Studies on the Reaction of Reduced Vitamin B12Derivatives with the Nitrosyl ­Hydride (HNO) Donor Angeli's Salt: HNO Oxidizes the Transition-Metal Center of Cob(I)alamin

2015 ◽  
Vol 2015 (23) ◽  
pp. 3825-3834 ◽  
Author(s):  
Harishchandra Subedi ◽  
Nicola E. Brasch
Keyword(s):  
Transition Metal ◽  
Metal Center ◽  
Nitrosyl Hydride ◽  
Angeli's Salt

Some Problems in the Oxidative Addition and Binding of an Ethylene to a Transition Metal Center.

1987 ◽  
Vol 6 (4) ◽  
pp. 902-902
Author(s):  
Jerome Silestre ◽  
Maria Calhorda ◽  
Roald Hoffman ◽  
Page Stoutland ◽  
Robert Bergman
Keyword(s):  
Transition Metal ◽  
Oxidative Addition ◽  
Metal Center

The First Coordination of an (α-Diazo)phosphine to a Transition-Metal Center

2003 ◽  
Vol 22 (7) ◽  
pp. 1358-1360 ◽  
Author(s):  
Emmanuelle Despagnet-Ayoub ◽  
Heinz Gornitzka ◽  
John Fawcett ◽  
Philip W. Dyer ◽  
Didier Bourissou ◽  
...  
Keyword(s):  
Transition Metal ◽  
Metal Center

Übergangsmetallkomplexe mit Schwefelliganden, LXV. Diastereospezifische Alkylierung von [Mo(NO)2(′S2′)2]2- zu chiralen [Mo(NO)2(′RS4')]-Komplexen mit chirotopen und prostereogenen Mo-Zentren / Transition Metal Complexes with Sulfur Ligands, LXV. Diastereospecific Alkylation of [Mo(NO)2(′S2')2]2- to Chiral [Mo(NO)2(′RS4')] Complexes with Chirotopic and Prostereogenic Mo-Centers

1991 ◽  
Vol 46 (10) ◽  
pp. 1343-1348 ◽  
Author(s):  
Dieter Sellmann ◽  
Franz Grasser ◽  
Falk Knoch ◽  
Matthias Moll
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Parent Compound ◽  
Metal Center ◽  
Chiral Complexes ◽  
Metal Centers ◽  
Electronic Character

In order to investigate how chirotopicity and stereogenicity of metal centers influence the enantioselectivity of metal centered reactions the stereogenic properties of metal centers in chiral complexes have to be varied without changing their electronic character. Diastereospecific alkylation of [Mo(NO)2(′S2′ )2]2- by racemic 1,2-dibromopropane and 1,2-dibromobutane yields the title complexes [Mo(NO)2(′MeS4′ )] and [Mo(NO)2(′EtS4′)] that differ from the parent compound [Mo(NO)2('S4′)] with respect to the stereogenicity of the metal center and allow future investigations of the question raised above.

Redox reactivity of transition-metal phthalocyanines: ligand radical formation vs. metal center oxidation

1985 ◽  
Vol 89 (18) ◽  
pp. 3890-3894 ◽  
Author(s):  
D. K. Geiger ◽  
G. Ferraudi ◽  
K. Madden ◽  
J. Granifo ◽  
D. P. Rillema
Keyword(s):  
Transition Metal ◽  
Metal Center ◽  
Radical Formation ◽  
Metal Phthalocyanines ◽  
Redox Reactivity

Synthesis of one-dimensional bis-porphyrinic compounds with a transition metal complex as bridging unit

2004 ◽  
Vol 08 (01) ◽  
pp. 82-92 ◽  
Author(s):  
Jean-Claude Chambron ◽  
Jean-Paul Collin ◽  
Isabelle Dixon ◽  
Valérie Heitz ◽  
Xavier J. Salom-Roig ◽  
...  
Keyword(s):  
Transition Metal ◽  
Spatial Arrangement ◽  
Metal Center ◽  
Central Complex ◽  
Octahedral Complex ◽  
Central Position ◽  
Bipy Ligand ◽  
Central Transition ◽  
Terpyridine Ligands ◽  
Transfer Properties

Linear multicomponent systems, consisting of two porphyrins attached to a central transition metal center, have been prepared and some of their electron- or energy transfer properties have been studied. Each porphyrin is covalently bound to a bidentate or a terdentate ligand, these coordinating molecules being gathered around the metal to afford the desired structure. The spatial arrangement is such that the porphyrinic components are located at both ends of an axis, the transition metal occupying its center. The edge-to-edge distance between the porphyrins is relatively large (~ 20 to 25 Å) and, due to the rigidity of the connectors, it is very well controlled. Three different strategies have been used to construct such assemblies. In the first approach, the porphyrinic fragments are attached at the back of 2,2′,6′,2″-terpyridine ligands (terpy), on the central position (4′). After reaction with an appropriate metal center (ruthenium(II) or iridium(III)), an octahedral complex is obtained which constitutes the central part of the assembly, whereas the porphyrins are at the periphery of the central complex. The second strategy involves the preparation of a 5,5′-disubstituted 2,2′-bipyridine (bipy) ligand followed by its coordination to ruthenium(II). Subsequently, the porphyrinic nuclei are constructed at both ends of the substituents, leading to a linear geometry with a central complex and two laterally-disposed porphyrins. Finally, a very special ligand has been designed and synthesized, which incorporates two 1,10-phenanthroline nuclei (phen). This ligand can wrap itself around an octahedral center (ruthenium(II)) so as to generate a helical arrangement. Both ends of the single-stranded helix can subsequently be attached to porphyrins.

α-Pyridinyl Alcohols, α,α’-Pyridine Diols, α-Bipyridinyl Alcohols, and α,α’-Bipyridine Diols as Structure Motifs Towards Important Organic Molecules and Transition Metal Complexes

2020 ◽  
Vol 17 (5) ◽  
pp. 344-366
Author(s):  
Tegene T. Tole ◽  
Johannes H.L. Jordaan ◽  
Hermanus C.M. Vosloo
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Single Molecule ◽  
Organic Molecules ◽  
Metal Cluster ◽  
Metal Center ◽  
Phosphine Ligands ◽  
High Ability ◽  
Metal Centers

Background: The preparation and use of pyridinyl alcohols as ligands showed incredible increment in the past three decades. Important property of pyridinyl alcoholato ligands is their strong basicity, which is mainly due to the lack of resonance stabilization of the corresponding anion. This strongly basic anionic nature gives them high ability to make bridges between metal centers rather than to bind to only one metal center in a terminal fashion. They are needed as ligands due to their ability to interact with transition metals both covalently (with oxygen) and hemilabile coordination (through nitrogen). Objective: The review focuses on the wide application of α-pyridinyl alcohols, α,α’-pyridine diols, α- bipyridinyl alcohols, and α,α’-bipyridine diols as structure motifs in the preparation of important organic molecules which is due to their strongly basic anionic nature. Conclusion: It is clear from the review that in addition to their synthetic utility in the homogeneous and asymmetric catalytic reactions, the preparation of the crown ethers, cyclic and acyclic ethers, coordinated borates (boronic esters), pyridinyl-phosphine ligands, pyridinyl-phosphite ligands, and pyridinyl-phosphinite ligands is the other broad area of application of pyridinyl alcohols. In addition to the aforementioned applications they are used for modeling mode of action of enzymes and some therapeutic agents. Their strongly basic anionic nature gives them high ability to make bridges between metal centers rather than to bind to only one metal center in a terminal fashion in the synthesis of transition metal cluster complexes. Not least numbers of single molecule magnets that can be used as storage of high density information were the result of transition metal complexes of pyridinyl alcoholato ligands.

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