Synthesis and characterization of a new macrocyclic Schiff base derived from 2,6-diaminopyridine and 1,10-bis(2-formylphenyl)-1,4,7,10-tetraoxadecane and its Cu(II), Ni(II), Pb(II), Co(III) and La(III) complexes

Polyether complexes of groups 13 and 14

Notable aspects of the chemistry of polyether complexes of group 13 and 14 elements are reviewed.

Synthesis, characterization and experimental, theoretical, electrochemical, antioxidant and antibacterial study of a new Schiff base and its complexes

A new Schiff base ligand was synthesized by reaction of salicylaldehyde with 1,6-bis(4-chloro-2-aminophenoxy)hexane. Then the Schiff base complexes were synthesized by metal salts and the Schiff base. The metal to ligand ratio of metal complexes was found to be 1:1. The Cu(II) complex is proposed to be square planar and the Co(II), Ni(II), Mn(II) and Zn(II) complexes are proposed to be tetrahedral geometry. The Ti(III) and V(III) complexes are proposed to be a capped octahedron in which a seventh ligand has been added to triangular face. The complexes are non-electrolytes as shown by their molar conductivities (ΛM). The structure of metal complexes is proposed from elemental analysis, FT-IR, UV-vis, magnetic susceptibility measurements, molar conductivity measurements, Mass Spectra and thermal gravimetric analysis. In addition antimicrobial and antioxidant studies, cyclic voltammetry of the complexes, theoretical 1H NMR and HOMO-LUMO energy calculations of the new di-functional ligand were done.

Spectroscopic characterization of Lanthanoid derived from a hexadentate macrocyclic ligand: study on antifungal capacity of complexes

Complexes of Ce(III), Nd(III), Sm(III) and Eu(III) were synthesized with NO-donor 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. The ligand was obtained by the condensation of 2,6-diacetylpyridine with thiourea and characterized by elemental analysis, mass, IR and (1)H NMR spectral studies. All the complexes were characterized by elemental analyses, molar conductance measurements, magnetic susceptibility measurements, IR, mass, electronic spectral techniques and thermal studies. The ligand acts as a hexadentate and coordinated through four nitrogen atoms of azomethine groups and two nitrogen atoms of pyridine ring. The value of spectral parameters i.e. nephelauxetic effect (b), covalency factor (b(1/2)), Sinha parameter (δ%) and covalency angular overlap parameter (η) account for the covalent nature of the complexes. The macrocyclic ligand and its Lanthanoid were tested in vitro against two plant pathogenic fungi in order to assess their antifungal capacity.

Synthesis and characterization of 1,2-bis(2-(5-bromo-2-hydroxybenzilidenamino)-4-chlorophenoxy)ethane and its metal complexes: an experimental, theoretical, electrochemical, antioxidant and antibacterial study

A new Schiff base ligand was synthesized by reaction of 5-bromosalicylaldehyde with 1,2-bis(4-chloro-2-aminophenoxy)ethane. Then the Schiff base complexes were synthesized by the reaction of metal salts and the novel Schiff base. The molar conductivity properties of the complexes were studied and found out that the complexes are nonelectrolytes. The structures of the ligand and its metal complexes were characterized by elemental analysis, FT-IR, UV-VIS, magnetic susceptibility measurements, molar conductivity measurements, and thermal gravimetric analysis. In addition antioxidant, theoretical NMR studies and cyclic voltammetry of the complexes were done. Two methods namely metal chelating activity and diphenylpicrylhydrazyl (DPPH) radical scavenging method were used to determine the antioxidant activity, and antibacterial properties of the compounds were also studied.

Synthesis and characterization of some new Cu(II), Ni(II) and Zn(II) complexes with salicylidene thiosemicarbazones: antibacterial, antifungal and in vitro antileukemia activity

Thirty two new Cu(II), Ni(II) and Zn(II) complexes (1–32) with salicylidene thiosemicarbazones (H₂L¹–H₂L¹⁰) were synthesized. Salicylidene thiosemicarbazones, of general formula (X)N-NH-C(S)-NH(Y), were prepared through the condensation reaction of 2-hydroxybenzaldehyde and its derivatives (X) with thiosemicarbazide or 4-phenylthiosemicarbazide (Y = H, C₆H₅). The characterization of the new formed compounds was done by ¹H-NMR, ¹³C-NMR, IR spectroscopy, elemental analysis, magnetochemical, thermoanalytical and molar conductance measurements. In addition, the structure of the complex 5 has been determined by X-ray diffraction method. All ligands and metal complexes were tested as inhibitors of human leukemia (HL-60) cells growth and antibacterial and antifungal activities.

Coordination behavior of tetraaza [N₄] ligand towards Co(II), Ni(II), Cu(II), Cu(I) and Pd(II) complexes: synthesis, spectroscopic characterization and anticancer activity

Novel eight Co(II), Ni(II), Cu(II), Cu(I) and Pd(II) complexes with [N(4)] ligand (L) i.e. 2-amino-N-{2-[(2-aminobenzoyl)amino]ethyl}benzamide have been synthesized and structurally characterized by elemental analysis, spectral, thermal (TG/DTG), magnetic, and molar conductivity measurements. On the basis of IR, mass, electronic and EPR spectral studies an octahedral geometry has been proposed for Co(II), Ni(II) complexes and Cu(II) chloride complex, square-pyramidal for Cu(I) bromide complex. For Cu(II) nitrate complex (6), Pd(II) complex (8) square planar geometry was proposed. The EPR data of Cu(II) complexes in powdered form indicate d(x2-y2) ground state of Cu(II) ion. The antitumor activity of the synthesized ligand and some selected metal complexes has been studied. The palladium(II) complex (8) was found to display cytotoxicity (IC(50)=25.6 and 41 μM) against human breast cancer cell line MCF-7 and human hepatocarcinoma HEPG2 cell line.

Synthesis of Complexes of Pb(II), Cd(II), Zn(II), Ni(II), La(III) and Cu(II) with a Schiff Base Macrocyclic Ligand Containing Pyridine

1,5-bis(2-formylphenyl)pentane (synthesised from 1,5 dibromopentane and salicylaldehyde). reacts with 2,6-diaminopyridine to give a new macrocyclic ligand that gives Cu(II), Ni(II), Pb(II), Zn(II), Cd(II) and La(III) complexes by reaction with Cu(NO3)2·3H2O, Ni(NO3)2·6H2O, Pb(NO3)2, Zn(NO3)2·6H2O, Cd(NO3)2·4H2O and La(NO3)3·6H2O respectively. The ligand and its metal complexes have been characterised by elemental analysis, IR, 1H and 13C NMR, UV-Vis spectra, magnetic susceptibility, conductivity measurements and mass spectra. All complexes are diamagnetic and the Cu(II) complex is binuclear.

Lanthanide complexes derived from hexadentate macrocyclic ligand: synthesis, spectroscopic and thermal investigation

The lanthanide complexes derived from (3,5,13,15-tetramethyl 2,6,12,16,21-22-hexaazatricyclo[15.3.I(1-17)I(7-11)]cosa-1(21),2,5,7,9,11(22),12,15,17,19-decane) were synthesized. The complexes were found to have general composition [Ln(L)X(2).H(2)O]X, where Ln=La(3+), Ce(3+), Nd(3+), Sm(3+) and Eu(3+) and X=NO(3)(-) and Cl(-). The ligand was characterized by elemental analyses, IR, Mass, and (1)H NMR spectral studies. All the complexes were characterized by elemental analyses, molar conductance measurements, magnetic susceptibility measurements, IR, Mass, electronic spectral techniques and thermal studies. The ligand acts as a hexadentate and coordinates through four nitrogen atoms of azomethine groups and two nitrogen of pyridine ring. The lanthanum complexes are diamagnetic while the other Ln(III) complexes are paramagnetic. The spectral parameters i.e. nephelauxetic ratio (beta), covalency factor (b(1/2)), Sinha parameter (delta%) and covalency angular overlap parameter (eta) have been calculated from absorption spectra of Nd(III) and Sm(III) complexes. These parameters suggest the metal-ligand covalent bonding. In the present study, the complexes were found to have coordination number nine.

Synthesis and Spectral Studies of Macrocyclic Pb(II), Zn(II) and La(III) Complexes by Template Reaction of 1,4-Bis(3-Aminopropoxy)Butane with Metal Nitrate and Salicylaldehyde Derivatives

Six new macrocyclic complexes are synthesised by template reaction of 1,4-bis(3-aminopropoxy)butane with metal nitrate and 1,7-bis(2-formylphenyl)-1,4,7-trioxaheptane or 1,10-bis(2-formylphenyl)-1,4,7,10-tetraoxadecane and their structures are proposed on the basis of elemental analysis, FTIR, UV-Vis, molar conductivity measurements, 1H NMR and mass spectra. The complexes are 1:2 electrolytes for Pb(II),Zn(II) complexes and 1:3 electrolytes for La(III) as shown by their molar conductivities (Λm) in DMSO at 10−3 mol L−1. The configurations of La(III) and Zn(II) complexes are proposed to probably octahedral.

Synthesis and characterisation of Schiff base macrocyclic Pb(II), Zn(II), Cd(II) and La(III) complexes by template reaction of (±)-trans-1,2-diaminocyclohexane with metal nitrates and salicylaldehyde derivatives

Eight macrocyclic complexes have been synthesised by template reaction of (±)- trans-1,2-diaminocyclohexane with metal nitrates and 1,10-bis(2-formylphenyl)-1,4,7,10-tetraoxadecane or 1,7-bis(2-formylphenyl)-1,4,7-trioxaheptane, and their structures are proposed on the basis of elemental analysis, FT-IR, UV-Vis, molar conductivity measurements, 1H The complexes NMR and mass spectra. The metal-to-ligand molar ratios are 1:1 in the complexes, which are 1:2 electrolytes for Pb(II), Cd(II) and Zn(II) and 1:3 electrolytes for La(III)