Topological degeneracy of magnetic orbitals in organic biradicals mediated by metal ions: triplet ground state in a titanium(IV) complex of Schiff base diquinone radical ligands

1992 ◽  
pp. 630 ◽  
Author(s):  
Andrea Caneschi ◽  
Andrea Dei ◽  
Dante Gatteschi
Keyword(s):  
Schiff Base ◽  
Metal Ions ◽  
Ground State ◽  
Triplet Ground State

Compounds of Copper(II) and Nickel(II) with 6,8,8,13,13,15-Hexamethyl-1,2,4,5,9,12- hexaazacyclopentadeca-5,15(1)-diene and Some 3-Substituted Homologues

1998 ◽  
Vol 51 (7) ◽  
pp. 611 ◽  
Author(s):  
Neil F. Curtis ◽  
Olga P. Gladkikh ◽  
David C. Weatherburn ◽  
John S. De Courcey ◽  
T. Neil M. Waters
Keyword(s):  
Metal Ions ◽  
Ground State ◽  
Mirror Symmetry ◽  
Macrocyclic Ligand ◽  
The Other ◽  
Singlet Ground State ◽  
Triplet Ground State ◽  
Square Planar

Copper(II) and nickel(II) compounds, [M(L)]2+, of the macrocyclic ligand 6,8,8,13,13,15-hexamethyl-1,2,4,5,9,12-hexaazacyclopentadeca-5,15(1)-diene are formed by reaction of compounds of 4,4,9,9-tetramethyl-5,8-diazadodecane-2,11-dione dihydrazone with methanal. Analogous reactions with aldehydes RHCO, or ketones RR′CO, form compounds of 3-R or 3-RR′ substituted ligands, [M(r- L)]2+ or [M(rr′-L)]2+, respectively. The nickel(II) cations form singlet ground state salts, e.g. [Ni(L)]X2, X = [ClO4]- or ½[ZnCl4]2-, and also triplet ground state compounds, e.g. [Ni(L) (NCS)2] and [Ni(L)(X)] (ClO4) (X = NO2-, C2O42-, N3-, etc.). The structures of [Cu(L)] (ClO4)2, [Ni(L)] (ClO4)2, the 3-propyl compound formed from butanal, [Cu(pr-L)] (ClO4)2.H2O, and the compounds of 9,11,11,16,16,18-hexamethyl-7,8,12,15,19,20-hexaazaspiro[5.14]eicosa-8,18(1)-diene (chex-L), formed from cyclohexanone, namely [Cu(chex-L)] (ClO4)2.MeOH, [Ni(chex-L)] (ClO4)2, and [Ni(chex-L)] (ClO4)2.MeOH, were determined. All have the metal ions in tetrahedrally twisted square-planar coordination, by N1, N5, N9 and N12 , with N9N12-rac, for the (L) and (pr-L) compounds, or by the structurally equivalent N3, N7, N10 and N14, with N7N10-rac, for the (chex-L) compounds. The [Cu(L)]2+ and [Cu(pr-L)]2+cations have saddle-like macrocycle conformations, with approximate mirror symmetry, while the other compounds have ′twisted′ macrocycle conformations with approximate twofold symmetry {[Cu(L)] (ClO4)2, C15H32Cl2CuN6O8, orthorhombic,P 212121, a 8·562(7), b 13·096(8), c 20·257(6) Å, Z 4, R 0·041 for 1540 reflections; [Ni(L)] (ClO4)2, C15H32Cl2N6NiO8, orthorhombic, P21/n, a 13·500(3), b 9·207(2), c 19·478(5) Å, β 103·94(2)°, Z 4, R1 0·055 for 2650 reflections; [Cu(Pr-L)] (ClO4)2.H2O, C18H40Cl2CuN6O9, monoclinic, C 2, a 24·229(5), b 13·780(3), c 8·877(2) Å, β 108·79(3)°, Z 4, R1 0·067 for 1765 reflections; [Cu(chex-L)] (ClO4)2.MeOH, C21H44Cl2CuN6O9, monoclinic, C 2/c, a 17·086(5), b 24·539(2), c 14·496(1) Å, β 89·94(2), Z 8, R1 0·072 for 2521 reflections; [Ni(chex-L)] (ClO4)2, C20H40Cl2N6NiO8, monoclinic, P 21/c, a 14·820(2), b 18·599(4), c 10·282(1) Å, β 106·26(1)°, Z 4, R1 0·067 for 2552 reflections; [Ni(chex-L)] (ClO4)2.MeOH, C21H44Cl2CuN6O9, monoclinic, C 2/c, a 14·451(2), b 24·11(2), c 16·740(3) Å, β 90·14(1)°, Z 8, R1 0·064 for 2598 reflections}.

Synthesis, Characterization and in vitro Biological Evaluation of a New Schiff Base Derived from Drug and its Complexes with Transition Metal Ions

2018 ◽  
Vol 69 (7) ◽  
pp. 1678-1681
Author(s):  
Amina Mumtaz ◽  
Tariq Mahmud ◽  
M. R. J. Elsegood ◽  
G. W. Weaver
Keyword(s):  
Schiff Base ◽  
Transition Metal ◽  
Metal Ions ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Free Ligand ◽  
Transition Metal Ions ◽  
Biological Evaluation ◽  
Pyridoxal Hydrochloride

New series of copper (II), cobalt (II), zinc (II), nickel (II), manganese (II), iron (II) complexes of a novel Schiff base were prepared by the condensation of sulphadizine and pyridoxal hydrochloride. The ligand and metal complexes were characterized by utilizing different instrumental procedures like microanalysis, thermogravimetric examination and spectroscopy. The integrated ligand and transition metal complexes were screened against various bacteria and fungus. The studies demonstrated the enhanced activity of metal complexes against reported microbes when compared with free ligand.

Efficient Preconcentration of Cu2+, Zn2+ and Fe3+ with an Agarose-Schiff Base Sorbent

2007 ◽  
Vol 72 (7) ◽  
pp. 908-916 ◽  
Author(s):  
Payman Hashemi ◽  
Hatam Hassanvand ◽  
Hossain Naeimi
Keyword(s):  
Schiff Base ◽  
Metal Ions ◽  
Metal Ion ◽  
Good Accuracy ◽  
Kinetic Studies ◽  
Sample Volume ◽  
Effects Of Ph ◽  
Glass Column ◽  
High Concentrations ◽  
Ph Range

Sorption and preconcentration of Cu2+, Zn2+ and Fe3+ on a salen-type Schiff base, 2,2'- [ethane-1,2-diylbis(nitrilomethylidyne)]bis(2-methylphenol), chemically immobilized on a highly crosslinked agarose support, were studied. Kinetic studies showed higher sorption rates of Cu2+ and Fe3+ in comparison with Zn2+. Half-times (t1/2) of 31, 106 and 58 s were obtained for sorption of Cu2+, Zn2+ and Fe3+ by the sorbent, respectively. Effects of pH, eluent concentration and volume, ionic strength, buffer concentration, sample volume and interferences on the recovery of the metal ions were investigated. A 5-ml portion of 0.4 M HCl solution was sufficient for quantitative elution of the metal ions from 0.5 ml of the sorbent packed in a 6.5 mm i.d. glass column. Quantitative recoveries were obtained in a pH range 5.5-6.5 for all the analytes. The volumes to be concentrated exceeding 500 ml, ionic strengths as high as 0.5 mol l-1, and acetate buffer concentrations up to 0.3 mol l-1 for Zn2+ and 0.4 mol l-1 for Cu2+ and Fe3+ did not have any significant effect on the recoveries. The system tolerated relatively high concentrations of diverse ions. Preconcentration factors up to 100 and detection limits of 0.31, 0.16 and 1.73 μg l-1 were obtained for Cu2+, Zn2+ and Fe3+, respectively, for their determination by a flame AAS instrument. The method was successfully applied to the metal ion determinations in several river water samples with good accuracy.

scholarly journals Utilization and simulation of innovative new binuclear Co(ii), Ni(ii), Cu(ii), and Zn(ii) diimine Schiff base complexes in sterilization and coronavirus resistance (Covid-19)

2021 ◽  
Vol 19 (1) ◽  
pp. 772-784
Author(s):  
Moamen S. Refat ◽  
Ahmed Gaber ◽  
Walaa F. Alsanie ◽  
Mohamed I. Kobeasy ◽  
Rozan Zakaria ◽  
...  
Keyword(s):  
Schiff Base ◽  
Molecular Docking ◽  
Metal Ions ◽  
Free Ligand ◽  
Schiff Base Complexes ◽  
Hydroxyl Groups ◽  
Binuclear Complexes ◽  
Central Metal ◽  
H Nmr ◽  
Biological Studies

Abstract This article aimed at the synthesis and molecular docking assessment of new diimine Schiff base ligand, namely 2-((E)-(2-((Z)-2-(4-chlorophenyl)-2-hydroxyvinyl)hydrazono) methyl)-6-methoxyphenol (methoxy-diim), via the condensation of 1-(4-chloro-phenyl)-2-hydrazino-ethenol compound with 2-((E)-(2-((Z)-2-(4-chlorophenyl)-2-hydroxy vinyl) hydrazono)methyl)-6-methoxyphenol in acetic acid as well as the preparation of new binuclear complexes of Co(ii), Ni(ii), Cu(ii), and Zn(ii). The following synthesized complexes were prepared in a ratio of 2:1 (metal/ligand). The 1H-NMR, UV-Vis, and FTIR spectroscopic data; molar conductivity measurements; and microanalytical, XRD, TGA/DTG, and biological studies were carried out to determine the molecular structure of these complexes. According to the spectroscopic analysis, the two central metal ions were coordinated with the diamine ligand via the nitrogen of the hydrazine and oxygen of the hydroxyl groups for the first metal ions and via the nitrogen of the hydrazine and oxygen of the phenol group for the second metal ions. Molecular docking for the free ligand was carried out against the breast cancer 3hb5-oxidoreductase and the 4o1v-protein binding kidney cancer and COVID-19 protease, and good results were obtained.

Complexes of water-soluble hexadentate schiff base ligands with a number of metal ions

Polyhedron ◽  
1988 ◽  
Vol 7 (19-20) ◽  
pp. 1881-1889 ◽  
Author(s):  
Dennis F. Evans ◽  
David A. Jakubovic
Keyword(s):  
Schiff Base ◽  
Metal Ions ◽  
Water Soluble ◽  
Schiff Base Ligands
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