Metal Complexes of Biologically Important Ligands, CLXXVI.[1] Formation of Peptides within the Coordination Sphere of Metal Ions and of Classical and Organometallic Complexes and Some Aspects of Prebiotic Chemistry

2011 ◽  
Vol 637 (12) ◽  
pp. 1647-1672 ◽  
Author(s):  
Wolfgang Beck
Keyword(s):  
Metal Ions ◽  
Metal Complexes ◽  
Coordination Sphere ◽  
Prebiotic Chemistry ◽  
Organometallic Complexes

scholarly journals Dynamic Helicity Control of Oligo(salamo)-Based Metal Helicates

Inorganics ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 80 ◽  
Author(s):  
Shigehisa Akine
Keyword(s):  
Chemical Modification ◽  
Metal Ions ◽  
Metal Complexes ◽  
Coordination Sphere ◽  
Review Article ◽  
Fluoride Ion ◽  
Dynamic Feature ◽  
Helical Structures ◽  
External Stimuli ◽  
Ethylene Unit

Much attention has recently focused on helical structures that can change their helicity in response to external stimuli. The requirements for the invertible helical structures are a dynamic feature and well-defined structures. In this context, helical metal complexes with a labile coordination sphere have a great advantage. There are several types of dynamic helicity controls, including the responsive helicity inversion. In this review article, dynamic helical structures based on oligo(salamo) metal complexes are described as one of the possible designs. The introduction of chiral carboxylate ions into Zn3La tetranuclear structures as an additive is effective to control the P/M ratio of the helix. The dynamic helicity inversion can be achieved by chemical modification, such as protonation/deprotonation or desilylation with fluoride ion. When (S)-2-hydroxypropyl groups are introduced into the oligo(salamo) ligand, the helicity of the resultant complexes is sensitively influenced by the metal ions. The replacement of the metal ions based on the affinity trend resulted in a sequential multistep helicity inversion. Chiral salen derivatives are also effective to bias the helicity; by incorporating the gauche/anti transformation of a 1,2-disubstituted ethylene unit, a fully predictable helicity inversion system was achieved, in which the helicity can be controlled by the molecular lengths of the diammonium guests.

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.

Induction of Apoptosis by Nano‐Synthesized Complexes of H2L and its Cu(II) Complex in Human Hepatocellular Carcinoma Cells

2020 ◽  
Vol 20 ◽  
Author(s):  
Thoria Diab ◽  
Tarek M. Mohamed ◽  
Alaa Hamed ◽  
Mohamed Gaber
Keyword(s):  
Cell Cycle ◽  
Metal Complexes ◽  
Hepg2 Cells ◽  
Therapeutic Potential ◽  
Free Ligand ◽  
Organometallic Complexes ◽  
Phase Cell ◽  
Sod Activity ◽  
Induced Apoptosis

Background: Chemotherapy is currently the most utilized treatment for cancer. Therapeutic potential of metal complexes in cancer therapy has attracted a lot of interest. The mechanisms of action of most organometallic complexes are poorly understood. Objective: This study was designed to explore the mechanisms governing the anti-proliferative effect of the free ligand N1,N6‐bis((2‐hydroxynaphthalin‐1‐yl)methinyl)) adipohydrazone (H2L) and its complexes of Mn(II), Co(II), Ni(II) and Cu(II). Methods: Cells were exposed to H2L or its metal complexes where cell viability determined by MTT assay. Cell cycle was analysed by flow cytometry. In addition, qRT-PCR was used to monitor the expression of Bax and Bcl-2. Moreover, molecular docking was carried out to find the potentiality of Cu(II) complex as an inhibitor of Adenosine Deaminase (ADA). ADA, Superoxide Dismutase (SOD) and reduced Glutathione (GSH) levels were measured in the most affected cancer cell line. Results: The obtained results demonstrated that H2L and its Cu(II) complex exhibited a strong cytotoxic activity compared to other complexes against HepG2 cells (IC50 = 4.14±0.036μM/ml and 3.2±0.02μM/ml), respectively. Both H2L and its Cu(II) complex induced G2/M phase cell cycle arrest in HepG2 cells. Additionally, they induced apoptosis in HepG2 cells via upregulation of Bax and downregulation of Bcl-2. Interestingly, the activity of ADA was decreased by 2.8 fold in HepG2 cells treated with Cu(II) complex compared to untreated cells. An increase of SOD activity and GSH level in HepG2 cells compared to control was observed. Conclusion: The results concluded that Cu(II) complex of H2L induced apoptosis in HepG2 cells. Further studies are needed to confirm its anti-cancer effect in vivo.

scholarly journals Carbonic Anhydrase Inhibitors Part 721 Synthesis and Antiglaucoma Properties of Metal Complexes of p-Fluorobenzolamide

1999 ◽  
Vol 6 (2) ◽  
pp. 67-73 ◽  
Author(s):  
Claudiu T. Supuran ◽  
Andrea Scozzafava ◽  
Luca Menabuoni ◽  
Francesco Mincione ◽  
Fabrizio Briganti ◽  
...  
Keyword(s):  
Intraocular Pressure ◽  
Carbonic Anhydrase ◽  
Metal Ions ◽  
Metal Complexes ◽  
Carbonic Anhydrase Inhibitors ◽  
Physico Chemical ◽  
New Compounds

Metal complexes of a heterocyclic sulfonamides possessing very strong carbonic anhydrase (CA) inhibitory properties, i.e., 5-(p-fluorobenzenesulfonylamido)-1,3,4-thiadiazole-2-sulfonamide (p-fluorobenzolamide) were prepared. The new complexes contained metal ions such as Zn(II), Cu(II), Co(II), Ni(II), Cd(II) and Mn(II). The new compounds were characterized by standard physico-chemical procedures, and assayed as inhibitors of three CA isozymes, CA I, II and IV. Very good inhibition has been evidenced both for the parent sulfonamides as well as for the prepared complexes, against all three investigated isozymes. Some of these new complexes as well as the parent sulfonamide, strongly lowered intraocular pressure (IOP) in normotensive rabbits when administered as a 2% solution into the eye.

Radioactive Tracer Study Performed in a Dipole Geometry in a Highly Conductive Fracture Zone

1990 ◽  
Vol 212 ◽  
Author(s):  
Johan Byegård ◽  
Gunnar Skarnemark ◽  
Mats Skålberg
Keyword(s):  
Metal Ions ◽  
Metal Complexes ◽  
Fracture Zone ◽  
Radioactive Tracer ◽  
Tracer Experiment ◽  
Tracer Study ◽  
Redox Potentials ◽  
Chemical Analogue

ABSTRACTA radioactive tracer experiment has been performed in a highly conductive fracture zone, using a dipole geometry. Anions (131I− and 82Br−) and complexed metal ions (51Cr-EDTA, 58Co-EDTA, 111In-EDTA, 140La-DOTA, 160Tb-EDTA, 169Yb-EDTA and 177Lu-DOTA) have been injected and their properties as non-sorbing tracers were evaluated. Besides, studies of slightlysorbing cations (24Na+, 58Co2+, 86Rb+ and 201T1+) were performed. 99mTcO4 and its chemical analogue 186ReO4 were also injected to study the behaviour of Tc at low redox-potentials. Breakthrough was obtained for Re and for all metal complexes and anions. Some differences in the recovery yields could be seen. No transport of cations, except for Na, could be measured. No breakthrough of Tc could be observed. This indicates that TcO4− was reduced and sorbed.

scholarly journals Synthesis characterization of Cr(III), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) complexes of 2,12-dimethyl-3-13-di-n-propyl-l,4,ll,14-tetraazacycloeicosa-1,13,l1,13-tetraene

2002 ◽  
Vol 67 (12) ◽  
pp. 825-832 ◽  
Author(s):  
Raghu Prasad ◽  
Mala Mathur
Keyword(s):  
Metal Ions ◽  
Metal Complexes ◽  
Electronic Spectra ◽  
Magnetic Measurements ◽  
Elemental Analyses

Metal complexes of a 20-membered tetraazamacrocycle 2,12-dimethyl-3,13-di-n-propyl 1,4,11,14-tetraazacycloeicosa-1,3,11,13-tetraene(L) of the type [MLX2]X(M=Cr(III), Fe(III); X=NO3)[CoLNO3]NO3, [NiL(NO3)2], [CuL]Cl2 and [ZnLCl2]have been prepared by 2+2 cyclocondensation of 2,3-hexanedione with 1,6-diaminohexane in the presence of metal ions as templates. These complexes were characterized by elemental analyses, conductances, IR and electronic spectra and magnetic measurements.

scholarly journals Synthesis and Spectral Analysis of Some Metal Ions Complexes with Mixed Ligands of Schiff Base and 1, 10-Phenanthroline

2017 ◽  
Vol 14 (1) ◽  
pp. 135-147
Author(s):  
Baghdad Science Journal
Keyword(s):  
Schiff Base ◽  
Metal Ions ◽  
Metal Complexes ◽  
Mass Spectrometer ◽  
Schiff Base Ligand ◽  
Metal Ion ◽  
Molecular Structures ◽  
Spectroscopic Techniques ◽  
Metal Ion Complexes ◽  
Free Schiff Base

The free Schiff base ligand (HL1) is prepared by being mixed with the co-ligand 1, 10-phenanthroline (L2). The product then is reacted with metal ions: (Cr+3, Fe+3, Co+2, Ni+2, Cu+2 and Cd+2) to get new metal ion complexes. The ligand is prepared and its metal ion complexes are characterized by physic-chemical spectroscopic techniques such as: FT-IR, UV-Vis, spectra, mass spectrometer, molar conductivity, magnetic moment, metal content, chloride content and microanalysis (C.H.N) techniques. The results show the formation of the free Schiff base ligand (HL1). The fragments of the prepared free Schiff base ligand are identified by the mass spectrometer technique. All the analysis of ligand and its metal complexes are in good agreement with the theoretical values indicating the purity of Schiff base ligand and the metal complexes. From the above data, the molecular structures for all the metal complexes are proposed to be octahedral

scholarly journals X-ray crystallographic insights into post-synthetic metalation products in a metal–organic framework

2017 ◽  
Vol 375 (2084) ◽  
pp. 20160028 ◽  
Author(s):  
Michael T. Huxley ◽  
Campbell J. Coghlan ◽  
Witold M. Bloch ◽  
Alexandre Burgun ◽  
Christian J. Doonan ◽  
...  
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Coordination Sphere ◽  
Metal Organic Frameworks ◽  
Void Space ◽  
X Ray ◽  
X Ray Crystallography ◽  
Metal Nitrates ◽  
Metal Organic

Post-synthetic modification of metal–organic frameworks (MOFs) facilitates a strategic transformation of potentially inert frameworks into functionalized materials, tailoring them for specific applications. In particular, the post-synthetic incorporation of transition-metal complexes within MOFs, a process known as ‘metalation’, is a particularly promising avenue towards functionalizing MOFs. Herein, we describe the post-synthetic metalation of a microporous MOF with various transition-metal nitrates. The parent framework, 1 , contains free-nitrogen donor chelation sites, which readily coordinate metal complexes in a single-crystal to single-crystal transformation which, remarkably, can be readily monitored by X-ray crystallography. The presence of an open void surrounding the chelation site in 1 prompted us to investigate the effect of the MOF pore environment on included metal complexes, particularly examining whether void space would induce changes in the coordination sphere of chelated complexes reminiscent of those found in the solution state. To test this hypothesis, we systematically metalated 1 with first-row transition-metal nitrates and elucidated the coordination environment of the respective transition-metal complexes using X-ray crystallography. Comparison of the coordination sphere parameters of coordinated transition-metal complexes in 1 against equivalent solid- and solution-state species suggests that the void space in 1 does not markedly influence the coordination sphere of chelated species but we show notably different post-synthetic metalation outcomes when different solvents are used. This article is part of the themed issue ‘Coordination polymers and metal–organic frameworks: materials by design’.

Modulating extraction and retention of fluorinated β-diketonate metal complexes in perfluorocarbons through the use of non-fluorinated neutral ligands

2021 ◽  
Vol 8 (20) ◽  
pp. 4488-4496
Author(s):  
Tyler L. King ◽  
Orhi Esarte Palomero ◽  
Dawson A. Grimes ◽  
Sean T. Goralski ◽  
Richard A. Jones ◽  
...  
Keyword(s):  
Medical Imaging ◽  
Metal Ions ◽  
Metal Complexes ◽  
Synergistic Extraction ◽  
Donor Ligands ◽  
Nuclear Fuels ◽  
Nitrogen Donor Ligands ◽  
Nitrogen Donor ◽  
Neutral Ligands

Extraction of metal ions into perfluorocarbon solvent with a fluorinated acac ligand is described as well as synergistic extraction with neutral nitrogen donor ligands. Applications include catalysis, nuclear fuels reprocessing, and medical imaging.

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