ChemInform Abstract: Calixarene Complexes with Soft Metal Ions

ChemInform ◽  
2009 ◽  
Vol 40 (20) ◽  
Author(s):  
Wanda Sliwa ◽  
Malgorzata Deska
Keyword(s):  
Metal Ions ◽  
Soft Metal

scholarly journals Coordination chemistry of glutathione.

1999 ◽  
Vol 46 (3) ◽  
pp. 567-580 ◽  
Author(s):  
A Krezel ◽  
W Bal
Keyword(s):  
Glutamic Acid ◽  
Metal Ions ◽  
Metal Ion ◽  
Reduced Glutathione ◽  
Transition Metal Ions ◽  
Oxidized Glutathione ◽  
Binding Modes ◽  
Glutamic Acid Residue ◽  
Reduced And Oxidized Glutathione ◽  
Soft Metal

The metal ion coordination abilities of reduced and oxidized glutathione are reviewed. Reduced glutathione (GSH) is a very versatile ligand, forming stable complexes with both hard and soft metal ions. Several general binding modes of GSH are described. Soft metal ions coordinate exclusively or primarily through thiol sulfur. Hard ones prefer the amino acid-like moiety of the glutamic acid residue. Several transition metal ions can additionally coordinate to the peptide nitrogen of the gamma-Glu-Cys bond. Oxidized glutathione lacks the thiol function. Nevertheless, it proves to be a surprisingly efficient ligand for a range of metal ions, coordinating them primarily through the donors of the glutamic acid residue.

Comparative inhibition of hepatic hydroxymethylbilane synthase by both hard and soft metal cations

1984 ◽  
Vol 62 (1) ◽  
pp. 49-54 ◽  
Author(s):  
D. J. Farmer ◽  
B. R. Hollebone
Keyword(s):  
Metal Ions ◽  
Metal Ion ◽  
Ph Dependence ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Wide Range ◽  
Chemical Behaviour ◽  
Soft Metal ◽  
Hardness Values

The in vitro inhibition of hydroxymethylbilane synthase (EC 4.3.1.8, uroporphyrinogen I synthetase) obtained from livers of Sprague–Dawley rats has been studied with a wide range of di- and tri-valent metal ions. After purification by cell lysis, heat treatment, and centrifugation, the stable, soluble enzyme yielded sigmoidal inhibition curves with increasing concentrations of each of the 16 test ions. Using the negative logarithm of metal concentration for 50% inhibition (the pM50 value), the metal ions could be classified according to their Klopman hardness values. Very soft ions including Hg2+, intermediate ions including Cr3+, and very hard ions including Al3+ all yielded large pM50 values indicating strong inhibition. In comparison to known metal-ion chemical behaviour, these three ions could indicate three different types of inhibitory binding sites at or near the active site: Hg2+ corresponding to sulfur in cysteine, Cr3+ corresponding to nitrogen in histidine, and Al3+ corresponding to oxygen in carboxyl groups. The presence of the first two sites is also indicated by the pH dependence of activity.

METAL ION-LIGAND INTERACTION: HSAB PRINCIPLE VERSUS NBO AND AIM VIEW POINTS

2006 ◽  
Vol 05 (01) ◽  
pp. 87-98 ◽  
Author(s):  
AFSHAN MOHAJERI ◽  
MARYAM ABASI
Keyword(s):  
Metal Ions ◽  
Metal Ion ◽  
Hard Metal ◽  
Quantitative Model ◽  
Interaction Energies ◽  
Ligand Interaction ◽  
Hsab Principle ◽  
Soft Metal ◽  
Aim And Nbo ◽  
Soft Acid

Ab initio calculations were performed to study the applicability and reliability of the semi quantitative model based on the local hard-soft acid-base principle in studying the interaction of metal ions with ligands. The particular attention is devoted to the interaction of CO , CN - and SCN - as the base with some hard metal ions ( Li +, Na +, K +) and some soft metal ions ( Pd +2, Ag +2, Cd +2) as acids. The interaction energies were calculated using the HSAB principle and compared with the values obtained by the conventional MP2 method. The results show that the HSAB principle does not work in many cases and it fails to predict correct values for interaction energies. The AIM and NBO analyses were also performed to characterize the nature of the metal ion-ligand interaction. It is found that the charge transfers have great significance in the interaction of metal ions with ligands.

scholarly journals Novel Bifunctional [16]aneS4-Derived Chelators for Soft Radiometals

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4603
Author(s):  
Natan J. W. Straathof ◽  
Charlotte B. Magnus ◽  
Fedor Zhuravlev ◽  
Andreas I. Jensen
Keyword(s):  
Carboxylic Acid ◽  
Metal Ions ◽  
Lewis Acid ◽  
Radionuclide Therapy ◽  
Targeted Radionuclide Therapy ◽  
Bifunctional Chelators ◽  
Soft Metal ◽  
Radiopharmaceutical Chemistry ◽  
Selection Of ◽  
General Method

The field of targeted radionuclide therapy is rapidly growing, highlighting the need for wider radionuclide availability. Soft Lewis acid ions, such as radioisotopes of platinum, rhodium and palladium, are particularly underdeveloped. This is due in part to a lack of compatible bifunctional chelators. These allow for the practical bioconjugation to targeting vectors, in turn enabling radiolabeling. The [16]andS4 macrocycle has been reported to chelate a number of relevant soft metal ions. In this work, we present a procedure for synthesizing [16]andS4 in 45% yield (five steps, 12% overall yield), together with a selection of strategies for preparing bifunctional derivatives. An ester-linked N-hydroxysuccimide ester (NHS, seven steps, 4% overall yield), an ether-linked isothiocyanate (NCS, eight steps, 5% overall yield) and an azide derivative were prepared. In addition, a new route to a carbon-carbon linked carboxylic acid functionalized derivative is presented. Finally, a general method for conjugating the NHS and NCS derivatives to a polar peptide (octreotide) is presented, by dissolution in water:acetonitrile (1:1), buffered to pH 9.4 using borate. The reported compounds will be readily applicable in radiopharmaceutical chemistry, by facilitating the labeling of a range of molecules, including peptides, with relevant soft radiometal ions.

scholarly journals Calixarene complexes with soft metal ions

ARKIVOC ◽  
2008 ◽  
Vol 2008 (1) ◽  
pp. 87-127 ◽  
Author(s):  
Wanda Sliwa ◽  
Malgorzata Deska
Keyword(s):  
Metal Ions ◽  
Soft Metal

scholarly journals Soft metal ions, Cd(II) and Hg (II), induce triple-stranded α-helical assembly and folding of a de novo designed peptide in their trigonal geometries

2000 ◽  
Vol 9 (7) ◽  
pp. 1327-1333 ◽  
Author(s):  
Xiangqun Li ◽  
Kazuo Suzuki ◽  
Ayumi Kashiwada ◽  
Hidekazu Hiroaki ◽  
Daisuke Kohda ◽  
...  
Keyword(s):  
Metal Ions ◽  
De Novo ◽  
Soft Metal

Extended supramolecular [3×3] Mn9 grid arrays organized by Ag(I) and Au(III)  — structural and magnetic properties

2014 ◽  
Vol 92 (10) ◽  
pp. 966-974 ◽  
Author(s):  
Victoria A. Milway ◽  
Louise N. Dawe ◽  
Laurence K. Thompson
Keyword(s):  
Magnetic Properties ◽  
Metal Ions ◽  
Ground States ◽  
Structural Data ◽  
Outer Sphere ◽  
Molecular Organization ◽  
Gold Complex ◽  
Magnetic Exchange ◽  
Soft Metal ◽  
Structural And Magnetic Properties

A square [3×3] Mn(II)9 supramolecular grid complex with appended ligand SEt groups provides a focus for extended molecular organization through outer-sphere interactions with soft metal ions. Reactions with Ag(I) and Au(III) led to extended 3D arrays in complexes [Mn9(SEt2poap)6]Ag5.75(CF3SO3)2(NO3)9.75(H2O)18 (4), [Mn9(SEt2poap)6][Ag(CN)2]2 [Ag3(CN)5](OH)2(H2O)18 (5), and [Mn9(SEt2poap-3H)4(SEt2poap-2H)2(AuCl3)4] (AuCl4)3.25Cl1.75(H2O)14 (6), involving Mn9 [3×3] square grids with external Ag–S contacts, but with Au(III) extended organization resulting through Au–N ligand contacts only. Structural and magnetic properties are discussed. In the gold complex, magnetic and structural data revealed that Au(III) behaves as an oxidant, leading to oxidation of some corner Mn(II) sites in the grid to Mn(III). Intra-grid magnetic exchange is antiferromagnetic in all cases (J = −4.4 cm−1 (4), J = −5.0 cm−1 (5)), leading to noncompensation of spins because of the odd number of metal ions and low-spin ground states.

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