Solid-State93Nb and13C NMR Investigations of Half-Sandwich Niobium(I) and Niobium(V) Cyclopentadienyl Complexes

2005 ◽  
Vol 109 (32) ◽  
pp. 7073-7087 ◽  
Author(s):  
Andy Y. H. Lo ◽  
Thomas E. Bitterwolf ◽  
Charles L. B. Macdonald ◽  
Robert W. Schurko
Keyword(s):  
Cyclopentadienyl Complexes ◽  
Half Sandwich

ChemInform Abstract: Half-Sandwich Cyclopentadienyl Complexes of Germanium, Tin, and Lead with Additional Metal Olefin Interactions.

ChemInform ◽  
1989 ◽  
Vol 20 (32) ◽  
Author(s):  
F. X. KOHL ◽  
R. DICKBREDER ◽  
P. JUTZI ◽  
G. MUELLER ◽  
B. HUBER
Keyword(s):  
Germanium Tin ◽  
Cyclopentadienyl Complexes ◽  
Half Sandwich

Antimicrobial properties of half-sandwich Ir(iii) cyclopentadienyl complexes with pyridylbenzimidazole ligands

2020 ◽  
Vol 49 (14) ◽  
pp. 4491-4501
Author(s):  
Ahmed M. Mansour ◽  
Krzysztof Radacki
Keyword(s):  
Antibacterial Activity ◽  
Metal Content ◽  
Antimicrobial Properties ◽  
Ethyl Group ◽  
Cyclopentadienyl Complexes ◽  
Half Sandwich

Ethyl group determined the toxicity of pyridylbenzimidazole Ir(iii) compounds and exchange of the group with sulfonate led to diminishing of the antibacterial activity. Increasing the metal content per complex, 3, gave rise to a compound with no toxicity.

Half- Sandwich cyclopentadienylruthenium(II) Complexes: A New Antimalarial Chemotype

2020 ◽  
Author(s):  
Sofia Alexandra Milheiro ◽  
Joana Gonçalves ◽  
Ricardo Lopes ◽  
Margarida Madureira ◽  
Lis Lobo ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Blood Stage ◽  
Nuclear Accumulation ◽  
Selective Absorption ◽  
Asexual Parasite ◽  
Single Digit ◽  
Liver Stage ◽  
Dual Stage ◽  
Fluorescent Compounds ◽  
Half Sandwich

<p><a>A small library of “half-sandwich” cyclopentadienylruthenium(II) compounds of general formula [(</a>η<sup>5</sup>-C<sub>5</sub>R<sub>5</sub>)Ru(PPh<sub>3</sub>)(N-N)][PF<sub>6</sub>], a scaffold hitherto unfeatured in the toolbox of antiplasmodials, was screened for activity against the blood stage of CQ-sensitive 3D7-GFP, CQ-resistant Dd2 and artemisinin-resistant IPC5202 <i>Plasmodium falciparum</i> strains, and the liver stage of <i>P. berghei</i>. The best performing compounds displayed dual-stage activity, with single-digit nM IC<sub>50</sub> values against blood stage malaria parasites, nM activity against liver stage parasites, and residual cytotoxicity against mammalian cells (HepG2, Huh7). Parasitic absorption/distribution of 7-nitrobenzoxadiazole-appended fluorescent compounds <b>Ru4</b> and <b>Ru5</b> was investigated by confocal fluorescence microscopy, revealing parasite-selective absorption in infected erythrocytes and nuclear accumulation of both compounds. The lead compound <b>Ru2</b> impaired asexual parasite differentiation, exhibiting fast parasiticidal activity against both ring and trophozoite stages of a synchronized <i>P. falciparum</i> 3D7 strain. These results point to cyclopentadienylruthenium(II) complexes as a highly promising chemotype for the development of dual-stage antiplasmodials.</p>

Thermally Stable Half-Sandwich Benzhydryl Ln(II) (Ln = Sm, Yb) Complexes Supported by Sterically Demanding Carbazolyl and Fluorenyl Ligands

2019 ◽  
Vol 38 (24) ◽  
pp. 4615-4624 ◽  
Author(s):  
Alexander N. Selikhov ◽  
Andrey S. Shavyrin ◽  
Anton V. Cherkasov ◽  
Georgy K. Fukin ◽  
Alexander A. Trifonov
Keyword(s):  
Thermally Stable ◽  
Sterically Demanding ◽  
Half Sandwich

scholarly journals Osmium–arene complexes with high potency towards Mycobacterium tuberculosis

Metallomics ◽  
2021 ◽  
Vol 13 (4) ◽  
Author(s):  
James P C Coverdale ◽  
Collette S Guy ◽  
Hannah E Bridgewater ◽  
Russell J Needham ◽  
Elizabeth Fullam ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Global Health ◽  
Mechanism Of Action ◽  
Health Problem ◽  
Normal Lung ◽  
Lung Cells ◽  
Redox Mechanism ◽  
Human Lung Cells ◽  
Half Sandwich ◽  
Global Health Problem

Abstract The treatment of tuberculosis (TB) poses a major challenge as frontline therapeutic agents become increasingly ineffective with the emergence and spread of drug-resistant strains of Mycobacterium tuberculosis (Mtb). To combat this global health problem, new antitubercular agents with novel modes of action are needed. We have screened a close family of 17 organometallic half-sandwich Os(II) complexes [(arene)Os(phenyl-azo/imino-pyridine)(Cl/I)]+Y– containing various arenes (p-cymene, biphenyl, or terphenyl), and NMe2, F, Cl, or Br phenyl or pyridyl substituents, for activity towards Mtb in comparison with normal human lung cells (MRC5). In general, complexes with a monodentate iodido ligand were more potent than chlorido complexes, and the five most potent iodido complexes (MIC 1.25–2.5 µM) have an electron-donating Me2N or OH substituent on the phenyl ring. As expected, the counter anion Y (PF6–, Cl–, I–) had little effect on the activity. The pattern of potency of the complexes towards Mtb is similar to that towards human cells, perhaps because in both cases intracellular thiols are likely to be involved in their activation and their redox mechanism of action. The most active complex against Mtb is the p-cymene Os(II) NMe2-phenyl-azopyridine iodido complex (2), a relatively inert complex that also exhibits potent activity towards cancer cells. The uptake of Os from complex 2 by Mtb is rapid and peaks after 6 h, with temperature-dependence studies suggesting a major role for active transport. Significance to Metallomics Antimicrobial resistance is a global health problem. New advances are urgently needed in the discovery of new antibiotics with novel mechanisms of action. Half-sandwich organometallic complexes offer a versatile platform for drug design. We show that with an appropriate choice of the arene, an N,N-chelated ligand, and monodentate ligand, half-sandwich organo–osmium(II) complexes can exhibit potent activity towards Mycobacterium tuberculosis (Mtb), the leading cause of death from a single infectious agent. The patterns of activity of the 17 azo- and imino-pyridine complexes studied here towards Mtb and normal lung cells suggest a common redox mechanism of action involving intracellular thiols.

scholarly journals Half-sandwich organometallic Ru and Rh complexes of (N,N) donor compounds: effect of ligand methylation on solution speciation and anticancer activity

2021 ◽  
Author(s):  
János P. Mészáros ◽  
Veronika F. S. Pape ◽  
Gergely Szakács ◽  
Gábor Németi ◽  
Márk Dénes ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Anticancer Activity ◽  
Polypyridyl Complexes ◽  
Solution Behaviour ◽  
Half Sandwich ◽  
Solution Speciation

A series of half-sandwich polypyridyl complexes was synthesized and compared focusing on structural, cytotoxic and aqueous solution behaviour. The formula of the synthesized complexes is [M(arene)(N,N)Cl]Cl, where M: Ru or...

scholarly journals New Bifunctional Bis(azairidacycle) with Axial Chirality via Double Cyclometalation of 2,2′-Bis(aminomethyl)-1,1′-binaphthyl

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1165
Author(s):  
Yasuhiro Sato ◽  
Yuichi Kawata ◽  
Shungo Yasui ◽  
Yoshihito Kayaki ◽  
Takao Ikariya
Keyword(s):  
Hydrogen Transfer ◽  
Bond Cleavage ◽  
Enantiomeric Excess ◽  
Transfer Hydrogenation ◽  
Catalyst Precursor ◽  
Asymmetric Catalysts ◽  
Axially Chiral ◽  
Diastereomeric Mixture ◽  
Raney Ni ◽  
Half Sandwich

As a candidate for bifunctional asymmetric catalysts containing a half-sandwich C–N chelating Ir(III) framework (azairidacycle), a dinuclear Ir complex with an axially chiral linkage is newly designed. An expedient synthesis of chiral 2,2′-bis(aminomethyl)-1,1′-binaphthyl (1) from 1,1-bi-2-naphthol (BINOL) was accomplished by a three-step process involving nickel-catalyzed cyanation and subsequent reduction with Raney-Ni and KBH4. The reaction of (S)-1 with an equimolar amount of [IrCl2Cp*]2 (Cp* = η5–C5(CH3)5) in the presence of sodium acetate in acetonitrile at 80 °C gave a diastereomeric mixture of new dinuclear dichloridodiiridium complexes (5) through the double C–H bond cleavage, as confirmed by 1H NMR spectroscopy. A loss of the central chirality on the Ir centers of 5 was demonstrated by treatment with KOC(CH3)3 to generate the corresponding 16e amidoiridium complex 6. The following hydrogen transfer from 2-propanol to 6 provided diastereomers of hydrido(amine)iridium retaining the bis(azairidacycle) architecture. The dinuclear chlorido(amine)iridium 5 can serve as a catalyst precursor for the asymmetric transfer hydrogenation of acetophenone with a substrate to a catalyst ratio of 200 in the presence of KOC(CH3)3 in 2-propanol, leading to (S)-1-phenylethanol with up to an enantiomeric excess (ee) of 67%.

Allenylidene and diazoalkane complexes of a half-sandwich mixed phosphine – phosphinite ruthenium fragment

2021 ◽  
Vol 519 ◽  
pp. 120277
Author(s):  
Nuria Álvarez-Pazos ◽  
Jorge Bravo ◽  
Ana M. Graña ◽  
Soledad García-Fontán
Keyword(s):  
Half Sandwich

Half-Sandwich Ru(p-cymene) Compounds with Diphosphanes: In Vitro and In Vivo Evaluation As Potential Anticancer Metallodrugs

2021 ◽  
Vol 60 (5) ◽  
pp. 2914-2930
Author(s):  
Oscar A. Lenis-Rojas ◽  
M. Paula Robalo ◽  
Ana Isabel Tomaz ◽  
Alexandra R. Fernandes ◽  
Catarina Roma-Rodrigues ◽  
...  
Keyword(s):  
In Vivo Evaluation ◽  
Half Sandwich ◽  
Anticancer Metallodrugs
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