities of the ligand and its complexes, as growth inhibiting agents, have been screened in vitro against several species of bacteria and plant pathogenic fungi.