scholarly journals Force-Modulated Reductive Elimination from Platinum(II) Diaryl Complexes

2020 ◽  
Author(s):  
Yichen Yu ◽  
Liqi Wang ◽  
Chenxu Wang ◽  
Yancong Tian ◽  
Roman Boulatov ◽  
...  
Keyword(s):  
Transition Metal ◽  
Transition Metal Complexes ◽  
Free Ligand ◽  
Reductive Elimination ◽  
Mechanical Force ◽  
Mechanical Forces ◽  
Bite Angle ◽  
Restoring Forces ◽  
Rate Behavior ◽  
Ground State Geometry

<div><p>Coupled mechanical forces are known to drive a range of covalent chemical reactions, but the interplay of mechanical force applied to a spectator ligand and transition metal reactivity is relatively unexplored. Here we report the effect of mechanical force on the rate of C(sp<sup>2</sup>)-C(sp<sup>2</sup>) reductive elimination from platinum(II) diaryl complexes containing macrocyclic bis(phosphine) force probe ligands. Compressive forces decreased the rate of reductive elimination whereas extension forces increased the rate of reductive elimination relative to the strain-free MeOBiphep complex with a 3.4-fold change in rate over a ~290 pN range of restoring forces. The natural bite angle of the free ligand changes with force, but <sup>31</sup>P NMR analysis strongly suggests no significant force-induced perturbation of the ground state geometry of the (P–P)PtAr<sub>2</sub> complexes. Rather, the force/rate behavior observed across this range of forces (from ca. 65 pN in compression to >200 pN in extension) for reductive elimination is attributed to the coupling of force to the elongation of the O<b><sup>…</sup></b>O distance in the transition state for reductive elimination. The results suggest opportunities to experimentally map geometry changes associated with reactions in transition metal complexes and potential strat-egies for force-modulated catalysis. </p></div><br>

scholarly journals Force-Modulated Reductive Elimination from Platinum(II) Diaryl Complexes

2020 ◽  
Author(s):  
Yichen Yu ◽  
Liqi Wang ◽  
Chenxu Wang ◽  
Yancong Tian ◽  
Roman Boulatov ◽  
...  
Keyword(s):  
Transition Metal ◽  
Transition Metal Complexes ◽  
Free Ligand ◽  
Reductive Elimination ◽  
Mechanical Force ◽  
Mechanical Forces ◽  
Bite Angle ◽  
Restoring Forces ◽  
Rate Behavior ◽  
Ground State Geometry

<div><p>Coupled mechanical forces are known to drive a range of covalent chemical reactions, but the interplay of mechanical force applied to a spectator ligand and transition metal reactivity is relatively unexplored. Here we report the effect of mechanical force on the rate of C(sp<sup>2</sup>)-C(sp<sup>2</sup>) reductive elimination from platinum(II) diaryl complexes containing macrocyclic bis(phosphine) force probe ligands. Compressive forces decreased the rate of reductive elimination whereas extension forces increased the rate of reductive elimination relative to the strain-free MeOBiphep complex with a 3.4-fold change in rate over a ~290 pN range of restoring forces. The natural bite angle of the free ligand changes with force, but <sup>31</sup>P NMR analysis strongly suggests no significant force-induced perturbation of the ground state geometry of the (P–P)PtAr<sub>2</sub> complexes. Rather, the force/rate behavior observed across this range of forces (from ca. 65 pN in compression to >200 pN in extension) for reductive elimination is attributed to the coupling of force to the elongation of the O<b><sup>…</sup></b>O distance in the transition state for reductive elimination. The results suggest opportunities to experimentally map geometry changes associated with reactions in transition metal complexes and potential strat-egies for force-modulated catalysis. </p></div><br>

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.

ChemInform Abstract: Wide Bite Angle Diphosphines: Xantphos Ligands in Transition Metal Complexes and Catalysis

ChemInform ◽  
2010 ◽  
Vol 33 (6) ◽  
pp. no-no
Author(s):  
Paul C. J. Kamer ◽  
Piet W. N. M. van Leeuwen ◽  
Joost N. H. Reek
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Bite Angle

scholarly journals Ultraviolet Radiation and Salinity-Induced Physiological Changes and Scytonemin Induction in Cyanobacteria Isolated from Diverse Habitats

2021 ◽  
Vol 12 (3) ◽  
pp. 3590-3606
Keyword(s):  
Antimicrobial Activity ◽  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Antimicrobial Agents ◽  
Free Ligand ◽  
The Novel ◽  
Bacterial Strains ◽  
Resistant Strains ◽  
Antimicrobial And Antifungal Activity

A novel series of transition metal (II) complexes (5a-h) were conveniently synthesized via reaction of important transition metals (Co, Cu, Zn, Ni) with (E)-N-(4-methylbenzylidene)-2-((Z)-(4-methylbenzylidene)amino)benzamide Schiff base (3) which was previously synthesized by reacting 2- aminobenzohydrazide (1) with 4-methylbenzaldehyde (2). The synthesized metal complexes' structure was elucidated by IR, NMR, mass, and elemental analysis. Additionally, we also evaluated the antioxidant, antimicrobial and antifungal activity of the synthesized metal complexes. The bioassay of the novel transition metal complexes envisioned that compounds5eand5c showed better antimicrobial activity than the free ligand, and compounds5g and 5a showed good activity against most bacterial strains. On the other hand, hydrated metal complexes 5b, 5d, 5f, and 5h showed moderate to good antimicrobial activity. In comparison with ascorbic acid, most of the metal complexes showed moderate to good antioxidant activity. The current bioassay was investigated and proved that the compounds 5e and 5c as antimicrobial agents act on highly resistant strains of microbes.

scholarly journals Synthesis and Spectral Investigations of Polymeric Hydrazone Schiff Base and its Transition Metal Complexes with Promising Antimicrobial, Anti-Angeogenic and DNA Photo-Cleavage Activities

2019 ◽  
Vol 31 (10) ◽  
pp. 2331-2336 ◽  
Author(s):  
Manoj Kumar ◽  
Anita Rani ◽  
Hardeep Singh Tuli ◽  
Rajshree Khare ◽  
Vinit Parkash
Keyword(s):  
Schiff Base ◽  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Schiff Base Ligand ◽  
Biological Activities ◽  
Free Ligand ◽  
Ft Ir ◽  
Bacteria And Fungi

This report describes the synthesis and exploration of novel Schiff base ligand in the form of a polymer (heptamer) which was prepared by reaction between 3,4-diacetyl-2,5-hexanedione and hydrazine hydrate in ethanol. On further reaction of Schiff base with transition metals ions (Co and Cu) leads to formation of its transition metal complexes. The structural identification of Schiff base ligand and its transition metal complexes were characterized by classical structural techniques like FT-IR, NMR and mass spectra. The free ligand and its transition metal complexes have been screened for in vitro biological activities against various strains of bacteria and fungi. The prepared Schiff base and its metal complexes were also screened for antiangiogenic activity. The results have shown the remarkable antimicrobial and antiangiogenic activities of the Schiff base and its metal complexes.

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