First example of bridge mono-coordination mode for the ligand 1,8-bis-(2-pyridyl)-3,6-dithiaoctane (pdto) in a Co(II) tetrahedral complex

Polyhedron ◽  
2014 ◽  
Vol 74 ◽  
pp. 72-78 ◽  
Author(s):  
Vanessa Ramírez-Delgado ◽  
Ricardo Emmanuel Morales León ◽  
Luis Felipe Hernández-Ayala ◽  
Victor Angel Ramírez Coutiño ◽  
Francisco Javier Rodríguez ◽  
...  
Keyword(s):  
Coordination Mode ◽  
Tetrahedral Complex

A novel coordination mode for dithiatetrazocines: preparation, x-ray structure, and fluxional behavior of [Pt(PPh3)(1,5-Ph4P2N4S2)]2

1990 ◽  
Vol 29 (17) ◽  
pp. 3068-3069 ◽  
Author(s):  
Tristram Chivers ◽  
Mark Edwards ◽  
Pramesh N. Kapoor ◽  
Auke Meetsma ◽  
Johan C. Van de Grampel ◽  
...  
Keyword(s):  
Coordination Mode ◽  
X Ray

scholarly journals The Role of the Disulfide Bridge in the Copper (II) Binding by the Cyclic His4-Peptide

2021 ◽  
Vol 22 (12) ◽  
pp. 6458
Author(s):  
Aleksandra Pieniężna ◽  
Weronika Witak ◽  
Aneta Szymańska ◽  
Justyna Brasuń
Keyword(s):  
Metal Ions ◽  
Coordination Mode ◽  
Transition Metal Ions ◽  
Disulfide Bridge ◽  
Chain Flexibility ◽  
Vis Spectroscopy ◽  
Ph Range ◽  
Cd Studies ◽  
Metal Ratios

In this paper, we present studies on the influence of the disulfide bridge on the copper (II) ions’ binding abilities by the cyclic His4-peptide. The studied ligand HKHPHRHC-S-S-C consists of nine amino acids. The cyclic structure was obtained through a disulfide bridge between two cysteinyl groups. Moreover, this peptide is characterized by the presence of four His residues in the sequence, which makes it an interesting ligand for transition metal ions. The potentiometric and spectroscopic (UV-Vis spectroscopy and circular dichroism spectroscopy (CD)) studies were carried out in various molar ligand to metal ratios: 2:1, 1:1, and 1:2, in the pH range of 2.5–11 at 25 °C. The results showed that the cyclic His4-peptide promotes dinuclear complexes in each of these systems and forms the final dinuclear species with the {NIm, 3N-amide}{NIm, 3N-amide} coordination mode. The obtained data shows that cyclization by the formation of the disulfide bond has an impact on the peptide chain flexibility and appearance of additional potential donors for metal ions and influences the copper (II) ions’ coordination.

A 4-acyl-5-pyrazolone ligand (HQ) in N-unidentate coordination mode in a Rh(CO)2Cl(HQ)-type complex

2004 ◽  
Vol 7 (2) ◽  
pp. 235-237 ◽  
Author(s):  
Augusto Cingolani ◽  
Fabio Marchetti ◽  
Claudio Pettinari ◽  
Riccardo Pettinari ◽  
Brian W. Skelton ◽  
...  
Keyword(s):  
Coordination Mode ◽  
Type Complex

scholarly journals Iron(II) complexes of dimethyltriazacyclophane

2018 ◽  
Vol 74 (12) ◽  
pp. 1641-1649
Author(s):  
Wei-Tsung Lee ◽  
Matthias Zeller ◽  
David Upp ◽  
Yuliya Politanska ◽  
Doug Steinman ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Solid State ◽  
Dft Calculations ◽  
Density Functional Calculations ◽  
Density Functional ◽  
Coordination Mode ◽  
Functional Theory ◽  
Metal Centers ◽  
Bonding Interaction

Treatment of the ortho-triazacyclophane 1,4-dimethyltribenzo[b,e,h][1,4,7]triazacyclonona-2,5,8-triene [(C6H5)3(NH)(NCH3)2, L1] with Fe[N(SiMe3)2]2 yields the dimeric iron(II) complex bis(μ-1,4-dimethyltribenzo[b,e,h][1,4,7]triazacyclonona-2,5,8-trien-7-ido)bis[(μ-1,4-dimethyltribenzo[b,e,h][1,4,7]triazacyclonona-2,5,8-trien-7-ido)iron(II)], [Fe(C20H18N3)4] or Fe2(L1)4 (9). Dissolution of 9 in tetrahydrofuran (THF) results in solvation by two THF ligands and the formation of a simpler monoiron complex, namely bis(μ-1,4-dimethyltribenzo[b,e,h][1,4,7]triazacyclonona-2,5,8-trien-7-ido-κN 7)bis(tetrahydrofuran-κO)iron(II), [Fe(C20H18N3)2(C4H8O)2] or (L1)2Fe(THF)2 (10). The reaction is reversible and 10 reverts in vacuo to diiron complex 9. In the structures of both 9 and 10, the monoanionic triazacyclophane ligand L1− is observed in only the less-symmetric saddle conformation. No bowl-shaped crown conformers are observed in the solid state, thus preventing chelating κ3-coordination to the metal as had been proposed earlier based on density functional theory (DFT) calculations. Instead, the L1− ligands are bound in either a η2-chelating fashion through the amide and one amine donor (for one of the four ligands of 9), or solely through their amide N atoms in an even simpler monodentate η1-coordination mode. Density functional calculations on dimer 9 revealed nearly full cationic charges on each Fe atom and no bonding interaction between the two metal centers, consistent with the relatively long Fe...Fe distance of 2.912 (1) Å observed in the solid state.

scholarly journals Synthesis andin vitroAntitumor Potency of (Cyclohexane-1,2-Diamine)Platinum(II) Complexes with Aminotris(Methylenephosphonic Acid) as Bone-Seeking Ligand

2005 ◽  
Vol 3 (3-4) ◽  
pp. 179-190 ◽  
Author(s):  
Markus Galanski ◽  
Susanna Slaby ◽  
Michael A. Jakupec ◽  
Bernhard K. Keppler
Keyword(s):  
Dna Adducts ◽  
Coordination Mode ◽  
Carcinoma Cell ◽  
Platinum Complexes ◽  
Ovarian Carcinoma Cell Line ◽  
Aminoacetic Acid ◽  
Structure Activity ◽  
Cellular Processing ◽  
Diamine Ligands

In order to develop platinum complexes with selective activity in primary and secondary bone malignancies and with the aim to optimize antitumor activity, platinum(II) complexes with aminotris(methylenephosphonic acid) as bone-seeking (osteotropic) ligand have been synthesized, characterized and tested in the cisplatin-sensitive ovarian carcinoma cell line CH1. As non-leaving diamine ligands, which are decisive for the cellular processing of DNA adducts,cis-R,S-cyclohexane-1,2-diamine,trans-S,S-cyclohexane-1,2-diamine andtrans-R,R-cyclohexane-1,2-diamine have been used, resulting in complexes 1, 2, and 3, respectively. The cytotoxicity of the complexes under investigation decreases in the order 3>2>1 which is in accord with structure-activity relationships with other (cyclohexane-1,2- diamine)platinum(II) and platinum(IV) complexes: Bothtranscomplexes (2 and 3) display a higherin vitropotency than the correspondingcisisomer (I), with thetrans-R,Risomer (3) being the most active in this series. In comparison to the analogous (cyclohexane-1,2-diamine)platinum(II) complexes with bis(phosphonomethyl)aminoacetic acid as osteotropic carrier ligand, the cytotoxicity of 1-3 was found to be 1.5 – 2 fold higher, which is explainable by a different coordination mode of the phosphonic acid ligands (acetato versus phosphonato).

Coordination mode and reactivity of copper(II) complexes with kasugamycin

2001 ◽  
Vol 85 (2-3) ◽  
pp. 99-105 ◽  
Author(s):  
Małgorzata Jeżowska-Bojczuk ◽  
Wojciech Leśniak
Keyword(s):  
Coordination Mode
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