scholarly journals Electronic Consequences of Ligand Substitution at Heterometal Centers in Polyoxovanadium Clusters: Controlling the Redox Properties through Heterometal Coordination Number

2020 ◽  
Vol 26 (44) ◽  
pp. 9905-9914 ◽  
Author(s):  
Rachel L. Meyer ◽  
Montaha H. Anjass ◽  
Brittney E. Petel ◽  
William W. Brennessel ◽  
Carsten Streb ◽  
...  
Keyword(s):  
Coordination Number ◽  
Ligand Substitution ◽  
Redox Properties

Accessing relatively electron poor cerium(iv) hydrazido complexes by lithium cation promoted ligand reduction

2016 ◽  
Vol 45 (38) ◽  
pp. 15249-15258 ◽  
Author(s):  
Jessica R. Levin ◽  
Thibault Cheisson ◽  
Patrick J. Carroll ◽  
Eric J. Schelter
Keyword(s):  
General Formula ◽  
Ligand Substitution ◽  
Redox Properties ◽  
Lithium Cation

A series of substituted N,N′-diarylhydrazines (ArNHNHAr) were reacted with Ce(iii)[N(SiMe3)2]3 and LiN(SiMe3)2 to form complexes of general formula Li4(OEt2)4 [Ce(iv)(ArNNAr)4] where the spectroscopic and redox properties were affected by the ligand substitution.

Ligand Substitution Reactions

2007 ◽  
Author(s):  
Robert B. Jordan
Keyword(s):  
Transition State ◽  
Coordination Number ◽  
Reaction Rate ◽  
Ligand Substitution ◽  
Substitution Reactions ◽  
Definite Evidence ◽  
Oxidation Reduction ◽  
Leaving Group ◽  
Group 2 ◽  
Ligand Substitution Reactions

In ligand substitution reactions, one or more ligands around a metal ion are replaced by other ligands. In many ways, all inorganic reactions can be classified as either substitution or oxidation-reduction reactions, so that substitution reactions represent a major type of inorganic process. Some examples of substitution reactions follow: The operational approach was first expounded in 1965 in a monograph by Langford and Gray. It is an attempt to classify reaction mechanisms in relation to the type of information that kinetic studies of various types can provide. It delineates what can be said about the mechanism on the basis of the observations from certain types of experiments. The mechanism is classified by two properties, its stoichiometric character and its intimate character. The Stoichiometric mechanism can be determined from the kinetic behavior of one system. The classifications are as follows: 1. Dissociative (D): an intermediate of lower coordination number than the reactant can be identified. 2. Associative (A): an intermediate of larger coordination number than the reactant can be identified. 3. Interchange (I): no detectable intermediate can be found. The intimate mechanism can be determined from a series of experiments in which the nature of the reactants is changed in a systematic way. The classifications are as follows: 1. Dissociative activation (d): the reaction rate is more sensitive to changes in the leaving group. 2. Associative activation (a): the reaction rate is more sensitive to changes in the entering group. This terminology has largely replaced the SN1, SN2 and so on type of nomenclature that is still used in physical organic chemistry. These terminologies are compared and further explained as follows: Dissociative [D = SN1 (limiting)]: there is definite evidence of an intermediate of reduced coordination number. The bond between the metal and the leaving group has been completely broken in the transition state without any bond making to the entering group. Dissociative interchange (1d= SN1): there is no definite evidence of an intermediate. In the transition state, there is a large degree of bond breaking to the leaving group and a small amount of bond making to the entering group.

Ligand substitution and redox properties of 4-picolylaminepentacyanoferrate(II)

1986 ◽  
Vol 11 (6) ◽  
pp. 213-217 ◽  
Author(s):  
Patricia A. M. Williams ◽  
Pedro J. Aymonino
Keyword(s):  
Ligand Substitution ◽  
Redox Properties

Synthesis and Photochemical Properties of Re(I) Tricarbonyl Complexes Bound to Thione and Thiazole-2-ylidene Ligands

2020 ◽  
Author(s):  
Matthew Stout ◽  
Brian Skelton ◽  
Alexandre N. Sobolev ◽  
Paolo Raiteri ◽  
Massimiliano Massi ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Excited States ◽  
Ligand Exchange ◽  
Ligand Substitution ◽  
Bidentate Ligand ◽  
The Other ◽  
Ligand Exchange Reaction ◽  
Multiple Products ◽  
Ligand Charge Transfer ◽  
Photochemical Properties

<p>Three Re(I) tricarbonyl complexes, with general formulation Re(N^L)(CO)<sub>3</sub>X (where N^L is a bidentate ligand containing a pyridine functionalized in the position 2 with a thione or a thiazol-2-ylidene group and X is either chloro or bromo) were synthesized and their reactivity explored in terms of solvent-dependent ligand substitution, both in the ground and excited states. When dissolved in acetonitrile, the complexes bound to the thione ligand underwent ligand exchange with the solvent resulting in the formation of Re(NCMe)<sub>2</sub>(CO)<sub>3</sub>X. The exchange was found to be reversible, and the starting complex was reformed upon removal of the solvent. On the other hand, the complexes appeared inert in dichloromethane or acetone. Conversely, the complex bound to the thiazole-2-ylidene ligand did not display any ligand exchange reaction in the dark, but underwent photoactivated ligand substitution when excited to its lowest metal-to-ligand charge transfer manifold. Photolysis of this complex in acetonitrile generated multiple products, including Re(I) tricarbonyl and dicarbonyl solvato-complexes as well as free thiazole-2-ylidene ligand.</p>

Bond-length distributions for ions bonded to oxygen: Results for the lanthanides and actinides and discussion of the f-block contraction

2017 ◽  
Author(s):  
Olivier Charles Gagné
Keyword(s):  
Bond Length ◽  
Coordination Number ◽  
Lanthanide Ions ◽  
Lanthanide Contraction ◽  
Trivalent Lanthanide ◽  
Actinide Ions

Bond-length distributions have been examined for eighty-four configurations of the lanthanide ions and twenty-two configurations of the actinide ions bonded to oxygen. The lanthanide contraction for the trivalent lanthanide ions bonded to O<sup>2-</sup> is shown to vary as a function of coordination number and to diminish in scale with increasing coordination number.

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