Spectroscopic characterization of chromium(III), manganese(II) and nickel(II) complexes with a nitrogen donor tetradentate, 12-membered azamacrocyclic ligand

The complexes of Cr(III), Mn(II) and Ni(II) were synthesized with macrocyclic ligand i.e. 5,11-dimethyl-6,12-diethyl-dione-1,2,4,7,9,10-hexazacyclododeca -1,4,6,10-tetraene. The ligand (L) was prepared by [2+2] condensation reaction of 2,3-pentanedione and semicarbazide hydrochloride. These complexes were found to have the general composition [Cr(L)X(2)]X and [M(L)X(2)] (where M=Mn(II) and Ni(II); X=Cl(-), NO(3)(-), (1/2)SO(4)(2-), NCS(-) and L=ligand [N(6)]). The ligand and its transition metal complexes were characterized by the elemental analysis, 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 these complexes except sulphato complexes which are of five coordinated geometry.     

Spectroscopy: the study of DNA cleavage by newly synthesized polydentate macrocyclic ligand and its copper(II) complexes

A novel hexadentate nitrogen donor [N6] macrocyclic ligand, i.e. 2,6,12,16,21,22-hexaaza-3,5,13,15-tetramethyl-4,14-diethyl-tricyclo-[15.3.1.1(7-11)]docosane-1(21),2,5,7(22),8,10,12,15,17,19-decaene (L), has been synthesized. Copper(II) complexes with this ligand have been prepared and subjected to elemental analyses, molar conductance measurements, magnetic susceptibility measurements, mass, 1H NMR (ligand), IR, electronic, and EPR spectral studies. On the basis of molar conductance the complexes may be formulated as [Cu(L)X2] [X = Cl(-), Br(-), NO3(-) and CH3COO(-)] due to their nonelectrolytic nature in N,N'-dimethylformamide (DMF). All the complexes are of the high spin type and are six coordinated. On the basis of IR, electronic and EPR spectral studies tetragonal geometry has been assigned to the Cu(II) complexes. The interaction of these complexes with calf thymus DNA has been explored by using absorption, emission, viscosity measurements, electrochemical studies and DNA cleavage. All the experimental results suggest that the complexes bind to DNA and also promote the cleavage plasmid pBR 322, in the presence of H2O2 and ascorbic acid.     

Spectroscopic and biological approach of Ni(II) and Cu(II) complexes of 2-pyridinecarboxaldehyde thiosemicarbazone

Ni(II) and Cu(II) complexes having the general composition [M(L)(2)X(2)] [where L=2-pyridinecarboxaldehyde thiosemicarbazone, M=Ni(II) and Cu(II), X=Cl(-), NO(3)(-) and 1/2 SO(4)(2-)] have been synthesized. All the metal complexes were characterized by elemental analysis, molar conductance, magnetic moment, mass, IR, EPR and electronic spectral studies. The magnetic moment measurements of the complexes indicate that all the complexes are of high-spin type. On the basis of spectral studies an octahedral geometry has been assigned for Ni(II) complexes whereas tetragonal geometry for Cu(II) except [Cu(L)(2)SO(4)] which posseses five coordinated geometry. The ligand and its metal complexes were screened against phytopathogenic fungi and bacteria in vitro.     

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 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.     

EPR and electronic spectral studies on Co(II), Ni(II) and Cu(II) complexes with a new tetradentate [N4] macrocyclic ligand and their biological activity

Cobalt(II), nickel(II) and copper(II) complexes having the general composition M(L)X2 (where M = CO(II), Ni(II) and Cu(II), L = ligand, i.e. 3,4,12,13-tetraketo-2,5,11,14,19,20-hexaazatricyclo[13.3.1.1(6-10)]cosane; 1(19),6,8,10(20),15,17-hexaene and X stands for Cl-; NO3- and SO42-), have been prepared. The structure of the complexes has been elucidated by elemental analysis, molar conductance, magnetic susceptibility measurements, mass, IR, electronic and EPR spectral studies. The magnetic moment measurements of the complexes indicate that the metal ion is in high-spin state. On the basis of IR, electronic and EPR spectral studies an octahedral geometry was assigned for Co(II) and Ni(II) complexes whereas tetragonal geometry for Cu(II) complexes. This ligand and its complexes were also screened against bacteria and pathogenic fungi in vitro.     

Spectroscopic approach in the characterization of the copper(II) complexes of isatin-3,2'-quinolyl-hydrazones and their adducts

Copper(II) complexes of isatin-3,2'-quinolyl-hydrazones of the type [Cu(L)X] (where X=Cl(-), Br(-), NO(3)(-), CH(3)COO(-) and ClO(4)(-)] and their adducts Cu(L)X.2Y [where Y=pyridine or dioxane and X=Cl(-), Br(-), NO(3)(-) and ClO(4)(-)] have been synthesized under controlled experimental conditions and characterized by using the modern spectroscopic and physicochemical techniques viz. IR, electronic, EPR, elemental analysis, magnetic moment susceptibility measurements and molar conductance, etc. On the basis of spectral studies a four coordinated square planer geometry is assigned for Cu(L)X type complexes whereas the adducts (Cu(L)X.2Y were found to have a six coordinated octahedral geometry.     

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.     

EPR, IR and electronic spectral studies on Ni(II) and Cu(II) complexes with N-donor tetradentate [N4] macrocyclic ligand

Nickel(II) and copper(II) complexes are synthesized with a novel tetradentate macrocyclic ligand, i.e. 2,6,12,16,21,22-hexaaza;3,5,13,15-tetraphenyltricyclo[15,3,1,1(7-11)] docosa;1(21),2,5,7,9,11(22),12,15,17,19-decaene (L) and characterized by the elemental analysis, magnetic susceptibility measurements, mass, (1)H NMR, IR, electronic and EPR spectral studies. All the complexes are non-electrolytic in nature. Thus, these may be formulated as [M(L)X(2)] [M=Ni(II), Cu(II) and X=Cl(-), NO(3)(-) and (1/2)SO(4)(2-)]. Ni(II) and Cu(II) complexes show magnetic moments corresponding to two and one unpaired electron, respectively. On the basis of IR, electronic and EPR spectral studies an octahedral geometry has been assigned for Ni(II) and tetragonal geometry for Cu(II) complexes.     

EPR, mass, electronic, IR spectroscopic and thermal studies of bimetallic copper(II) complexes with tetradentate ligand, 1,4-diformyl piperazine bis(carbohydrazone)

The synthesis of novel bimetallic Cu(II) complexes with general stoichiometry [Cu(2)(H(2)L)X(2)(H(2)O)(2)], [Cu(2)(H(2)L)(CH(3)COO)(2)] and [Cu(2)(H(2)L)SO(4)(H(2)O)(2)] (where H(2)L=dideprotonated ligand and X=NO(3)(-) and Cl(-)) derived from tetradentate ligand obtained by the condensation of 1,4-diformyl piperazine with carbohydrazide has been discussed. The complexes were characterized by elemental analyses, molar conductance measurements, magnetic susceptibility measurements, IR, mass, UV, EPR spectral studies and thermogravimetric analyses. The value of magnetic moments indicates that the complexes are paramagnetic and show the antiferromagnetic interaction between the two metal centres. The complexes possess the square planar coordination environment. The values of covalency measurements, i.e., in-plane sigma-bonding alpha(2), in-plane pi-bonding beta(2) and orbital reduction factor k indicate the covalent nature of complexes.     

EPR, mass, IR, electronic, and magnetic studies on copper(II) complexes of semicarbazones and thiosemicarbazones

Copper(II) complexes having the general composition Cu(L)(2)X(2) [where L = isopropyl methyl ketone semicarbazone (LLA), isopropyl methyl ketone thiosemicarbazone (LLB), 4-aminoacetophenone semicarbazone (LLC), and 4-aminoacetophenone thiosemicarbazone (LLD) and X = Cl(-), 1/2SO(4)(2-)] have been synthesized. All the Cu(II) complexes reported here have been characterized by elemental analyses, molar conductance, magnetic moment susceptibility, EI mass, (1)H NMR, IR, EPR, and electronic spectral studies. All the complexes were found to have magnetic moments corresponding to one unpaired electrons. The possible geometries of the complexes were assigned on the basis of EPR, electronic, and infrared spectral studies.     

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.     

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.     

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.     

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.     

Spectroscopic evaluation of Co(II), Ni(II) and Cu(II) complexes derived from thiosemicarbazone and semicarbazone

Co(II), Ni(II) and Cu(II) complexes were synthesized with thiosemicarbazone (L(1)) and semicarbazone (L(2)) derived from 2-acetyl furan. These complexes were characterized by elemental analysis, molar conductance, magnetic moment, mass, IR, electronic and EPR spectral studies. The molar conductance measurement of the complexes in DMSO corresponds to non-electrolytic nature. All the complexes are of high-spin type. On the basis of different spectral studies six coordinated geometry may be assigned for all the complexes except Co(L)(2)(SO(4)) and Cu(L)(2)(SO(4)) [where L=L(1) and L(2)] which are of five coordinated square pyramidal geometry.     

Synthesis,spectral, and antifungal studies of transition metal complexes with sixteen-membered hexadentate macrocylic ligand

A novel hexadentate nitrogen donor [N₆] macrocyclic ligand viz, 1,5,11,15,21,22-hexaaza-2,14-dimethyl-l4,12-diphenyltricyclo[15.3.1.I(7–11)]docosane[1,4,6,8,10(22)-11,14,16,18,20(21)]decaene (L), has been synthesised. The Co (II), Ni (II), and Cu (II) complexes with this ligand have been prepared and subjected to elemental analysis, molar conductance, magnetic susceptibility measurements, mass, ¹H NMR (ligand), IR, electronic, and ESR spectral studies and electrochemical investigation. On the basis of molar conductance the complexes can be formulated as [M(L)]X₂ (where M = Co (II), Ni (II), Cu (II) and X = Cl⁻ and NO₃⁻) due to their 1: 2 electrolytic nature in DMSO. All the complexes are of the high-spin type and are six-coordinated. On the basis of IR, electronic, and ESR spectral studies, an octahedral geometry has been assigned for the Co(II) and Ni(II) complexes, whereas a tetragonal geometry for the Cu(II) complexes was found. Antimicrobial activity of L and its complexes as growth inhibiting agents have been screened in vitro against two species (F. moniliformae and R. solani) of plant pathogenic fungi. The text was submitted by the authors in English.     

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.     

EPR, magnetic and spectral studies of copper(II) and nickel(II) complexes of schiff base macrocyclic ligand derived from thiosemicarbazide and glyoxal

A new macrocylic Schiff base 1,2,5,6,8,11-hexaazacyclododeca-7,12-dithione-2,4,8,10-tetraene(H(2)L(4)) containing thiosemicarbazone moiety is readily prepared and characterized for the first time with fairly good yield. Macrocylic ligand (H(2)L(4)) is prepared from the mesocyle 6-ethoxy-4-thio-2,3,5-triazine(H(2)L(3)) in ethanol with copper chloride acting as template using high dilution technique. The complexes of macrocylic ligand with a general composition M(H(2)L(4))X(2) [where M=Cu(II) or Ni(II); H(2)L(4)=1,2,5,6,8,11-hexaazacyclo dodeca-7,12-dithione-2,4,8,10-tetraene; X= Cl(-), NO(3)(-), (1)/(2)SO(4)(2-)] and ML(4) (where metal salt used to synthesize complex is copper acetate and nickel thiocyanate) have been synthesized. The complexes were characterized on the basis of elemental analysis, molar conductance, magnetic susceptibility, IR, electronic, 1H NMR, mass and EPR spectral studies. The complexes from H(2)L(4) show different stoichiometry ratio and with a variable grade of deprotonation in the ligand, depending upon the salt used and working conditions.     

Synthesis, molecular modeling and spectroscopic characterization of nickel(II), copper(II), complexes of new 16-membered mixed-donor macrocyclic schiff base ligand incorporating a pendant alcohol function

Complexes of Cu(II) and Ni(II) of the composition [M(L)X] [where M=Ni(II), Cu(II) and X=Cl-, NO3-, CH3COO-] were synthesized with 1,5-dioxo-9,10-diaza-3,ol-tribenzo-(7,6,10,11,14,15) peptadecane, a N2O2 macrocyclic ligand. The complexes were characterized by elemental analysis, molar conductance measurements, UV-vis, IR, 1H NMR, 13C NMR, EPR and molecular modeling studies. All the complexes are non-electrolyte in nature. On the basis of spectral studies, an octahedral geometry has been assigned for Ni(II) complexes and a tetragonal geometry for Cu(II) complexes.